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Biomedical subjects

A Gilai

Publications and source records attributed to A Gilai.

15 recordsLinked to original sources
PubMed1991

[Familial hypobetalipoproteinemia with steatorrhea and malabsorption].

In a family in which the father was the mother's uncle, 3 of the 7 children were affected by a syndrome of malabsorption with various clinical symptoms. Diarrhea appeared in 2 of the children at birth, and in the third child at six months. The diarrhea led to failure-to-thrive, muscular wasting and abdominal swelling. However, the children improved spontaneously over the years. During childhood all 3 had manifest steatorrhea. Serum cholesterol was between 39 and 100 mg/dl, while triglycerides were normal to high. Reevaluation during the past year revealed areflexia, deficiency of vitamins A and E and of apoproteins A and B, and prolonged PT time in 2 of the children. Electron and light microscopy of small intestinal biopsies revealed vacuoles in the enterocytes. Electrophysiological tests revealed major disturbances in sensory conduction and brain-stem function. These cases differ from those described in the literature. Although in hypobetalipoproteinemia, 1 of the parents would be expected to be heterozygous and have low serum levels of APO B, in this family the parents had normal levels. Their children had low levels of serum APO A, while in patients with hypobetalipoproteinemia the levels are normal. There is a report of a case of deficiencies of both apolipoproteins, but the patient was asymptomatic, had chylomicronemia after a prolonged fast, and lower cholesterol levels than our patients. 8 other cases of apolipoprotein deficiency have been reported with biochemical characteristics similar to those of our patients, but with retention of chylomicrons in the small intestine.

Apoproteins↗
PubMed1988

Abnormal orbicularis oculi reflex response in sleep apnea secondary to acromegaly. Evidence of pontomedullary dysfunction in sleep apnea syndrome.

Severe sleep apnea was present in a patient with upper airway obstruction due to acromegaly. The study of orbicularis oculi reflex responses (OORR) disclosed a marked prolongation of the late response prior to tracheostomy. Following the surgical relief of upper airway obstruction, sleep apnea disappeared, and the latency of the late response of the OORR was dramatically reduced but failed to normalize. The OORR and especially its late response were normal in a patient with acromegaly who did not experience sleep apnea. In two patients with sleep apnea, but without acromegaly, the late responses of the OORR were abnormal. It is suggested that the presence of abnormal OORR in sleep apnea may reflect a basic defect in pontomedullary control of respiration during sleep.

Acromegaly↗
PubMed1987

Familial intestinal pseudoobstruction dominated by a progressive neurologic disease at a young age.

Chronic neuropathic intestinal pseudoobstruction is a rare entity, characterized by recurrent episodes of bowel obstruction without a mechanical obstructive cause. We report five members of two Jewish-Iranian families in whom chronic neuropathic intestinal pseudoobstruction was associated with an identical and unique progressive severe neuronal disease. It appeared within the first two decades of life. The disease consisted of external ophthalmoplegia, ptosis, and severe sensory and motor peripheral neuropathy. Three patients also had neuronal hearing loss. There was no evidence of central nervous system involvement and all patients were mentally intact. The combined disease was confirmed by radiologic, electrophysiologic, and histologic studies. Specific nutritional deficiencies, toxic elements, and systemic diseases affecting both the gastrointestinal tract and the nervous system were ruled out. It seems that these patients suffer from an autosomal recessive, presently unrecognized variant, of chronic neuropathic intestinal pseudoobstruction. In a patient with severe peripheral neuropathy of unknown etiology associated with symptoms suggestive of intestinal obstruction, the possibility of chronic neuropathic intestinal pseudoobstruction has to be considered.

Adolescent↗
PubMed1987

Familial progressive neuronal disease and chronic idiopathic intestinal pseudo-obstruction.

Chronic idiopathic intestinal pseudo-obstruction (CIIP) is characterized by recurrent episodes of bowel obstruction without mechanical cause. In five members of two Jewish-Iranian families, CIIP was associated with progressive neuronal disease, starting before age 30, with ophthalmoplegia, sensorimotor peripheral neuropathy, and hearing loss. There was no evidence of CNS involvement. The pattern suggested autosomal recessive inheritance.

