Radiomic Analysis to Predict Histopathologically Confirmed Pseudoprogression in Glioblastoma Patients

Purpose

Pseudoprogression mimicking recurrent glioblastoma remains a diagnostic challenge that may adversely confound or delay appropriate treatment or clinical trial enrollment. We sought to build a radiomic classifier to predict pseudoprogression in patients with primary isocitrate dehydrogenase wild type glioblastoma.

Methods and Materials

We retrospectively examined a training cohort of 74 patients with isocitrate dehydrogenase wild type glioblastomas with brain magnetic resonance imaging including dynamic contrast enhanced T1 perfusion before resection of an enhancing lesion indeterminate for recurrent tumor or pseudoprogression. A recursive feature elimination random forest classifier was built using nested cross-validation without and with O⁶-methylguanine-DNA methyltransferase status to predict pseudoprogression.

Results

A classifier constructed with cross-validation on the training cohort achieved an area under the receiver operating curve of 81% for predicting pseudoprogression. This was further improved to 89% with the addition of O⁶-methylguanine-DNA methyltransferase status into the classifier.

Conclusions

Our results suggest that radiomic analysis of contrast T1-weighted images and magnetic resonance imaging perfusion images can assist the prompt diagnosis of pseudoprogression. Validation on external and independent data sets is necessary to verify these advanced analyses, which can be performed on routinely acquired clinical images and may help inform clinical treatment decisions.

Diagnostic value of radiomics and machine learning with dynamic contrast-enhanced magnetic resonance imaging for patients with atypical ductal hyperplasia in predicting malignant upgrade

Purpose

To investigate whether radiomics features extracted from magnetic resonance imaging (MRI) of patients with biopsy-proven atypical ductal hyperplasia (ADH) coupled with machine learning can differentiate high-risk lesions that will upgrade to malignancy at surgery from those that will not, and to determine if qualitatively and semi-quantitatively assessed imaging features, clinical factors, and image-guided biopsy technical factors are associated with upgrade rate.

Methods

This retrospective study included 127 patients with 139 breast lesions yielding ADH at biopsy who were assessed with multiparametric MRI prior to biopsy. Two radiologists assessed all lesions independently and with a third reader in consensus according to the BI-RADS lexicon. Univariate analysis and multivariate modeling were performed to identify significant radiomic features to be included in a machine learning model to discriminate between lesions that upgraded to malignancy on surgery from those that did not.

Results

Of 139 lesions, 28 were upgraded to malignancy at surgery, while 111 were not upgraded. Diagnostic accuracy was 53.6%, specificity 79.2%, and sensitivity 15.3% for the model developed from pre-contrast features, and 60.7%, 86%, and 22.8% for the model developed from delta radiomics datasets. No significant associations were found between any radiologist-assessed lesion parameters and upgrade status. There was a significant correlation between the number of specimens sampled during biopsy and upgrade status (p = 0.003).

Conclusion

Radiomics analysis coupled with machine learning did not predict upgrade status of ADH. The only significant result from this analysis is between the number of specimens sampled during biopsy procedure and upgrade status at surgery.

MRI-based machine learning radiomics can predict HER2 expression level and pathologic response after neoadjuvant therapy in HER2 overexpressing breast cancer

Background

To use clinical and MRI radiomic features coupled with machine learning to assess HER2 expression level and predict pathologic response (pCR) in HER2 overexpressing breast cancer patients receiving neoadjuvant chemotherapy (NAC).

Methods

This retrospective study included 311 patients. pCR was defined as no residual invasive carcinoma in the breast or axillary lymph nodes (ypT0/isN0). Radiomics/statistical analysis was performed using MATLAB and CERR software. After ROC and correlation analysis, selected radiomics parameters were advanced to machine learning modelling alongside clinical MRI-based parameters (lesion type, multifocality, size, nodal status). For predicting pCR, the data was split into a training and test set (80:20).

Findings

The overall pCR rate was 60.5% (188/311). The final model to predict HER2 heterogeneity utilised three MRI parameters (two clinical, one radiomic) for a sensitivity of 99.3% (277/279), specificity of 81.3% (26/32), and diagnostic accuracy of 97.4% (303/311). The final model to predict pCR included six MRI parameters (two clinical, four radiomic) for a sensitivity of 86.5% (32/37), specificity of 80.0% (20/25), and diagnostic accuracy of 83.9% (52/62) (test set); these results were independent of age and ER status, and outperformed the best model developed using clinical parameters only (p=0.029, comparison of proportion Chi-squared test).

