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Biomedical subjects

K Thompson

Publications and source records attributed to K Thompson.

At least 181 records · Page 10Linked to original sources
PubMed1986

Midforceps deliveries: long-term outcome of infants.

Infants delivered by midforceps between 1976 and 1982 were evaluated for evidence of developmental delay or neurological deficit by chart review. The 110 infants who were followed for at least 2 years were compared to a matched group of infants delivered by cesarean section. The cesarean section group was matched for the immediate indication for delivery (dystocia or fetal distress), birth weight, gestational age, sex, and race. There was no significant difference in abnormal outcomes in the two groups.

Birth Injuries↗
PubMed1986

Synovial chondromatosis of the temporomandibular joint presenting as a parotid mass: possibility of confusion with benign mixed tumor.

Synovial chondromatosis is a rare metaplastic disorder of synovium in which cartilaginous nodules are produced within joint spaces. An unusual case involving the temporomandibular joint, with extension of the lesion beyond the joint capsule into the parotid gland, is described. The patient had a history of previous superficial parotidectomy for a "benign mixed tumor." Review of the histologic features revealed both lesions to be identical. The reason for confusion between the two diagnoses is discussed.

Adenoma, Pleomorphic↗
PubMed1986

Diagnosis and quantitation of pulmonary arteriovenous malformations by factor analysis.

The diagnosis of a pulmonary arteriovenous malformation (AVM) was made by performing a computer-assisted first-pass cardiopulmonary imaging procedure using Tc-99m pertechnetate and processing the image information using factor analysis. This analytical technique is capable of separating partially overlapping structures by automatically extracting factors with different temporal behavior (time-activity curves) which correspond to functional areas without anatomic constraint. This procedure was accomplished successfully despite the presence of four-chamber enlargement, mitral stenosis and regurgitation, tricuspid regurgitation, chronic obstructive pulmonary disease and pulmonary hypertension. The magnitude of the right-to-left shunt resulting from the AVM was quantitated using both the factor analysis data and an independent Tc-99m MAA computer-assisted imaging procedure. Both methods gave comparable values.

Arteriovenous Malformations↗
PubMed1986

A primary genetic map of chromosome 13q.

We have constructed a primary genetic map spanning most of human chromosome 13. A total of 14 polymorphic DNA sequences and one protein polymorphism provided, after construction of haplotypes, seven markers for the long arm of this chromosome. A panel of cell lines from 30 three-generation families with large sibship size served as the sample set. Pairwise cross analysis of the inheritance patterns of the marker loci established that six of the seven loci constituted a single linkage group; the seventh was localized by physical means. Significantly higher recombination rates were found in female than in male meioses in several intervals. The six closely linked loci were arranged, based on the two-point data, in three clusters, and a number of alternate gene orders were excluded by three-point linkage tests. The order and spacing of the individual loci were refined by linkage analyses that considered five loci jointly.

Chromosome Banding↗
PubMed1986

Assessment of developmental time periods and risks of brain damage in the fetus and neonate.

The life cycles of 18 infants with neurologic morbidity were divided into antepartum, intrapartum, neonatal and infant time periods. Specific events related to risks for each infant were assigned to these periods. In almost all the children multiple, rather than single, fetal, neonatal and infant risks were found, and along with the multiple risks, multiple time periods were found during which the risks occurred. It is difficult, and often impossible, to relate infant neurologic morbidity to a single event or time period.

Brain Damage, Chronic↗
PubMed1985

The midforceps: maternal and neonatal outcomes.

A retrospective review of midforceps deliveries occurring between 1976 and 1982 at a county teaching hospital is presented. Midforceps deliveries were performed in 0.8% of deliveries (176 of 21,414) during this period, a rate reflecting the general admonition against potentially traumatic injury to the infant. Under these conditions, midforceps deliveries were associated with active and second-stage labor abnormalities, abnormal fetal heart rate patterns, maternal perineal lacerations, low 1-minute Apgar scores, and neonatal cephalohematomas more frequently than were deliveries of the remainder of the patients. Epidural anesthesia was significantly associated with midforceps deliveries. Midforceps patients were matched to similar groups who were delivered by cesarean section or low forceps or who had spontaneous births. The findings do not document an increase in short-term neonatal morbidity in the midforceps group under the conditions described.

Birth Injuries↗
PubMed1985

Long-term neurological morbidity in breech and vertex births.

Seventy frank breech fetuses delivered vaginally, alive at the onset of labor, and without major congenital anomalies were matched by birth weight and race with a breech infant born by cesarean section, a vertex infant born vaginally, and a vertex infant born by cesarean section. Long-term neurological abnormality was determined from time of hospital discharge through a minimum of 2 years of age. The results document the absence of significant differences with respect to major brain damage effected by birth route changes for breech fetuses and between the entire breech and vertex populations.

Birth Weight↗
PubMed1985

Bactericidal effects of photoradiation therapy with hematoporphyrin derivative.

