The Stages of Sleep

Sleep begins with NREM sleep, progressing through the three basic NREM sleep stages, sleep stages 1 and 2 and slow wave sleep. NREM sleep is then followed by a relatively short REM sleep episode. The time between falling asleep and the end of the REM episode constitutes a sleep cycle.

NREM Sleep

Stage 1
Sleep is very light sleep and it occurs during transitions from awake to asleep. Your muscle tone begins to decrease during this stage but slow eye movement continues. Most people don’t even notice that they’re sleeping at this point.

Stage 2 
During this stage of sleep, eye movements stop, and brain waves slow—with intermittent rapid wave bursts called “sleep spindles”. Most people when woken-up from stage 2 sleep realize that they were sleeping. If you’ve ever woken someone up during this stage, you probably noticed that the person slowly opened their eyes, looked around confusedly, and then went back to sleep.

Stages 3 and 4 (slow-wave sleep) 
In these stages brain waves slow further to a pattern called “delta waves” mixed with occasional spurts of faster waves. Heart rate and body temperature continue to drop, along with blood pressure and muscle tone. Eye movements remain absent. This is the deepest most restorative stage of sleep. If your alarm clock goes off during slow-wave sleep, you may feel confused and groggy for several minutes after waking up.

REM Sleep

This is when you do most of your dreaming, and is a time when your brain is actively encoding lessons that you learned and memories that you made throughout the day. Some people have called this type of sleep “paradoxical sleep” because it involves relatively fast brain activity and irregular heart rate and blood pressure, as well as characteristic rapid eye movements. During REM sleep your limbs are temporarily paralyzed, perhaps to keep your body from acting out action packed dreams.

Your sleep progresses through these cycles of NREM and REM sleep about every 90 minutes. Your brain engages in most slow wave sleep earlier in the night, which will ensure you get enough of this most restorative sleep state even if you cut your night short by an early morning meeting. If this happens to be the case, just remember that you can always catch up on sleep with a short nap during the day!

- StanfordOnline SOM, Staying Fit

How safe is the Pfizer vaccine and how was it done so quickly?

The article was originally posted on Malaysiakini, with subscription-based to the full access. I have taken some points that I concern most.

Who or what are Pfizer and BioNTech - Pfizer is an American pharmaceutical giant and BioNTech is a German biotechnology company. The duo collaborated to develop a Covid-19 vaccine that uses messenger RNA (mRNA or messenger ribonucleic acid). In November last year, they announced that their vaccine candidate had 95 percent efficacy in a Phase III trial and subsequently published their findings in the New England Journal of Medicine. Officially, the vaccine is known as 'BNT162b2'.

How does the vaccine work - The basis of the Pfizer-BioNTech vaccine is its mRNA. Simply put, many vaccines introduce a virus into the system to generate antibodies but this vaccine contains genetic instructions which make the body mount an immune response without the introduction of the virus.

How is this vaccine administered - By injection of one dose to the upper arm, followed by a second dose 21 days later.

How safe is the vaccine - This is out of 43,252 participants enrolled in the trial, about half who were assigned to receive the vaccine while the other half received the dummy treatment. Milder reactions typical for a working vaccine are more common, since they are designed to provoke an immune response. These include fatigue, headache, muscle pain, chills, joint pain and fever. Such reactions are more common among younger people, especially after the second dose. In most cases, these reactions dissipated in a couple of days. Following the vaccine rollout in the UK and the US, however, there had been reports that some vaccine recipients also suffered severe allergic reactions. For the record, VAERS is a publicly accessible database where US patients and clinicians can report adverse events that occur after vaccination.

Malaysia's National Pharmaceutical Regulatory Agency (NPRA) has a similar system in place and publishes annual reports on the complaints it receives. The government also plans to use the MySejahtera app to collect reports on adverse reactions suspected to be linked to Covid-19 vaccines.

How effective is this vaccine? - The Pfizer-BioNTech clinical trial reported an efficacy rate of 52 percent after the first dose and 95 percent after the second dose. The benefits begin to become apparent about 14 days after the first dose.