Interpretation

The machine learning models, including both clinical and radiomics MRI features, can be used to assess HER2 expression level and can predict pCR after NAC in HER2 overexpressing breast cancer patients.

Funding

NIH/NCI (P30CA008748), Susan G. Komen Foundation, Breast Cancer Research Foundation, Spanish Foundation Alfonso Martin Escudero, European School of Radiology.

Effects of orientation change during environmental learning on age-related difference in spatial memory

It has been suggested that older adults suffer a greater degree of decline in environmental learning when navigating in an environment than when reading a map of the environment. However, the two types of spatial learning differ not only in perspectives (i.e., navigation is done with a ground-level perspective; a map is read from an aerial perspective) but also in orientations (i.e., orientations vary during navigation; spatial information is drawn from a single orientation in a map), making it unclear which factor critically affects older adults' spatial learning. The present study addressed this issue by having younger and older participants learn the layout of a large-scale environment through an aerial movie that contained changes in orientations from which the environment was depicted. Results showed that older participants' memories for the environmental layout were as distorted as those created through a ground-level movie (which involved the same orientation changes), whereas they formed more accurate memories through another aerial movie in which an orientation was fixed. By contrast, younger participants learned the environment equally well from the three movies. Taken together, these findings suggest that there is age-related alteration specifically in the ability to process multiple orientations of an environment while encoding its layout in memory. It is inferred that this alteration stems from functional deterioration of the medial temporal lobe, and possibly that of posterior cingulate areas as well (e.g., the retrosplenial cortex), in late adulthood.

Minkowski functionals: An MRI texture analysis tool for determination of the aggressiveness of breast cancer

BACKGROUND

This work aims to see whether Minkowski Functionals can be used to distinguish between cancer types before chemotherapy treatment has begun, and whether a response to treatment can be predicted by an initial scan alone.

METHODS

Fat-nulled T1w 3T DCE-MRI scans were taken of 100 cases of biopsy confirmed breast cancer and a series of binary images created on lesion containing slices. Minkowski Functionals were calculated for each binary image and the change in these values as the binary threshold was raised was described using 6(th) order polynomials. These polynomials were used to compare between patient subgroups, for triple negative breast cancer (TNBC) status, chemotherapy response, biopsy grade, nodal status, and lymphovascular invasion status.

RESULTS

When using Minkowski Functionals statistically significant (P < 0.05) differences were found between TNBC status, biopsy grade, and lymphovascular invasion status subgroups for all methodologies. The analysis performance did not appear to be affected by the number of threshold steps used. Most notably, very strong differences (P ≤ 0.01) were found between TNBC and other intrinsic subtype patients. When analyzed with a binary logistic regression model, an area under the curve value of 0.917 (0.846-0.987, 95% confidence interval) for TNBC classification was found.

CONCLUSION

The method of texture analysis presented here provides a novel way to characterize tumors, and demonstrates clear differences between cancer groups which are detectable before treatment begins, and can help with treatment planning as a valuable prognosis tool.

Can probiotic yogurt prevent diarrhoea in children on antibiotics? A double-blind, randomised, placebo-controlled study

OBJECTIVE

To estimate the efficacy of a probiotic yogurt compared to a pasteurised yogurt for the prevention of antibiotic-associated diarrhoea in children.

DESIGN AND SETTING

This was a multisite, randomised, double-blind, placebo-controlled clinical trial conducted between September 2009 and 2012. The study was conducted through general practices and pharmacies in Launceston, Tasmania, Australia.

PARTICIPANTS AND INTERVENTIONS

Children (aged 1-12 years) prescribed antibiotics, were randomised to receive 200 g/day of either yogurt (probiotic) containing Lactobacillus rhamnosus GG (LGG), Bifidobacterium lactis (Bb-12) and Lactobacillus acidophilus (La-5) or a pasteurised yogurt (placebo) for the same duration as their antibiotic treatment.

