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Biomedical subjects

J P Blount

Publications and source records attributed to J P Blount.

13 recordsLinked to original sources
PubMed2005

The results of compression forces applied to the isolated human calvaria.

Data for the force necessary to fracture the isolated calvaria (skull cap) are not available in the extant literature. Twenty dry adult calvaria were tested to failure quasistatically at the vertex using a 15-kN load cell. The forces necessary to fracture or cause diastasis of calvarial sutures were then documented and gross examination of the specimens made. Failure forces had a mean measurement of 2772 N. Initial fractures did not cross suture lines. Prior to complete destruction of the calvaria there were 7 specimens in which all sutures of the calvaria became diastatic, 6 specimens in which the calvaria became diastatic along only the coronal sutures, 2 specimens in which the calvaria became diastatic along only the sagittal suture and 5 specimens in which there were diagonal linear parietal bone fractures. Our hopes are that these data may contribute to the structural design of more safer protective devices for use in our society, assist in predicting injury and aid in the construction of treatment paradigms.

Adult↗
PubMed2001

Spinal lipomas.

Lipomas of the spinal cord are among the most fascinating lesions encountered by the pediatric neurosurgeon. An understanding of spinal lipomas may, however, be difficult because the terminology used to describe the accumulations of spinal fat is confusing, inconsistently applied, and at times contradictory. An anatomical characterization of lipomas may assist in understanding these lesions. Lipomas of the spinal cord are very rare and cause symptoms related to mass effect and secondary compressive myelopathy. Lipomas of the conus medullaris (or lipomyelomeningocele) are the most common form of fatty masses in the spine and can be divided into dorsal, caudal, and transitional forms. These lesions are a manifestation of occult spinal dysraphism and a common cause of the tethered cord syndrome (TCS). The natural history of untreated lipomyelomeningocele, although incompletely understood, appears to be progressive neurological deterioration with loss of bladder control. Timely, careful surgical intervention may prevent significant neurological deterioration and progressive disability in the majority of children harboring these lesions. In surgical intervention the surgeon seeks to disrupt the connection between the fibrofatty mass and underlying cord as well as to reestablish normal anatomical planes. Several intraoperative video segments illustrating lipomyelomeningocele resection are included in this paper. Lipomas of the terminal filum (fatty filum) are truly occult and are also associated with TCS. Surgical treatment of filum lipomas carries significantly lower risk than that for lipomas of the conus medullaris. Again, the goal of surgery is to disrupt the connection between the abnormal fibrofatty tissue and the underlying spinal cord.

Biomechanical Phenomena↗
PubMed2001

Histological appearance of a chronically stimulated vagus nerve in a pediatric patient.

Histological analysis of chronically stimulated human vagus nerves is lacking in the literature. In this study, we describe the first microscopic findings in a chronically stimulated left vagus nerve from a pediatric patient. Our results show many histological changes in and around the stimulated nerve with severe demyelination. Further long-term clinical and postmortem examinations of chronically stimulated vagus nerves in both children and adults are needed to ascertain whether prolonged exposure to electrical current can cause clinical dysfunction of this nerve.

Brain↗
PubMed2001

Preliminary observations on the association between simple metopic ridging in children without trigonocephaly and the Chiari I malformation.

Historically, there have been no accounts of an association between simple metopic ridging and the Chiari I malformation. We prospectively evaluated 50 children with simple metopic ridges and found that 30% of these patients had a Chiari I malformation. During the period in which this screening for simple metopic ridges was performed, only 9% of the total patient population (324) was diagnosed as having a Chiari I malformation. We hypothesize that small decreases in anterior fossa volume in children with a simple metopic ridge and no other clinical findings of trigonocephaly may increase their chance of having a Chiari I malformation that becomes symptomatic. In addition, simple metopic ridging should perhaps be added to the list of bony anomalies associated with the Chiari I malformation, such as atlantal assimilation and retroverted odontoid processes. Future studies aimed at calculating anterior fossa volumes in children with a Chiari I malformation and imaging all children with simple metopic ridges are now necessary to ascertain if there is an increased risk of these patients becoming symptomatic with a hindbrain hernia or having a hindbrain hernia, respectively.

Adolescent↗
PubMed2001

Surgical landmarks for the proximal portion of the axillary nerve.

