Why can’t I take an antibiotic for my cold: A primer on viruses.

This is another article I put up on my Medium.com account.

 

As I’ve mentioned in a prior post, and is likely noted in other posts on my blog (and numerous medicine related sites), a virus is genetic material — either DNA or RNA — encapsulated in a protein coat. In some cases there is also a lipid envelope around the protein coat.

This gets to the crux of why antibiotics don’t work on viruses. Viruses need a living cell to reproduce, and does so by co opting the metabolic pathways of the host cell it invades. Normal cells use DNA to pass genetic information from one (cell) generation to the next. The DNA gets transcribed into RNA which is then taken to the cytoplasm of the cell (in eukaryotic cells) or other parts of the cell (in bacteria/non eukarotic cells), where proteins and ribosomes/ribosomal RNA read the RNA and ‘transcribe’ it into a protein.

In some cases, viruses do code for novel (relative to cells) enzymes and/or proteins. EG, reverse transcriptase in HIV viruses (HIV is a RNA based virus, but it’s genetic code is converted to DNA for replication). Other viruses replicate the RNA directly for future virus particles. However, as I note above, the vast majority of the replication is done by the cell’s own proteins.

This is why antibiotics don’t work on viruses. Bacteria have have different types of cell walls than human cells. They require chemicals that our cells just don’t use. Penicillins and cephalosporins interfere with the cell wall construction as an example. Other antibiotics target pathways our cells don’t have (eg, trimethaprim-sulfamathoxazole targets folate production in bacteria. Our cells don’t produce folate so it doesn’t affect us). There are other examples that could be used as well that utilize a chemical’s affinity for a bacterial protein/enzyme more than for the equivalent in human cells.

Having said this, there are some antiviral drugs for some (not all) viruses. These target the proteins viruses code for that are novel to the specific virus/virus family.

Now at this point, you might be thinking “well, my great aunt _namehere_ was told she had a viral pneumonia, but when she got admitted to the hospital she was given antibiotics”. In some cases, a viral infection goes through its course and the person can develop a secondary infection that’s bacterial in nature. In that case, antibiotics might be warranted. Or she was given them to prevent the superinfection/secondary infection. This is true of any viral illness, even corona viruses, rhinoviruses and covid 19.

Coronavirus biology 101

This is a post I put up in my Medium.com account.

Initially I was going to write specifically about covid19 and how to prevent getting (perhaps — or at least decreasing the chances of getting) it. I realized there are more than enough articles already about that subject and can be found on the CDC website.

Instead I decided to write more generically about Coronaviruses and doing so, hopefully address questions some people might have, and that might not be answered by posts that deal with coronovid19. First of all a virus, unlike bacteria, algae, fungi and animal cells, is just a bunch of genetic material encapsulated by protien (and in some cases, a lipid coat). They don’t have any mechanism to move, metabolize, ingest nutrients, replicate genetic material etc. Viruses are entirely dependent on infecting cells, and co-opting their metabolic pathways to reproduce. With some, there are some genes that code for things that cells — be they bacteria or eukariots — don’t have. An example would be Reverse Transcriptase in HIV viruses (Reverse Transcriptase reads RNA from the HIV genome and encodes it into DNA for use in viral replication. The virus is still dependent on the cell for the actual copying and reproduction of said genetic material and of making new viruses).

In the case of Coronaviruses, the genetic material is single stranded RNA. There are other families of RNA based viruses, such as Rhabdoviruses (EG the virus that causes rabies), Orthomyxoviruses (one such causes Measles), and others. The virus that causes HIV also uses RNA as genetic material, but by some classifications isn’t considered an RNA virus because the RNA has to be coded back into DNA for replication.