OUTCOMES

Stool frequency and consistency were recorded for the duration of treatment plus 1 week. Primary outcome was stool frequency and consistency, classified at different levels of diarrhoea severity. Due to the small number of cases of diarrhoea, comparisons between groups were made using Fisher's exact analysis.

RESULTS

72 children commenced and 70 children (36 placebo and 34 probiotic) completed the trial. There were no incidents of severe diarrhoea (stool consistency ≥6, ≥3 stools/day for ≥2 consecutive days) in the probiotic group and six in the placebo group (Fisher's exact p=0.025). There was also only one episode of minor diarrhoea (stool consistency ≥5, ≥2 stools/day for ≥2 days in the probiotic group compared to 21 in the placebo group (Fisher's exact p<0.001). The probiotic group reported fewer adverse events (1 had abdominal pain, 1 vomited and 1 had headache) than the placebo group (6 had abdominal pain, 4 had loss of appetite and 1 had nausea).

CONCLUSIONS

A yogurt combination of LGG, La-5 and Bb-12 is an effective method for reducing the incidence of antibiotic-associated diarrhoea in children.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry ACTRN12609000281291.

III. Instantaneous inhibition by compound 48/80 of tissue factor-initiated extrinsic coagulation is mediated by the downregulation of factor VII activation

Our previous study has demonstrated a unique biological function of compound 48/80 (48/80) in the downregulation of monocytic tissue factor (TF)-initiated hypercoagulation in response to bacterial endotoxin (lipopolysaccharide, LPS) [A. J. Chu et al. (1999) Biochim. Biophys. Acta 1472, 386-395]. The inhibition was not due to the blockade of LPS cell signaling as evidenced by the unaffected LPS-induced TF synthesis. In the present study, we investigate the direct inhibitory action of 48/80 on the extrinsic coagulation cascade. TF-initiated coagulation was assayed by a single-stage clotting assay. Chromogenic assays dissected the extrinsic pathway to measure the activities of FVII, FX, and prothrombin by monitoring the hydrolyses of nitroaniline-conjugated substrates, identifying the inhibitory site(s). We report that 48/80 in vitro instantaneously inhibited rabbit brain thromboplastin (rbTF)-initiated coagulation in a dose-dependent manner. 48/80 preferentially inhibited FVII activation without any detectable effect on FVIIa, FXa, and thrombin activities. Neither FX activation nor prothrombin activation was affected. The significant inhibition on FVII activation was found to be noncompetitive with a fourfold reduction in the apparent Vmax of FVIIa formation from 7.1 to 1.7 nM/min, while the apparent Km (approximately 365 nM) remained unaffected. Western blotting analysis further confirmed that FVIIa formation derived from FVII was significantly diminished by 48/80, which was accompanied by blocked FVII binding to rbTF. In conclusion, 48/80 readily blocked FVII binding to rbTF, leading to diminished FVII activation and FVIIa formation. As a result, TF-initiated extrinsic coagulation was downregulated.

Extracellular Ca(2+) suppresses endotoxin-inducible tissue factor activation in monocytic THP-1 cells

BACKGROUND

Monocytic tissue factor (TF), an initiator of extrinsic blood coagulation, is often activated under various inflammatory conditions including endotoxemia. This activation could be a contributing factor to the manifestation of disseminated intravascular coagulation following septic shock.

HYPOTHESIS

We herein determine if extracellular Ca(2+) ([Ca(2+)](ex)) regulates bacterial endotoxin (LPS)-inducible monocytic TF activation.

METHODS

We have employed a model monocytic cell line (THP-1) to explore the mode of action of [Ca(2+)](ex) on the modulation of LPS-induced TF activation. TF activity was measured by a single stage clotting assay, while TF expression as well as LPS recognition and its receptor expression were studied in immunofluorescent approaches.

RESULTS

LPS-induced TF activation was inversely correlated to [Ca(2+)](ex). Upon exposure of THP-1 cells to LPS (1.5 microg ml(-1)) for 6 h in the Hanks' medium without CaCl(2), TF was activated by nearly 10-fold. TF activation appreciably decreased with the increasing [Ca(2+)](ex). No more than 3.5-fold TF activation was detected at 5 mM [Ca(2+)](ex). Consistent with the significantly lower degree of TF activation, LPS-induced TF expression at 5 mM [Ca(2+)](ex) was 60 per cent less than that without [Ca(2+)](ex). FACScan analysis showed that LPS recognition was significantly blocked at 5 mM [Ca(2+)](ex) which however had no effect on the expression of CD14 and CD11b, the proposed major LPS receptors. Moreover, LPS binding in vitro was significantly inhibited by 5 mM CaCl(2).

