A genome-wide CRISPR screen identifies DPM1 as a modifier of DPAGT1 deficiency and ER stress

Partial loss-of-function mutations in glycosylation pathways underlie a set of rare diseases called Congenital Disorders of Glycosylation (CDGs). In particular, DPAGT1-CDG is caused by mutations in the gene encoding the first step in N-glycosylation, DPAGT1, and this disorder currently lacks effective therapies. To identify potential therapeutic targets for DPAGT1-CDG, we performed CRISPR knockout screens in Drosophila cells for genes associated with better survival and glycoprotein levels under DPAGT1 inhibition. We identified hundreds of candidate genes that may be of therapeutic benefit. Intriguingly, inhibition of the mannosyltransferase Dpm1, or its downstream glycosylation pathways, could rescue two in vivo models of DPAGT1 inhibition and ER stress, even though impairment of these pathways alone usually causes CDGs. While both in vivo models ostensibly cause cellular stress (through DPAGT1 inhibition or a misfolded protein), we found a novel difference in fructose metabolism that may indicate glycolysis as a modulator of DPAGT1-CDG. Our results provide new therapeutic targets for DPAGT1-CDG, include the unique finding of Dpm1-related pathways rescuing DPAGT1 inhibition, and reveal a novel interaction between fructose metabolism and ER stress.

Lung cancer physicians' referral practices for palliative care consultation

BACKGROUND

Integration of palliative care with standard oncologic care improves quality of life and survival of lung cancer patients. We surveyed physicians to identify factors influencing their decisions for referral to palliative care.

METHODS

We provided a self-administered questionnaire to physicians caring for lung cancer patients at five medical centers. The questionnaire asked about practices and views with respect to palliative care referral. We used multiple regression analysis to identify predictors of low referral rates (<25%).

RESULTS

Of 155 physicians who returned survey responses, 75 (48%) reported referring <25% of patients for palliative care consultation. Multivariate analysis, controlling for provider characteristics, found that low referral rates were associated with physicians' concerns that palliative care referral would alarm patients and families [odds ratio (OR) 0.45, 95% confidence interval (CI) 0.21-0.98], while the belief that palliative care specialists have more time to discuss complex issues (OR 3.07, 95% CI 1.56-6.02) was associated with higher rates of referral.

CONCLUSIONS

Although palliative care consultation is increasingly available and recommended throughout the trajectory of lung cancer, our data indicate it is underutilized. Understanding factors influencing decisions to refer can be used to improve integration of palliative care as part of lung cancer management.

A rare case of primary lung adenocarcinoma detected by routine liquid-based cervical cytology

Cervical cytology is mainly used for the screening and detection of early cervical cancers and its precursors. Rarely, detection of malignant cells in cervical cytology specimens is the first manifestation of an extrauterine (EU) malignancy. We report a case of a 49-year-old female in which adenocarcinoma initially diagnosed on routine, liquid-based cervical cytology led to the detection of a primary lung cancer.

Pulmonary embolism in the elderly

The elderly are at increased risk for pulmonary embolism because of both the conditions common to this age group, and the immobility that often accompanies them. Whether aging alone represents a hypercoagulable state is unclear. The incidence of pulmonary embolism rises with age, however, as does pulmonary embolism mortality. The diagnosis of pulmonary embolism is difficult and frequently missed because elderly patients and their physicians may attribute nonspecific symptoms to underlying cardiopulmonary disease or to age itself. Routine laboratory examinations are also nonspecific. Lower extremity studies to diagnose DVT should always be pursued because a positive study results in identical treatment, without the need for further testing. D-dimer concentrations are useful when low, but are commonly elevated in the elderly because of other comorbid conditions. Lung scanning remains the most common initial study to diagnose pulmonary embolism, although spiral CT is as sensitive and specific. Pulmonary angiography should always be considered when the initial studies are nondiagnostic and clinical suspicion is high, and this test is well tolerated in the elderly. The role of newer diagnostic techniques, such as MR imaging, cannot be determined until well-designed outcomes trials are completed. Prophylaxis with appropriate pharmacologic agents or mechanical measures should be administered not only to patients undergoing hip or knee reconstruction surgery, but to all bed-ridden elderly medical and general surgery patients. Treatment for pulmonary embolism with anticoagulation reduces the mortality rate and should be administered in all elderly patients without contraindications. In addition, thrombolysis should be considered for all hemodynamically unstable patients with pulmonary embolism, regardless of age. Vena caval filters are warranted when anticoagulation is contraindicated, although evidence of the long-term benefit of these devices is lacking. At present, pulmonary embolism is underdiagnosed and undertreated in the elderly. By heightening awareness of this diagnosis and its appropriate management in this age group, considerable morbidity and mortality may be avoided.

