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covid19: corticosteroids, male susceptibility, evaluating health, remdesivir, coagulation factors

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from The Lancet, ‘the four horsemen of a viral apocalpse’

 

Canto: So short-course use of some steroids was being advocated in the medcram update 88, though without thorough RCT evidence. 

Jacinta: Well, data was presented from the Oxford RCT on those on oxygen or on ventilators showing a statistically significant reduction of mortality from short-course (up to 10 days) low dosage of dexamethasone, a freely-available steroid medication. The study involved some 2000 patients, but only those severely afflicted were helped by the medication. 

Canto: An interesting aside to the data is that in the study males outnumbered females by almost 2 to 1, and that accords with the overall ratio of male to female covid19 patients Dr Seheult is finding, which rather shocked me. Why would more males be coming down with the disease? Presumably that’s not the infection rate, but the rate at which they need to be hospitalised. 

Jacinta: Yes, you’re right, according to this Australian site (unfortunately undated):

Reports continue to emerge that men are significantly more vulnerable to COVID-19 than women. The commonly held perception that more men smoke and this makes them more susceptible along with other lifestyle factors does not tell the whole picture. White House COVID-19 Task Force director Dr Deborah Birx highlighted a “concerning trend” that men in all age brackets were becoming seriously ill from the virus at a higher rate than women, including younger males.

They’re suggesting more research needs to be done on this gender difference, for health issues in general. Some are claiming that estrogen makes a difference. In any case I think cardiovascular problems are more common in males – but maybe not so much in younger males. 

Canto: So update 89 is fairly short, and deals with US data about cases and deaths, most of it out of date now, and more on corticosteroids and the dangers of unsupervised use. Update 90 introduces us to a tool I’ve never heard of called ‘Discern’. Very useful for we autodidacts in helping us, for example, to enlighten our doctors as to our condition. Discern is a tool for evaluating internet health info, such as medcram’s updates on youtube, or anything else on youtube. The instrument asks you to evaluate the material according to 16 different criteria. Interestingly, this tool has been tested on covid19 material by a study out of Poland done in March. The results weren’t so good, especially for news channels. 

Jacinta: Yes, physicians’ information did best – but of course we don’t go to news channels for health information, and we’d advise against anyone else doing so. The study evaluated the Discern tool itself and found it excellent, then used the tool to evaluate health information, specifically on youtube. Of course know that there’s ‘viral misinformation’ from various news outlets that gets posted on youtube. And good to see that the medcram updates were some of the most highly rated using the Discern tool. 

Canto: So we’re now into reporting from early July with update 91. It starts by looking at a ‘covid risk calculator’ in which you can type in your age, gender, BMI, underlying conditions, waist circumference, and other data which you might need a full medical checkup to find out about (and that’s overdue for me), including, for example, %FMD, a measure I’ve never heard of, but which has to do with endothelial function. 

Jacinta: FMD stands for fibromuscular dysplasia. The Johns Hopkins medicine site describes it as a rare blood vessel disease in which the cells of some arteries become more stiff and fibrous and less flexible. This leads to weakness and damage. Not sure how it relates to covid19 but surely any pre-existing blood vessel damage is a danger for those contracting the virus. 

Canto: Right, so it’s unlikely anyone will know offhand their percentage of FMD. I don’t even know my HDL and LDL levels, never mind my HbA1c or lipids. I’d love to be able to take measures of all these myself, without visiting a doctor.

Jacinta: Typical male control freak. So all of this is to measure your risk of covid19 hospitalisation, ICU admission or mortality. Fun times. So next the update looks at Gilead, the makers of the antiviral remdesivir, who donated all their supplies of the drug to the USA in early May. But of course they kept manufacturing the drug and have to recoup the money they spent researching, developing and trialling it etc. The Wall Street Journal reports that a typical course of the drug will cost over $3000 per patient. Interestingly the Trump administration is wanting the drug to stay in the USA as much as possible, rather than be available overseas, and is spending money to that effect. 

