http://otolaryngologyinafrica.net/blogging/ a blogsite of the otolaryngologyinafrica.net en-us Nucleus CMS v3.50 © Weblog http://backend.userland.com/rss http://otolaryngologyinafrica.net/blogging//nucleus/nucleus2.gif http://otolaryngologyinafrica.net/blogging/ http://otolaryngologyinafrica.net/blogging/index.php?itemid=10 excessive noise generated in the universe, especially the developing countries, and use same to generate electricity, enough to supply the energy needs of these countries. Just exactly how this could be achieved shouldn't be rocket science, as nature, in form of delicate transduction mechanism of the inner ear already provided us with the blueprint.
Virtually all current sources of electricity used in developing countries - hydro-dam, Thermal plants, gas turbines, Coal generating plants - as well as other artificial alternatives (generators) and social contraptions (lorries, cars, diesel engines, caterpillars, discotheques, social and political gatherings generate tremendous amount of sound.
What is so exciting about this form of energy is that it is infinitely renewable, as sound generated can be captured, stored, and reuse. It is also likely to have the best green credential among alternative energy sources. Imagine the scenario where you are short of electricity, and all you need to do is power on your stereo to highest volume (with ear muff and bolted doors of course!) for few minutes, and pronto, you have enough "suel" for your local electric supply for days.
To be realistic, an equally green alternative to amplify the energy generated, and transport it over a long distance would need to be invented.
Subsequent aspect of this blog will examine in detail technical feasibility of the Sonar Electricity generation]]> General http://otolaryngologyinafrica.net/blogging/index.php?itemid=10 Sat, 28 Jun 2008 08:00:33 +0100 http://otolaryngologyinafrica.net/blogging/index.php?itemid=9 Lin J et al, 2007], and once lost, there is no regeneration of such hair cells in human [Lowenheim H et al, 2008]. After moderate cochlear trauma, hair cells degenerate and their places are taken by phalangeal scars formed by differentiated supporting cells [Rapheal, Kim, Ozumi & Izumikawa, 2007].
With hearing aids and cochlear implants offering limited improvement in hearing loss restoration, attention of clinicians and researchers is turned towards regenerative medicine especially stem cells therapy. A key goal in developing therapy for sensorineural deafness is the identification of strategies to replace lost hair cells [ Breuskin, Bodson, Thelen, et al, 2007].
One approach to hair cell regeneration targets cochlear stem cells /progenitors which are known to be quiescent in the Organ of Corti, and the genes they expressed, with the purpose of inducing such cells to differentiate into hair cells (inducible stem cells therapy), while other approach (Molecular therapy) borrows from the knowledge of spontaneous regeneration of avian organ of Corti, by targeting the supporting cells that are known to lose their differentiated features after severe insults or prolonged hearing loss and become a simple, flat epithelium. Gene disruption of the cell cycle inhibitor p27(Kip1) allows supporting cell proliferation in the organ of Corti in vivo. Furthermore, in vitro studies indicate that newly generated cells may differentiate into hair cells after p27(Kip1) disruption [Lowenheim H et al, 2008].
In either of these strategies, hair cell specific genes known to be essential for hair cell differentiation or maintenance such as ATOH1, POU4F3, GFI1, and miRNA-183 will be utilized with the hope of completely restoring hearing to all patients with hearing loss [Pauley, Kopecky, Beiel et al, 2008].
Finally, the issue of best route to introduce stem cells into the cochlea for deafness theapy is also being addressed. Injection via lateral wall cochleostomy was recently described [Bogaets S et al, 2008].]]> Otology http://otolaryngologyinafrica.net/blogging/index.php?itemid=9 Sat, 17 May 2008 22:49:15 +0100 http://otolaryngologyinafrica.net/blogging/index.php?itemid=8 Being the first Barany Meeting to feature didactic teaching session, the first day featured lectures on basic physics, neurophysiology, neurology, otology, ophthalomology, multi-sensory interactions, and audiology that a neuro-otologist is expected to fathom.
Distinguished speakers at this session include Herman Kingma, Straussman D, Lloyd Minor, M. Magnusson, Zee D, Adolfo Bronstein and a representative on Linda Luxon.
A warm welcome dinner at International Conference Centre, Kyoto, followed.
the next three days featured 2 plenary sessions ((1)Self motion and Perception; and (2) Oculomotor System and adaptive plasticity); 2 lunchtime lectures (speakers were Cohen b (US A) and Brandt T (Germany), multiple oral, podium and poster sessions, as well as 14 symposiums on topics like Meniere's disease and related disorders, Posture and locomotion, Genetics, development and regenration; Clinical testing for vestibular function; Pursuit vestibular interaction, Neural mechanism of self motion perception, Positional and Positioning vertigo, Visual-vestibular interaction, Vertical eye movements, Autonomic functions and Migraine, Visual backup mechanism to the VOR, and Vestibular compensation.
