Reaction of peripheral nerves to vascular and bacterial injuries.

Mouse sciatic nerves were subjected to devascularization, M. leprae inoculation, and combined insult of devascularization + footpad inoculation (FPI). Changes were seen in FPI nerves only after eight months, but in cases of combined insult, changes were evident in hours. Both the groups showed initial loss of small myelinated fibres. No proliferation of Schwann cells was in FPI nerves, but in combined insult it was maximum after two weeks. Presence of M. leprae seems to be arresting Schwann cell activity after two weeks. Blood vessels showed increased endothelial cell cytoplasm, basement membrane proliferation and villi formation. These changes seem to be specific of endoneurial blood vessels of leprosy nerves. Increased number of mast cells seems to be specific of devascularized and FPI nerves. Increased number of macrophages expressed low immunity of devascularized nerves. Eosinophils migrated to endoneurium as a result of leakage of axoplasm.

Fc and complement receptor integrity of polymorphonuclear (PMN) cells following thermal injury.

In patients sustaining thermal injury, a sequential study was formulated to evaluate Fc and complement receptor expression of polymorphonuclear cells (PMN). Additionally, the role of factors in burn sera and maturity of PMN cells in the circulation were studied. The salient features of the study were: Marked reduction in Fc receptor expression by the 5th day of injury in both survivors and non-survivors. Thereafter levels gradually increased in survivors, though they were still below the normal range. In non-survivors, the depression was severe and persistent. In contrast to Fc receptor expression, complement receptor integrity was not grossly affected in both survivors and non-survivors. Burn sera collected from survivors on the 5th and 13th post-burn day showed reduction in Fc receptor expression of normal PMN cells, whereas sera obtained a month after the injury exhibited no inhibitory effect. Non-survivors sera inhibited Fc receptor expression of normal PMN cells on 5th, 13th and 21st post-burn days. The appearance, increase and disappearance of immature PMN cells in the circulation was correlated with the clinical progress of the patient. Mechanisms involved in the aberrations and its implications are discussed.

Ultrastructure of sciatic nerve of armadillo infected with Mycobacterium leprae.

Ultrastructural observation of sciatic nerves from eight Armadillos were made. Six animals had intravenous inoculation of M. leprae, one had of foot pad, while one had natural leprosy. The available nerves were biopsied at various time sequence ranging from five weeks to twenty four months. Semithin sections did not reveal any neuropathy. Ultrastructurally perineurium was thick and endoneurial collagen was increased. Initially demyelination of non-myelinated fibres was seen in all nerves irrespective of mode of infection. This was followed by demyelination of small myelinated fibres. Active remyelination was predominantly after 17 months. Schwann cell activity was increased and various stages of division were seen. Bacilli were extracellular, intraxonal, in endothelium and in perineurium. Significant observations were on blood vessels. These observations are discussed.

Histopathology of vitiliginous skin.

A histological study of 74 vitiligo cases revealed inflammatory and degenerative changes in the epidermis, papillation, blood vessels, sweat glands and ducts, sebaceous glands and hair follicles, dermis (connective tissue), and dermal nerves and nerve endings.

Study of thickened nerves in a leprosy endemic region. Part II--Ultrastructural and tease fibre study.

Ten out of sixteen cases of thickened nerves labelled as having idiopathic neuropathy showed hypertrophic changes, when their peripheral nerves were observed under light microscopy. Electron microscopy of seven nerves revealed more details. The reactions in various parameters of nerves were recorded. The significant observation was of one case harbouring Lepra bacilli as seen under electron microscope and having other changes similar to changes seen in early cases of leprosy. Two cases were also thought to have leprosy on the basis of the ultrastructural observation on their nerves. These could have been missed otherwise.

Study of evolution of nerve damage in leprosy. Part II--Observations on the index branch of the radial cutaneous nerve in contacts of leprosy.

A total of 35 contacts from 20 families of lepromatous index cases were screened clinically. All of them were subjected for nerve conduction velocity (NCV) studies of both left and right index branch of the radial cutaneous (IRC) nerve. Fifteen of these nerves were biopsied. Out of 15 IRC nerves biopsied 10 had slightly reduced average NCV values and 5 were normal. Four nerves out of 10 where average NCV was reduced and 1 nerve out of 5 where NCV was normal showed significant ultrastructural changes and higher percentage of segmental demyelination (10%--13%). There was a striking similarity between the changes seen in the IRC nerves of early cases of leprosy and of contacts.

Study of the evolution of nerve damage in leprosy. Part I--Lesions of the index branch of the radial cutaneous nerve in early leprosy.

A total of six index finger branch of the radial cutaneous (IRC) nerves from three BL, two BB and one BT cases of leprosy, with less than 6 months history of disease were subjected for nerve conduction velocity (NCV) studies followed by biopsy. The biopsy was divided into three parts and subjected for light microscopy quantitative histology, electron-microscopy and fibre tease studies. The nerves revealed a slight reduction in NCV and a varying degree of segmental demyelination ranging from 10% to 35%. The earliest changes observed were the thickening and proliferation of Schwann cell processes of the unmyelinated fibres and degeneration of their axons regardless of the type of leprosy.