Because viruses don’t have the proteins/cell parts/etc to replicate themselves, as I note above, they’re dependent on a host cell for replication. This is why antibiotics don’t work for the common cold (or other viral illnesses. Though in some cases, such as HIV and some viruses closely related to the chicken pox virus, there are antivirals that work). As they don’t have a cell wall that’s different from our on cells’ walls, antibiotics that affect the building of the bacterial cell walls won’t work. For example, penicillin and cephalosporins interfere with an enzyme and chemical specific to what bacteria use to make cell walls. Other antibiotics interefere with enzymes and other proteins that are different enough from human cell proteins that the antibiotics don’t affect us. Others (eg, bactrim, aka trimethaprim-sulfamethoxazole) interefere with bacteria specific metabolic pathways.

Having said that, some viruses do need a particular enzyme or protein to reproduce that human (and mammalian cells in general) don’t have and do provide a target for medications. These are different than antibiotics.

As for coronaviruses, many are respiratory pathogens. In humans some coronoviruses cause the common cold. As one might expect or know, transmission can be through inhaling droplets that have active virus in them (and is why sneezing and coughing can spread the common cold, COVID-19, and so forth — the virus particles can become aerosolized). They can remain infectious on surfaces. Though the amount of time they can remain viable and therefore infectious is different for each virus and varies as well due to environmental conditions.

Anyhow, I hope this helps people understand why for viral illnesses, doctors don’t just hand out antibiotics. For COVID 19 information, use the link I have at the start of this post (it will take you to the appropriate page at the CDC).

Do Social Ties Affect Our Health? | NIH News in Health

Source:

Do social ties affect our health

This article caught my attention. In medical school we’re taught about physiology, anatomy, pathology of diseases and treatment of diseases. Yes, we do rotate through a psychiatry rotation in our third year of medical school, and in some specialties (pediatrics, for example) social aspects of health are kept in mind (some specifics probably vary from state to state, but physicians are mandated reporters for such things as child abuse and elder abue) as kids, for example, don’t raise themselves. Abuse of any kind can affect growth, development and health – especially if it involves physical abuse, starvation, etc (sexual abuse as horrific as it is, is a whole other post and not the topic of this blog post).

Some studies have indicated people who attend religious services are healthier than those who don’t. Though it has been a while since I’ve looked at the literature for this, and I think some studies make the effect to be murkier or not as solid as some might make it, these are my thoughts on it:

  1. It’s not some supernatural being, or belief in one, that makes one healthier, but the fact as someone who is involved in a community, and a purpose larger than onself.
    1. 1a) I’d add, however, that this probably includes athiests and agnostics who aren’t church/mosque/temple goers, but are involved promoting athiest ideals and in the community at large.
  2. Being part of a community might mean access to people who can help older (or otherwise impared) community members to doctors appointments, help with food, etc.
  3. Being part of a community can also help alleiviate stress levels.
  4. Married people live longer, presuming the marriage is a healthy one. Though it’s important to be part of a a community larger than 2 as well.

For more information, follow the link above.

 

Sleep, Part 2

I realize it’s been a while since my last post. As promised, I’m putting up this addtional post on sleep.

Getting adequate sleep promotes good health, and is important in functioning well during the day.  This includes driving (if you’re sleep deprived, it’s as though you’re driving with a high blood alcohol level!). Rather than totally repeat what I posted last time, I’ll  talk mostly about how to maintain good sleep hygiene.

  1. Go to sleep and wake up at the same time every day, even on weekends.
  2. Avoid sedatives (even alcohol) to go to sleep. Granted there might be occasions where using something like Zolpidem for a night or two is apropriate, but all medications can effect the sleep cycle in untoward ways (some affect how deeply one sleeps, others can affect how much REM sleep one gets).
  3. If you snore (if you live alone you might not know), or are overweight there’s a high chance of you having OSA (obstructive sleep apnea). OSA can predispose one to arrythymias, diabetes, and daytime sleepiness for starters.
  4. Don’t eat within three hours of eating (this is more to prevent reflux than food’s effect on sleeping) and avoid caffeinated beverages too late in the day.
  5. Certain foods such as cherries can affect melatonin levels (whether it is because they contain melatonin or affect it’s degredation by the body is a different story), so having foods which can increase melatonin levels might help sleep. Though my preference would be to have whole, unrefined foods rather than taking suppliments.
  6. Regular exercise can help people sleep better.
  7. As mentioned in the previous post, if you can’t fall asleep in about 10-15 minutes, get out of bed and do something else for a while
  8. Use getting into bed for sleeping (and enjoying one’s spouse/significant other), not for reading, watching TV or other activities.

