Mayaro virus: a forest virus primed for a trip to the city?

Mayaro virus (MAYV) is an emerging arthropod-borne virus (arbovirus). Infection by MAYV can produce Mayaro virus disease (MAYVD) which is usually a clinically diagnosed, acute, febrile illness associated with prolonged and painful joint inflammation and swelling. MAYVD may be clinically indistinguishable from dengue, chikungunya fever, malaria, rabies, measles or other arboviral diseases. The full spectrum of disease, sequelae, routes of infection, virus shedding and any rarer means of transmission remain undefined. MAYVD cases in humans have so far been localised to Central and South America, particularly regions in and around the Amazon basin. MAYV usually circulates in a sylvan cycle of forest mosquitoes and vertebrates, however it has also been found in more urban locations alongside anthropophilic (preferring humans) insect vectors. If transmission via anthropophilic mosquitoes becomes more efficient following viral change, or existing vectors change their habitat and biting habits, the risk of urban establishment and further spread into non-forested areas will grow. Surveillance, testing and vector control remain key to monitoring and preventing global spread and establishment. The possibility of MAYV becoming further urbanized is worthy of note, consideration and action to ensure MAYV does not spread beyond the forests and establish in the world's cities.

An investigation to devise an index for the measurement of the degree of aortic incompetence - abstract

From earlier investigations it seemed that under certain conditions a pneumatic cuff acted like a valve on the peripheral blood vessels in a limb when it was inflated to certain pressures. It was therefore decided to see whether a pneumatic cuff could be employed as a valve on the brachial artery in aortic incompetence , and by obstructing the regurgitant flow of blood provide a means of measuring its volume. The procedure adopted was to measure forearm and hand blood flow plethysmographically and examine the influence of various pneumatic cuff pressures on this blood flow. It was interesting to observe in some instances how effectively this approach increased the forward flow. However, a cuff with a steady pressure is unlikely to be a satisfactory "valve", and it was therefore decided to improve on this approach by having a pressure cuff in which the pressure could be quickly applied and released at any desired point in the cardiac cycle. Thus, in aortic incompetence where regurgitation was likely to occur, the cuff could be released only during the ejection phase and applied for the remainder, or regurgitant part, of the cardiac cycle. The basis of this technique was to employ an electrocardiograph and trigger from its R-wave a sliding pneumatic valve which applied or released the pressure at pre-determined times during the cardiac cycle. The use of this approach has been compared with the earlier technique and has produced greater forward flows, as measured plethysmographically, in the forearm and hand. The purpose of this communication is to describe these techniques and demonstrate the results obtained by the two methods in measuring regurgitation in the brachial artery in aortic incompetence. It is hoped that an accurate index of aortic incompetence may be eventually obtained by the use of these techniques (AU)

An index for the measurement of the degree of aortic incompetence

It has been noted that under certain conditions a standard sphygmomanometer cuff may act as a valve on the peripheral blood vessles. A pneumatic cuff was employed as a valve on the brachial artery in aortic incompetence, and by obstructing the regurgitant blood a means for measuring its volume was devised. The principle on which this method is based is that of using a special type of sphygmomanometer cuff which at certain pressures exerts a valve-like action on the brachial artery. In aortic incompetence the cuff prevents some of the backward flow, thus increasing the foreward flow. This increase in foreward flow, measured plethysmographically, is used as a basis for calculating indices of regurgitation. The essential feature of this technique is the measurement of forearm-hand blood flows by venous occlusion plethysmography with the limb in the upward and vertical position, and at high ambient temperatures of 30 to 32 oC. A high degree of regurgitation may be indicated by this technic (Summary)

The graphic recording of the rate of drainage of blood from the veins of the legs

The purpose of this technique was to devise a method to study certain aspects of the aetiology of varicose veins in pregnancy and whether the developing foetus causes a mechanical obstruction of the venous drainage of the lower limbs. Such a technique might be of use in the study of other clinical conditions. The technique to be described is for the graphic recording of the rate of venous drainage from the legs by gravity. The procedure involves the use of a tilting table and a limb plethysmograph. The initial angle of the limb volume change following the completion of the tilting was recorded and from this the venous drainage rated was calculated. The results indicate the freedom with which venous drainage occurs and the lack of resistance that exists to the venous outflow from the lower limbs. The validity of the measurements derived from the technique was examined by causing venous obstruction by a positive Valsalva procedure and by examining the records during and after pregnancy. Other techniques have been evolved to investigate the part played in the production of varicose veins by: (1) changes in venous valvular competency and (2) venous tone (AU)

An investigation to devise an index for the measurement of the degree of aortic incompetence

From earlier investigations it became apparent that under certain conditions a standard sphygmomanometer cuff might act as a valve on the peripheral blood vessels. It was considered worthy of investigation to see whether a pneumatic cuff could be employed as a valve on the brachial artery in aortic incompetence, and by obstructing the regurgitant blood provide a means for measuring its volume. The procedure adopted was to measure forearm and hand blood flow plethysmographically and examine the influence of various pressures applied in a pneumatic cuff on this blood flow. The purpose of the communication is to report on the technique employed, the results obtained and the evaluation of their use in measuring aortic regurgitation (AU)

The influence of certain factors, vitamin B12 and aureomycin, on the growth of protein-deficient children (abstract only)

A study was made to examine the influence of vitamin B12 and aureomycin upon the rate of growth in protein-deficient children. The results of this study present evidence for a slight positive effect of aureomycin upon the rate of weight increase, but no effect upon the rate of height increase. The results show that vitamin B12 has no positive effect upon the rate of height increase. The nutritional status was observed to be low. Among the observations made were clinical examinations, growth measurements, biochemical measurements and a direct dietary survey. There is no evidence to suggest that either aureomycin or vitamin B12 would be of practical value in alleviating the malnutrition found in such areas as the Caribbean (AU)

The influence of vitamin B12 and aureomycin upon the growth of protein deficient children

A study was made to examine the influence of vitamin B12 and aureomycin upon the growth in protein-deficient children. The results of this study present evidence for a slight positive effect of aureomycin upon the rate of weight increase, but no effect upon the rate of height increase. The result show that vitamin B12 has no positive effect upon weight or height increments. The nutritional status was observed to be low. Among the observations made were clinical examinations, growth measurements, biochemical measurements and a direct dietary survey. There is no evidence to suggest that either aureomycin or vitamin B12 would be of practical value in alleviating the malnutrition found in such areas as the Caribbean. (summary)

The control of the external secretion of the pancreas

A brief note is presented on the present state of knowledge regarding the mechanisms controlling pancreatic secretion. The parasympathetic nervous system and the harmone pancreozymin are described as having an ecbolic influence upon the pancreas. The hormone secretin has a hydrokinetic influence on the pancreas (AU)

Volume changes in forearm and hand following release of obstruction to venous return

Observations were made on the changes that occur in the volume of the forearm and hand following the release of an obstruction to the venous return. The presence of three phases has been confirmed: a) a rapid primary decrement (P.D.) followed occasionally by b) an increase in volume (Hump), and finally c) a secondary decrement (S.D.) as the limb volume gradually returned to normal. It is suggested that the primary decrement in limb volume (P.D.) is largely venous in origin and is probably due to the rapid initial ejection of blood from the limb as the large veins recover their normal size and calibre. An index of venous distensibility is suggested which might provide a means of indirectly measuring venous tone.(AU)