CONCLUSION

Our results demonstrate that [Ca(2+)](ex) blocked LPS recognition without affecting its receptor expression on THP-1 monocytes. This insensitivity to LPS thereby resulted in the depressed inducible monocytic TF expression and activation.

I. Suppression by compound 48/80 of bacterial endotoxin-inducible monocytic tissue factor activity: direct blockade of factor VII binding to THP-1 monocytes

Hypercoagulation with upregulated monocytic tissue factor (TF) activity often occurs under a variety of inflammatory conditions including endotoxemia. The antagonism to bacterial endotoxin (LPS) signaling often results in the depression in TF upregulation. We herein report that compound 48/80 (48/80) significantly depressed LPS-induced TF activity in human and cebus monkey peripheral blood monocytes. Employing a model monocyte-like cell line (THP-1), we explored the regulatory mechanism to identify the inhibitory site(s) of 48/80. We determine whether the inhibition results from the blockade of LPS signaling. 48/80 dose-dependently inhibited LPS-induced TF activity. Chase of LPS-challenged cells with 48/80 also significantly offset TF upregulation. In immunofluorescent approaches, FACScan analysis revealed that 48/80 had no effect on either LPS recognition or the expression of its receptors (CD14 and CD11b). Moreover, LPS-induced TF expression as well as synthesis remained unaffected in the presence of 48/80. Consistent with the independence of LPS action, 48/80 was also able to inhibit TF activity induced by A23187, ionomycin, or Quin-2 AM. Interestingly, 48/80 significantly decreased the FVII binding to either resting or LPS-challenged cells. In conclusion, our results elucidate that the inhibitory action of 48/80 was independent of LPS signaling including recognition, receptor expression, and the induced TF expression/ synthesis. However, 48/80 was able to directly block FVII binding to monocytic TF, thereby resulting in such antagonism to LPS-induced TF-initiated extrinsic coagulation.

Effect of refrigeration on shear bond strength of three dentin bonding systems

PURPOSE

To determine whether use of dentin bonding agents directly from refrigerated storage would have adverse effects on their shear bond strength to dentin.

MATERIALS AND METHODS

Resin-based composite cylinders were bonded to dentin on the ground occlusal surfaces of 60 extracted human molars using three different dentin bonding systems at 3.0 degrees C and 23.5 degrees C. The cylinders were then debonded using an Instron testing machine in compression mode at 0.5 mm/sec. The results were interpreted with t-test and Student-Newman-Keuls post hoc analysis.

RESULTS

Scotchbond Multi-Purpose demonstrated significantly lower shear bond strengths at 23.5 degrees C (P < 0.05) than all other groups at both 3.0 degrees C and 23.5 degrees C. All-Bond 2 and Prime & Bond had higher shear bond strengths at refrigerated temperature, but the differences were insignificant in magnitude.

Advancing wave-like epitheliopathy. Clinical features and treatment

PURPOSE

The purpose of the study is to describe an entity referred to as advancing wave-like epitheliopathy and successful treatment of this keratopathy with 1% silver nitrate solution.

METHODS

Eleven eyes of 7 patients were identified with advancing wave-like epitheliopathy. A thorough history and physical examination was performed on each patient, and attempts were made to identify the cause for the epitheliopathy. Six eyes with associated visual loss due to the epitheliopathy involving the visual axis were treated with 1% silver nitrate solution to the superior conjunctival limbus.

RESULTS

Possible causes for the epitheliopathy included use of antiglaucomatous medications or contact lens care solutions (6 of 11 eyes), soft contact lens wear (4 of 11 eyes), a history of ocular surgery (3 of 11 eyes), or the presence of an underlying dermatologic or inflammatory disorder (3 of 11 eyes). All patients treated with 1% silver nitrate solution (6 of 6 eyes) experienced resolution of their symptoms with either complete or partial resolution of the epitheliopathy.

