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Biomedical subjects

R J Ignelzi

Publications and source records attributed to R J Ignelzi.

At least 19 recordsLinked to original sources
PubMed1983

An analysis of the nuclear sodium content of human normal glia as well as tumors of glial and nonglial origin.

Normal human brain nuclei and nuclei obtained from glioblastoma, as well as other primary brain and metastatic tumors, were analyzed for their sodium content. The greatest concentration of sodium was found in glial tumor nuclei with lesser amounts in normal glial nuclei and least amounts in nuclei from nonglial tumors. This data supports our hypothesis that glial nuclei sequester brain sodium and also suggests that sodium in the nucleus may be important in glial mitogenesis.

Brain Chemistry↗
PubMed1981

Measurement of pain: patient preference does not confound pain measurement.

Chronic pain patients reported pain intensity on each of 3 pain intensity scales, the visual analog, numerical and adjectival scales, and then ranked the scales in order of perceived best communication of pain intensity. All patients were able to complete an adjectival scale but 11% were unable to complete a visual analog scale and 2% failed at a numeric scale. The intensity of the pain ratings on the 3 scales were significantly correlated and there were no reliable differences in reported intensity as a function of preference. Pain intensity was reliably higher on each scale for depressed-anxious patients as compared to non-depressed/non-anxious patients. Patients completing all 3 scales indicated a significant preference for the adjectival scale but the basis for this preference did not appear related to sex, etiology of pain, affective variables nor selected psychological variables. These data indicate that pain scale preference does not influence pain intensity report. Nevertheless, there are some clinical situations in which a numeric scale is likely to yield a better measure of pain intensity.

Chronic Disease↗
PubMed1981

Repetitive electrical stimulation of peripheral nerve and spinal cord activity.

Spinal cord neuron and dorsal column fiber responses to electrical stimulation of the sciatic nerve in anesthetized cats were recorded before, during, and after periods of repetitive electrical stimulation of the sciatic nerve through an implantable nerve cuff stimulator device of the type and method used in human patients for pain relief. In previous publications from this laboratory using similar experimental conditions, we reported that repetitive electrical stimulation of the peripheral nerve suppressed all components of the compound action potential of nerves. The present study confirms that 5 percent of the spinal cord units studied showed facilitated discharge, 46 percent showed inhibited or depressed discharge, 36 percent underwent no change, and 13 percent showed equivocal responses to repetitive electrical stimulation. Inhibition of dorsal column fiber activity following repetitive electrical stimulation of peripheral nerve is not consistent with the Melzack-Wall gate hypothesis in which suppression of small fiber nociceptive input is mediated by large fiber activity. Our work suggests that the most commonly observed effect of electroanalgesia is to cause a more diffuse depression of nociceptive as well as nonnociceptive spinal cord activity.

Action Potentials↗
PubMed1981

Protective effect of pentobarbital on ischemic brain cell nuclei.

Cerebral ischemia occurs not only as a primary event but also as an important secondary phenomenon in many forms of brain insult. Many therapeutic regimens have been used empirically to combat various insults to the brain, and the barbiturates have received much attention lately. The present study demonstrates that pentobarbital administered before the onset of global ischemia ameliorates sodium and potassium loses from brain cell nuclei, which may be important in the etiology of the cell swelling seen in this model. Evidence is presented that this protective effect may occur through an energy-dependent, cooperative process.

Animals↗
PubMed1980

Light element abundance in brain nuclei using energy dispersive x-ray analysis and atomic absorption spectrophotometry.

A comparative study of light element (congruent to ion) abundance in isolated brain nuclei, using atomic absorption (AA) spectrophotometry and the scanning electron microscope mode of energy dispersive x-ray analysis (EDXA), demonstrated similar statistical trends in the abundance of Na, Mg, and K at 0 time and at 4 min of total brain ischemia. The obtained correlation strengthens the validity of the comparison of quantitative and semi-quantitative procedures. The EDXA technique represents a new approach to the study of ionic shifts in brain ischemia that may prove useful in other areas of brain research as well.

Animals↗
PubMed1980

Sodium, potassium, and metabolic studies of glial, liver, and kidney nuclei under anoxic-ischemic conditions.

