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Biomedical subjects

C M Harper

Publications and source records attributed to C M Harper.

66 records · Page 4Linked to original sources
PubMed1988

An electroencephalographic study of glossopharyngeal neuralgia with syncope.

In the case described, electroencephalography (EEG) proved valuable for determining the nature of spells of loss of consciousness with brief clonic jerks associated with ear and throat pain. A 70-year-old woman had a history of episodic brief attacks of pain below the right ear and deep in the neck that had started three years previously. The spells became more severe and progressed to loss of awareness associated with clonic jerks of the extremities. Because of a concern that the spells represented seizures, an EEG was performed, with electrocardiographic monitoring. Multiple spells were recorded; they began with profound bradycardia followed by generalized slow-wave activity and then by suppression of all EEG activity correlating with loss of consciousness and clonic jerking. The spells were thought to represent syncopal attacks associated with glossopharyngeal neuralgia.

Aged↗
PubMed1988

Lumbar radiculopathy after spinal fusion for scoliosis.

In 184 patients with no preoperative neurologic deficit who underwent operation for idiopathic scoliosis, somatosensory evoked potential monitoring was used. Four patients had neurologic deficits postoperatively. Two patients developed mild signs of intraspinal lesions involving upper motor neurons at high lumbar levels that resolved over 3-5 months. These patients and two others developed evidence of unilateral, moderate, lower motor neuron damage that was confirmed on electromyography. No changes in somatosensory evoked potentials occurred in these patients. Lumbar root damage may be difficult to recognize after operation and should be considered in patients with neurologic deficit after scoliosis surgery.

Adolescent↗
PubMed1988

Physiology and complications of bed rest.

Prolonged bed rest causes major cardiovascular, respiratory, musculoskeletal, and neuropsychological changes. Complications often result from these effects of bed rest, especially when aging has already decreased the reserves in these systems. These problems can be limited by judicious prescription of modified bed rest.

Aged↗
PubMed1987

Chemical carcinogen-induced decreases in genomic 5-methyldeoxycytidine content of normal human bronchial epithelial cells.

The genomic content of DNA 5-methyldeoxycytidine (m5dC) was measured in dividing normal human bronchial epithelial cells treated with a broad range of chemical carcinogens. At noncytotoxic concentrations, all of the carcinogenic agents tested significantly reduced cellular DNA m5dC content whereas the weakly carcinogenic and noncarcinogenic agents, benzo[e]pyrene and phenanthrene (respectively), did not. These reductions varied from 8% to 31% depending on the agent and the donor cells. The reductions in genomic m5dC levels were concentration dependent for the carcinogenic polycyclic aromatic hydrocarbon benzo[a]pyrene. We speculate that carcinogen-induced perturbation of DNA m5dC patterns may lead to heritable changes in gene expression and contribute to the molecular alterations involved in the initiation and the subsequent steps of the carcinogenesis process.

Carcinogens↗
PubMed1987

Physicochemical characterization of photoaffinity-labeled angiotensin II receptors.

Specific receptor sites for angiotensin II (AII) were analyzed in the adrenal cortex and other target tissues including liver, anterior pituitary gland, and smooth muscle, after covalent labeling with the radioactive photoaffinity analog 125I-[Sar1,(4-N3)Phe8]-AII. The photoreactive AII derivative retained high affinity for adrenal receptors and full steroidogenic activity in adrenal glomerulosa cells. In bovine adrenal cortex, covalent labeling of AII receptors by the photoreactive analog was specifically inhibited by [Sar1]AII with an IC50 of about 5 nM. The Mr of the covalent AII-receptor complex during polyacrylamide gel electrophoresis of the labeled protein under reducing conditions was 58,000. Under non-reducing conditions, a minor band with Mr of 105,000 was also observed. Two labeled species were also found during gel permeation chromatography of the detergent-solubilized complex, with Mrs of 64,000 and 86,000. The pl of the solubilized photolabeled complex was absorbed to wheat germ lectin Sepharose 6MB and could be eluted by N-acetylglucosamine. The Mrs of specific AII-binding sites in several target tissues, determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, showed target tissues, determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, showed significant differences within and between species. The most striking differences were between rat adrenal cortex (79,000) and both rat liver (60,000) and bovine adrenal cortex (58,000). After enzymatic deglycosylation, the Mr of the major component present in the bovine and rat adrenal cortex decreased by 40% and 55% to 35,000 and 34,000, respectively, suggesting that variations in carbohydrate content contribute to the physical heterogeneity of AII receptors in individual target tissues.