The meeting also featured a special lecture by Ito M (Japan) titled Multiple Equilibrium function of the Cerebellum.
Africa was represented at this meeting by myself and Dr Louis Hofmeyer from Pretoria, with 3 poster presentations to our credit.
The social aspect of the meeting was impressive with visits to temples, peppered with traditional Japanese music and dances, and of course inspiring hospitality, all to the credit of Prof. Juichi Ito, the LOC chairman.
]]> General http://otolaryngologyinafrica.net/blogging/index.php?itemid=8 Mon, 7 Apr 2008 12:38:46 +0100 http://otolaryngologyinafrica.net/blogging/index.php?itemid=7 It is worrisome that due to conspicuous abscence of central hearing aid distribution and regulation in most parts of Africa, a large number of hearing-impaired are left to deal directly with hearing aid dispensers, most of whom are profit driven.
Now the paradox of letting someone largely un-informed about technology as complex as hearing aid loose to a profit-driven private hearing-aid dispenser is best imagined. The result might be the increasing report of non-user (personal observation) among paediatric patients fitted with hearing aid.
The point is we do know that the hearing aid prescription procedure for infants and young children should be based on real-ear aided gain rather than insertion gain(Seward R, 1995; Dillon H, 2001). Children, unlike adults cannot voice their complaints if the HA is uncomfortably loud or produces irritating noise. The outcome might be the child's rejection of the HA anytime it is switched on.
The paradox is the poorly regulated field of hearing aid distribution system in Africa produces more non-users (in theory) which in turn worsen the statistics on hearing impaired.
But how can we regulate hearing aids fitting if we do not possess means of assessing that the hearing aid meets minimum criteria of standard expected for hearing aids? We have witnessed situations where greedy but hearless traders imported tinnitus maskers and sell them as hearing aids! We have also witnessed situation where low quality hearing aids, not recommended for use in countries they emanated from, get imported to Africa - all in the name of 'Africans are poor people' But a child carrying poor hearing aid is worse off than a child not aided at all.
One solution is to establish regional acoustic laboratories (if individual countries of Africa cannot afford one) to regulate (See hyperlink ) and oversee regional dispensation and fitting of hearing aids in Africa.
Biodun]]> General http://otolaryngologyinafrica.net/blogging/index.php?itemid=7 Tue, 26 Feb 2008 05:08:36 +0100 http://otolaryngologyinafrica.net/blogging/index.php?itemid=6 First, I lost a friend and a mentor-of-sort - Dr Eribo - A retired pediatrician, who was like a non-biogical dad to me over the past one-and-half decade.
Secondly, tried as much as I could, I was unable to secure a flight to Sierra Leone for the WACS meeting, where I was scheduled to give two papers. This is due to over-booking of the only airliner that flies that route from Nigeria. Attempts to break down the flight was futile. as Ghana airways, the other option cannot be reached and booked from Nigeria - was told Ghana airways no longer have operational base in Nigeria.
Thirdly, I read this interesting article (Elshaug, Moss, Hiller & Madden, 2008) published in January 5 edition of BMJ providing evendence base from published literature tothe effect that upper airway surgery should not be the first line treatment for OSAS - wait a minute! that refrain is familiar!! - and that even where CPAP (the recommended first line treatment by this paper) and even the adjunctive weight reduction have failed, mandibular advancement devices may be considered as second line, with the surgical option considered as last option, and patient informed of inconsistent result of surgery!
The lead authors of this paper were all public health specialists. I am not sure whether otolaryngologists, writing on same subject could have arrived at same conclusion.
As for otolaryngologists practicing in Africa, even the issue of extensive sleep centre investigations prior to upper airway surgery for OSAS is a luxury as many centres lack such specialized sleep centers, and surgery is oftened offered on the conviction of the surgeon of possible benefits to such patients who are more likely to have explored every other alternative therapy before presenting to otorhinolaryngologists
Biodun ]]> Rhinology http://otolaryngologyinafrica.net/blogging/index.php?itemid=6 Sat, 9 Feb 2008 13:49:45 +0100 http://otolaryngologyinafrica.net/blogging/index.php?itemid=5 A quick medline search for the term 'cellphone and the ear' returned 46 references
This is hardly suprising. After all, you don't hold your cellphone over your eyes, nose, leg or abdomen when making or taking a call, but over your pinna, temporal region including the mastoid area
Otological effects of cell phone use, like other medical effects, could be theoretically classified into thermal, non-thermal, and the so-called geno-toxic effects.
In general, the reported otologic effects of cell phone use could be visualized as relating to three issues:
1. Heat generated by cellphone battery
2. Radiofrequency emmsion from the cell phone,and from the base stations
3. Noise generated from cell phone applications - radios, MP3 players, etc

