Health Newsletter:September 2003
Related Links:| Leptin Levels Lung Disease Heart Disease | SARS Respiratory Infections Influenza | Asthma Allergies Lung Disease | Stillbirth Miscarriage Pregnancy | West Nile Virus Yellow Fever Flu Vaccine |
From WebHealth
Contents |
Poor Lungs And Heart Attacks Related To Leptin Levels
It is known from the medical literature that poor lung function can often lead to heart attacks making it one of the important causes of premature death for patients with poor lungs (due to emphysema, chronic bronchitis, COPD etc.).
A research team led by Dr. Don Sin from the University of Alberta, Edmonton, Canada, asked the question recently whether there may be a circulating factor that would be responsible for this association of poor lung function and increased cardiovascular disease.
They studied serum leptin and a variety of other inflammatory markers such as C reactive protein, leukocytes, and fibrinogen in 2808 participants in the Third National Health, Nutrition, and Examination Survey. Apart from blood tests they also measured lung function by spirometry (forced expiratory volume in 1 second, called FEV1). The leptin levels found in these patients were then divided into 5 groups from low to high levels. They also carefully adjusted the data for body mass index, sex, age and other factors. They compared the group with the lowest leptin concentration (lowest quintile) with the highest group of leptin concentration (highest quintile) and looked for any significant differences in any of the markers.
Results
The highest quintile group (high leptin in blood samples) had also the highest other inflammatory markers in their blood (C-reactive protein, leukocytes and fibrinogen). This group was the one that was associated with advanced lung diseases as well as heart disease. The authors of this study, which was recently published in a medical journal (Thorax 2003;58:695-698), concluded that leptin plays an important role, if not the major role, in the development of both chronic lung disease and cardiovascular complications.
Links to lung disease: Lung Disease Links to heart attacks: Heart Disease
SARS Due To SARS-Associated Coronavirus (SARS-CoV)
A comprehensive paper was recently published online July 22, 2003 (Lancet 2003; 362: 263-70) regarding the causative microorganism of SARS.
Several investigators have collaborated in this study from viral laboratories of Rotterdam/The Netherlands, Hong Kong Special Administrative Region/China , Singapore, London/UK, Hamburg/Germany, Paris/France and Geneva/Switzerland.
This study involved isolation of the SARS-associated coronavirus (SARS-CoV) from SARS patients who died from the disease, propagation of the virus in an experimental animal model (cynomolgus macaques) and causing SARS again with an injection of the isolated virus back into a healthy experimental animal.
This, according to the authors (Dr. Thijs Kuiken et al.), fulfils the Koch's postulates, which is one of the fundamental laws in microbiology that has to be fulfilled in order to claim a new infective organism. Dr. Robert Koch was a German physician who had detected the causative organisms of anthrax, tuberculosis and cholera and won the Nobel price for physiology and medicine in 1905. He developed the four original Koch's postulates that were subsequently modified to a total of six. Here is a run down of the postulates and how it relates to SARS:
1. The specific organism should be present in all cases of animals suffering from a specific disease, but should not be found in healthy animals.
For SARS this was fulfilled as this study, which was based on a thorough analysis of 436 patients in six countries, showed. 75% of the suspected cases were found in postmortem studies to contain the SARS-associated coronavirus (SARS-CoV). In some patients other infectious agents could also be isolated, but the primary causative agent was SARS-CoV.
2. The specific organism should be isolated from a diseased animal and grown in pure culture on artificial laboratory media.
Using an experimental animal model, the virus was able to be isolated from a diseased person and injected into a healthy animal that turned sick with SARS. From this animal the virus could be isolated again from cells of the infected airways and grown in tissue culture.
3. This freshly isolated microorganism, when inoculated into a healthy laboratory animal, should cause the same disease as in the original animal.
As already explained under point 2 above, this has been shown with SARS.
4. The microorganism should be able to be isolated again in pure culture from the experimental infection.
This was proven in this paper regarding SARS. It was even done with genetic markers that were still present after passage from postmortem human tissue into an experimental animal and from the final respiratory tissue isolate of this newly infected animal.
5. The infective agent can be filtered and the filtrate contains the infective agent.
This was proven for SARS and the exact classification of the virus was possible because of the advanced genetic knowledge that is now available.
6. When the virus enters the body or the experimental animal, there are signs of the immune system attempting to rid the body of the infectious organism.
Sophisticated immune tests were performed that showed in more than one way that the immune system attempted to rid the body of SARS, but was eventually overwhelmed in the cases that did not survive.
Summary
This paper has conclusively proven that SARS is caused by a new type of coronavirus, SARS-associated coronavirus (SARS-CoV). In about 12% of cases there was another virus type present, such as human metapneumovirus. This occasionally was also present in lethal SARS cases as a secondary virus. Some other flu-type viruses were also found in the non-SARS cases. However, this paper has shown that SARS-associated coronavirus (SARS-CoV) is what causes SARS.