CONCLUSIONS

Advancing wave-like epitheliopathy is a keratopathy characterized by centripetally advancing waves of coarse, irregular epithelium arising from the superior limbus. The cause appears to be multifactorial. Symptoms include ocular redness, irritation, and a decrease in visual acuity if the visual axis is involved. Application of 1% silver nitrate solution to the superior limbus is well tolerated and effective in treating this condition.

Ureteral lithotripsy with the electromechanical impactor

Electrohydraulic lithotripsy (EHL) of ureteral calculi has proved to be an effective and relatively inexpensive method of intracorporeal lithotripsy. However, the potential for significant ureteral injury is an everpresent concern with conventional EHL. The electromechanical impactor (EMI), an innovative modification of a standard EHL probe, has been shown in initial investigations to be capable of fragmenting urinary calculi with a greater margin of safety. Herein, we describe our preliminary experience with this new device in 23 patients with ureteral calculi. In nine patients selected to undergo EMI treatment, the device could not be employed because of either inability to access the stone with the large endoscope required (six cases) or device malfunction (three cases). Among the patients in whom the EMI was used, five required an additional modality of intracorporeal lithotripsy to complete stone fragmentation. In the remaining nine patients, stone fragmentation was achieved with the EMI as the sole modality of lithotripsy, for an overall success rate of 39% (9/23). There were no complications directly related to use of the EMI as noted endoscopically or on postoperative imaging. The EMI appears to be a safe device for intracorporeal lithotripsy. Its application to a large population of patients with ureteral stones may be limited by the probe size (5F), which precludes its use with the smaller rigid and flexible ureteroscopes.

The management of impalement injury

Four cases of impalement injury are described. The principles of management are discussed, these being minimal manipulation of the object before and during transport, preoperative planning, a multidisciplinary approach, and wound care.

Compensated speckle imaging: theory and experimental results

Previous analyses have predicted that improved power-spectrum estimation results from application of speckle-imaging postprocessing to compensated astronomical images. We report the first results, to our knowledge, of compensated-speckle-imaging experiments, conducted at a compensated telescope operated by the U.S. Air Force, that confirm these predictions. The power-spectrum signal-to-noise ratio is used as the metric for evaluating the performance. We report the results of power-spectrum estimation for a single star and three binary stars, and we reconstruct images of the binary stars using the bispectrum method to obtain the Fourier phase of the object. Compensated and uncompensated results are compared. A previously derived expression that expresses the power-spectrum signal-to-noise ratio in terms of the compensated optical transfer function statistics and object parameters is verified by experimental data.

Effects of various concomitant medications on gastric alcohol dehydrogenase and the first-pass metabolism of ethanol

Inhibition of gastric alcohol dehydrogenase (ADH) has been shown to enhance alcohol absorption in man under certain circumstances. To determine whether various medications might affect alcohol absorption, we screened 18 compounds for an effect on ADH. Salicylic acid, acetaminophen, propranolol, ethacrynic acid, and three H2-receptor antagonists all inhibited rat gastric ADH in vitro, indicating that several commonly used medications have the potential to enhance alcohol absorption. Of these, cimetidine, ranitidine, and nizatidine were studied further to define their effect on alcohol absorption in man and to assess the clinical relevance of the effect. Both ranitidine and nizatidine enhanced the absorption of small doses of alcohol (0.15 g/kg) in the morning by 63% and 64% and increased Cmax by 48% and 54% respectively (p less than 0.001), effects similar to those reported by others for cimetidine. The effect of ranitidine given before dinner was greatly attenuated with increases in Cmax of 8% (NS) and AUC of 21% (p = 0.02). Cimetidine 800 mg hs did not affect the absorption of 0.15 g/kg alcohol given in the evening, and cimetidine 400 mg bid decreased absorption by 14% (p = 0.11). Cimetidine 300 mg qid had no effect on larger doses of alcohol given at dinner. We conclude that many commonly used medications affect gastric ADH, but that the increase in the actual amount of alcohol absorbed is quite small, and demonstrable only under special conditions.