Adolescent↗
PubMed1987

Involvement of the peripheral nervous system in temporal arteritis-polymyalgia rheumatica. Report of 3 cases and review of the literature.

Involvement of the peripheral nervous system is very uncommon in the temporal arteritis-polymyalgia rheumatica syndrome. Three different presentations of the involvement can be recognized: mononeuropathy, polyneuropathy and brachial neuropathy--C-5 radiculopathy. We report 3 patients in whom peripheral nerve symptomatology dominated the clinical picture of the disease, and review 20 previously published cases.

Aged↗
PubMed1986

Hypovitaminosis E induced neuropathy in exocrine pancreatic failure.

A 4 year old girl with congenital nerve deafness and pancreatic insufficiency had incapacitating ataxia. Electrophysiological studies of the median nerve and the brain stem evoked response were abnormal. Serum vitamin E concentration was low. After intramuscular injections of vitamin E the ataxia disappeared and electrophysiological variables reverted to normal.

Ataxia↗
PubMed1979

Structural changes in single muscle fibers after stimulation at a low frequency.

Direct stimulation of single muscle fibers from Xenopus laevis at a frequency of 1 Hz results in a decline of the peak isometric twitch tension after about 200 twitches. Fibers were chemically fixed in glutaraldehyde after a varying number of twitches and at several fatigue levels, and the ultrastructural appearance was compared with that of resting fibers treated by identical fixation methods. No gross structural abnormalities were observed but subtle changes occurred. The mitochondria of stimulated fibers contain granules of normal size and number. The inner crista width is constant but the matrix width is increased on stimulation. These changes would not compromise ATP production. The myofibrils are normal except for a slight swelling in the myosin lattice. The transverse system (T system) and sarcoplasmic reticulum are intact. The minor diameter of the transverse tubule (T tubule) is increased slightly in stimulated fibers. The gap between the T-TC membranes stays constant at about 110 A, but tiny connecting pillars are seen to cross this gap more frequently in stimulated fibers (21 +/- 5% triads) than in resting fibers (8 +/- 6%). In stimulated fibers there is a marked increase in the electron dense content of the terminal cisternae (TC). Inasmuch as the observed structural changes correlate with the number of twitches but not with the fatigue level, it is concluded that TC density and T-TC pillar formation are related to the normal mechanisms of excitation-contraction coupling.

Action Potentials↗
PubMed1979

Intracellular localization of markers within injected or cut frog muscle fibers.

Many experimental procedures require drastic alterations of muscle fibers, such as cutting the fiber or injecting molecular probes through microelectrodes. We report the ultrastructure of similarly altered muscle fibers and the intracellular distribution of injected horseradish peroxidase (HRP). Cut fibers appear structurally normal at distances greater than 500 microM from the cut end, however, the structure deteriorates nearer to the cut. HRP diffuses longitudinally about 2,000 micrometer from the cut end and the concentration is uniform over the fiber's cross section. If HRP is introduced intracellularly either by pressure injection or through a nick in the sarcolemma, it distributes in a C-shaped annulus extending approximately 2,000 micrometer longitudinally and 1-20 micrometer radially. The ultrastructure of injected or nicked fibers appears normal. The HRP freely entered the junctional gap between T-system and sarcoplasmic reticulum (SR) but was excluded from either structure. Occasionally, a light pillar could be seen between T-system and SR; the space of these pillars suggest they are the central area of the "feet" appearing light against the dark marker.

Animals↗
PubMed1979

H reflex analysis of segmental reflex excitability in flexor and extensor muscles.

In normal adults, H reflexes are commonly found only in the antigravity calf and flexor carpi radialis (FCR) muscles. However, these responses may be more widespread if agonist muscles contract. This study demonstrates that H reflexes may be found in the peroneal (P) and anterior tibialis (TA) muscles in the leg and the extensor digitorum communis (EDC) muscle in the arm on contraction of the antagonistic calf and flexor carpi radialis muscles, respectively. H reflexes were also elicited regularly in the EDC by passive extension of the wrist. The data indicate physiologic unity of comparably acting human antigravity muscles and their antagonists in both the upper and lower extremities, and imply an important functional role of group II afferent fibers in normal motor system activity.

