Influence of sublingual nitroglycerin on the digital circulation of man.

By means of the digital rheoplethysmographic (RPG) method, the effect of sublingually administered nitroglycerin (NTG), 1/200 gr (0.3 mg), on the digital circulation was studied in 17 normal subjects and 5 patients with ischemic heart disease and angina pectoris. NTG produced dilatation of all digital vessels, reflected especially by increases in total digital volume. NTG produced marked changes in the dicrotic notch of the pulse wave, noted also in inflow volume curves but not in outflow volume curves. The dicrotic notch was displaced later on the descending limb of the digital pulse wave and became deeper and more prominent after NTG. It is suggested that NTG produces disproportionate dilatation of the arterial system, having its greatest effect on arteries near the heart, including the coronaries and great vessels branching off the aorta, and on left intraventricular cavity pressure. This greater regional vasodilatation of vessels near the heart could delay closure of the aortic valve, producing a delayed and prominent dicrotic notch of the pulse wave.

Two pumps and one heart: studies and theoretic considerations.

Using 2 pumps specially constructed to simulate the right and left ventricles of the heart of man, it was shown that very small differences in output per stroke of the 2 pumps will result in a significant change in the volume of the "pulmonary" circulatory system and could become "pathophysiologically" important with time. These studies demonstrate that both ventricles must be well synchronized and regulated to maintain good health and to prevent dyspnea and other manifestations of CHF. They also indicate the inadequacy of the conventional methods used for measuring cardiac output in man and the need to measure stroke volume or cardiac output of both ventricles separately and simultaneously. It must not be assumed that the cardiac output is always equal for both ventricles even in the presence of myocardial disease. An explanation is introduced for the acute onset of dyspnea associated with angina pectoris and with exercise. Also, the concept that the ventricles fill, at least in part, by "sucking" action is presented, with support from these and other theoretic considerations.

Coxsackievirus B4 infection of sympathetic ganglia in squirrel monkeys.

Lumbar sympathetic ganglionitis was found by light microscopy in 2 of 17 (12%) squirrel monkeys (Saimiri sciureus) experimentally infected with Coxsackievirus B4. This finding shows that viruses can cause ganglionitis which, in turn, must cause autonomic nervous system dysfunction. Such viral ganglionitis may explain some diseases, including cardiovascular ones, of poorly understood or unknown etiology which present with manifestations of dysfunction of the sympathetic nervous system.

Review of pulsing electromagnetic field therapy and its possible application to horses.

The relevant literature on electrostimulation in general, and pulsing electromagnetic fields in particular, is reviewed. DC current influences cell behaviour by affecting transmembrane ion transport, which is often under enzymatic control. Pulsing electromagnetic fields influence cell functions through adsorption of ions or dipole formation at the cell membrane. Invasive and non-invasive DC current stimulation is compared to pulsing electromagnetic fields. The mode of application of pulsing electromagnetic fields to the equine limb and suggested treatment times are briefly discussed. Two case reports are used to illustrate the effect of pulsing electromagnetic fields in equine fracture treatment.

The digital circulation in congestive heart failure.

Congestive heart failure (CHF) is a complex clinical entity which is still little understood pathophysiologically. Unless it is in the intractable state it responds well to therapy. It has been known for many years that the peripheral circulation can be dramatically altered when CHF is progressively and rapidly developing and worsening. As compensation develops, these changes gradually return to normal. We have long been studying the digital circulation of patients with CHF and have been impressed with the changes in the behavior of the peripheral blood vessels in these patients.

Coxsackievirus B4 hepatitis in monkeys.

Hepatitis was produced by Coxsackievirus B4, an agent highly infectious to man, in 3 of 9 experimentally infected squirrel monkeys. Although the virus could not be isolated from the livers of these monkeys, viral antigen was found in the liver cells of one monkey with severe hepatitis by direct immunofluorescent antibody staining, and a virus crystal was found in the kidney of this monkey by electron microscopy. These and previous studies strongly suggest that the Coxsackievirus can exist in the liver and other tissues in a dormant or slow viral state.

Coxsackievirus B4 nephritis in the squirrel monkey.

Seventeen squirrel monkeys (Saimiri sciureus) were experimentally infected with Coxsackievirus B4, and the kidneys, as well as other organs, were studied for pathological changes induced by the virus. Seven (41%) of these monkeys developed renal lesions--interstitial and glomerular. The Coxsackievirus was identified in 4 of these 7 monkeys (by isolation from the renal tissue in 2, by immunofluorescence staining of viral antigen in 1, and by electron microscopic finding of viral particles in 1). The renal lesions produced by Coxsackieviral infection described in this report resemble those seen in renal disease in man. These findings support the concept that viruses can produce glomerular and interstitial renal disease. This report also describes a good animal model for the study of viral disease of the kidney.

Experimental viral arthritis.

An early, acute arthritis was observed in 8 of 22 mice experimentally infected with respiratory syncytial virus. No abnormalities were found in the joints of the 12 control mice. The pathological changes in joints of the infected animals included pannus formation and erosion, resembling changes that occur in arthritis in man, including rheumatoid arthritis. It is proposed, therefore, that viruses may play an aetiological role in acute and chronic arthritis in man. These investigations provide a model for studying pathology of arthritis in mice produced by a virus which also infects man.