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Jonathan Rogers
Jonathan Rogers

3. The Cold REPACK


The protein α-actinin-3 expressed in fast-twitch skeletal muscle fiber is absent in 1.5 billion people worldwide due to homozygosity for a nonsense polymorphism in ACTN3 (R577X). The prevalence of the 577X allele increased as modern humans moved to colder climates, suggesting a link between α-actinin-3 deficiency and improved cold tolerance. Here, we show that humans lacking α-actinin-3 (XX) are superior in maintaining core body temperature during cold-water immersion due to changes in skeletal muscle thermogenesis. Muscles of XX individuals displayed a shift toward more slow-twitch isoforms of myosin heavy chain (MyHC) and sarcoplasmic reticulum (SR) proteins, accompanied by altered neuronal muscle activation resulting in increased tone rather than overt shivering. Experiments on Actn3 knockout mice showed no alterations in brown adipose tissue (BAT) properties that could explain the improved cold tolerance in XX individuals. Thus, this study provides a mechanism for the positive selection of the ACTN3 X-allele in cold climates and supports a key thermogenic role of skeletal muscle during cold exposure in humans.




3. The Cold



A 1998 systematic review (which did not include a quantitative synthesis of data) suggested that zinc was beneficial in reducing the duration and severity of cold symptoms.4 A meta-analysis published in 2000 found that zinc was ineffective compared with placebo in reducing the likelihood that cold symptoms were present after 7 days.5 A meta-analysis published in June 2011 concluded that zinc lozenges reduce the duration of cold symptoms by 12% to 48%, but only at daily doses >75 mg.6


Primary outcomes included the duration of symptoms, the severity of symptoms, and the incidence of the common cold in prevention studies. Secondary outcomes included the proportion of patients symptomatic after 3, 5, and 7 days of treatment, the time to resolution of individual symptoms (eg, cough), change in individual symptom scores, school absences, antibiotic use, and adverse effects.


Ten studies reported on duration of symptoms; 6 of them were similar enough to allow for pooling of results. The pooled results showed that patients who took zinc had a shorter duration of cold symptoms (0.97 days; 95% confidence interval [CI], -1.56 to -0.38), compared with those on placebo. Pooled results from 5 trials revealed that zinc significantly reduced the severity of symptoms by a standard effect size of 0.39 (95% CI, -0.77 to -0.02), which is considered a small to moderate effect.


In addition, 2 prevention trials found that zinc can reduce the incidence of colds in children, whether it is taken as a syrup or in tablet form. There have been few trials of zinc for prophylaxis of the common cold, and no previous meta-analyses included preventive studies.7 This Cochrane review substantiates the effectiveness of zinc for prophylaxis of the common cold in young children.


Flight planning into a CTA may be accomplished prior to flight. Use the predicted coldest temperature for plus or minus 1 hour of the estimated time of arrival and compare against the CTA published temperature. If the predicted temperature is at or below CTA temperature, calculate an altitude correction using TBL 7-3-1. This correction may be used at the CTA if the actual arrival temperature is the same as the temperature used to calculate the altitude correction during preflight planning.


When executing an approach with vertical guidance at a CTA (i.e., ILS, localizer performance with vertical guidance (LPV), LNAV/VNAV), pilots are reminded to intersect the glideslope/glidepath at the corrected intermediate altitude (if applicable) and follow the published glideslope/glidepath to the corrected minima. The ILS glideslope and WAAS generated glidepath are unaffected by cold temperatures and provide vertical guidance to the corrected DA. Begin descent on the ILS glideslope or WAAS generated glidepath when directed by aircraft instrumentation. Temperature affects the precise final approach fix (PFAF) true altitude where a baro-VNAV generated glidepath begins. The PFAF altitude must be corrected when below the CTA temperature restriction for the intermediate segment or outside of the baro-VNAV temperature restriction when using the LNAV/VNAV line of minima to the corrected DA.


The corrected DA or MDA does not affect the visibility minima published for the approach. With the application of a cold temperature correction to the DA or MDA, the airplane should be in a position on the glideslope/glidepath or at the published missed approach point to identify the runway environment.


Common colds are the main reason that children miss school and adults miss work. Each year in the United States, there are millions of cases of the common cold. Adults have an average of 2-3 colds per year, and children have even more.


