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Biomedical subjects

E T Hedley-Whyte

Publications and source records attributed to E T Hedley-Whyte.

At least 109 records · Page 6Linked to original sources
PubMed1985

Ataxic Creutzfeldt-Jakob disease: diagnostic techniques and neuropathologic observations in early disease.

We studied two cases of ataxic Creutzfeldt-Jakob disease. EEG, CT, evoked responses, and CSF were normal in one purely ataxic patient. Diagnosis was established by cerebellar biopsy. Autopsy demonstrated devastating spongiform changes in the cerebellum, basal ganglia, and thalamus with rare focal changes in cerebral cortex. In the second patient, late generalized changes developed with dementia. Diagnostic studies included abnormal visual evoked responses, CSF with abnormal oligoclonal bands and IgG, and subacute spongiform encephalopathy in frontal lobe biopsy. Early diagnosis is best established by biopsy of brain areas most likely to be involved on the basis of clinical neurologic findings.

Ataxia↗
PubMed1985

Cervical diastematomyelia presenting in adulthood. Case report.

A case of cervical diastematomyelia in an adult is reported. The patient first noted sensory and motor symptoms at 34 years of age after two episodes of cervical trauma. Metrizamide computerized tomography myelography of the cervical spine and cord showed the region of diastematomyelia and revealed a spur containing both bone and fat tissue projecting into the spinal canal and cord. The spur arose from the laminae and spinous processes of C-2 and C-3, and was successfully excised. Postoperatively, the patient's deficits gradually improved. The literature concerning adult cervical diastematomyelia is reviewed.

Adult↗
PubMed1984

Sex-linked hereditary bilateral anophthalmos. Pathologic and radiologic correlation.

A 27-year-old man had X-linked true anophthalmos. No evidence of optic globe, nerves, or chiasm was found. Rudimentary structures suggesting optic tracts were present. Lateral geniculate nuclei were present but gliotic. Calcarine cortex was thinner but had usual lamination. The normal patches of cytochrome oxidase activity in layers II and III of visual cortex were absent.

Adult↗
PubMed1984

Limitations of tetrazolium salts in delineating infarcted brain.

Tetrazolium salts, histochemical indicators of mitochondrial respiratory enzymes, have been used by some pathologists to detect infarcts in myocardium. We explored the utility of this technique in detecting experimental brain infarcts and report our findings. Infarcts were produced in cats, gerbils, and rats by unilateral temporal and permanent cerebral vessel occlusion. After various time periods the animals were killed, and their brains were reacted with 2,3,5, triphenyl, 2H-tetrazolium chloride (TTC). The experimental and contralateral hemispheres were examined by light and electron microscopy. The TTC-stained tissue was correlated with histology. In some situations the histological condition of the tissue correlated well with the TTC staining results. Brain regions supplied by temporarily occluded vessels and judged infarcted by light and electron microscopy did not stain. In these regions less than 6% of the mitochondria were intact. In brain tissue from animals with permanent vessel occlusion (no reflow) mitochondria were intact despite the fact that other cellular organelles, such as nuclei, were destroyed. TTC stained such mitochondria and as a result could not distinguish infarcted brain in complete ischemia situations (no reflow). Another draw back to this staining procedure was 36 h after infarction macrophages with intact mitochondria would replace damage neurons and be stained. Under ideal conditions though this technique can detect irreversibly damaged brain as early as 2.5 h after artery occlusion.

Animals↗
PubMed1983

Idiopathic hemochromatosis (IHC): dementia and ataxia as presenting signs.

Idiopathic hemochromatosis (IHC) is a genetically determined impairment in control of iron absorption that results in excessive parenchymal iron deposition, particularly in the liver. Of patients with IHC, 50% have little or no chemical evidence of liver dysfunction. Cirrhosis may be clinically occult, but still cause a syndrome of chronic hepatocerebral degeneration. Two patients are reported with IHC and a syndrome of ataxia, rigidity, myoclonic jerks, and dementia. Other associated symptoms may include diminished libido, decreased hearing, peripheral neuropathy, and large joint disease. Because symptoms of IHC can be reversed by phlebotomy, appropriate laboratory studies should be considered to exclude IHC in any patient with unexplained dementia, encephalopathy, and gait ataxia.

Aged↗
PubMed1983

Localized brainstem ischemic damage and Ondine's curse after near-drowning.

A 19-year-old man was a victim of near-drowning in fresh water. After he was resuscitated, examination showed nystagmus, absent gag reflex, diminished facial sensation, dysmetria of all limbs, and failure of automatic respiration. His intellect was perfectly preserved. Eight months later, he died suddenly, and the essential neuropathologic findings were limited to the lower brainstem. There was marked neuronal depletion bilaterally in the nucleus gracilis, nucleus cuneatus, nucleus of the tractus solitarius, nucleus ambiguus, and nucleus retroambiguus; several other lower-brainstem nuclei showed evidence of damage, but to lesser extent. The neuropathologic findings seem to have been an unusual consequence of anoxia-ischemia and support previous concepts of the anatomical localization of the human respiratory centers.

Adult↗
PubMed1982

Primary cerebellopontine progressive multifocal leukoencephalopathy diagnosed premortem by cerebellar biopsy.

A subacute progressive cerebellar brainstem syndrome developed in a patient with systemic lupus erythematosus in remission. Cerebellar biopsy documented the diagnosis of progressive multifocal leukoencephalopathy (PML). Data from this patient and 10 others in the literature emphasize the need to consider this diagnosis when ataxia develops in any patient with underlying malignancy, chronic infection, or other disease that involves immunological incompetence. Although the ataxic form of PML is not of nosological relevance, early diagnosis may eventually have therapeutic importance.