 

 

Sleep

Perhaps with this topic I should suggest people read it with a dose of caffeine to prevent the induction of sleep. Apart from exercise, it’s probably the thing that people in western cultures get too little of. Getting the right amount of sleep is important. Even though eight hours is what is usually quoted as what we need every night, the reality is some people might only need seven hours and others nine.

It’s important to sleep long enough to get into REM sleep several times. REM sleep is the period of sleep where dreams occur. It isn’t totally clear why we dream but it seems to be related to consolidating memories. It may also be beneficial to mental health.

However it is not just the total amount of hours we get, but the quality that counts as well. The quality of the sleep is important as well. If someone wakes up multiple times because they have obstructive sleep apnea (OSA) they might not wake up feeling rested. OSA also predisposes to hypertension, arrhythmias, and fatigue.  If one is fatigued enough, even things like driving can be dangerous (if you haven’ slept enough and are fatigued enough, you can be driving as if you’ve had too much to drink).

Insomnia and non refreshing sleep can have many causes.  Whether it’s OSA, restless leg syndrome, depression, or other causes, treating underlying causes can often improve sleep quality without the use of medications such as Zolpidem. Getting good sleep hygiene is important to getting and remaining asleep. Going to bed the same time every night is important, even on weekends and  vacations. Waking up the same time every day is important. If you can’t fall asleep within about 10-15 minutes of getting into bed, it’s suggested that you get up and do something else for a while, like reading.  If having good sleep hygiene doesn’t help one’s insomnia, talk with your doctor to see what else can be done, and consider referral to a sleep specialist.

I realize this blog post is a bit on the short side. I will hopefully be writing another post about going into more detail about sleep, causes of insomnia, how to sleep better, etc in the near future.

Food and Health.

This won’t be an all-inclusive blog posting. To be all inclusive would require a novel, or at least novella, length blog post. People who have read earlier blog posts will know that I’m a fan of people eating healthy and not a huge fan of “fad diets”. The best healthy diet is the one you can adhere to.

As I’ve mentioned in other posts, and can be found online, diet and other lifestyle options can affect one’s chances of developing various chronic diseases. Though in this post I’ll be limiting myself to diet, and just a few things about it as well – and save other comments and suggestions for another time.

One piece of advice I can remember getting is to make sure one’s plate (ok, the food on one’s plate) is colorful as in having a lot of different colors. Granted in some cases (carrots and spinach) the colors don’t really indicate that they’re both high in the Vitamin A precursor Beta – Carotene, but both are (and have different profiles of how much of other healthy vitamins and fiber they have). Making sure that there are differently colored foods also means you’re likely to get other benefits. Both blueberries and cherries have a lot of antioxidants in them which can affect health. Though I think that we tend to look at their antioxidant effects too much at the expense of other effects they might have, such as on sugar absorption and metabolism. Never mind that blueberries and cherries also contain some fiber. There is growing evidence that blueberries can help prevent/treat type 2 diabetes. This doesn’t mean, however, that eating them replaces medications such as metformin, acarbose, rosiglitazone, and many others. Cherries may carry a similar benefit.  Tart cherries are touted to have anti-inflammatory effects and might help reduce the need for non steroidals in some people.