Viruses that cause colds can spread from infected people to others through the air and close personal contact. You can also get infected through contact with stool (poop) or respiratory secretions from an infected person. This can happen when you shake hands with someone who has a cold, or touch a surface, like a doorknob, that has respiratory viruses on it, then touch your eyes, mouth, or nose.


There is no cure for a cold. To feel better, you should get lots of rest and drink plenty of fluids. Over-the-counter medicines may help ease symptoms but will not make your cold go away any faster. Always read the label and use medications as directed. Talk to your doctor before giving your child nonprescription cold medicines, since some medicines contain ingredients that are not recommended for children. Learn more about symptom relief of upper respiratory infections, including colds.


Antibiotics will not help you recover from a cold caused by a respiratory virus. They do not work against viruses, and they may make it harder for your body to fight future bacterial infections if you take them unnecessarily. Learn more about when antibiotics work.


You should also call your doctor right away if you are at high risk for serious flu complications and get flu symptoms such as fever, chills, and muscle or body aches. People at high risk for flu complications include young children (younger than 5 years old), adults 65 years and older, pregnant women, and people with certain medical conditions such as asthma, diabetes, and heart disease.Your doctor can determine if you or your child has a cold or the flu and can recommend treatment to help with symptoms.


Many different respiratory viruses can cause the common cold, but rhinoviruses are the most common. Rhinoviruses can also trigger asthma attacks and have been linked to sinus and ear infections. Other viruses that can cause colds include respiratory syncytial virus, human parainfluenza viruses, adenovirus, common human coronaviruses, and human metapneumovirus.


The flu, which is caused by influenza viruses, also spreads and causes illness around the same time as the common cold. Because these two illnesses have similar symptoms, it can be difficult (or even impossible) to tell the difference between them based on symptoms alone. In general, flu symptoms are worse than the common cold and can include fever or feeling feverish/chills, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches and fatigue (tiredness). Flu can also have very serious complications. CDC recommends a yearly flu vaccination as the first and best way to prevent the flu. If you get the flu, antiviral drugs may be a treatment option.


A cold is a contagious upper respiratory infection that affects your nose, throat, sinuses and windpipe (trachea). You may have heard that the common cold is a coronavirus. In fact, more than 200 different types of viruses can cause a cold. The most common cold virus is the rhinovirus.


Within one to three days of picking up a cold virus, you may notice a tickle in your throat. About half of all people with colds report a tickly or sore throat as their first symptom. Other common cold symptoms you may experience during this early stage include:


Rhinoviruses cause up to 50% of common colds. There are more than 100 different rhinoviruses. But other types of viruses, such as coronaviruses, can also cause colds. More than 200 different viruses can cause a cold.


Cold viruses can live on objects for several hours. Babies often pick up objects that other babies have touched. If a baby touches something that has cold germs on it, then touches their mouth, eyes or nose, the germs can infect them.


Typically, a physical exam is enough to determine if you have a cold. You may need tests if the provider suspects you have COVID-19, the flu or another condition. The provider may give you a nasal swab test (cotton swab rubbed inside your nose) to check for these viruses. Chest X-rays can rule out other conditions, such as bronchitis or pneumonia.


The best way to prevent your baby from catching a cold is to keep them away from people who have colds. If possible, keep your baby home. A virus that causes a mild illness in an older child or an adult can cause a more serious one in an infant.


Coronaviruses are a group of viruses that can cause upper respiratory infections. While rhinoviruses cause most types of common cold, coronaviruses do cause some. Most people recover quickly from these common colds.


Coronaviruses may also travel into your lungs and lead to pneumonia and other complications that can be fatal. The novel (new) coronavirus discovered in 2019 causes a specific disease known as COVID-19. Early symptoms that make COVID-19 different from the common cold include:


It can be hard to tell whether you have a cold or the flu since many of the symptoms are the same. Both are widespread during the colder months and affect your upper respiratory system. But different viruses cause cold and flu. The flu comes from the influenza virus, while many other types of viruses cause colds.


A chest cold, or short-term (acute) bronchitis, causes irritation and a buildup of mucus in your lungs. Common colds turn into chest colds when the virus travels from your nose and throat to your lungs. Occasionally, bacteria cause chest colds. 041b061a72


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