Dissociation of bradykinin-induced plasma exudation and reactivity in the peripheral airways

To determine if bradykinin, a potential mediator of asthma, acts, at least in part, at the level of the peripheral airways, we used a wedged bronchoscope technique to study asthmatic and normal subjects. Baseline peripheral airways resistance (Rp) was measured in the right upper lobe. Subjects then received saline, followed by increasing doses of bradykinin, aerosolized through the bronchoscope. Rp was measured after each challenge. At the end of the procedure, bronchoalveolar lavage was performed in both the challenged and a control segment. Fibrinogen content of recovered lavage fluids was measured as an index of plasma exudation. Bradykinin induced a dose-dependent increase in Rp in the asthmatics, but did not effect Rp in normal subjects. In asthmatics, there was no significant correlation between peripheral airways reactivity and whole lung reactivity to bradykinin. Fibronogen increased significantly in both groups after bradykinin challenge, and there was no significant difference between postchallenge levels for the two groups. Thus, hyperreactivity of the peripheral airways in asthmatics is not directly due to plasma exudation. The ability of bradykinin to increase peripheral airways resistance in asthmatic, but not in normal, subjects is consistent with a role of this peptide as a mediator of asthma.

Allergen-induced hyperresponsiveness to bradykinin is more pronounced than that to methacholine

Bradykinin reduces airflow in asthmatic patients via indirect mechanism(s), possibly involving sensory nerve stimulation and increased vascular permeability. We hypothesized that allergen inhalation, which affects reactivity of nerves and vessels, would differentially alter reactivity to bradykinin and the smooth muscle spasmogen methacholine. We compared reactivity to methacholine and bradykinin 1, 2, 4, 7, 11, and 14 days after allergen provocation in 12 atopic asthmatic patients with stable baseline reactivity to bradykinin. Maximal allergen-induced shifts from baseline in reactivity were 0.73 +/- 0.12 log unit for bradykinin compared with 0.27 +/- 0.13 log units for methacholine (P = 0.0005). Nine subjects showed significant increases in bradykinin reactivity, with four subjects increasing reactivity by > 1 log unit. Moreover, the maximal mean change in bradykinin reactivity occurred 2 days postallergen. Thus, allergen-induced changes in reactivity to bradykinin and methacholine differ in magnitude and time course. Bradykinin inhalational challenge provides a sensitive index of the airway's response to allergen.

Metabolism of intranasally applied cocaine

Surprisingly little is known about the metabolism and toxicity of cocaine in man. In this study serum obtained following nasal surgery was assayed for benzoylecgonine (the major metabolite of cocaine) by radioimmunoassay. It was found that cocaine was rapidly hydrolyzed in the serum. Benzoylecgonine was detectable in the serum at 15 minutes. The peak blood level of the metabolite appeared at 4.5 hours with a peak concentrations of 872.9 ng/ml. The half time clearance of the metabolite from the serum was 5.5 hours. A discussion of variables which must be considered in deriving, by a scientific method, a maximum safe clinical dose is presented.

Radioimmunoassay of methaqualone and its monohydroxy metabolites in urine

A commercial radioimmunoassay kit was evaluated for efficacy in detecting methaqualone or its metabolites in urine of persons receiving this drug. The drug and its unconjugated 3'- and 4'-monohydroxy metabolites could be detected equally well. The unconjugated alpha-monohydroxy metabolite was about 80% as reactive and the unconjugated 6-monohydroxy metabolite reacted only very weakly. Quantitation of the conjugated metabolites was less sensitive than of unconjugated. Nineteen urine specimens which reacted positively to radioimmunoassay and which thin-layer chromatography had shown to contain methaqualone and its metabolites were also examined by gas-liquid chromatography. Those specimens that reacted strongly to radioimmunoassay contained high concentrations of the drug or its metabolites. In the specimens examined by gas-liquid chromatography, the apparent concentrations of the metabolites were generally higher than those of the drug itself. Methaqualone in combination with its unconjugated metabolites reacted additively with the radioimmunoassay, resembling the same concentration of parent drug alone. Detection limits were between 10-200 mug/liter.