Human paranasal sinuses and selective brain cooling: A ventilation system activated by yawning?

Human paranasal sinuses and selective brain cooling: A ventilation system activated by yawning?
Medical Hypotheses
Volume 77, Issue 6 , Pages 970-973, December 2011

• Andrew C. Gallup

  AFFILIATIONS

  • Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, United States
  • Corresponding author. Tel.: +1 518 727 2473; fax: +1 609 258 7892.
  
, 
• Gary D. Hack

Abstract 

The function of the paranasal sinuses has been a controversial subject since the time of Galen, with many different theories advanced about their biological significance. For one, the paranasal sinuses have been regarded as warmers of respiratory air, when in actuality these structures appear to function in cooling the blood. In fact, human paranasal sinuses have been shown to have higher volumes in individuals living in warmer climates, and thus may be considered radiators of the brain. The literature suggests that the transfer of cool venous blood from the paranasal sinuses to the dura mater may provide a mechanism for the convection process of cooling produced by the evaporation of mucus within human sinuses. In turn, the dura mater may transmit these temperature changes, initiated by the cool venous blood from the heat-dissipating surfaces of the sinuses, to the cerebrospinal fluid compartments. Furthermore, it has recently been demonstrated in cadaveric dissections that the thin bony posterior wall of the maxillary sinus serves as an origin for both medial and lateral pterygoid muscle segments, an anatomic finding that had been previously underappreciated in the literature. The present authors hypothesize that the thin posterior wall of the maxillary sinus may flex during yawning, operating like a bellows pump, actively ventilating the sinus system, and thus facilitating brain cooling. Such a powered ventilation system has not previously been described in humans, although an analogous system has been reported in birds.

Influence of lipoproteins and fibrinogen on pathogenesis of sudden sensorineural hearing loss

• The Journal of Laryngology & Otology (2011), 125: 258-261
• Copyright © JLO (1984) Limited 2010
• Z Oreskovic^a1, D Shejbal^a2, G Bicanic^a3 c1 and B Kekic^a4

^a1 Department of Anesthesiology and Intensive Care, Clinical Hospital Center Zagreb, Zagreb, Croatia

^a2 Department of Otorhinolaryngology, City Hospital Pakrac, Zagreb, Croatia

^a3 University Clinic for Orthopedic Surgery, Clinical Hospital Center Zagreb, Zagreb, Croatia

^a4 University Clinic for Otorhinolaryngology, Sestre Milosrdnice Clinical Hospital, Zagreb, Croatia

Abstract

Aim: To evaluate the relationship between lipoproteins, fibrinogen and sudden sensorineural hearing loss in a Croatian population. Since pathological derangement of lipoproteins and fibrinogen could be one of the causes of sudden sensorineural hearing loss, we hypothesised that patients with sudden sensorineural hearing loss would have more abnormal fibrinogen and lipoprotein concentrations, compared with subjects with normal hearing.

Methods: Plasma concentrations of cholesterol, fibrinogen and triglycerides in patients with sudden sensorineural hearing loss were compared with those in a control group (i.e. subjects with normal hearing function).

Results: Patients with sudden sensorineural hearing loss had significantly higher plasma concentrations of cholesterol and low density lipoprotein cholesterol, compared with controls.

Conclusion: Higher cholesterol and low density lipoprotein cholesterol concentrations were found in patients with sudden sensorineural hearing loss, within a Croatian population. Cholesterol and low density lipoprotein cholesterol concentrations may be important factors in the pathogenesis of sudden sensorineural hearing loss, and should be assessed during the investigation of patients with this condition.

