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Biomedical subjects

K Iqbal

Publications and source records attributed to K Iqbal.

At least 181 records · Page 10Linked to original sources
PubMed1982

Reduction of neuronal specific protein and some neurotransmitters in the infantile neuroaxonal dystrophy (INAD).

INAD with classical clinicopathological features was seen in three children of one family. They presented with a history of regression after the age of 1.5 years and died in mental institutions at the ages of 6, 7 and 9. Two of them had postmortem neuropathological studies, one had brain biopsy and one biochemical study. The following observations have been made; I. Histological--(1) some axonal loss with almost total absence of neurofilaments in dystrophic neurites and (2) marked degenerative changes and loss of synaptic vesicles; II. Biochemical--(1) the decrease of the neurofilament polypeptides by up to 75% and (2) a reduction of some neurotransmitter enzymes. The presence of intermitochondrial septate junctions. The neurofilament protein is specific to neurons and makes up a large percentage of their protein content. Neurofilaments have been implicated in several cellular functions such as intracellular transport and in the maintenance of cell structure. The decrease of neurofilament protein in our case is compatible with our morphological findings where we found decreased numbers of axons and an almost total absence of neurofilaments in the affected neurites.

Axons↗
PubMed1981

Abnormal fibrils from scrapie-infected brain.

Abnormal fibrillary structures, designated "scrapie-associated fibrils" (SAF), have been observed using negative stain techniques in subfractions of brains from scrapie-affected animals. SAF have been observed in all combinations of strain of scrapie agent and strain or species of host examined, regardless of their histopathology, in particular the presence or absence of amyloid plaques. SAF consist either of two or four filaments. They are morphologically dissimilar to the normal brain fibrils--microtubules, neurofilaments, glial filaments, and F actin. However, SAF do bear a resemblance to amyloid.

Amyloid↗
PubMed1981

Relapsing experimental allergic encephalomyelitis induced with isolated myelin and with myelin basic protein plus myelin lipids.

To test the ability of different spinal cord fractions to reproduce the clinicopathological features of relapsing experimental allergic encephalomyelitis (R-EAE), groups of young guinea pigs were inoculated with: (1) spinal cord myelin; (2) delipidated myelin; (3) reconstituted myelin and (4) MBP plus myelin lipids. The four sets of antigens induced acute EAE in most of the animals tested. During an observation period of 18 months, only one clinical relapse was observed in animals sensitized with myelin and with MBP plus myelin lipids. Extensive CNS demyelination was found in relapsing animals injected with myelin. No demyelinated lesions were observed in non-relapsing animals. By contrast, half of the surviving guinea pigs injected with MBP plus myelin lipids had demyelinated lesions, irrespective of whether they relapsed or not. The inability of the spinal cord myelin fractions to fully reproduce the R-EAE model suggest that other non-myelin antigens may be involved in the pathogenesis of multiple relapses.

Animals↗
PubMed1981

The loss of neuron-specific proteins during the course of Wallerian degeneration of optic and sciatic nerve.

To identify axonal proteins which are unique constituents of neurons, the spectrum of detectable proteins of degenerating nerves has been compared with that of intact control nerves from the same animals. Wallerian degeneration was induced in rabbits by unilateral transection of the optic and sciatic nerves. Proteins of nerve homogenates were compared by sodium dodecyl sulfate-gel electrophoresis and by two-dimensional electrophoresis. Four non-myelin proteins disappear from degenerating nerve. These include the three neurofilament proteins (P68, P150, and P200) and a polypeptide with a molecular weight of about 65,000 daltons (P65) which is not associated with filaments.

Animals↗
PubMed1980

Central cholinergic activity in aluminum-induced neurofibrillary degeneration.

Choline acetyltransferase (CAT) and acetylcholinesterase (AChE) activities were measured in spinal cord homogenates from rabbits with aluminum-induced neurofibrillary degeneration and a group of saline-treated, age-matched controls. All aluminum-treated animals showed neurofibrillary changes in the spinal cord, but CAT and AChE activities were not significantly different from levels in control animals. These results are at variance with the greatly reduced activity of these enzymes observed in Alzheimer disease and senile dementia of the Alzheimer type.

Acetylcholinesterase↗
PubMed1980

Regional distribution of choline acetyltransferase and acetylcholinesterase in rabbit brain.

Regional distribution of choline acetyltransferase (CAT) and acetylcholinesterase (AChE) in seventeen regions of the rabbit CNS has been determined by means of the cation exchange radiometric method. A significant correlation has been found between the activities of AChE and CAT which allows computation of their potencies. A comparison between activities of the cholinergic enzymes in the human and rabbit brain has been discussed.

