Biomedical subjects

J W Keating

Publications and source records attributed to J W Keating.

8 recordsLinked to original sources

PubMed1992

The acute effects of ethanol and acetaldehyde on rates of protein synthesis in type I and type II fibre-rich skeletal muscles of the rat.

Young rats were injected with either ethanol (75 mmol/kg), acetaldehyde (2.8 mmol/kg) or isovolumetric amounts of NaCl (0.15 mol/l, i.e. controls) with or without inhibitors of alcohol dehydrogenase (4-methylpyrazole) or aldehyde dehydrogenase (cyanamide). After 2.5 hr, fractional rates of protein synthesis (i.e. ks) in the soleus (Type I fibre-rich) and plantaris (Type II fibre-rich) muscles were measured. Ethanol alone reduced ks in both soleus and plantaris muscles, by approx. 25%. Pretreatment of ethanol-dosed rats with 4-methylpyrazole raised plasma ethanol levels and reduced ks in the soleus and plantaris by approx. 35%. Pretreatment of ethanol-dosed rats with cyanamide also increased plasma ethanol and further potentiated the effects of ethanol by reducing ks in the soleus and plantaris by approx. 65%. Acetaldehyde alone reduced ks by approx. 15%, and this effect was not significantly altered by 4-methylpyrazole pretreatment. In some instances, the plantaris was slightly more sensitive to ethanol and acetaldehyde than the soleus. Similar conclusions were derived when data were expressed relative to either RNA or DNA. The data thus suggest that the ethanol-induced inhibition of skeletal muscle protein synthesis may possibly be independently mediated by both ethanol and acetaldehyde.

Acetaldehyde↗

PubMed1991

Bone collagen, mineral and trace element composition, histomorphometry and urinary hydroxyproline excretion in chronically-treated alcohol-fed rats.

(1) We examined the possibility that enhanced fragility of the bony skeleton in alcohol abusers may be a consequence of a reduction in collagen composition. Male rats were fed a liquid diet containing 36% of total calories as ethanol; controls were pair-fed iso-caloric glucose. At 3, 7 and 14 days of treatment, collagen contents of tibia were unaltered, but small and significant reductions (15-30%) were observed at 28 and 42 days of treatment. Urinary hydroxyproline excretion was increased by 40-60% at 42 days of treatment, suggesting enhanced collagen degradation. (2) Bones of rats treated with ethanol for 42 days had significantly reduced mineral content (approximately 20%) with accompanying reductions in phosphate, calcium, copper and magnesium, but not sodium or potassium. Water content was unaltered, but tibial zinc and iron were increased by approximately 15%. (3) Histomorphometric analysis of bones taken at 42 days showed significant reductions in cortical bone thickness of lower tibia (by 28%). The thickness of the upper cortices and cancellous bone of the tibia was unaffected. Reductions in trabecular bone volume (approx. 25%) did not achieve statistical significance. (4) These observations are consistent with the known enhanced fragility of bones in alcoholic rats. The regional susceptibility of the tibia may be related to reduced load bearing as a result of muscle atrophy.

Alcohol Drinking↗

PubMed1984

Neuroimaging of the spine.

This article addresses the subject of available technology and techniques of neuroimaging of the spine. It also reviews broad areas of neuropathology such as congenital anomalies, degenerative joint disease, the postoperative spine, disorders of the spinal cord, neoplasia, trauma, and infection. A general approach to the radiographic diagnosis of spinal disorders is covered.

Humans↗

PubMed1982

Recognition of lumbar disk disease: comparison of myelography and computed tomography.

A retrospective study was devised to determine the correlation between myelography and computed tomography (CT) in the recognition of abnormalities of the lumbar intervertebral disk. A group of 106 patients was studied who had had both myelography and CT within a 6 week period. Each examination was interpreted separately by a neuroradiologist who had no access to the patients' clinical findings or the results of any radiologic studies. On comparison of 290 interspace levels, there was agreement in definite abnormalities in 70%. Most discrepancies were due to suspicious findings and inconclusive studies of both kinds. In particular, there was poor correlation between the two examinations in the diagnosis of a slightly bulging disk. The major discrepancy rate was less than 5% overall and less than 1% among patients without prior surgery. On the basis of these findings, a diagnostic algorithm is suggested that would facilitate the workup of a similar group of patients.

False Negative Reactions↗

PubMed1982

Cerebellar vermal atrophy in psychiatric patients.

Our findings indicate that a notable number of patients who have functional psychosis (50%) or seizures (38%) show cerebellar vermal atrophy on visual inspection of CAT head scans, in contrast to 0.5% to 3.7% of patients with other disorders. In addition to the visual reading of 1700 scans in the present study, we used two methods to demonstrate cerebellar vermal atrophy objectively: (i) low-density measurements of the posterior fossa in relationship to total brain area, and (ii) sagittal reconstruction of the vermis. We postulate that cerebellar vermal atrophy reduces the cerebellum's inhibitory influences on activity of the rostral forebrain structures where unit overactivity has been correlated with emotional dyscontrol and clinical seizures. We further postulate that cerebellar vermal atrophy reduces facilitory activity of the brain's pleasure system (septal region).

Adult↗

PubMed1978

Remote effects of neuroblastoma.

Neuroblastoma, which is primarily an extracranial disease, has remote manifestations which can be confusing. Neurologic signs and symptoms such as opsoclonus (dancing eyes), ataxia, blindness, and cord paralysis may precede by several months the manifestations of the primary tumor in a distant site such as the abdomen. Descriptions of nine cases demonstrate the various modes of presentation and some of the unusual aspects of this disease. The recent advent of computed tomography requires a reevaluation of the neuroradiologic approach to the evaluation of neuroblastoma.

Bone Neoplasms↗

PubMed1976

Localized giant pseudopolyposis in ulcerative colitis.

A case of localized giant pseudopolyposis in ulcertative colitis is discussed in which a mass effect mimicked tumor. The fulminant collection of pseudopolyps was palable in the epigastrium on physical exam and caused a partial obstruction to the retrograde flow of barium. Carcinoma is a worrisome possibility in ulcerative colitis, but localized giant pseudopolyposis may also present as a mass.

Adult↗

PubMedDate not supplied

False-positive CT gas cisternogram.

Nonfilling of the normal internal auditory canal on computed tomographic (CT) gas cisternography was observed in seven (11%) of 62 cases in a retrospective study of three series of gas cisternograms. The meatal surface of the fluid-filled canal was convex and pointed, simulating a small acoustic neuroma. A meniscus effect at the gas-cerebrospinal fluid interface was considered the probable cause of nonfilling of the canal with gas. Shaking the patient's head briskly after injection of gas into the spinal fluid will facilitate filling of the internal auditory canal with gas. Bone erosion in the canal or meatus suggests the presence of acoustic neuroma. In the absence of conclusive findings of neuroma, persistent nonfilling of the canal is an indication for repeat cisternography with an alternate contrast medium.

Adult↗