How was it developed so quickly?

This boils down to reduced red tape, increased funding, and an ample supply volunteers signing up for vaccine trials. All these factors come together to ensure researchers can spend more time working and less time waiting.

Health systems specialist Dr Khor SK explained that much of the 10-year timeline for developing a typical vaccine is spent waiting for funding to come through and waiting for various committees to meet and grant the necessary approvals, rather than conducting research.

In contrast, governments and philanthropies have channelled more money into Covid-19 vaccine research than any other branch of science in 2020. Scientists were also able to build on previous research on vaccines and older coronaviruses, and there was a much greater degree of data sharing and competition to create the Covid-19 vaccine than other vaccines.

In addition, researchers at Pfizer, Moderna, and AstraZeneca were each able to recruit tens of thousands of volunteers for their respective clinical trials. Khor said such large numbers usually take two to five years to recruit, but finding volunteers in the middle of the Covid-19 pandemic was much easier. “This vaccine is a triumph of science. After NPRA approvals, we should be confident in its safety.

 Why are children excluded from receiving the Covid-19 vaccine - The current crop of Covid-19 vaccines have yet to be tested on children under the age of 12, or in some cases, the tests are still ongoing and have yet to yield any results. In the case of the Pfizer vaccine, for example, the youngest participants are 16 years old. The government aims to vaccinate at least 70 percent of Malaysia’s population to achieve herd immunity against Covid-19.

 Is it compulsory - No. Science, Technology and Innovation Minister Khairy Jamaluddin said Covid-19 vaccination will be voluntary. The vaccines will be made available for free to any Malaysian who wants it. Khairy Jamaluddin said the government is also considering whether to provide free vaccination for migrant workers, to help achieve the herd immunity target. 

Who will get the vaccines first - Khairy, who co-chairs the committee, said frontliners such as Health Ministry staff, police, armed forces, Immigration Department personnel and others will be among the first. Older folk and those with chronic diseases will also sit higher on the priority list as they are more susceptible to the worst effects of Covid-19 including a higher mortality rate. Those interested in the vaccine will be able to register their interest through the MySejahtera app and also use the app to monitor any side effects that may arise.

This instalment of KiniGuide was compiled by FAISAL ASYRAF.
URL: https://www.malaysiakini.com/news/558083

霍乱与公共卫生

霍乱与工业革命如影随形：工业化和城市化进展使得城市疯狂膨胀——1860年的伦敦是全世界最大的城市，人口达到320万。由于人们生活在骇人听闻的不卫生条件下，这也导致了同样巨大的健康风险。霍乱爆发时，伦敦城里有20万座私人化粪池；废物和垃圾填满沟渠，散落小巷。但工业革命也在改造科学，尤其是医学，传统智慧在逐渐让位于实证调查。

当时的人们相信，患上霍乱是因为吸入了瘴气（受污染的空气）。医生用阿片类药物和浸出液来治疗患者。虽然几百年来的证据都表明放血治疗毫无用处甚至有害，但给患者放血对抗感染，仍是一种被广为接受的处置措施。使用阿片类药物至少能缓解痛苦。

一位名不见经传的医生约翰·斯诺（John Snow）私下认为霍乱是通过水而非空气传播的。1854年8月31日，伦敦苏活区爆发霍乱，让斯诺找到了证明自己理论的机会。不到10天，该地区就死了500人，幸存者纷纷逃离。但斯诺没有逃跑。相反，他去受害者的家里拜访，询问家人，倒推患者染病的步骤，并在街区地图上绘制出死亡情况。他很快意识到，几乎所有的受害者都存在一个共同点：他们住得很近，都是从宽街上的水泵取水的。他亲自去水泵抽了水，放到显微镜下检查，发现了他所谓的“白色絮状颗粒”。他正确地推断出，这些颗粒就是霍乱的根源。