(Accepted June 15 2010)

(Online publication November 05 2010)

Correspondence:

^c1 Address for correspondence: Dr Goran Bicanic, University Clinic for Orthopedic Surgery, Clinical Hospital Center Zagreb, Salata 6-7, 10000 Zagreb, Croatia Fax: +385 1 4818810 E-mail: gbic@mef.hr

Footnotes

Dr G Bicanic takes responsibility for the integrity of the content of the paper

Competing interests: None declared

Breakthrough In Allergic Asthma Treatments To Put Squeeze On Sneeze, UK

Breakthrough In Allergic Asthma Treatments To Put Squeeze On Sneeze, UK



A major breakthrough in creating effective new treatments for allergic asthma has been discovered by Asthma UK funded scientists at King's College London. 

The discovery is the culmination of over fifteen years of Asthma UK-funded research, and the findings are published today in the journal Nature Structural & Molecular Biology. 

The painstaking work conducted by a team of scientists led by Professor Brian Sutton at the MRC-Asthma UK Centre in Allergic Mechanisms of Asthma at King's College London, revealed the precise shape of an important molecule called IgE as it binds to receptor proteins on the surface of mast cells in the lungs. 

Scientists built up a picture of IgE's shape down to the location of each individual atom by firing X-rays at purified protein crystals and measuring how the rays were deflected. Using this technique they were also able to reveal how IgE moves and twists as it attaches to the receptor.

With further funding from Asthma UK, the team is now testing a library of small chemical compounds, looking for ones that have the potential to block the interaction between IgE and its receptor and prevent the development of asthma. 

There are hundreds of thousands of mast cells crawling through the lining of our lungs, each of which holds thousands of histamine-containing granules. In a person with allergic asthma, IgE molecules sit on the surface of these cells. Then, when the individual comes into contact with an allergen such as grass pollen, it sticks to the IgE, provoking the mast cells to release their granules. Histamine causes breathlessness, wheezing and other asthma symptoms by narrowing the airways and triggering inflammation. 

Although allergens from grass pollen, pets, house-dust mites and other sources all have different shapes, all of them trigger asthma and allergy symptoms by binding to IgE on mast cells. Hence, a drug that can prevent IgE from interacting with mast cells would help anyone with allergic asthma, no matter what triggers their allergy. 

The breakthrough is an essential step towards chemically-based drugs, such as those now being developed by Professor Sutton, which can be given in tablet form. 

Professor Brian Sutton from King's says: 'We are immensely proud of our achievement. Thousands of hours of work by my team, plus that of our collaborators, has brought us to an incredibly exciting point. 

'Armed with the precise structure of IgE bound to its receptor we stand a great chance of being able to create hugely effective new treatments for allergic asthma.' 

Dr Elaine Vickers, Research Relations Manager at Asthma UK, says: 'In the UK, 5.4 million people have asthma and almost 80% of them say they have allergies which affect their asthma control. 

'The impact of potential new treatments for allergic asthma resulting from this work could have an enormous impact on the quality of life of people across both the UK and the world.' 

Source: 
Asthma UK 

Omalizumab: Anti-IgE Therapy in Allergy

Current Allergy and Asthma Reports (Jan 2011)

 Kopp MV 

Omalizumab is a humanized, monoclonal anti-IgE antibody that binds specifically to circulating IgE molecules, thus interrupting the allergic cascade. Omalizumab has been shown to be highly effective in treating children and adults with moderate to severe allergic asthma. Beyond this indication, the mode of action itself suggests that omalizumab is not only an antiasthmatic drug but also a promising therapeutic option for various allergic conditions, including allergic rhinitis, food allergy, urticaria, allergic bronchopulmonary aspergillosis, insect hypersensitivity, and atopic dermatitis. However, data from double-blind, placebo-controlled clinical trials are only available for allergic rhinitis and moderate to severe bronchial asthma. The aim of this review is to discuss the current clinical data as well as possible further indications of omalizumab treatment

Vocal cord dysfunction: what do we know?