With respect to the first, Tahvanainen K et al (2007) studied the effect of cellular phone use on ear canal temperature using thermistors, and observed that RF exposure to a cellular phone, either using 900 or 1800 MHz with their maximal allowed antenna powers, increases the temperature in the ear canal.
Effects of cellphone use resulting directly from RF emmision reported ranges from insiginificant (McIntosh RL et al, 2008), Paglialonga A et al, 2007, Parazzini M et al, 2007, to anecdoctal report of tinnitus, and vertigo, to even development of vestibular schwannomaEven the much-observed temporal headache reported by powered cell phone users and dubbed is believed not to be due to RF exposure according to a double blind trial conducted by Oftedal G, Straume A, Johnsson A, & Stovner LJ, 2007..
It must be stressed however that the study of otological effects of cellphone is an ongoing project, and requires meticulous, well designed prospective large scale trials to have epidemiological relevance.
Biodun]]> General http://otolaryngologyinafrica.net/blogging/index.php?itemid=5 Sun, 27 Jan 2008 20:04:40 +0100 http://otolaryngologyinafrica.net/blogging/index.php?itemid=4 Though I declined to give immediate response, referring him to a colleague, because I was on my way to sort out other issues, I believe this topic should form the blog topic for this week.

I must stress that the age old cliche - no gains without pains - appears true even to the petroleum industry, where development of oil and gas often comes with a terrible cost in human health. It is also pertinent to stress that

1. Natural gas is closely related to crude oil, both substances believed to have formed in the earth's crust as a result of transformation of organic matter due to the heat and pressure of the overlying rock.
2. All oil deposits contain natural gas, although natural gas is often found without oil.
3.The composition of natural gas varies, depending on the origin, type, genesis, and location of the deposit, geological structure of the region, and other factors.
4.Saturated alipahtic hydrocarbons - methane and its homologues - are the chief constituents of natural gas, while other gases like hydrogen sulfide (H2S), nitrogen, carbon dioxide and helium are also found in lesser quantity, variable according to geographical region.
It is also pertinent to note that while the intention of a flare is to protect onsite oil workers by disposing combustion products of oil exploration, in situation of absence of the needed capacities and equipment for gas collection and processing, far away from work site, such products often end up in site few kilometers from the industry, usually within 30 kilometers radius.Oto-rhino-laryngological effects due to gas flaring could be from the process itself, from direct effect of the gases on human, and from indirect effects on the environment.
The major oto-rhino-laryngological effect resulting from the process of producing gas flare is noise emenating from gas flare stations. Odigure & AbdulKareem - in a study of deterministic model for noise dispersion from gas flaring - reported that noise intensity level reduces with increasing in distance from the flare point and that weather conditions has an important influence on noise dispersion. The sequelae of significant noise exposure in noise induced haering loss.
Hydrocarbons as a group are known to cause carcinogenic, neurotoxic, fetotoxic and teratogenic effects. These effects depend on the nature of the toxicant, exposure time, and environmental conditions. Most of the direct effect of gas flare in human are noted following chronic exposure to multiple gas flare and include the following:
Benzene - exposure cause marrow depression leading to aplastic anemia, with thrombocytopenia that can lead to severe epistaxis.