OBJECT: The proximal segment of the axillary nerve (ANp) is often difficult to identify without extensive dissection deep into the axilla. The present study was performed to find reliable surgical landmarks for this nerve. METHODS: Thirty dissections of human cadavers were performed to determine the relationships between the ANp and specific anatomical structures. The authors found that the ANp is consistently located within an anatomical triangle constructed by lines passing between the coracobrachialis and pectoralis minor muscles and the axillary artery. In addition, the ANp was routinely found 4 cm distal to the coracoid process of the scapula. CONCLUSIONS: These findings should assist the surgeon in locating the ANp during brachial plexus reconstruction.

Aged↗
PubMed2000

Alcohol abusers' and nonabusers' distraction by alcohol and concern-related stimuli.

Alcohol abusers' and nonabusers' attentional distraction for neutral, alcohol-related, and concern-related (personally relevant) words was assessed with a word-word color-naming task. Abusers, unlike nonabusers, showed greater attentional distraction for alcohol-related than concern-related words. Exploratory analyses indicated that abusers who were more distracted by alcohol-related than concern-related stimuli (i.e., "alcohol distracted") responded more slowly to neutral words than "concern-distracted" participants. The results suggest that the relative degree of distraction by alcohol versus other personally relevant stimuli holds promise for understanding the cognitive and motivational processes underlying alcohol abuse.

Adult↗
PubMed1996

Diabetic patients' alcohol use and quality of life: relationships with prescribed treatment compliance among older males.

One hundred fifty-four males attending an outpatient diabetes clinic were interviewed to determine the incidence of alcohol use among them and to identify mechanisms by which alcohol use adversely affects the control of diabetes. Specifically, we determined how diabetic patients' use of alcohol is related to compliance with their diabetes treatment regimen, and diabetic patients' expectations of benefits from drinking alcohol and actual alcohol use is related to their quality of life. Greater alcohol use was related to poorer prescribed insulin injection compliance (p < 0.01), and stronger expectations of immediate, positive consequences of drinking alcohol were related to several indices of lower quality of life (p < 0.005). These results imply interactive relationships among diabetics' alcohol use and expectancies, treatment compliance, and quality of life.

Aged↗
PubMed1996

Intrathecal granuloma complicating chronic spinal infusion of morphine. Report of three cases.

Intrathecal morphine delivered by implanted pumps has been used in the treatment of pain caused by terminal cancer. Some authors supports its use in benign pain as well. The authors present three cases in which chronic infiltration of intraspinal narcotic medication was complicated by the formation of a granulomatous mass that became large enough to exert mass effect and induce neurological dysfunction.

Adult↗
PubMed1993

Complications in ventricular cerebrospinal fluid shunting.

The development of effective cerebrospinal fluid (CSF) shunts represents a landmark achievement in neurosurgery. This success, however, has been tempered by a high incidence of serious complications that accompany the diversion of CSF. This article examines the various complications of CSF shunting, including proximal, valve, and distal obstruction; infection; and other rare complications, and management of these complications.

Cerebrospinal Fluid Shunts↗
PubMedDate not supplied

Transplantation of human fetal tissue from spontaneous abortions to a rodent model of Parkinson's disease.

The use of human fetal tissue from elective abortions for cell transplantation therapies has been the subject of considerable controversy. Because of concerns regarding the use of tissue from elective abortions, tissue from spontaneous abortions has been suggested as an alternate donor source. In the present study we have evaluated human fetal tissue from spontaneous abortions to assess its viability, growth potential, and functional expression. Viable cells (Grade I) from a donor (7 wk postconception) were transplanted as a suspension into the striatum of rats with unilateral 6-OHDA lesions of the nigrostriatal pathway. A second group of animals received solid grafts of tissue from a Grade I donor 14 wk postconception. Tissue from Grade II and III specimens were not sufficiently viable for transplantation. Locomotor responses were monitored over a period of 15 wk and revealed an amelioration of rotational asymmetry by animals that received tissue from the 7 wk donor. Animals receiving tissue from the 14 wk donor showed no functional improvement. We found numerous graft-derived tyrosine hydroxylase (TH) immunopositive neurons contained within the transplantation site, and a rich plexus of TH-immunopositive fibers extending into the striatum of animals receiving tissue from the 7 wk donor. Animals receiving tissue from the 14 wk donor exhibited tissue necrosis at the transplant site and were devoid of TH-immunopositive neurons. These results suggest that human fetal ventral mesencephalic cells from spontaneous abortions can survive and develop after transplantation, and rectify locomotor deficits associated with experimental parkinsonism if the donor tissue is of the appropriate gestational age at the time of implantation. Our study further suggests, however, that the availability of tissue from spontaneous abortions of sufficient viability is quite limited and may thus restrict its potential use in cell transplantation therapies for Parkinson's disease.

Animals↗