The clinical spectrum of Staphylococcus aureus pulmonary infection

Staphylococcus aureus causes serious pulmonary infections in adults. Prior descriptions of this entity have depended on diagnosis of expectorated sputum cultures that are often contaminated. To better characterize this infection, we retrospectively reviewed the medical records of 31 adults with S aureus pulmonary infection diagnosed by culture specimens uncontaminated by the upper respiratory flora. Our results support the concept that S aureus pulmonary infections usually occur in older adults (sixth decade or older) with concomitant illnesses that are typically nosocomial. However, in contrast to previous reports, the chest roentgenograms in these patients typically showed multilobar infiltrates (60 percent), predominantly in the lower lobes (64 percent), and often bilateral (48 percent). Pleural involvement (48 percent) was more common than previously reported, and abscess formation (16 percent) occurred infrequently. Sputum cultures were found to be sensitive but nonspecific diagnostic tools. Despite antibiotic therapy, reinfection occurred in 10 percent of patients and the mortality rate was 32 percent.

Calpain I activation is not correlated with aggregation in human platelets

Calpain-catalysed hydrolysis of platelet substrates such as cytoskeletal and calmodulin-binding proteins, and of protein kinase C, is assumed to contribute to platelet aggregation. We have measured calpain I activation by immunoblotting, and [Ca2+]i (cytoplasmic Ca2+ concn.) by fura-2 fluorescence, in parallel with measurement of aggregation, in stirred human platelets treated at different [Ca2+]ext (extend Ca2+ concns.) with A23187, leupeptin, phorbol ester and thrombin. Hydrolysis of actin-binding protein, and [3H]5-hydroxytryptamine release, were also measured in some cases. A rise in [Ca2+]i, platelet aggregation and calpain activation often occurred together. With some combinations of agonists and [Ca2+]ext, however, this correlation was clearly not maintained. It was shown: (a) that activation of calpain and its hydrolysis of platelet substrates were not strictly necessary conditions for platelet secretion and aggregation; (b) conversely, that calpain activation could occur without aggregation.

99Tcm-HMPAO single photon emission tomography in the diagnosis of cerebral barotrauma

Cerebral barotrauma, or the neurological manifestation of the "bends", is a relatively common disease of divers and aviators. To date, however, no-one has succeeded in demonstrating a cerebral or spinal cord lesion in vivo following a decompression incident, despite the presence of definitive clinical signs and symptoms of central nervous system involvement. This paper describes the use of 99Tcm-labelled hexamethylpropyleneamine oxime (99Tcm-HMPAO) with single photon emission tomography in a study of three individuals involved in driving accidents. All three suffered cerebral barotrauma during decompression and all exhibited clinical signs and symptoms of dysbarism to a varying degree. Imaging was performed at time intervals ranging from 2 h to several days following the incidents. The results showed well defined cerebral ischaemic lesions in all three subjects. We conclude that 99Tcm-HMPAO imaging provides a significant advance in locating and demonstrating cerebral lesions following barotrauma and will contribute greatly to our understanding of the pathophysiological processes involved.

Incidence and management of diarrhea during longterm auranofin therapy

The incidence, severity, and management of diarrhea during longterm administration of auranofin (AF)--up to 33 months--were evaluated prospectively in 137 patients with active rheumatoid arthritis. At least 1 episode of diarrhea was reported in 101 patients (74%), but the rate of occurrence/patient-months of therapy was 24% (569 events/2,370 patient-months of treatment). The monthly prevalence declined from a range of 30-40% during the initial 6 months to about 10% for patients treated for 18-24 months. Most diarrhea was intermittent and mild; only 11 patients (8%) discontinued treatment because of diarrheal symptoms. No intervention was required in 46 of the 101 patients affected. In 44 others, loose stools were successfully managed with antidiarrheal medications, a reduction in dosage, or both. Although diarrhea is a common event during AF administration, particularly early in therapy, for most patients it usually does not significantly interfere with treatment.