Adrenal Cortex↗
PubMed1986

Lack of production of thromboxane A2 by the sheep heart following coronary occlusion.

Blood pressure, heart rate and ECG were monitored continuously and coronary venous blood samples assayed for thromboxane B2. Arterio-coronary venous lactic acid differences were estimated. In anaesthetized sheep, 60 sec occlusions of the left circumflex coronary artery caused hypotension with little change in heart rate. Five minute occlusions produced similar changes accompanied by cardiac arrhythmias and a larger fall in blood pressure. In conscious sheep heart rate rose and blood pressure was maintained. ECG and lactic acid changes indicated severe myocardial ischaemia but not change in thromboxane release was detected. The apparent lack of involvement of thromboxane may reflect a relative inability of sheep platelets to produce this substance or a failure to provide an adequate stimulus for synthesis.

Anesthesia↗
PubMed1985

Intracranial hypertension in Behçet's disease: demonstration of sinus occlusion with use of digital subtraction angiography.

We describe two patients with Behçet's disease who had symptomatic intracranial hypertension due to cerebral venous sinus thrombosis. The sinus thrombosis was demonstrated by digital subtraction angiography. In those patients with Behçet's disease who have unexplained headaches, papilledema, and elevated cerebrospinal fluid pressure, venous digital subtraction angiography is an expedient, accurate, and safe procedure for demonstrating intracranial venous thrombosis.

Adolescent↗
PubMed1984

Isolation of choriomammotropin from the ovine placentome.

Placentomes, taken from ewes at 101-141 days gestation, were homogenized and subjected to differential and density gradient centrifugation. In the presence or absence of protease inhibitors, choriomammotropin (ovine chorionic somatomammotropin, oCS) was detected by radio-immunoassay, and banded at two positions in 30-60% w/v sucrose gradients. The first band (soluble form) eluted in the sample zone of the gradient and contained 33 +/- 6.1% (mean +/- s.e.m., n = 10) of the total oCS present in the gradient. The remainder (48 +/- 7.6%) of the oCS (particulate form) sedimented to 37.5-43% w/v sucrose. Both these bands became sharper with decreasing protein loaded onto the gradients. 125I-oCS, pre-equilibrated with a placentome preparation, eluted in the same position as the first band of endogenous oCS. When loaded onto a second gradient the second band eluted at 38-41% w/v sucrose, but after being subjected to ultrasonic disruption or treatment with Triton X-100 this oCS eluted in the sample zone. There was no correlation between gestational age of the ewe and the percentage oCS in either the soluble or particulate form, the concentration of oCS, or enrichment by protein. We have shown that following homogenization, differential and density gradient centrifugation, oCS exists in two forms. We suggest that the particulate form of the hormone is contained within the electron-dense granules of placentome cells. The soluble form may represent oCS in the process of secretion and hormone which has leached out of the granules during homogenization and centrifugation of the placentomes.

Animals↗
PubMed1981

Evaluation of the morphological and functional characteristics of murine thymic non-lymphoid cells grown in vitro.

During the past few years, several investigators have attempted to grow the epithelial component of the murine thymus as a monolayer in vitro in order to study its proposed physiological role in T-lymphocyte differentiation. However, using for the most part identical culture techniques, we have provided morphological, histochemical and functional evidence that the majority of murine thymic nonlymphoid cells grown in culture are epithelioid macrophages and that these macrophages and/or their soluble factors may be responsible for many functions previously attributed to thymic epithelium or "purified thymic hormones". This study emphasizes the absolute necessity and importance of extensive morphological and histochemical evaluation of cultured cells prior to their use in physiological studies. Furthermore, any conclusion regarding the function of thymic non-lymphoid cells in vitro must first take into account numerous species differences in the morphological and histochemical characteristics of these cells as noted both in our laboratory as well as by other investigators.

Animals↗