Symmetric force response of human masticatory muscles to stretch and unloading.

During chewing, the force exerted by the jaw-closing muscles must constantly adapt to changing resistances between the teeth, as the food is broken down. In the present study, the changes in biting force resulting from small, controlled displacements imposed on isometrically contracting jaw-closing muscles were measured. We found that the force changes resulting from small loading and unloading movements were normally highly symmetrical.

Effects of background noise on the response of rat and cat motoneurones to excitatory current transients.

1. We studied the responses of rat hypoglossal motoneurones to excitatory current transients (ECTs) using a brainstem slice preparation. Steady, repetitive discharge at rates of 12-25 impulses s-1 was elicited from the motoneurones by injecting long (40 s) steps of constant current.

[Awareness of the subjective vertical in weightlessness (results of Austrian-Russian experiment Optovert performed within the framework of the program Austromir, part III)].

Data about intersensory interactions and adaptations, dynamics of the adaptive shifts were obtained in short- and long-term space missions basing on the indices of the subjective optical vertical awareness evaluated in experiment "OPTOVERT" with the use of dedicated ingenious techniques and hard- and software. As was shown, the function of subjective optical vertical (SOV) awareness remained unaltered in microgravity; however, in the period of adaptation there was a significant growth of error in SOV awareness in the darkness, and against the vertical optokinetic stimulation. In prolonged microgravity SOV error returns to the norm both in the darkness and during stimulation while arising asymmetry differs from background in magnitude and directivity, exceeds the physiological norm and sustains throughout a mission.

[Spontaneous and visually-induced oculomotor reactions in microgravity (Results of Austrian-Russian Experiment "Optovert" performed within the frame of program "Austromir", part II)].

Results of investigation of spontaneous and induced by vertical linear and sinusoid optokinetic stimulation oculomotor reactions in short- and long-term space missions are reported. Adaptation to microgravity was shown to be associated with rearrangement in sensory interactions even on a background of good subjective well-being and absence of abnormal autonomous nervous reactions. In the early period of adaptation to microgravity records were made of modified spontaneous oculomotor activity (spontaneous vertical nystagmus) and vertical optokinetic nystagmus (VOKN) including alterations in amplitude and VOKN amplification coefficient.

[Crystalline cholesterol as a factor in thrombus formation].

The model using crystalline cholesterol as the thrombogenic process inductor was developed. Thrombi that are morphologically equivalent to the human arterial thrombi under atherosclerosis were created in experiment on standard animals. It was shown that the "head" (conglutinational part) of such thrombi includes the thrombocyte mass, organised into the system of branched trabeculae surrounded by leucocytal limbus.

Discharge patterns of tonically firing human motoneurones.

We have attempted to reconcile the different patterns of distribution of interspike intervals that are found in motoneurones made to discharge by intracellular injection of constant current in reduced animal preparations and by voluntary control in human subjects. We recorded long spike trains from single motor units in three human muscles made to discharge at constant mean frequencies with the help of auditory and visual feedback. The distribution of interspike intervals in each spike train was analysed quantitatively.

[The liquid crystal state of the lipids and atherosclerosis (a cell-culture study)].

It was discovered experimentally that the contact of the human embryonal fibroblasts with the detritus of atheromatous plaques with liquid crystal's (mesogenic) lipids activated proliferation of these cells. The same results were obtained during the contact of fibroblasts with the mesogenic mixture of cholesterol esters. At the same time the contact of embryonal fibroblasts with the amorphous (nonmesogenic) mixture of cholesterol esters does not promote the proliferative activity.

Responses of human masseter motor units to stretch.

1. The reflex responses to stretch were studied in single motor units and the surface electromyogram in human masseter. 2.

[Spontaneous and visually induced illusory responses in weightlessness (results of the Austrian-Russian experiment "Optovert" performed within the framework of the program "Austromir", part I)].

