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Biomedical subjects

S F Sun

Publications and source records attributed to S F Sun.

At least 37 records · Page 2Linked to original sources
PubMed1983

Distribution of electrical myotonia in myotonic muscular dystrophy.

Twenty-five successive patients with myotonic dystrophy were examined to determine the anatomical distribution of electrical myotonia. Proximal and distal limb muscles and orbicularis oris and masseter muscles were examined. Electrical myotonia was present in all muscles examined in only 3 patients. Moreover, of the 15 muscles examined, none showed myotonic discharges in every patient, the highest individual muscle involvement being 96%.

Adolescent↗
PubMed1983

Autosomal recessive generalized myotonia.

Two siblings and a first degree cousin of a consanguinous marriage were afflicted with recessive generalized myotonia (RGMy). All had muscle weakness which was particularly prominent after rest, thinning of the forearms, weakness of anterior compartment muscles, and muscular contractures. The first degree cousin was the most severely afflicted with congenital myotonia. Muscle biopsy and electromyography were consistent with a myopathy. Exercise after rest demonstrated a marked reduction in muscle membrane excitability in all patients.

Adult↗
PubMed1983

Myotonic dystrophy: limited electromyographic abnormalities in 2 definite cases.

Two women, aged 37 and 38, with definite myotonic dystrophy are presented. Neither patient had clinical myotonia although both experienced intermittent jaw tightness. Electromyographic (EMG) myotonia was seen only in the masseter muscle in one and in the masseter and flexor pollicis longus muscle in the other patient. The detection rate of EMG-myotonia in clinically normal heterozygotes increases if distal, proximal and cranial nerve innervated muscles are examined.

Adult↗
PubMed1982

Brachial plexopathy in patients with breast cancer: unusual electromyographic findings in two patients.

2 patients with breast cancer developed progressive brachial plexopathy. The unusual electrographic finding in both patients was conduction block (neuropraxia) along the medial cord of the brachial plexus. The plexus was explored in 1 patient. Constrictive connective tissue or another source of nerve entrapment was not identified. The exact cause of the conduction block remains unclear; its presence neither indicates a good prognosis nor an indication for surgical exploration.

Aged↗
PubMed1981

Diabetic thoracoabdominal neuropathy: clinical and electrodiagnostic features.

Five diabetic patients developed upper back or abdominal pain associated with substantial weight loss in three. Electrophysiological evidence of associated thoracoabdominal somatic neuropathy was found in all cases. Signs of a generalized neuropathy were present in two patients, and four had asymmetrical proximal leg weakness. At least two have improved spontaneously. The syndrome is closely related to diabetic amyotrophy; it is probably more common than is recognized.

Abdominal Muscles↗
PubMed1981

Injection injury of the sciatic nerve: unusual anatomic distribution of nerve damage.

Sciatic nerve damage by intragluteal injections tends to injure the peroneal nerve trunk more severely than the other components of the sciatic nerve. 2 patients with predominant or sole damage to the posterior tibial nerve trunk were observed. This distribution was documented electrophysiologically. Our cases are unusual and point to a wider spectrum of such injuries. It is also suggested that internal fibrosis of the nerve is of greatest importance as a pathogenetic mechanism in these injuries.

Adult↗
PubMed1978

Structural studies on the succinylated bovine serum albumin.

An analysis of succinylated bovine serum albumin showed that all of the 62 epsilon-amino groups of lysine residues, 13 hydroxyamino acid residues and 12 tyrosin residues were succinylated, but the succinylated tyrosines were later deacylated. Structural properties of the modified protein have been studied with circular dichroism and sedimentation velocity. At neutral pH (pH 7.60) and in a salt-free aqueous solution the modified protein is in an expanded form and its helical content is only 30% of that of unmodified protein. The increase of ionic strength restores the original conformation of the protein, whereas the increase of pH further disorganizes the structure of the protein. The results suggest that the electrostatic force alone is responsible for the compact structure of the protein molecule. The same mechanism is believed to underlie the effect of H3O+ and the effect of succinylation of the side chain groups on the conformation of bovine serum albumin.

Amino Acid Sequence↗
PubMed1975

Bovine serum albumin in lithium chloride solutions.

The effects of li+ and H3O+ on the conformation of bovine serum albumin in azqueous solutions at room temperature are compared. At low pH (high concentration of H3O+) the change in conformation of the protein is demonstrated by an increase in effective volume, a decrease in helical content and a blue shift of tyrosyl residue. A similar change is observed for the protein in highly concentrated LiC1 solution (6.0-7.0M) at neutral pH. However, the H3O+ is 12,000 times more powerful than the Li+ in destabilizing the protein molecule. This is consistent with their thermodynamic and kinetic properties, since the H3O+ is often different from the Li+ in several orders of magnitude. While the changes in structural properties of the protein are almost identical in both the acidic solution and the highly concentrated LiC1 solution, further study using dioxane as a probe suggests different mechanisms under which the changes occur. The effect of H3O+ is related to electrostatic force, whereas the effect of Li+ is related to both the electrostatic hydrophobic forces. These two major forces are believed to be responsible for the conformation of protein molecules.

Chlorides↗