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Biomedical subjects

K Valmikinathan

Publications and source records attributed to K Valmikinathan.

At least 19 recordsLinked to original sources

Serum pyruvate kinase in carriers of Duochenne muscular dystrophy.

Independent studies by two different groups (Madras and Edinburgh) have failed to confirm the suggestion that measurement of the serum level of pyruvate kinase (EC 2.7.1.40, PK) may be superior to measurement of the serum level of creatine kinase (EC 2.7.3.2, CK) for detecting female carriers of X-linked Duchenne muscular dystrophy (DMD). At present the serum level of creatine kinase remains the best test for this purpose.

Adult↗

Plasma lactate in anterior horn cell disease.

This communication reports biochemical findings in 7 patients with anterior horn cell disease. The diagnosis was confirmed by evidence of denervation in the EMG and mukle biopsy with normal motor conduction velocities. In 4 of these patients, upper extremities were involved in a symmetrical fashion. In 1, the upper and lower extremities were involved in a symmetrical fashion. In the other 2, one upper or lower extremity were respectively involved in isolation. Pyramidal tract signs were evident in 2 patients of this group. Seventh cranial nerve and 12th cranial nerve involvement were seen in 2 patients. None of the patients manifested 8th cranial nerve dysfunction. All of these 7 patients showed elevation of raised fasting plasma lactate, with normal plasma citrate and plasma pyruvate values. This is in contrast to the altered citrate and pyruvate levels described by other workers in other cases of anterior horn cell disease. The significant biochemical relationship are discussed.

Adolescent↗

Anterior horn cell disease seen in South India.

Thirty-two patients with clinical evidence of anterior horn cell dysfunction are descirbed. This group of patients could be divided into those with bulbar dysfunction, and those without. Eighth cranial nerve involvement was seen in 10%. The commonest perpheral distribution seen was symmetrical involvement of all four extremities. During the period of follow-up (1 to 5 years) none of the patients without bulbar dysfunction initially developed such symptoms. In all these patients electromyographic evidence of anterior horn cell disease was confirmed. The motor nerve conduction velocities in all of these patients were normal. None of them showed signs of pyramidal tract involvement. Muscle biopsy showed evidence of group fibre atrophy in 10 cases, was normal in 3, and showed a myopathic pattern in 1. Sural nerve biopsy obtained in a single patient was considered histologically normal. Plasma citrate and plasma pyruvate levels obtained in 5 patients of this group, showed elevated values for plasma citrate with normal plasma pyruvate levels. Conspicuous absence of pyramidal signs, elevated plasma citrate, normal plasma pyruvate values and the extremely slow progression suggest that this group of patients are different from other varieties of anterior horn cell dysfunction previously described.

Adolescent↗

Serum factors influencing creatine phosphokinase. In vitro studies using diffusates.

In vitro studies with diffusates obtained following dialysis of serum samples have enabled us to confirm the presence of inhibiting and activating factors influencing CPK activity. Activating factors are commonly found in many neuromuscular disorders like Duchenne muscular dystrophy (DMD), spinal muscular atrophy and hypothyroid neuromyopathy, and inhibiting factors in dermatomyositis. These findings are further elaborated during serial serum CPK studies after EMG in 3 cases of neurogenic atrophy and 1 case of DMD. The in vivo inhibitory and activating influence of serum factor(s) at 96 and 160 hr respectively after EMG was confirmed by in vitro studies with the diffusates of these serum samples. The functional variations of these diffusates are shown to be related to differences in the composition of these diffusates suggested by paper chromatography.

Creatine Kinase↗

Biochemical aspects of motor neurone disease--Madras pattern.

A detailed study of four cases of MND-Madras has shown a significantly low plasma citrate level in these subjects. Comparison with other related groups of neurological disorders indicates the citrate/pyruvate ratio to be of diagnostic value in MND-Madras. This seems to suggest that the pathophysiology of MND-Madras may centre round altered citrate metabolism.

Adult↗