Acetylcholinesterase↗
PubMed1979

Evidence that Alzheimer neurofibrillary tangles originate from neurotubules.

Antiserum against normal human neurotubules purified by in-vitro assembly precipitated both neurotubules and a polypeptide isolated from Alzheimer neurofibrillary tangles in Ouchterlony double-diffusion tests. The antiserum specifically labelled neurofibrillary tangles, in isolated neurons by immunofluorescence and in tissue sections by the peroxidase-antiperoxidase technique. These results indicate that neurofibrillary tangles in Alzheimer's disease probably originate from neurotubules.

Adult↗
PubMed1979

Alzheimer neurofibrillary tangles: antiserum and immunohistological staining.

A 50,000-dalton polypeptide has been purified from fractions enriched with neurofibrillary tangles of paired helical filaments from human autopsy specimens of Alzheimer disease and senile dementia of the Alzheimer type. An antiserum to this polypeptide was raised in a rabbit. This antiserum formed an immunoprecipitation line with the purified antigen and with human neurotubules in ouchterlony double-diffusion plates. The reactivity of the anti-paired helical filament protein serum with neurofibrillary tangles was studied by immunofluorescence on cryostat sections of hippocampus from Alzheimer autopsy tissue and by the peroxidase-antiperoxidase technique on paraffin sections of an Alzheimer brain biopsy. The tangles were stained with the antiserum in both systems. Preimmune rabbit serum and unrelated hyperimmune sera, used as controls, did not stain the tangles. These results show that the 50,000-dalton polypeptide purified from the neurofibrillary tangle-enriched fractions is a constituent of Alzheimer neurofibrillary tangles and, perhaps, of the paired helical filaments of which the tangles are composed.

Alzheimer Disease↗
PubMed1979

Brain aluminum in aging and Alzheimer disease.

Aluminum was assayed by atomic absorption spectroscopy in 274 brain samples, and assayed in neurons isolated in bulk from the frontal cortex of patients with Alzheimer dementia and from age-matched patients with no neurologic disease. Brain aluminum concentration increased with age, from late middle age to old age. There were no statistically significant differences in brain aluminum concentration between the 10 patients with Alzheimer disease (mean, 2.7 microgram per gram dry weight of tissue; mean age, 81 years), and the 9 nonneurologic controls (mean, 2.5 microgram per gram; mean age, 73 years). In both groups, the hippocampus had the highest concentration of aluminum (5.6 microgram per gram), and the corpus callosum the lowest (1.5 microgram per gram).

Adult↗
PubMed1978

Chemical relationship of the paired helical filaments of Alzheimer's dementia to normal human neurofilaments and neurotubules.

Intraneuronal fibrillary tangles are prominent features of several neurological diseases, including especially Alzheimer presenile and senile dementia, and to a much lesser degree in the normal aged human brain. These tangles are made up of abnormal fibrillar elements each about 22 nm at its widest, periodically reduced to 10 nm at about every 80 nm. Each abnormal fiber seems to be a pair of 10 nm filaments helically wound around each other. In this study the protein subunit of these paired helical filaments isolated from cases of Alzheimer's dementia was compared with the major protein subunits of normal neurofilaments and neurotubules by two-dimensional peptide maps of the tryptic or chymotryptic digests of these proteins labelled with 125I. The paired helical filament protein is very similar in its peptide maps to identically treated major neurofilament protein and to the beta monomer of neurotubule, while it is not so similar to the alpha tubulin. These data suggest that the paired helical filament protein subunit is closely related chemically to the normal neurofilament protein subunit, and the beta tubulin.

Alzheimer Disease↗
PubMed1978

Encephalitogenic properties of purified preparations of bovine oligodendrocytes tested in guinea pigs.

The present study has investigated central nervous system disease in guinea pigs inoculated with emulsions containing purified preparations of bovine oligodendroglia and their fractions isolated with or without trypsinization, whole bovine white matter or myelin basic protein (MBP). The MBP content of the oligodendroglial fractions was determined by radioimmunoassay. It was found that oligodendroglia prepared from trypsinized fresh brain contained minute amounts of MBP and did not induce disease. The corresponding cell fraction from non-trypsinized frozen brain was rich in MBP and induced disease. Bovine white matter and MBP induced typical experimental allergic encephalomyelitis (EAE). The structural preservation of the non-encephalitogenic trypsinized MBP-poor cells was very good and that of the encephalitogenic MBP-rich non-trypsinized cells very poor. It has been concluded that the encephalitogenicity observed was due to MBP, rather than to a specific oligodendroglial antigen.

Animals↗