Relationship between leukotriene C4 and an uteroglobin-like protein in nasal and tracheobronchial mucosa of children. Implication in acute respiratory illnesses

Secretions from the nose and nasopharynx (NPS) are more readily accessible than tracheobronchial secretions (TBS) for clinical investigations, but it is unclear whether changes in mediator release in the nasopharynx reflect similar changes in the tracheobronchial tree. In order to clarify this question, NPS and TBS were taken from 20 children with tracheotomy and tested for the presence of leukotriene C4 (LTC4) and uteroglobin-like protein (UTG-LP). LTC4 and UTG-LP were measured both when the children were healthy and when they had clinical evidence of an acute respiratory tract illness. The mean concentration of LTC4 in NPS and TBS increased during illness although the mean concentration in NPS was significantly higher than in TBS during respiratory illness. In healthy children UTG-LP was detected only in TBS. During acute respiratory illness the concentration of UTG-LP in TBS decreased but remained significantly higher than in NPS. Data presented in this study indicate that changes in the LTC4 concentration in NPS appear to reflect changes in LTC4 concentration in TBS although the levels of LTC4 in NPS were significantly higher than in TBS. An inverse correlation between the concentrations of LTC4 and UTG-LP in NPS and TBS was demonstrated.

Ulcerative keratitis associated with contact lens wear

A review of 573 cases of ulcerative keratitis cultured at the Bascom Palmer Eye Institute from January 1977 through September 1982 showed that 118 cases (21%) were associated with contact lens wear; of these, 64 were culture-positive. Of these culture-positive cases, 50 (78%) were caused by gram-negative bacteria, nine (14%) by gram-positive organisms, and two (3%) by fungal organisms. Of the 264 culture-positive ulcers not associated with contact lens wear, 119 (45%) were caused by gram-negative bacteria, 74 (28%) by gram-positive organisms, and 63 (24%) by fungal organisms. These statistically significant differences suggested that the organisms associated with ulcerative keratitis within our geographic region are modified by contact lens use. Pseudomonas was the organism most frequently isolated from ulcers associated with contact lenses and was responsible for nearly two thirds of the culture-positive cases.

Ischemic optic neuropathy secondary to intestinal hemorrhage

A 70-year-old man presented with bilateral ischemic optic neuropathy. Workup revealed anemia that proved to be secondary to blood loss from an occult small bowel sarcoma. Ischemic optic neuropathy is an uncommon complication of gastrointestinal hemorrhage. It is important to recognize the association of visual loss and severe blood loss when they occur concurrently, so that proper treatment may be promptly instituted.

Factitious asthma. Physiological approach to diagnosis

Three patients with recurrent emergency room visits and hospitalizations for bronchial asthma are described. Although each patient had respiratory distress associated with wheezing and an apparent response to conventional therapy, other features were inconsistent with the pathophysiology of asthma. These included absence of a significantly elevated alveolar-arterial oxygen tension difference, lack of roentgenographic hyperinflation, and normal small airway function soon after clinical response. Furthermore, bronchial hyperreactivity, a constant feature of asthma, was absent in all patients. Each patient demonstrated wheezing that was self-induced and heard loudest over the neck. Two patients had previous psychiatric illness, one of whom had been hospitalized for factitious fever. We believe that these patients had a form of factitious illness not previously described. Recognition of this syndrome may avoid unnecessary medical care and allow initiation of appropriate psychiatric follow-up.

Collective bargaining in higher education

Collective bargaining in higher education is a phenomenon that is less than 20 years old. This article chronicles the development of legal jurisdiction and the growth of bargaining activity in the public and private sectors. It focuses on the relevant differences between two- and four-year institutions in the public and private sectors as well as several of the major problem areas in higher education and their current legal status, including the Yeshiva decision. The author cites a number of inconsistent rulings that cover collective bargaining in higher education and takes the position that, in spite of all diversity and inconsistencies, the collective bargaining process continues to grow.

Herpetic canalicular obstruction

Primary herpes simplex infection may involve the lining of the lacrimal canaliculi and result in permanent strictures and epiphora. Five cases are reported and analyzed in combination with previously reported cases. Antiviral medication was not responsible for lacrimal drainage obstruction in these cases.

A controlled trial of naftidrofuryl (Praxilene) in the treatment of intermittent claudication

We present the results of a double-blind trial of naftidrofuryl (Praxilene) in the treatment of intermittent claudication. One hundred and twenty-eight patients were subjected to a standard walking test 3 and 6 months after treatment. There was no significant objective improvement attributable to the drug. Although both groups significantly increased their walking time to the onset of pain, those patients over 60 years old taking naftidrofuryl showed a significant improvement over their pretreatment walking times to onset of pain, whereas their controls did not.