Glial, liver, and kidney nuclei were studied under anoxic-ischemic conditions. It was found that glial nuclei were significantly depleted of sodium and potassium as early as 15 seconds after the insult, whereas liver and kidney nuclei were not. There was a concomitant significant drop in high-energy substrates (ATP, P-creatine, glucose) in both glial and brain homogenate, whereas these substrates remained relatively constant in kidney and began to drop only at the four-minute time point in liver. These unique observations in glial nuclei may have important implications in the glial swelling that is seen in ischemic states.

Animals↗
PubMed1980

Osteomyelitis of the skull following scalp reduction and hair plug transplantation.

A case of Staphylococcus aureus osteomyelitis of the skull following scalp reduction and hair plug transplantation is presented. Frontal and biparietal craniectomies were performed, adjacent galea and subcutaneous tissues were excised, and intravenous antibiotics were administered to eradicate the infection and forestall the development of sagittal sinus thrombosis. Persistent drainage of hair plug transplantation sites may suggest underlying osteomyelitis.

Hair↗
PubMed1980

Pain and its modulation. Part 1. Afferent mechanisms.

Our understanding of pain and its afferent modulation has undergone a great deal of modification in recent years as our knowledge of the sensory nervous system has expanded. In this review, current concepts are detailed in the perspective of present and potential clinical applications of basic science principles and theories to neurosurgical interventions. Beginning with peripheral receptors and fibers and traversing the peripheral nervous system to ultimately reach the central nervous system, the nociceptive information undergoes much integration and modification to affect the ultimate response of the organism to the original stimulus. At each point in the afferent pathways, various alternative neurosurgical ablative or augmentive approaches are available and might be appropriate for pain relief. For a variety of reasons many ablative procedures are being used less often in the treatment of chronic pain of a noncancerous origin, while the newer augmentive techniques are becoming more popular. On the other hand, at present ablative procedures are still used frequently for chronic pain associated with cancer, although the newer augmentive approaches are being tried in this area as well.

Afferent Pathways↗
PubMed1980

Pain and its modulation. Part 2. efferent mechanisms.

Recent studies of central nervous system effects on pain and on its efferent modulation have created new theories and have led to direct clinical applications that may in time eclipse more classical interventions. In this review electrical stimulation analgesia is presented as a paradigm of how basic science work has been applied clinically to produce some of the most exciting advances in recent years in the treatment of chronic pain. Opiate receptors and analgesia are presented in relationship to the descending inhibitory systems used in electroanalgesia. Neuromodulators and neurotransmitters important in pain modulation through complex inhibitory and excitatory pathways are discussed, with the roles of B-endorphin, enkephalin, serotonin, and other important biogenic amines being stressed. The neuropharmacology of pain as it is currently understood clinically suggests that psychotropic interventions may be quite useful in treating difficult pain problems.

Analgesia↗
PubMed1979

Excitability changes in peripheral nerve fibers after repetitive electrical stimulation. Implications in pain modulation.

The Melzack-Wall gate control theory has been invoked to explain the peripheral analgesia resulting from repetitive electrical stimulation of peripheral nerve. This model emphasizes presynaptic inhibitory interactions among afferent fiber terminals in the spinal cord. An alternative explanation, that of velocity change in peripheral nerve fiber conduction, has been suggested by compound action potential studies from our laboratory. The present study was designed to extend this work, and to investigate the single fiber changes subsequent to brief (5- to 20-minute) periods of repetitive, high frequency (180 to 200/sec) electrical stimulation through an implantable peripheral nerve cuff device of the type used clinically for pain relief. Most fibers, regardless of their diameter (estimated from conduction velocity), show one or more of the following characteristics: a transient slowing of conduction velocity, an increase in electrical threshold and/or a decrease in response probability following a period of repetitive electrical stimulation. This supports the hypothesis that there are changes in direct peripheral nerve fiber excitability occurring under conditions simulating clinical electroanalgesia.

Animals↗
PubMed1977

Post-irradiation pituitary sarcoma.

A fibrosarcoma developed in the pituitary fossa of a patient who had been irradiated 13 years previously for treatment of pituitary adenoma. The tumor was a large aggressively growing spindle cell neoplasm which eroded adjacent structures, causing increased intracranial pressure, and eventual cerebellar tonsillar herniation. In common with previously described post-irradiation sarcoma of the pituitary, this lesion developed in the path of irradiation after a long latent period, did not metastasize, and contained histologically recognizable benign appearing pituitary adenoma interspersed among the spindle cell tumor. The dose of radiation (5000 rads) also lay within the range associated with sarcomatous transformation.

Aged↗