Biomedical subjects
Publications and source records attributed to P D Larsen.
As the elderly population continues to expand, more elderly patients will undergo surgical procedures. This patient population provides challenges for perioperative nurses, surgeons, and anesthesia care providers. By understanding normal age-related body system changes that may affect anesthesia, perioperative management team members can prevent complications and provide positive outcomes for elderly surgical patients.
Although certain laboratory test results are expected to be outside the normal adult range in elderly patients, perioperative nurses must understand that these "normal abnormal" values are among the factors that make elderly patients more vulnerable to surgical risks. When preoperative testing reveals abnormalities, surgical procedures may be delayed while metabolic problems are treated. Prompt treatment of abnormal laboratory values and closer observation by perioperative nurses when elderly surgical patients laboratory values are borderline can help prevent negative consequences of surgical interventions in these patients.
The increasing number of elderly patients undergoing surgical procedures is a reality. Providing nursing care to these patients presents a challenge throughout their perioperative experiences. Knowledge of normal age-related changes coupled with data from preoperative assessments allows perioperative nurses to plan, implement, and evaluate care of elderly surgical patients with sensory losses.
We have examined in eight male volunteers the effect of midazolam sedation on the relationship between timing of spontaneous ventilations and heart beat. On 2 study days, subjects received either midazolam 0.1 mg kg-1 or saline placebo while recordings were made of ECG and ventilatory impedance pneumography. We observed in all midazolam-treated subjects clear evidence of synchronous or non-synchronous coupling between ventilation and heart beat. Non-synchronous coupling was seen in two placebo-treated subjects, one of whom had slept during the recording period. We conclude that cardioventilatory coupling is a major determinant of ventilatory timing in sedated subjects.
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Fluid and electrolyte management in the elderly is a tenuous situation. Because elderly patients have a decreased capacity to regulate extracellular volume, health care personnel must administer i.v. fluids carefully. Age-related renal changes subject elderly patients to a variety of potential problems. Astute assessment skills by the perioperative nurse, however, may reduce the chance of complications and ensure optimal patient outcomes.
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Explore the source record for details and available documents.
We measured transthyretin levels in the cerebrospinal fluid (CSF) of newborn infants, older children, patients with viral and bacterial meningitis, and adults with increased CSF protein levels. Neonatal CSF transthyretin levels are elevated disproportionately in comparison to levels in the other groups. We conclude that increased levels of transthyretin in the CSF of neonates are not explained by increased permeability of the blood-CSF barrier.
Genomic DNA from five previously unreported patients with glycerol kinase deficiency (GKD), dystrophic myopathy, and adrenal insufficiency were studied with genomic probes and cDNA probes for the Duchenne muscular dystrophy (DMD) locus. These individuals, together with those reported by ourselves and others, show that patients with a contiguous gene syndrome involving the DMD, GK, and adrenal hypoplasia congenita (AHC) loci have a broader distribution of microdeletion breakpoints than those observed among patients with classical DMD. This study demonstrates the use of the DMD cDNA probes to delineate the centromeric deletion breakpoints for patients with Xp21 microdeletions extending beyond the DMD locus. It also shows the practical diagnostic application of the DMD cDNA probes when the diagnosis of GKD is entertained in a patient with known DMD and only DNA is available for study.
Three familial cases of MELAS (mitochondrial encephalomyopathy with lactic acidosis and stroke) have been reported. We describe a family with four normal sons and an affected mother, son, and daughter. Although mitochondrial inheritance has been proposed, autosomal and X-linked dominant patterns are also possible. This family also illustrates the variability of expression of MELAS. The proband has the full syndrome, while the mother and daughter manifested less severe findings. All three did not develop symptoms until adulthood.
Transthyretin is an important choroid plexus-specific transport protein that has been reported to be both elevated and decreased in the CSF of multiple sclerosis patients. We report that CSF transthyretin levels are not altered in MS, indicating that choroid plexus function with respect to this protein is unaffected in this disease.
The case of an 11-year-old female with the clinical findings of Hallervorden-Spatz syndrome, including progressive dystonia, dysarthria, disturbances of gait, and retinal pigmentary degeneration, is presented. The differential diagnosis of childhood dystonia and retinal pigmentary degeneration associated with neurological conditions is discussed. The presence of basal ganglia densities on computed tomography scanning in this patient may aid in future premortem diagnosis of this rare disease.
We describe a 14-year-old boy who was severely debilitated by the neurological syndrome associated with vitamin E deficiency secondary to chronic cholestatic liver disease. In addition to the usual neurological deficits described with this deficiency, the patient had severe bulbar weakness and vision loss which we attribute to the degree and duration of his vitamin E deficiency. Vitamin A deficiency may have contributed to his visual disturbance. Early recognition of vitamin E deficiency is important, as the neurological and visual disorders which result are treatable.
To characterize the antibody response to the Epstein-Barr virus (EBV) in MS, we studied serum anti-EBV nuclear antigen (anti-EBNA) and anti-EBV capsid antigen (anti-EBVCA) titers. Both titers were assayed in 93 age- and sex-matched pairs of MS patients and controls. Anti-EBVCA titers were measured by indirect immunofluorescence and anti-EBNA titers by anticomplement immunofluorescence. The seropositivity rate of both anti-EBVCA and anti-EBNA in MS patients was 100%, compared with 84% in controls (p less than 0.0001). Both anti-EBVCA and anti-EBNA titers were significantly higher in MS patients than in controls (p less than 0.0001). The data suggest that EBV has a significant seroepidemiologic association with MS, but they do not define what role EBV antibodies play in the pathogenesis of the disease.
The case of a 4 1/2-year-old boy with congenital vertical ocular motor apraxia who was otherwise developmentally and neurologically normal is reported. The presence of perinatal hypoxia in this patient may have been etiologic. While the presence of a supranuclear vertical ocular motor abnormality usually suggests a serious, acquired neurologic or systemic disease it may rarely occur as an isolated congenital finding, as demonstrated in this case.
We studied infectious and immune mechanisms in demyelinating disease. The clinical diagnosis in this study of 313 consecutive cases of multiple sclerosis (MS) was based on the clinical conclusions of two or more neurologists and definite abnormalities in CSF IgG. Measurement of antibodies to six microbial agents was compared in 313 patients with MS and 406 controls in the same age range. Using a standardized immunofluorescent antibody (IFA) technique, we found a significantly higher prevalence of Epstein-Barr virus (EBV) infection and a higher level of serum viral capsid antigen IgG antibody titer in the MS population than in the controls. The MS population had a lower cytomegalovirus (CMV) infection rate and lower CMV complement fixing antibody production than controls. Except for the higher measles infection rate and antibody titer in patients with MS, data on the other viruses did not differ from controls.