Study of the evolution of nerve damage in leprosy. Part I--Lesions of the index branch of the radial cutaneous nerve in early leprosy / Study of evolution of nerve damage in leprosy. Part II--Observations on the index branch of the radial cutaneous nerve in contacts of leprosy

A total of six index finger branch of the radial cutaneous (IRC) nerves from three BL, two BB and one BT cases of leprosy, with less than 6 months history of disease were subjected for nerve conduction velocity (NCV) studies followed by biopsy. The biopsy was divided into three parts and subjected for light microscopy quantitative histology, electron-microscopy and fibre tease studies. The nerves revealed a slight reduction in NCV and a varying degree of segmental demyelination ranging from 10% to 35%. The earliest changes observed were the thickening and proliferation of Schwann cell processes of the unmyelinated fibres and degeneration of their axons regardless of the type of leprosy. A total of 35 contacts from 20 families of lepromatous index cases were screened clinically. All of them were subjected for nerve conduction velocity (NCV) studies of both left and right index branch of the radial cutaneous (IRC) nerve. Fifteen of these nerves were biopsied. Out of 15 IRC nerves biopsied 10 had slightly reduced average NCV values and 5 were normal. Four nerves out of 10 where average NCV was reduced and 1 nerve out of 5 where NCV was normal showed significant ultrastructural changes and higher percentage of segmental demyelination (10%--13%). There was a striking similarity between the changes seen in the IRC nerves of early cases of leprosy and of contacts.

Teased fibre study of early nerve lesions in leprosy and in contacts, with electrophysiological correlates.

A teased fibre technique was used to study 19 biopsies of the index finger branch of the radial cutaneous nerve of leprosy patients and contacts. These were compared with four normal nerves. Five nerves were from patients with preclinical nerve lesions, five from leprosy patients with minimal sensory nerve impairment, and five from contacts of lepromatous leprosy. The extent of demyelination in preclinical nerve lesions in leprosy and in contacts of leprosy is recorded. The usefulness of nerve conduction velocity studies in early leprosy patients and in contacts is discussed.

Teased fibre study of early nerve lesions in leprosy and in contacts, with electrophysiological correlates

A teased fibre technique was used to study 19 biopsies of the index finger branch of the radial cutaneous nerve of leprosy patients and contacts. These were compared with four normal nerves. Five nerves were from patients with preclinical nerve lesions, five from leprosy patients with minimal sensory nerve impairment, and five from contacts of lepromatous leprosy. The extent of demyelination in preclinical nerve lesions in leprosy and in contacts of leprosy is recorded. The usefulness of nerve conduction velocity studies in early leprosy patients and in contacts is discussed.

Quantitative, histologic and ultrastructural studies of the index branch of the radial cutaneous nerve in leprosy and its correlation with electrophysiologic study.

A correlative study of clinical, electrophysiological, quantitative, histopathologic and ultrastructural changes seen in 13 instances of the index branch of the radial cutaneous nerve was undertaken in leprosy patients. Testing by graded nylon proved to be more reliable than any other conventional clinical tests. The quantitative studies revealed that small-sized fiber loss was encountered in the early stages of nerve involvement in leprosy followed by loss of large-sized fibers with or without increase in small-sized fibers. Segmental dymyelination of small-sized fibers was seen in early stages of degeneration in leprosy nerves irrespective of type of leprosy. Wallerian degeneration was encountered in advanced stages with total destruction of the nerves. At the ultrastructural level clinically normal nerves of leprosy patients (LN series) showed minimal but significant changes, such as thickening of the basement membrane of perineurial cells, as well as an increase in the amount of collagen between the perineurial layers. Marked increases in the amount of endoneurial collagen were noticed. Axons devoid of myelin, probably demyelinated fibers, were occasionally observed. Slight proliferation of the basement membrane of the endothelial cells was also observed. These changes were of a more advanced nature in the clinically involved cases of leprosy (L series). Two BL types of cases from the L series, showed presence of M. leprae in Schwann cell cytoplasm of myelinated and unmyelinated fibers, perineurial cells, in endothelial cells and macrophages. In cases having impaired sensory modalities (L series), thickening of the perineurium was due to increase in the number of layers of perineurial cells in addition to the increase in collagen. Probably one of the ways in which unmyelinated fibers degenerate is by splitting the Schwann cell columns and extrusion of the axons. Collagen pockets were seen in the LN series of cases. These are probably the degenerated nonmyelinated fibers being replaced by collagen fibrils. Postoperative clinical charting was done on the patient whose IRC nerves were removed. It showed complete restoration of all modalities of sensation in the area of its distribution by the end of three months.