Link to SARS chapter of WebHealth: Respiratory Infections
Asthma And Wheezing Influenced By Family Lifestyle (Swedish Study)
A new study from Sweden was published by Dr. Magnus Wickman and colleagues,from the Karolinska Hospital in Stockholm, in the medical journal Allergy 2003;58:730-731,742-747. The authors of this study were analyzing data of a prospective birth cohort study of 4089 children who were born in Sweden between 1994 and 1996.
The families were given health questionaires at the age of 2 months to assess whether the family was adhering to the allergy prevention guidelines (see below). Questionaires were again given at the age of 1 year and 2 years of these children. Specific questions were asked regarding environmental conditions in the house where the children lived. In the mid 1990's allergy prevention guidelines were strongly recommended to the public in Sweden regarding the value of breast feeding, the avoidance of smoking inside the house in the presence of children, also that a house should be kept well ventilated and without dampness. All of these factors, as was stressed by the allergists in Sweden who organized the campaign, would protect the immune system from allergies against molds, dust mites as well as cigarette smoke and should reduce the rates of asthma. Here are the results in tabular form.
| Swedish family lifestyle study | ||
| Agreement with allergy guidelines: | % of asthma and wheezing at ages 1 and 2 of child: | |
| 1 year | 2 years | |
| Yes (all three measures followed) | 6.8% | 12.6% |
| No (one or none of measures followed) | 17.9% | 24.1% |
As can be seen from this table, which is based on families without allergic parents, a two-fold drop of asthma and wheezing occured when the allergy prevention guidelines were followed in the house. With allergic parents the children had an even greater benefit as the reduction of asthma and wheezing was three-fold when compared to controls who did not follow the guidelines. This is one of the few studies, which shows conclusively that allergy prevention works!
Link to asthma chapter of WebHealth: Lung Disease
Stillbirth Associated With High Coffee Consumption In Pregnancy
A study entitled "Maternal consumption of coffee during pregnancy and stillbirth and infant death in first year of life" by Dr. K. Wisborg et al. was published recently in the British Medical Journal (BMJ 2003; 326: 420-423).
The pregnancy outcome of 18,478 women who completed a questionnaire at their first prenatal visit was studied. They were asked about coffee consumption and the following 4 groups were identified: group 1 consisted of the 43% of women who drank no coffee. Group 2 (34%) drank 1-3 cups per day, group 3 drank 4-7 cups per day (18%). Group 4 drank 8 or more cups per day (5%).
Here are the results in tabular form.
| Stillbirth coffee study | ||
| Groups with varying amounts of coffee consumption: | Risk increase of stillbirth compared to group 1 as a control group | |
| group 2 (1-3 cups per day) | - 30% | |
| group 3 (4-7 cups per day) | 80% | |
| group 4 (8 or more cups per day) | 300% | |
The surprising result was that a small amount of coffee (1-3 cups per day) was actually reducing the risk of stillbirth by 30% when compared to women who drank no coffee at all. However, from 4 cups of coffee per day or more there was a sharp increase of stillbirths within the first year (=sum of stillbirths and deaths within the first year of life).
The authors suggest that physicians should advise their pregnant patients to limit coffee consumption in pregnancy to 1 or 2 cups of coffee or the equivalent of caffeinated drinks per day as a precautionary measure.
West Nile Virus (WNV) Vaccine Being Tested In Humans
According to Dr. Tom Monath, the scientific officer of the Acambis pharmaceutical company, human trials on a new vaccine for West Nile virus (WNV) can begin as soon as the FDA will give the green light (likely in October of 2003).
At the 2003 World Vaccine Conference in Montreal/Canada this summer Dr. Monath explained that Acambis has been doing research for a new vaccine against WNV since 1999 when this virus arrived in New York. The virus belongs into the same group of flaviviruses as dengue fever, yellow fever and Japanese encephalitis.
Yellow fever has been successfully prevented by vaccination with a live vaccine that has been modified considerably (called 17D attenuated vaccine). This strain is basically a harmless virus, which will induce a strong immune response in 100% of vaccinated people. If this is repeated every 10 years, a vaccinated person would be safe to travel in yellow fever infested areas. Based on this knowledge the researchers of Acambis have created a chimera virus(update 2006) where the yellow fever vaccine ( attenuated virus 17D) is used as a vehicle in the center while the surface has been modified by incorporating parts of the WNV into its envelope. As this new vaccine virus has qualities of both the yellow fever vaccine virus and the WNV, it is called a chimera virus. The same technology has already been successfully applied to two other flavivirus vaccines, namely the dengue fever vaccine and the Japanese encephalitis vaccine.
The new WNV vaccine has been tested extensively in mice and monkeys and has been found sofar to be very safe and it is mounting a very good immune response. It is timely that human trials are being done now starting this fall as WNV seems to be expanding rapidly throughout the United States and Canada. The vaccine would be needed particularly for older people as in them the WNV disease presents much more violently with a higher death rate. However, visitors from Europe to the US and Canada will likely want to protect themselves as well before they travel.