European Respiratory Journal 37 (1), 194-200 (Jan 2011)

Kenn K, Balkissoon R 

Vocal cord dysfunction (VCD) is a disorder caused by episodic unintentional paradoxical adduction of the vocal cords, which may induce acute severe dyspnoea attacks not responsive to conventional asthma therapy. The aetiology of VCD is complex and often multifactorial. The essential pathophysiology is that of a hyperfunctional laryngeal reflex to protect the lower airway as a result of any combination of post-nasal drip, gastro-oesophageal reflux, laryngopharyngeal reflux and/or psychological conditions. Laryngoscopic demonstration of the paradoxical motion while wheezing or stridorous is considered the diagnostic gold standard. Speech therapy, including the use of special relaxed-throat breathing patterns is effective for VCD that is purely of the functional nature. Knowledge of the clinical features of VCD and identifying factors that may be contributing to the development of VCD can provide adequate clues to the correct diagnosis and management.

Efficacy and safety of timothy grass allergy immunotherapy tablet treatment in North American adults

Journal of Allergy and Clinical Immunology (JACI) 127 (1), 72-80.e2 (Jan 2011)

Nelson HS, Nolte H, Creticos P, Maloney J, Wu J, Bernstein DI 

BACKGROUND Immunotherapy for allergic rhinoconjunctivitis (ARC) in North America is generally administered subcutaneously, but alternative formulations might be safer and more convenient. Trials of sublingual formulations in North America are needed to confirm European efficacy and safety data. 

OBJECTIVEWe sought to investigate the efficacy and safety of timothy grass allergy immunotherapy tablet (AIT) treatment in North American subjects with ARC. 

METHODS Four hundred thirty-nine adults with grass pollen-induced ARC with or without asthma were randomized to once-daily 2,800 bioequivalent allergen units of standardized grass AIT (oral lyophilisate, Phleum pratense, 75,000 standardized quality tablet, containing approximately 15 μg of Phl p 5) or placebo approximately 16 weeks before the 2009 grass pollen season (GPS). The primary end point was the average total combined score of the daily symptom score and the daily medication score during the GPS. Rhinoconjunctivitis Quality of Life Questionnaire with standardized activities (RQLQ[S]) scores, Phl p 5-specific IgG4 levels, and IgE-blocking factor levels were additional end points. Adverse events (AEs) were monitored for safety. 

RESULTS Relative to placebo, grass AIT treatment improved total combined scores by 20% (P = .005), daily symptom scores by 18% (P = .02), and RQLQ(S) scores by 17% (P = .02). Daily medication scores were improved by 26% and trended toward significance (P = .08). Phl p 5-specific IgG4 and IgE-blocking factor levels were higher after grass AIT treatment compared with those after placebo at the end of the GPS (P <.001). Grass AIT treatment was safe and well tolerated. The majority of AEs were transient mild local reactions with no investigator-diagnosed grass AIT-related serious AEs or reports of anaphylactic shock/respiratory compromise. In the grass AIT group, 1 subject received epinephrine after experiencing a possible grade 1 systemic reaction (local site reactions, chest discomfort, and rash). 

CONCLUSIONS Timothy grass AIT treatment (cross-reactive with related Pooideae grasses) was demonstrated to be effective, generally safe, and well tolerated in North American adults with grass pollen-induced ARC.

Effectiveness criteria for the topical application of glucocorticosteroids to the treatment of exudative otitis media associated with allergic rhinitis

Vestnik Otorinolaringologii (5), 32-34 (2010)

Poliakova SD, Popova EA 

We undertook comparative analysis of ciliotoxic effect of glucocorticosteroids frequently used for catheterization of the eustachian tube in patients presenting with exudative otitis media and concomitant allergic rhinitis. It was shown that the recovery of transport function of ciliary epithelium and appreciable clinical effect of the treatment were achieved by the application of mometasone furoate. Dexamethasone was next to mometasone in terms of efficiency whereas hydrocortisone produced much lower beneficial effect. It is concluded that, taking into account high bioavailability of dexametasone and hydrocortisone (>80%) and contraindications to their intranasal administration, the preference should be given to medications with lower bioavailability.