Adult↗
PubMed1978

Latency-relaxation in single muscle fibres.

1. Latency relaxation and twitch tension were recorded simultaneously in single isolated muscle fibres of Xenopus laevis. 2. During low frequency (0.6 or 1 pulse/sec) repetitive stimulation, three successive phases of twitch tension were observed: negative staricase (a slight drop in tension), positive staircase (about 15% increase in tension) and fatigue. At the same time the amplitude of latency relaxation decreased monotonically, and near the peak of positive staircase, the amplitude decreased almost to an undetectable level. 3. The application of caffeine (0.1--1.5 mM) increased peak twitch tension by 15--200%, but decreased the latency relaxation amplitude by 30--93%. 4. The application of Ca-release inhibitors, deuterium oxide and dantrolene sodium, caused a 43--89% decline in peak twitch tension but no change in latency relaxation amplitude. 5. The lack of correlation between changes in peak twitch tension and latency relaxation amplitude suggests that latency relaxation is associated with the mechanism which triggers Ca2+ relase rather than with Ca2+ release itself.

Animals↗
PubMed1976

Dye absorption changes in single muscle fibers: an application of an automatic balancing circuit.

It is very difficult to record small potential changes in the presence of a large background voltage that drifts. This is particularly true in recording optical changes during excitation of nerve and muscle because the optical changes are usually very small compared with the background. We describe a convenient circuit, which is useful under these circumstances. This circuit automatically balances the background drift. Using this circuit we recorded light absorption changes during excitation of single muscle fibers stained with a fluorescence dye merocyanine 540. The optical change consists of three components. The first component presumably reflects the action potential of the surface membrane and the T-system. The second and the third components are perhaps the movement artifacts from latency relaxation followed by contraction.

Action Potentials↗
PubMed1976

Electromechanical coupling in tubular muscle fibers. II. Resistance and capacitance of one transverse tubule.

In tubular muscle fibers of the yellow scorpion the transverse tubules are arranged in a radial symmetry. This particular morphology, enables one to derive values for electrical components of one transverse tubule (TT) by treating the TT as a core conductor rather than a complex network. The electrical properties of tubular muscle fibers were completely characterized and analyzed by measuring two independent functions of frequency, i.e., the characteristic impedance and the propagation function. The impedance of a single tubular muscle fiber was determined with microelectrodes over the frequency range 1 Hz to 1.5 kHz. The results were fitted to a possible equivalent circuit model which is based on morphological evidence. The average component values for this model are: Ri = 209 omega-cm, Rm, and RT = 980 omega-cm2 (referred to unit area of surface membrane), Cm and CT = 0.9 muF/cm2, and RL = 103 omega-cm. Relating the equivalent circuit to ultrastructure shows that the average component values are consistent with the hypothesis that the TT is open to the extracellular medium, the electrical capacity of surface and TT membranes is about 1 muF/cm2, and the spread of surface depolarization into the TT is attenuated by about 25%.

Animals↗
PubMed1972

Electromechanical coupling in tubular muscle fibers. I. The organization of tubular muscle fibers in the scorpion Leiurus quinquestriatus.

The tubular fibers of the claw-closer muscle of the scorpion have a central core containing nuclei and mitochondria. The myofibrils have the shape of thin lamellae (1 micro) extending radially from the core to the surface membrane (20 micro). The thick myofilaments are organized in a hexagonal array with orbits of 10-13 thin myofilaments. The ratio of thick-to-thin filaments is 1:5. Transverse tubular system (TS) openings are located between lamellated myofibrils. In each sarcomere two TS's are found, one on each side of the H band. The TS is composed of a transverse tubule and tubular pockets (TP). The TP's form diadic contact with the terminal cisternae of the sarcoplasmic reticulum. The TS can be traced from the cell membrane down to the cell core. The surface area of the TS was calculated to be six times that of the outer surface membrane.

Action Potentials↗