Chest Radiology- A Case of Azygous Lobe

By Dr Deepu
The lungs are normally divided into five lobes by three main fissures .
 Occasionally, invaginations of the visceral pleura create accessory fissures that separate individual bronchopulmonary segments into accessory lobes .
 An azygos lobe is found in approximately 0.4% of patients . In contrast to other accessory lobes, the azygos lobe does not correspond to a distinct anatomical bronchopulmonary segment .

It forms during embryogenesis when the precursor of the azygos vein fails to migrate to its medial position in the mediastinum, where it normally arches over the origin of the right upper lobe bronchus.
 This gives rise to the following characteristics, which are visible on a standard chest x-ray

: the laterally displaced azygos vein lies between folds of parietal pleura, also referred to as the mesoazygos, where it assumes a characteristic teardrop shape ; the mesoazygos indents the right upper lobe, thereby creating the accessory (azygos) fissure, which is similar in shape to an inverted comma; the fissure delineates the azygos lobe, located superomedially ; laterally, the pleural folds of the mesoazygos separate before reaching the chest wall, resulting in a radiopaque triangular area ; and medially, the tracheobronchial angle appears empty .

 An azygos lobe may be confused with a pathological air space such as a bulla or abscess . In addition, the abnormally located azygos vein may be mistaken for a pulmonary nodule, while a consolidated azygos lobe may be confused with a mass . An understanding of the pathogenesis and characteristic x-ray features of the azygos lobe will enable an accurate diagnosis in most cases .
 If the x-ray findings are equivocal, computed tomography will be diagnostic .

Nicotine-degrading bacteria show therapeutic promise in smoking cessation!!

An early-phase study developing a new drug to aid smoking cessation has found that an enzyme made in the lab could digest nicotine before it reaches the brain.

In the Journal of the American Chemical Society, scientists from The Scripps Research Institute (TSRI) report how the enzyme can consume nicotine, indicating the potential to significantly reduce the length of time that nicotine remains in the blood.

The team assessed a protein extracted from Pseudomonas putida bacteria in mouse models. P. putida was originally isolated from a tobacco field and is now known to rely on nicotine as its sole source of carbon and nitrogen. The team isolated the nicotine-degrading enzyme, NicA2, from the bacteria to establish whether this protein was stable and whether the process would continue once the protein was isolated.

The results showed that the protein reduced the half-life of the nicotine from one cigarette from 2–3 hours to 9–15 minutes. The team found no evidence of any negative physical or behavioural effects of the enzyme on the mice and, at this stage, the by-products from the process of breaking down the nicotine do not appear to be toxic.

The authors state that further studies are necessary, particularly with regard to any human immune-response to the protein.

Bigger Families May Deal With More Viral Infections

HealthDay (8/7, Preidt) reports that “being part of a big family boosts the risk of passing on viral infections that cause colds, flu and other respiratory woes,” according to a study published in Clinical Infectious Diseases journal. The study of “108 people from 26 Utah families” revealed that “people in childless households were infected with viruses an average of three to four weeks a year.” Viral infections “rose to 18 weeks a year in families with one child, and up to 45 weeks a year in households with six children,” the study found.

        Meanwhile, HealthDay (8/7, Preidt) reports, “An online program that encourages people to wash their hands reduced the spread of cold and flu viruses within families,” according to a study published online in The Lancet that involved some 20,000 UK adults. The online “program also led to fewer gastrointestinal illnesses, doctor appointments and antibiotic prescriptions,” the study found.

Opposition To Larger Health Warnings Grows In India

The Deccan (IND) Herald (7/30) reports that opposition to health warnings covering 85% of tobacco packages in India has expanded from the tobacco industry to include 13 petitions from groups such as the CII (Confederation of Indian Industry) and ASSOCHAM (Associated Chambers of Commerce Of India) while no major hospitals have supported the measure. The piece notes that 26 petitions support larger warnings, however, as the Lok Sabha Committee on Subordinate Legislation prepares to issue a report on the matter to the House.

Optical Fluorescent Molecular Real-Time Imaging During Surgery May Be Used To Differentiate Lung Adenocarcinomas From Normal Lung Parenchyma

MedPage Today (8/4, Jackson) reports that research indicates that “optical fluorescent molecular real-time imaging during surgery can be used to differentiate lung adenocarcinomas from surrounding normal lung parenchyma.” The findings were published in The Journal of Thoracic and Cardiovascular Surgery.

Lung Function May Decline In Patients With Moderate To Severe COPD After Steroid Withdrawal

MedPage Today (8/5, Minerd) reports that research indicated that individuals “with moderate to severe chronic obstructive pulmonary disease (COPD) experienced significant decreases in lung function for up to 5 years after discontinuing long-term inhaled corticosteroid (ICS) treatment.” Additionally, these individuals “experienced steady worsening in airway hyperresponsiveness (AHR) and quality of life.” The findings were published in CHEST Journal.

Limited Resection May Not Be Equivalent To Lobectomy When Used To Treat Older Patients With Stage IA Lung Cancer Of Invasive Cell Types

MedPage Today (8/6, Jackson) reports that research suggests that “limited resection is not equivalent to lobectomy when used to treat older patients with stage IA lung cancer of invasive cell types, namely invasive adenocarcinoma and squamous cell carcinoma.” Rather, “these patients may be considered for completion lobectomy or for adjuvant treatments,” researchers “report online in the Journal of Clinical Oncology.”