Benzene - carcinogenic can lead to leukemia
Toluene is a chemical with one methyl group in the benzene ring. Toluene is a potent central nervous system toxicant leading to narcosis, incoordination, emotional lability, and subjective symptoms such as headache and fatigue. Incoordination can present to ENT surgeon as vertigo.

Xylene(s) are fetotoxic including delayed development, decreased fetal body weights and altered enzyme activities; they may cause CNS depression in acute exposures resulting in dizziness, staggering, drowsiness and unconsciousness.

Styrene (vinyl benzene, ethenyl-benzene) is an irritant of the skin, eyes, and mucous membranes and a CNS depressant. Upper respiratory tract and eye-irritation have been reported at 50 ppm. Common ENT presentation is chronic cattarh. This will contribute to the general eye, nose, throat and mucous membrane irritation (which may be mis-diagnosed as allergic rhinitis) and the odor will be found very disagreeable.

Exposure to dioxins and furans is well established as the cause of chloracne - a dermatological condition distinguished by the distribution of the lesions mostly on the face and behind the ears.Chloracne should be suspected in anyone living within area exposed to flared gases, presenting with predominance of open nodules (comedones) and straw colored cysts, atypically distributed, inflammatory cysts and abscesses on the face behind the
ears, on the neck scalp and buttocks, which recedes slowly after exposure is reduced.
Chronic exposure to dioxins carries a long-term excess risk of soft tissue sarcoma.
Occult cancer: Cancer of unknown primaries: high rate ratios of unknown primary site (M/F) are often attributed to multi-focal exposure from exposure to many potential carcinogens.
The most significant cause of thyroid cancers in humans is radiation with many studies reporting an association between radiation exposure and subsequent thyroid malignancies. 42 Radioactive nuclides are common components of the crude oil-gas-water mix that is brought to surface.

Indirect Effect of gas flare:
chronic stress leading to auto immune disease like type II diabetes, rheumatoid arthritis, Graves disease, Hashimoto's disease
cyclical chemical chemical sensitivity - can present as vertigo, tinnitus, headache, memory loss, and insomnia.
effects on the environent - global warming, seepage of toxic gas into wells, rivers.
Effect on marine organisms - fish and other marine organisms consumed by man
Effect on plants ecosystem.

It must be concluded that gas flaring is not the only source of contaminated petroleum gas in the atmosphere and hydrosphere, as pipeline damages (moslty from vandalization) can lead to hazardous impacts on water ecosystems.
References
1. Stanislav Patin. Natural gas in the marine environment.
2. James Argo PhD. UNHEALTHY EFFECTS OF UPSTREAM OIL AND GAS FLARING
3. A. S. Abdulkareem & O. Odigure. Deterministic Model for Noise Dispersion from Gas Flaring: A Case Study of Niger – Delta Area of Nigeria
4. Burstyn I, Senthilselvan A, Kim HM, Cherry NM, Pietroniro E, Waldner C. Industrial sources influence air concentrations of hydrogen sulfide and sulfur dioxide in rural areas of western Canada.(J Air Waste Manag Assoc. 2007 Oct;57(10):1241-50)
Biodun Olusesi
]]> General http://otolaryngologyinafrica.net/blogging/index.php?itemid=4 Tue, 15 Jan 2008 22:50:39 +0100 http://otolaryngologyinafrica.net/blogging/index.php?itemid=3 most recent residents' forum is dedicated to this topic.
The annoying thing about this common form of ototoxicity is that there is conflicting report about whether it is dose related or not.
In my clinical experience I have encountered several cases, but the most dramatic being an undergraduate female student who had just a shot of 80mg intramuscular gentamicin given by her GP, with profound ototoxicity resulting! The perplexing question has always been the exact mechanism by which gentamicin causes ototoxicity. It is postulated that to be able to cross the blood - labyrinthine barrier, possible mechanisms for ototoxicity resulting from gentamicin include:
1. extravasation between endothelial cells
2. Via damaged membrane of necrotic blood-labyrinthine barrier
3. Trancytosis across strial endothelial cells coprising the blood-labyrinthine barrier
4. Cell regulated trancellular transport, analogous to non-endocytotic uptake in vitro