Canto: Hmm. Is that protectionism? 

Jacinta: Yes I suppose. It’s not surprising that a country wants to look after its own first, especially via a product produced within its own borders. But I suspect this government would’t be interested in helping any other country – unless there was a quid pro quo. And there’s another antiviral, favipiravir, currently being trialled in Japan and the USA (I mean as of early July), and a vaccine, developed in China, is being used on the Chinese military in what seems a rather rushed and somewhat secretive fashion – we don’t know if they got the soldiers’ permission on this seemingly untried vaccine. At least at the phase 3 level.

Canto: Very CCP. 

Jacinta: So onto update 92, and we revisit the electron transport chain, with four successive electron transfers converting molecular oxygen into water. Problems within this chain can produce reactive oxygen species (ROS) such as superoxide, hydrogen peroxide and hydroxy radicals, which are destructive in excess. We also look, yet again, at covid19’s impact on angiotensin and particularly the production of superoxide, which in turn causes endothelial dysfunction, increased von Willebrand factor activity, which leads to thrombosis. People were presenting as ‘happy hypoxics’, looking and feeling fine but with very low oxygen levels, and autopsies revealed ‘microthrombi in the interalveolar septa’ of victims’ lungs. All this leading to a paper published in The Lancet which looked at factors in this process of coagulation and thrombosis:

We assessed markers of endothelial cell and platelet activation, including VWF antigen, soluble thrombomodulin [a marker of endothelial cell activation], soluble P-selectin [a marker of endothelial cell and platelet activation], and soluble CD40 ligand [a marker of platelet and T-cell activation], as well as coagulation factors, endogenous anticoagulants, and fibrinolytic enzymes.

So this was about getting to the bottom of the increased clotting. And the results were hardly surprising, but the final discussion section is worth quoting at length, as it seems to capture much that we know about covid19’s effects (at least short-term effects) at the moment: 

We therefore propose that COVID-19-associated coagulopathy is an endotheliopathy that results in augmented VWF release, platelet activation, and hypercoagulability, leading to the clinical prothrombotic manifestations of COVID-19-associated coagulopathy, which can include venous, arterial, and microvascular thrombosis. The factors responsible for this endotheliopathy and platelet activation are uncertain but could include direct viral infection of endothelial cells, collateral damage to the tissue as a result of immune infiltration and activation, complement activation, or any number of inflammatory cytokines believed to play a role in COVID-19 disease.

They suggest anti-platelet therapy and endothelial cell modification treatments as well as anticoagulation treatments, and they suggest some agents ‘which might have therapeutic potential’.

Canto: Potential? You’d think they’d be onto all this by now. 

Jacinta: Well there’s also potential for untried medications – at least untried in this context – to go terribly wrong. And it’s also likely that some hospitals are already onto using the safer forms of treatment. Dr Seheult speaks of the antioxidant N-acetylcysteine (NAC) in this context, as it has been shown to be a thrombolytic when used intravenously. There are studies pending on the effects of NAC in treating covid19 patients. 

Canto: Now, I’ve just been watching something on monoclonal antibodies as perhaps the most promising treatment yet, short of a vaccine. Can you explain….

Jacinta: Yes I’ll try, maybe next time.

References

Coronavirus Pandemic Update 88: Dexamethasone History & Mortality Benefit Data Released From UK

Coronavirus Pandemic Update 89: COVID 19 Infections Rising in Many States; Dexamethasone Cautions

Coronavirus Pandemic Update 90: Assess The Quality of COVID-19 Info With A Validated Research Tool

Coronavirus Pandemic Update 91: Remdesivir Pricing & Disparities in Drug Availability

Coronavirus Pandemic Update 92: Blood Clots & COVID-19 – New Research & Potential Role of NAC

amhf.org.au/covid_19

http://www.discern.org.uk

https://www.thelancet.com/journals/lanhae/article/PIIS2352-3026(20)30216-7/fulltext

 

covid-19 stuff: NAC, glutathione, RT-PCR testing, re-positives

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So, more struggles with biochemistry. Update 70 talks again about N-acetylcysteine (NAC), but goes on to talk about glutathione, and whether glutathione itself might be a type of medication. So let’s get clear, or try to.