Hematoporphyrin derivative (Hpd) localizes selectively in malignant and rapidly metabolizing tissues and undergoes a cytotoxic reaction when exposed to light of a specific wavelength. Hpd has been studied extensively with regard to the diagnosis and treatment of tumors but not with regard to bactericidal activity. This investigation assessed the effect of light-activated Hpd on various microorganisms, on human polymorphonuclear leukocytes, and on the interactions of polymorphonuclear leukocytes and bacteria. Light-activated Hpd was 99.9% bactericidal against Staphylococcus aureus, Streptococcus faecalis, Bacteroides fragilis, Streptococcus M-G intermedius, Streptococcus mutans, Peptostreptococcus anaerobius, Peptococcus magnus, and Clostridium perfringens, but did not affect Escherichia coli, Pseudomonas aeruginosa, or Candida albicans. Photoactivation of Hpd rendered 98% of polymorphonuclear leukocytes inviable. Combinations of light-activated Hpd and polymorphonuclear leukocytes had a 4-log (99.99%) bactericidal effect on both intra- and extracellular S. aureus. The ability of Hpd to localize in inflammatory tissues may have therapeutic applications in the treatment of abscesses.

Bacteria↗
PubMed1984

Synthesis, characterization and biologic effects of polybrominated naphthalenes.

Although polybrominated naphthalenes (PBNs) are contaminants of the commercial fire retardant fireMaster BP-6, the individual PBN isomers have not been identified. In order to study PBNs possessing an analogous level of bromination to those found in fireMaster BP-6, three synthetic PBN mixtures, averaging 5.0, 5.3, and 5.6 bromines per naphthalene were synthetized and partially characterized. The PBN mixtures were administered to immature male Wistar rats and found to be potent inducers of cytochrome P-450-dependent monooxygenases. At the lowest dose tested, 30 mumol X kg-1, each PBN mixture caused maximal induction of benzo[a]pyrene hydroxylase activity. On the basis of enzyme activities, ligand-binding spectra and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the PBN mixtures were determined to be 3-methylcholanthrene-type inducers of cytochrome P-450 (P-448), resembling qualitatively the most toxic polyhalogenated biphenyls, dibenzofurans, and dioxins in this respect. Liver weights were significantly increased and thymus weights diminished by PBN treatment. Light microscopy revealed proliferation of the smooth endoplasmic reticulum in periportal hepatocytes as a consistent change; some rats also had mild fatty changes in centrilobular hepatocytes. Thymuses displayed mild to marked depletion of cortical lymphocytes. The PBN mixtures were much more potent than fireMaster BP-6 in causing these effects; raising the possibility that PBNs are among the minor components of fireMaster BP-6 that contribute significantly to the toxicity of this environmental contaminant.

Animals↗
PubMed1984

Pharmacology, electrophysiology, and pharmacokinetics of mexiletine.

Mexiletine is a class I antiarrhythmic agent that is active after both oral and intravenous administration and similar in structure and activity to lidocaine. It decreases phase O maximal rate of depolarization (Vmax) by fast sodium channel blockade. The marked rate dependence of Vmax depression may explain mexiletine's lack of effect on normal conduction and its efficacy against ventricular tachyarrhythmias. Mexiletine significantly decreases the relative refractory period in His-Purkinje fibers without changing the sinus rate or atrioventricular and His-Purkinje conduction times. Action potential duration is usually shortened. Mexiletine may aggravate preexisting impairment of impulse generation and conduction. Uptake and distribution of mexiletine are rapid, systemic bioavailability is about 90%, and tissue distribution is extensive. Mexiletine is primarily metabolized in the liver; 10% to 15% is excreted unchanged in the urine. Elimination half-life is 9 to 11 hours after intravenous or oral administration. Microsomal enzyme induction shortens mexiletine's elimination half-life, whereas hepatic disease and acute myocardial infarction prolong it. Renal disease has little effect, although hemodialysis increases mexiletine clearance. Plasma concentrations from 0.75 to 2.0 mg/L are usually associated with a desirable therapeutic response.

Absorption↗
PubMed1984

Acute, life-threatening disease first appearing as odontogenic pain.

Rapidly spreading rhinocerebral infection by Phycomycetes (mucormycosis) in a diabetic patient with ketoacidosis is described. The dentist and dental specialists should be alert to the early signs and symptoms of this disease as they evaluate and follow patients who are debilitated and who have odontogenic pain. It cannot be overemphasized that a successful outcome is critically dependent on early recognition and prompt therapy, especially in a person with diabetic acidosis as death may occur within 2-5 days after the first symptoms appear.

Acute Disease↗
PubMed1984

Potential applications of free drug level monitoring in cardiovascular therapy.

Cardiovascular drugs, as a class, have low therapeutic indices, but also have great therapeutic potential. Plasma concentration information is therefore often of value when using these drugs. Unfortunately, the total plasma concentration may not reflect the concentration of pharmacologically active free drug, since a number of factors including disease states, heparin anticoagulation, non-linear binding characteristics, and in vitro artefacts can affect the protein binding of these agents. This may also explain their poor dose-response relationships and great interindividual variability in plasma concentration data. Careful studies relating bound and free drug concentration to pharmacological response may provide the clinician with a better guide to therapy, and enhance the usefulness of these drugs.

Anti-Arrhythmia Agents↗
PubMed1983

Analysis of the base substitutions found in the Xenopus laevis 5 S RNA pseudogene.

A 5 S RNA pseudogene is associated with the major oocyte 5 S RNA gene of Xenopus laevis. X. borealis has several oocyte specific 5 S RNA genes. Gene 1 is the dominant 5 S RNA gene. Gene 3 has sometimes been referred to as a pseudogene. We show that the base substitutions in the X. laevis 5 S pseudogene are non-random with respect to double and single-stranded regions of the 5 S RNA using the chi 2 test of homogeneity with Yates correction for continuity. In addition, conserved positions of eukaryotic 5 S RNAs are predominantly maintained. X. borealis gene 3 is random in mutations.

Animals↗