Dead space and snorkeling deaths on Maui

There were quite a few more than usual snorkeling drownings off the shores of Maui last year. Some of the newer full face masks for snorkeling may be to blame. Although the original models were quite close fitting in the face, clone models may have had enough dead space in the mask between the face and visor to explain passing out during their use leading to drowning.

What is dead space and how does it cause high CO2 pressures? As explained on this poster, we rely on almost completely emptying ourselves of the exhausted air we breathe out to prevent sucking carbon dioxide back into our bodies with our next breath. Too much re-circulation of exhaled air in a full face mask can defeat effective exhalation, allowing toxic levels of carbon dioxide to accumulate.

Cataract surgery and cognitive function

How did cataract surgery improve cognitive performance in the elderly without affecting the risk of true dementia? Likely by improving the ability of elderly persons to stay better informed of their environment, including their test settings. Some types of cognitive dysfunction are of sensory perception more than sensory processing.

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ABSTRACT

Effect of cataract surgery on cognitive function in elderly: Results of Fujiwara-kyo Eye Study

Kimie Miyata, Tadanobu Yoshikawa, Masayuki Morikawa, Masashi Mine, Nozomi Okamoto, Norio Kurumatani, Nahoko Ogata

Published: February 20, 2018

https://doi.org/10.1371/journal.pone.0192677

Purpose

To determine whether there is a significant association between prior cataract surgery and cognitive function in an elderly Japanese cohort.

Setting

Nara Medical University, Nara, Japan.

Design

The Fujiwara-kyo Eye Study was a cross-sectional epidemiological study.

Methods

The subjects were ≥ 68-years who lived in the Nara Prefecture and responded to recruitment notices. All of the subjects received comprehensive ophthalmological examinations, and answered questionnaires on their socio-demographic and medical history including prior cataract surgery. The association between prior cataract surgery and cognitive function was determined.

Results

A total of the 2764 subjects whose mean age was 76.3±4.8 years (±standard deviation) was studied. Of these, 668 individuals (24.2%) had undergone cataract surgery. Of these, 150 (5.4%) had dementia as determined by the Mini-Mental State Examination (MMSE) score ≤23, and 877 individuals (31.7%) had mild cognitive impairment (MCI; MMSE score 24–26). The subjects who had prior cataract surgery had significantly lower odds ratio (OR) of having MCI (OR = 0.78, 95% confidence interval; CI 0.64–0.96, P = 0.019) than those who had not had cataract surgery after adjusting for age, sex, body mass index, education, hypertension, diabetes, depression, and history of stroke. The OR was still lower when the visual acuity was also added to the adjusted factors (OR 0.79, 95% CI 0.64–0.97, P = 0.025). However, prior cataract surgery did not contribute significantly to the low OR for dementia.

Conclusions

Cataract surgery may play a role in reducing the risk of developing MCI independently of visual acuity but not for dementia

Final draft of NIH cell phone exposure study in rats does not show any brain tumor risk.

The final draft (not yet the officially published version) of the "TOXICOLOGY AND CARCINOGENESIS STUDIES IN Hsd:SPRAGUE DAWLEY SD RATS EXPOSED TO WHOLE-BODY RADIO FREQUENCY RADIATION AT A FREQUENCY (900 MHz) AND MODULATIONS (GSM AND CDMA) USED BY CELL PHONES " is out. Unlike the preliminary, midstudy data, there is no brain cancer or brain tumor risk found.

The Sprague-Dawley breed of rats seems prone to cardiac tumors, and there is a hint of an increase in the rats of those cardiac tumors in male but not female rats. Since, on the whole, these cardiac tumors do not tend to have any gender bias in rats in other studies, one finds even those results suspect.

Overall, there seems to be no real reason to avoid the use of cell phones because of cancer risk. I think that the study authors are writing as if they are really searching for a positive result in a study that had little to show.

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ABSTRACT

GSM- AND CDMA-MODULATED CELL PHONE RADIO FREQUENCY RADIATION

The predominant source of human exposure to radio frequency radiation (RFR) occurs through the use of cellular phone handsets. The Food and Drug Administration nominated cell phone RFR emission for toxicology and carcinogenicity testing in 1999. At that time, animal experiments were deemed crucial because meaningful human exposure data from epidemiological studies were not available. Male and female Hsd:Sprague Dawley SD rats were exposed to time-averaged whole-body specific absorption rates of Global System for Mobile Communications (GSM)- or Code Division Multiple Access (CDMA)-modulated cell phone RFR at frequencies of 900 MHz (herein referred to as “cell phone RFR”) in utero, during lactation, and after weaning for 28 days or 2 years. Genetic toxicology studies were conducted in rat peripheral blood erythrocytes and leukocytes, brain cells, and liver cells.

Under the conditions of this 2-year whole-body exposure study, there was some evidence of carcinogenic activity of GSM-modulated cell phone RFR at 900 MHz in male Hsd:Sprague Dawley SD rats based on the incidences of malignant schwannoma in the heart. The incidences of adenoma or carcinoma (combined) in the prostate gland, malignant glioma and benign or malignant granular cell tumors in the brain, adenoma of the pars distalis in the pituitary gland, pheochromocytoma (benign, malignant, or complex combined) in the adrenal medulla, and pancreatic islet cell adenoma or carcinoma (combined) may have been related to cell phone RFR exposure. There was no evidence of carcinogenic activity of GSM-modulated cell phone RFR at 900 MHz in female Hsd:Sprague Dawley SD rats administered 1.5, 3, or 6 W/kg. There was some evidence of carcinogenic activity of CDMAmodulated cell phone RFR at 900 MHz in male Hsd:Sprague Dawley SD rats based on the incidences of malignant schwannoma in the heart. The incidences of malignant glioma in the brain, adenoma of the pars distalis in the pituitary gland, and adenoma or carcinoma (combined) of the liver may have been related to cell phone RFR exposure. There was equivocal evidence of carcinogenic activity of CDMA-modulated cell phone RFR at 900 MHz in female Hsd:Sprague Dawley SD rats based on the incidences of malignant glioma in the brain and pheochromocytoma (benign, malignant, or complex combined) in the adrenal medulla.

Increases in nonneoplastic lesions in the heart, brain, and prostate gland of male rats, and of the heart, thyroid gland, and adrenal gland in female rats occurred with exposures to GSM cell phone RFR at 900 MHz. Increases in nonneoplastic lesions of the heart, brain, and prostate gland occurred in males, and of the brain in females exposed to CDMA cell phone RFR at 900 MHz.

Terror exposure and headache.

Stress has long been identified as a major causal factor in the occurrence of headaches. A recently published study in Norway looked at the survivors of a terrorist's attack on a boys camp in that country. Reference: HERE. This study showed a 4 fold increased incidence of tension and migraine headaches for those with terrorism exposure.

Rescue Palm Tree

In December of 2010, after Christmas, I went to the tide pools at Wai'opae, at Kapoho, on Puna of the Big Island. While walking on the ...