Bilateral optic nerve hypoplasia with unilateral retinal vessel abnormality

Optic nerve hypoplasia is an uncommon congenital defect of the optic nerve and retina, although recent studies show it occurs more frequently than previously thought. It is characterized by a small, pale optic disc, normal appearing retinal vasculature, and marked visual impairment. This condition may be unilateral or bilateral and familial cases have been described. It may be associated with other defects of the central nervous system but also occurs in otherwise normal individuals. It is different from aplasia of the optic nerve in which there is complete absence of the optic disc and retinal vasculature, usually in a badly malformed eye. The purpose of this communication is to describe the clinical and fluorescent appearance of an infant with bilateral optic nerve hypoplasia and the unilateral abnormality of retinal vessels.

Leukocyte larceny: a cause of spurious hypoxemia

Multiple blood specimens with different leukocyte counts from two patients with extreme leukocytosis secondary to leukemia and unexplained hypoxemia were tonometered with a gas of known oxygen concentration and the decay of oxygen tension (PO2) was measured over time. The decay in PO2 in the first 2 minutes for blood with leukocyte counts of between 55.2 X 10(3)/mm3 and 490.0 X 10(3)/mm3 ranged from 13 to 72 torr. The degree of PO2 decay was blunted by placing the blood on ice and was obliterated by adding potassium cyanide. Thus, extreme leukocytosis secondary to leukemia can cause spurious hypoxemia and spurious lowering of the mixed venous PO2 due to oxygen consumption by leukocytes ("leukocyte larceny").

PTFE (Goretex) femoropopliteal reconstruction for limb salvage

We present the results of the use of polytetrafluoroethylene (PTFE, Goretex) grafts for limb salvage in 20 cases of femoropopliteal or more distal arterial reconstruction. There appears to be no relationship between graft survival and 'run-off' or the overall disease state of the vessels. Cumulative graft patency was almost 50% at 6 months, which is in contrast with higher patency rates reported from other countries.

Respiratory therapy. Current practice in ambulatory patients with chronic airflow obstruction

The role of respiratory therapy in treating ambulatory patients with chronic obstructive pulmonary disease is becoming more clearly defined. Oxygen therapy on a continuous basis is needed for patients with arterial PO2 values below 45 mm Hg and should be considered for patients with arterial PO2 values between 45 and 55 mm Hg who have chronic cor pulmonale, erythrocytosis with hematocrit value greater than 55%, and disturbances of cognition and sleep. Concentrated bronchodilator and corticosteroid aerosols have established roles in therapy; the place of bland aerosols is less clear They may increase ease of expectoration and should be given by simple compressed-air nebulizer systems; their administration by brief periods of intermittent positive-pressure breathing is rarely justified. Three-positional, postural drainage with chest percussion and vibration may be helpful in mobilizing secretions in patients with severe disease.

Intramural lymphatic cyst of bovine heterograft

An intramural lymphatic cyst of a bovine heterograft is described. This previously unreported complication presented as a pulsatile mass in the thigh of an 84-year-old woman who had undergone vascular reconstruction 12 months previously. The clinical presentation, operative findings, and pathological findings are described, and the management of the case is discussed.

The haematological hazards of autotransfusion

Fourteen heparinized dogs were autotransfused from 1-5 to 6 times calculated blood volume. Five animals retransfused 12 litres from an intraperitoneal bleed had marked decreases in all cellular elements, haematuria and a large (82 percent) drop in fibrinogen. All these animals died within 12 hours and post-mortem examination revealed evidence of disseminated intravascular coagulopathy. The dogs in which a smaller volume (3-6 litres) was recycled showed similar, but less devastating, changes. Haematocrit and platelet count dropped by a half and fibrinogen by 20 per cent. A leucocytosis of about 30 000/mm3 occurred within 24 hours. Autotransfusion of salvaged blood which was not allowed extravascular tissue contact significantly lessened these adverse effects. We conclude that the risk of cellular destruction and defibrination in large volume intra-operative autotransfusion is significant and must be weighed against its potential benefits in each case, and that red cell and platelet damage results primarily from extravascular tissue contact and is therefore unavoidable.