The fatty acids one eats can also affect health profoundly. The N-3 (also known as omega-3) fatty acids not only help protect against heart disease, but also seem to have a role in preventing depression and helping treat it as well. Though depression as an inflammatory mediated illness has gotten some press (though at the moment I don’t have a reference for that, and who hasn’t felt miserable when (s)he has a cold or the flu), it also avoids the fact that N-3 and N-6 fatty acids also get incorporated into cell walls, including nerve cells. This incorporation also affects the fluidity of the cell walls and therefore how well receptors work as well as how easily (or hard) nerve cells release neurotransmitters.

My advice, as always, is to try to avoid getting vitamins and such through supplements for a few reasons:

  1. In some cases they can do more harm than good (especially true of fat soluble vitamins). In one study, smokers that took vitamin A supplements had higher rates of lung cancer than those that didn’t.
  2. You might not be getting all the relevant forms of particular vitamins. For example, there are different forms of vitamin K, some promote clotting, others bone health.
  3. With a varied diet, one can get enough vitamins and antioxidants without supplements. You have to eat anyhow, even if you buy pills.

There are several times, however, where it might be worthwhile. For example:

  1. If you have had a gastric bypass, or a stomach resection for another reason, taking supplemental B12 is important so as to keep stores normal.
  2.  If you have a disease, or take a medication, that interferes with absorption of particular vitamins (Crohn’s and other diseases that affect the ileum can interfere with absorption of B12, anti ulcer mediations do the same.)

I’ve talked about diet before (The Pantry Prescription) so I won’t go into it today. I may do an updated version of  that post in the future.

Anyhow, here are some references to a few of the things I’ve mentioned today:

Coultrap, S. J., Bickford, P. C. & Browning, M. D. Blueberry-enriched diet ameliorates age-related declines in NMDA receptor-dependent LTP. Age (Dordr) 30, 263-272 (2008).

Ren, T., Zhu, J., Zhu, L. & Cheng, M. The Combination of Blueberry Juice and Probiotics Ameliorate Non-Alcoholic Steatohepatitis (NASH) by Affecting SREBP-1c/PNPLA-3 Pathway via PPAR-α. Nutrients 9, (2017).

Stull, A. J. Blueberries’ Impact on Insulin Resistance and Glucose Intolerance. Antioxidants (Basel) 5, (2016).

Lee, Y. M. et al. Dietary Anthocyanins against Obesity and Inflammation. Nutrients 9, (2017).

Mazaherioun, M. et al. Long Chain n-3 Fatty Acids Improve Depression Syndrome in Type 2 Diabetes Mellitus. Iran J Public Health 47, 575-583 (2018).

Masoumi, S. Z. et al. Effect of Citalopram in Combination with Omega-3 on Depression in Post-menopausal Women: A Triple Blind Randomized Controlled Trial. J Clin Diagn Res 10, QC01-QC05 (2016).

Grant, R. & Guest, J. Role of Omega-3 PUFAs in Neurobiological Health. Adv Neurobiol 12, 247-274 (2016).

Husted, K. S. & Bouzinova, E. V. The importance of n-6/n-3 fatty acids ratio in the major depressive disorder. Medicina (Kaunas) 52, 139-147 (2016).

Kobayashi, M. et al. Dietary n-3 Polyunsaturated Fatty Acids in Late Pregnancy and Postpartum Depressive Symptom among Japanese Women. Front Psychiatry 8, 241 (2017).

Levant, B. & Healy-Stoffel, M. N-3 (Omega-3) Fatty Acids: Effects on Brain Dopamine Systems and Potential Role in the Etiology and Treatment of Neuropsychiatric Disorders. CNS Neurol Disord Drug Targets (2018).

Pusceddu, M. M., Kelly, P., Stanton, C., Cryan, J. F. & Dinan, T. G. N-3 Polyunsaturated Fatty Acids through the Lifespan: Implication for Psychopathology. Int J Neuropsychopharmacol 19, (2016).

 

Let the Sunshine In.