Glutathione is a naturally occurring and abundant thiol polypeptide in animal cells. A thiol has an SH (sulfanyl) group attached to a hydrocarbon chain, essentially. As we know, it’s an antioxidant which can be reduced by NAC, and they have structural relations. As Dr Seheult describes glutathione, it’s a combination of three amino acids, with cysteine at the centre. The other two are glycine and glutamate, and the cysteine and the glycine together effectively make up N-acetylcysteine – so NAC is described as a by-product or precursor of glutathione. A case report (regarded as the weakest level of scientific evidence) describes efficacious treatment of two patients with Covid-19-type symptoms using IV and oral glutathione. This and other studies and analyses seem to be begging for full-scale clinical trials to be carried out, but nothing as of mid-May. The treatments could be effective for hypoxemia in particular, due to the action on the disulphide bonds in VWF which are leading to platelet-rich thrombosis.

In his update 71 Seheult broaches the controversial topic of hydroxychloroquine, along with azithromycin and zinc. He suggests there’s evidence that hydroxychloroquine can act as a ‘zinc ionophore’, inducing zinc uptake into cells. Zinc inhibits the RNA-dependent RNA polymerase which SARS-CoV-2 utilises to reproduce. There has been a retrospective study suggesting that treatment with this combination may ‘result in a statistically significant reduction of mortality’, though maybe this hasn’t borne more careful analysis considering the cold water being poured on chloroquine as a treatment in recent months. It may be because it just doesn’t raise zinc levels sufficiently. The findings of the study do suggest the treatment has a statistically significant effect on reducing symptoms in hospitalised patients who are not in ICU – that is, they have relatively mild symptoms. No significant effect for ICU patients.

I should add here that now in August health authorities are warning against any unprescribed use of hydroxychloroquine as a prophylactic due to ineffectiveness and side-effects.

Update 72 began by looking at the sensitivity and specificity of antibody tests available, presumably in the USA. A study examined ‘four new commercially available serological assays [i.e blood serum tests]’, from three German and one US company, and it was found that they all ‘have a sufficient sensitivity and specificity for identifying individuals with past SARS-CoV2 infection’. Of course, the principal issue with the testing is the time it takes to receive results, but maybe that’ll be addressed anon.

Apparently (news to me in very safe – so far – South Australia where hardly anyone I know has had to be tested) there’s a difference between sensitivity and specificity, illustrated by the ‘spin’ and ‘snout’ mnemonic. For a highly specific test if you test positive you’re very sure to be in trouble, and for a highly sensitive test if you test negative you’re sure to be out of danger.

Dr Seheult next describes a retrospective study which looks at glycosylated haemoglobin (HbA1c) as a Covid-19 risk factor. A person’s HbA1c levels (how much glucose is attached to their haemoglobin) are a measure of diabetes. A1c (blood sugar level) is measured in percentages, with 5-6% being normal. The study found that ‘high HbA1c levels is associated with inflammation, hypercoagulability and low SaO2 [oxygen saturation] in Covid-19 patients, and the mortality rate (27.7%) is higher in patients with diabetes’. So HbA1c levels need to be looked at as a priority.

The update next looks at dentistry during the pandemic, for which there’s been little guidance, at least from the CDC. Apparently, during the AIDS crisis, dentists were viewed as modes of transmission, partly due to a NYT article on the subject. In any case, fewer people are now seeing their dentists for obvious reasons, which could lead to an oral health crisis. A number of diseases, including coronary disease, are linked to periodontal problems, so this can exacerbate the pandemic – and dental health, in Australia as in the USA, is not treated with the same gravitas as other forms of health.