Biopsy↗
PubMed1982

Unilateral white matter necrosis following carotid endarterectomy.

The authors report the first known example of hypoxic-ischemic white matter necrosis limited to one cerebral hemisphere. The patient was a 63-year-old man who developed signs of a stroke following a myocardial infarct after a left carotid endarterectomy and died seven days later. At autopsy, extensive necrosis of centrum semiovale was found only in the cerebral hemisphere supplied by the endoarterectomized carotid artery. A recent thrombus was found at the site of the endarterectomy, and the right common carotid artery was completely occluded by an old thrombus. This observation probably is explained by a well-established collateral blood supply to the right cerebral hemisphere, which protected it from the effects of the hypotension that accompanied the myocardial infarct.

Autopsy↗
PubMed1980

Effects of insulin-induced hypoglycemia on cerebrovascular permeability to horseradish peroxidase.

The effects of hypoglycemia on cerebrovascular permeability to a protein, horseradish peroxidase (HRP), were studied in mice given 3 or 8 units of crytalline zinc insulin intraperitoneally. HRP (10 mg in 0.1 ml saline) was injected intravenously 15 to 20 minutes prior to sacrifice. Both mildly and severely hypoglycemic groups of mice showed a drastic reduction in the normal transit of HRP across cerebral arterioles. The number of normally-stained vessel segments and of HRP-filled endothelial vesicles decreased in insulin-treated mice. In the brains of severely hypoglycemic mice, however, increased parenchymal HRP accumulation occurred. A ruptured blood vessel was found in the center of one-fourth of the focal exudates examined. Electron microscopic examination revealed thrombin, sometimes extending through the vessel wall, and hemorrhage, yet inter-endothelial tight junctions remained intact. Seizures were associated with severe hypoglycemia in 6 out of 10 mice with serum glucose levels below 40 mg/100 ml following 8 units of insulin, but the number of focal exudates per brain was similar in all 10 mice. We conclude that insulin-induced hypoglycemia is associated with decreased HRP transit across cerebral arterioles, and that severe insulin shock is also accompanied by actual rupture of vessel walls and extravasation of blood and HRP into the parenchyma of the brain.

Animals↗
PubMed1978

A contribution to the electron microscopic morphometric analysis of peripheral nerve.

Several aspects of data collection and analyses of peripheral nerve experiments employing light and electron microscopic morphometric techniques have not been adequately discussed in the literature. From statistical tests performed on nerve data, it was found that light compared with electron microscopic morphometry underestimates the number of small fibers. An optimum sampling strategy must take into account a potential bias toward small fibers introduced by measuring fibers from electronmicrographs. It must also take into account a potential bias introduced by the non-random distribution of nerve fibers of different sizes in nerves. These biases are offset by sampling a large enough number of fibers from large enough area electron micrographs. A method is presented for analysing periopheral nerve data using the nested analysis of variance. This requires first dividing the usual bimodal nerve fiber distribution into component normally distributed parts. The number of fibers in the two portions of a bimodal distribution must be considered in data analysis. Knowledge of the variances of parameters to be studied in any particular nerve is necessary for optimum sampling strategies.

Animals↗
PubMed1978

Long term post-traumatic retrograde corticospinal degeneration in man.

The spinal cord and brain of a man who died 18 years after a crush injury of lumbar segments contained some unusual lesions. There was a reduced number of myelinated axons in the corticospinal tracts as high as the fifth cervical segment. Such retrograde degeneration has been described in human pyramidal tracts only a few times. The results of reported studies of experimental retrograde degeneration have been inconsistent. The course of the fasciculus gracilis, as delineated by gliosis, was atypical, and an unusual glial nodule, possibly neoplastic, was present in the dorsal columns at C8.

Accidents, Traffic↗
PubMed1977

Morphometric analysis of the effects of exenteration and enucleation on the development of third and sixth cranial nerves in the rat.

The effects on rat cranial nerve growth of removing various amounts of extraocular muscle was studied using morphometric techniques. Growth in the third cranial nerves was found to be severely retarded when most of the muscle tissue was removed. By contrast, removal of the eye alone, leaving extraocular muscles relatively intact, was found to have little or no effect on the subsequent growth of third and sixth cranial nerve fibers and of extraocular muscle fibers. This conclusion could be drawn only through the application of statistical methods which take into account several generally unrecognized facts: frequency distributions of axon circumference and myelin sheath thickness are highly variable from nerve to nerve even in normal rats, which often have more large fibers in left than in right nerves. The bimodal nature of peripheral nerve fiber distributions precludes the use of such parametric tests as the commonly and inappropriately used t-test, but a non-parametric test such as the Kolmogorov-Smirnov test, extensively used in these studies, is inadequate for data comprising several sets of distributions to be compared. The application of the analysis of variance to some of the data and the merits of the procedure are discussed.

Abducens Nerve↗
PubMed1977

Ultrastructural localization of glial fibrillary acidic protein in mouse cerebellum by immunoperoxidase labeling.

Glial fibrillary acidic protein was localized at the electron microscope level in the cerebellum of adult mice by indirect immunoperoxidase histology. In confirmation of previous studies at the light microscope level, the antigen was detectable in astrocytes and their processes, but not in neurons or their processes, or in oligodendroglia. Astrocytic processes were stained in white matter, in the granular layet surrounding synaptic glomerular complexes, and in the molecular layer in the form of radially oriented fibers and of sheaths surrounding Purkinje cell dendrites. Astrocytic endfeet impinging on meninges and perivascular membranes were also antigen positive. In astrocytic perikarya and processes, the immunohistochemical reaction product appears both as a diffuse cytoplasmic label and as elongated strands, which by their distribution and frequency could be considered glial filaments.

Animals↗