With spring temperatures climbing higher, and with summer around the corner, I figure this is a good time to remind people about sun exposure, and using sunscreen. Too much sun exposure – or the use of tanning booths – is a risk factor for melanoma (one of the deadliest cancers) and of squamous cell carcinoma. This is especially true when one gets a sunburn. I forget where I read this statistic, but a sunburn doubles one’s risk of skin cancer (though before getting too panicky, it could mean going from a  1% chance to a 2% chance. Or 5% to 10%. I don’t want to quote exact numbers since I don’t have them handy and it probably also depends on how easily one gets a sunburn, location, skin tones, etc). This increase in risk is why I think doctors tend to encourage taking vitamin D supplements rather than suggesting sun exposure to get enough vitamin D.

However there are other reasons for getting some sunlight as one uses precautions to prevent sun burns:

  1. There might be other benefits to getting sun beyond its effects on vitamin D levels. Believe it or not it might help with blood pressure!! I’ll put a link at the end of this post.
  2. It might have effects on preventing other diseases as well, though it might be due to improved vitamin D levels and not some other effect light has on health.
  3. Getting outside and exercising can improve health (though any exercise, even if done indoors, such as exercising in a gym works too).

However to reduce the risk of skin cancer, there are several things one can do to minimize the risk:

  • Use Sunscreen, at least SPF 15. And reapply if you’ve gone swimming, sweated a lot or if it’s been a few hours since you last applied sunscreen.
  •  Use wide brimmed hats as much as possible. Baseball caps don’t cover your necks or the back of your neck.
  • Get sun early in the day, or later in the afternoon. In other words, don’t go out to get sun when the sunlight is at it’s strongest.
  • Remember, even if you’re only in the sun for 15 minutes, you can get sun damage so sunscreen is important even if you’ll be in the sun for short periods
  • wear long sleeves and long pants if possible.

 

Anyhow, Here is the link, and a couple of references for those who want to dig deeper into this topic.

Could the sun be good for your heart?

references:

Fernandes, M. R., & Barreto, W. D. R. (2017). Association between physical activity and vitamin D: A narrative literature review. Rev Assoc Med Bras (1992), 63(6), 550-556. doi:10.1590/1806-9282.63.06.550
Fleury, N., Geldenhuys, S., & Gorman, S. (2016). Sun Exposure and Its Effects on Human Health: Mechanisms through Which Sun Exposure Could Reduce the Risk of Developing Obesity and Cardiometabolic Dysfunction. Int J Environ Res Public Health, 13(10). doi:10.3390/ijerph13100999
Hoel, D. G., Berwick, M., de Gruijl, F. R., & Holick, M. F. (2016). The risks and benefits of sun exposure 2016. Dermatoendocrinol, 8(1), e1248325. doi:10.1080/19381980.2016.1248325
Langer-Gould, A., Lucas, R., Xiang, A. H., Chen, L. H., Wu, J., Gonzalez, E., . . . Barcellos, L. F. (2018). MS Sunshine Study: Sun Exposure But Not Vitamin D Is Associated with Multiple Sclerosis Risk in Blacks and Hispanics. Nutrients, 10(3). doi:10.3390/nu10030268
Rivas, M., Rojas, E., Araya, M. C., & Calaf, G. M. (2015). Ultraviolet light exposure, skin cancer risk and vitamin D production. Oncol Lett, 10(4), 2259-2264. doi:10.3892/ol.2015.3519
Santos Araújo, E. P. D., Queiroz, D. J. M., Neves, J. P. R., Lacerda, L. M., Gonçalves, M. D. C. R., & Carvalho, A. T. (2017). Prevalence of hypovitaminosis D and associated factors in adolescent students of a capital of northeastern Brazil. Nutr Hosp, 34(5), 1416-1423. doi:10.20960/nh.1097
Weller, R. B. (2016). Sunlight Has Cardiovascular Benefits Independently of Vitamin D. Blood Purif, 41(1-3), 130-134. doi:10.1159/000441266