Update 73 starts with a look at testing, particularly the reverse transcriptase polymerase chain reaction (RT-PCR) test. So the coronavirus has these spike proteins protruding from a bilipid membrane, with the RNA wrapped inside bound together by disulphide bonds and the like, I think. The protein shell around the virus is called the nucleocapsid. Of course the RNA’s code is specific to SARS-CoV2, so a test needs to look at a segment of the viral RNA and identify it with sufficient – essentially total – specificity. RNA is made up of the four base pairs adenine (A), uracil (U), guanine (G) and cytosine (C), with A pairing always with U and G with C. With that I’m going to switch to Scientific American for more detail.

A test starts with a sterile swab from the back of the nasal passage, aka a sample. Sample collection needs to be done properly, or it could lead to a false-negative result. If there’s viral RNA present, it’s extracted and used to produce a complementary strand of DNA – that’s where the reverse transcriptase enzyme comes in, reversing the usual transcription process from DNA to RNA. This material is then amplified – thousands of copies are made – to ensure a measurable result. The different available test kits generally vary in the segment of genetic material chosen.

I’m hearing that there are serious delays, in the USA at least, in delivering test results. This is extraordinary as, according to the Scientific American article, which is dated late March,

the FDA recently began granting emergency use authorization (EUA) to rapid diagnostic PCR tests that manufacturers say can deliver results in less than an hour. The authorization allows medical devices that have not yet been approved by the agency to be used during public health emergencies. 

What’s happening? According to very recent article from Quartz magazine, the problem is that there are too many kinds of tests. The EUA system was utilised, partly because of the urgency, partly because of the disastrous problem caused by the use of faulty reagents by the CDC back in February. Now there are about 150 tests that have been given EUA approval. Testing delays at first resulted mainly from lack of general lab equipment and PPR for the testers, but increasingly there are problems due to different types of tests, the variability of the tests, knowing which test to use, having the right equipment for each test, the prioritising of certain groups, such as front-line health workers, over others, confirmation of test results by other labs, and of course the overload in demand. We’re talking about the USA here, of course, and it just seems another case of lack of centralised control and uniformity in a state with a failed federal government.

Returning to update 73, Seheult describes a situation in which a SARS-Cov2-infected individual’s immune system has broken down the virus into ineffectual strands of RNA, proteins and other particles. It’s possible that a RT-PCR test could pick up on an RNA fragment, and produce a positive test result in these apparently recovered patients, and in fact this has often occurred. This is called a re-positive. The update describes a study by the South Korean CDC which provides valuable evidence on these re-positive cases. Some 280 re-positive subjects were studied, and about half of them displayed Covid-19 symptoms (on average 14 days after ‘recovery’). Presumably this re-positive finding was after they’d tested negative, i.e they’d first tested positive, then negative, then later positive again, though this isn’t clear. In any case, they checked a percentage of the subjects for antibodies and the result was almost entirely positive. They checked a larger sample for viral particles and found ‘not a single whole viral particle’, according to Dr Seheult, by which I presume he means anything that was replicable or active. They also looked at close contacts of the subjects, in large numbers, and all of them tested negative. So the finding was that these re-positives were, it seemed, the results of ultra-sensitive testing that was picking up viral RNA fragments that were in effect innocuous. This would seem to be a lesson for developing the right types of test. Hopefully a lesson learned.

References

Coronavirus Pandemic Update 70: Glutathione Deficiency, Oxidative Stress, and COVID 19

Coronavirus Pandemic Update 71: New Data on Adding Zinc to Hydroxychloroquine + Azithromycin

Coronavirus Pandemic Update 72: Dentists; Diabetes; Sensitivity of COVID-19 Antibody Tests

Coronavirus Pandemic Update 73: Relapse, Reinfections, & Re-Positives – The Likely Explanation

https://www.scientificamerican.com/article/heres-how-coronavirus-tests-work-and-who-offers-them/

https://qz.com/1886940/why-covid-19-test-results-take-so-long/

Written by stewart henderson

August 5, 2020 at 2:34 pm