One recent interesting study by Chun fui Dai & Peter S Steyger, utilized a murine model for ototoxicity and reported that the uptake of gentamicin by marginal cells is competitively inhibited by native unconjugated gentamicin, implying that non-specific trans-cytosis may be one of the rate limiting mechanisms responsible for transport of the particulate drug into strial tissues.If the mechanism of gentamicin ototoxicity is controversial, so is the claims of plethora of agents said to 'prevent' it, ranging from aspirin (Chen Y huang et al, 2007), to antioxidants - vitamin E, L-arginine, N-acetylcystein (Nordang & Anniko, 2005, Karheli et al, 2007, Feldman et al, 2007) to even acupuncture (Ma WJ et al, 2007). Yet a large number of these studies were carried out on animal models, with the possibility of human application a bit remote. More so, when there are no set criteria for identifying which individual will develop ototoxicity when given gentamicin - though recent interest is gradually turning to genetic screening of individuals with a question mark hanging on feasibility of such screening.

Biodun]]> Otology http://otolaryngologyinafrica.net/blogging/index.php?itemid=3 Fri, 11 Jan 2008 00:20:28 +0100 http://otolaryngologyinafrica.net/blogging/index.php?itemid=2
As an ENT Surgeon, I often reflect on what is supposed to be the best approach to such patients. Talking to colleagues, here in Nigeria and elsewhere in Africa, there seems to be 2 categories of opinions;
1. Some people believe the major thing Africa needs is a good hearing aid distribution system. The justification for this scchool of thought was based on the premise that majority of the hearing-impaired whose threshold is within the moderately severe to severe range cannot even afford hearing aids. The issue is further compounded by the health insurance systems in some African countries that omit hearing aids from their coverage. The fallout is the hearing-impaired is left to source for funds from similar indigent relatives to procure HA. I can recall a patient of mine who went to the bank to take a loan for his 3-year-old son's HAs, and within 6 weeks of fitting of the HAs, both got damaged (according to the dad, the boy actually broke the HA). With little or no warranty from the audiologist that fitted the hearing aids, the father was asked to come and pay additional money to get another set! The point I am making is this first group that believes we need good hearing aid distribution system may be right after all, but I am not convinced, because at least 50-60% of my patients who need HA manage somehow to procure it under the present private audiologist / audiometrician centered HA distribution system.

2. The second category, to which I belong is of the opinion that no matter how expensive, those hearing-impaired who are in the profound category and are desirous of having useful hearing should not be denied the opportunity. According to this category, the issue is not more or HAs distribution as in defining rigid criteria for HA fitting, some of which at present centre on trial-and-error, with considerable cost to patientsThis category is often confronted by the argument of the high cost of cochlear implants, the paucity of supporting professionals (speech therapist with CI training, audiologists, etc) in most African countries. Recently, it was revealed by a senior colleague who approached one of the major CI manufacturers with the purpose of establishing a CI centre in his institution, only to be told "Sorry we are not interested in dealing with your country, YOUR PEOPLE CANNOT AFFORD COCHLEAR IMPLANT". This sad truth, though annoying is what drove some clinicians in developing country to ruminating on the way forward for such patients. Take Egypt and S/Africa out of the map, and what you have is a large number of profoundly hearing impaired who are simply told to go and live with their disability!
In fairness to some implant manufacturers, trial of fly-in-fly-out CI have been made with donated implants (In Nigeria, at least 2 cases have been implanted to this author's knowledge, yet such efforts appear to be a drop in the ocean, taking into consideration the large amount of suitable candidates.

So, the central question is what is the best approach to resolving the CI issue in sub-Saharan Africa - HOW BEST CAN WE ASSIST THE PROFOUNDLY HEARING-IMPAIRED (AUDITORY NEUROPATHY EXCLUDED) WHO ARE INDIGENT YET DESIROUS OF HAVING USEFUL HEARING!

'Biodun Olusesi]]> General http://otolaryngologyinafrica.net/blogging/index.php?itemid=2 Thu, 10 Jan 2008 16:00:33 +0100