There presented the results of studying the mechanisms of intersensory interactions and sensory adaptations, the dynamics of the stability of adaptive changes in the short- and long-term space missions by phenomenology of spontaneous and visually-induced illusory responses. It is shown that adaptation to microgravity even under good subjective health condition and the absence of anomalous subjective reactions was accompanied the change in the interaction of the sensory systems. For the first time there recorded the previously unknown phenomena: an inversion of vertical vection illusion (VVI) on vertical and sinusoidal optokinetic stimulation; disruption of the perception of body scheme at the instant of VVI; the change of character and the initiation of VVI asymmetry; the decrease of thresholds and the intensity increase of VVI.

[Several mechanisms of immunological adaptation in the etiology of subacute infectious endocarditis].

The paper deals with the possibility of identifying the persons predisposed to the development of subacute septic endocarditis (SSE), with the prediction of the course of the disease and the clarification of reasons for the inefficiency of antibacterial therapy. The studies performed revealed the impairment of cooperative interaction of the immune system, which prevents it from fulfilling its main task, i.e.

A new approach to the estimation of post-synaptic potentials in human motoneurones.

A new method is described for estimating the shape of the compound post-synaptic potentials evoked by stimuli in human motoneurones. The method is based on changes in the duration of the interspike intervals in motor-unit spike trains that are time-locked to the stimulus. This is particularly helpful in estimating the profile of long-latency slow rise-time post-synaptic potentials that are difficult to estimate with other methods.

[Screening for deletion in patients with Duchenne's myodystrophy by multiplex amplification].

Patients with Duchenne muscular dystrophy were analyzed using the method of polymerase chain reaction in order to reveal deletions in the dystrophin gene. Deletions of different lengths and locations were detected in 28 of 78 ill boys. The highest number of deletions was detected in the 3'-end of the gene (the 45-50th exons).

Stretch reflexes in human masseter.

The reflex response to stretch in most contracting human muscles includes both a short-latency, probably monosynaptic, excitatory component, and a longer-latency, polysynaptic excitation. However, it has been claimed that stretch of the jaw-closing muscles evokes only the short-latency response in masseter. This question was re-examined, using controlled stretches of varied rates and durations.

[Ways to decrease postoperative hypothyroidism in patients with diffuse toxic goiter].

The authors note that postoperative hypothyrosis is observed much more often than recurrences of thyrotoxicosis in patients with diffuse toxic goiter. The incidence of hypothyrosis is associated with the amount of the remnants of tissue, its functional abilities, regeneration, state of the hormonal and immune systems of the organism. The authors describe their method of determining the mass of the thyroid residue.

[Health status of schoolchildren in industrially developed and rural areas of West Siberia].

Medical examinations of the schoolchildren living in West Siberian urban and rural ares have revealed a high prevalence of chronic diseases and functional abnormalities. Children referring to health groups I and II were not found. This makes it necessary to perform such studies as a component of medical and ecological monitoring and as the basis for children's health promotion.

An apparatus for controlled stretch of human jaw-closing muscles.

The design of a special-purpose muscle stretcher for reflex studies of the human jaw-closing muscles is described. The device is based on a servo-controlled electromagnetic vibrator which imposes controlled displacements on the lower jaw. The mechanics of the device keep jaw movements coaxial with the temporomandibular joint during the stretches.

Quantitative analysis of reflex responses in the averaged surface electromyogram.

The relationship between the averaged surface electromyogram (EMG) and the activity of motoneurones in reflex studies is analysed mathematically. This analysis reveals that, subject to certain conditions being met, the integral of the average of the unrectified EMG is linearly related to the activity of motor units in the muscle. This was tested with experimental data.

[Analysis of deletions in the dystrophin gene by the multiplex amplification method in patients suffering from Duchenne's muscular dystrophy].

Multiplex polymerase chain reaction was carried out with the material from 68 patients suffering from Duchenne muscular dystrophy in Moscow and Leningrad clinics. Six pairs of oligoprimers were used. Deletions were detected in the material from 22 patients.

[Use of nonradioactively labelled DNA-probes for DNA-diagnosis of Duchenne's muscular dystrophy].

Routinely, we detect 0,1 pg of plasmid DNA using the nonradioactive DNA labeling and detection kit produced by Boehringer Mannheim (FRG). Using the kit we have determined the carrier status of a woman in a family with a case of Duchenne muscular dystrophy by the blot hybridization technique.