虽然他的理论有违公认智慧，但斯诺还是设法说服了心存疑虑的市政官员，取下了宽街水泵的把手，迫使居民们去别处寻找水源。疫情立即结束。尽管还要过好些年，那些保守人士才愿意接受斯诺的结论，但斯诺观察所得的不容否定的真相，促使规划人员开始着手设计第一套现代城市污水系统。1870年，伦敦地下污水渠开始兴建，它建造得非常好，至今仍维持着良好的运转。

虽然这一努力并未得到大力的宣扬，但不可否认，约翰·斯诺对人类福祉做出了非凡的贡献：在这一领域，他被称为“流行病学之父”。他推动了人们对疾病的整体认识，并提升了公共卫生之于政府的重要性。尽管当时霍乱还在欧洲其他地区肆虐，但它从伦敦消失了，欧洲其他地方也注意到了伦敦的特别之处。没过多久，在每一个发达国家，城市规划人员和政治家都把保护供水放到了最为关键的地位。医学同样向前跃进了一大步，特别是在麻醉剂和消毒剂领域。婴儿死亡率急剧下降，人的预期寿命得到提升，不过，生育率仍然很高。1750年，遭受黑死病袭击期间，英格兰和威尔士的人口不到600万。到1851年，两地人口已接近1800万；到1900年，这个数字达到3300万。人类作为一个种族在生存竞争中遥遥领先。

--- 达雷尔布里克(Darrell Bricker) & 约翰伊比特森(John Ibbitson)，

《空荡荡的地球，全球人口下降的冲击》(Empty Planet)，机械工业出版社，2019。

A List of Medical Specialists and What They Do

Allergist or Immunologist - conducts the diagnosis and treatment of allergic conditions.Anesthesiologist - treats chronic pain syndromes; administers anesthesia and monitors the patient during surgery.

Cardiologist - treats heart disease

Dermatologist -treats skin diseases, including some skin cancers

Gastroenterologist - treats stomach disorders

Hematologist/Oncologist - treats diseases of the blood and blood-forming tissues (oncology including cancer and other tumors)

Internal Medicine Physician - treats diseases and disorders of internal structures of the body.

Nephrologist - treats kidney diseases.

Neurologist - treats diseases and disorders of the nervous system.

Neurosurgeon - conducts surgery of the nervous system.

Obstetrician - treats women during pregnancy and childbirth

Gynecologist - treats diseases of the female reproductive system and genital tract.

Nurse-Midwifery - manages a woman's health care, especially during pregnancy, delivery, and the postpartum period.

Occupational Medicine Physician - diagnoses and treats work-related disease or injury.

Ophthalmologist - treats eye defects, injuries, and diseases.

Oral and Maxillofacial Surgeon - surgically treats diseases, injuries, and defects of the hard and soft tissues of the face, mouth, and jaws.

Orthopaedic Surgeon - preserves and restores the function of the musculoskeletal system.

Otolaryngologist (Head and Neck Surgeon) - treats diseases of the ear, nose, and throat,and some diseases of the head and neck, including facial plastic surgery.

Pathologist - diagnoses and treats the study of the changes in body tissues and organs which cause or are caused by disease

Pediatrician - treats infants, toddlers, children and teenagers.

Plastic Surgeon - restores, reconstructs, corrects or improves in the shape and appearance of damaged body structures, especially the face.

Podiatrist - provides medical and surgical treatment of the foot.

Psychiatrist - treats patients with mental and emotional disorders.

Pulmonary Medicine Physician - diagnoses and treats lung disorders.

Radiation Onconlogist - diagnoses and treats disorders with the use of diagnostic imaging, including X-rays, sound waves, radioactive substances, and magnetic fields.

Diagnostic Radiologist - diagnoses and medically treats diseases and disorders of internal structures of the body.

Rheumatologist - treats rheumatic diseases, or conditions characterized by inflammation, soreness and stiffness of muscles, and pain in joints and associated structures

Urologist - diagnoses and treats the male and female urinary tract and the male reproductive system

from http://www.jmu.edu/esol/specialist_list.htm