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Biomedical subjects

K D Miller

Publications and source records attributed to K D Miller.

At least 19 recordsLinked to original sources
PubMed1992

Cine magnetic resonance imaging of the temporomandibular joint.

Magnetic resonance imaging (MRI) provides a significant amount of information about both the position of the meniscoligamentous complex and the osseous structures in evaluation of internal derangements of the temporomandibular joint (TMJ). With the advent of computer-driven cine displays, dynamic information is now available, providing cost-effective diagnostic evaluation similar to cine fluoroscopy with arthrography, but without the ionizing radiation exposure or discomfort. Using a bite block, a series of sagittal images are obtained with the patient "posing" at different degrees of jaw opening. The subsequent cine MRIs with "posed" motion are striking and very helpful in evaluating various types of TMJ dysfunction. At the authors' institution, 205 patients were examined with a history of TMJ arthralgia. Correlation of imaging studies and surgical findings reveals a sensitivity (98%) and specificity (96%) for identifying the meniscoligamentous complex.

Adolescent↗
PubMed1992

Development of orientation columns via competition between ON- and OFF-center inputs.

Development of orientation-selective receptive fields in primary visual cortex of higher mammals can occur through activity-dependent competition between ON-center and OFF-center inputs. This competition yields orientation and spatial-frequency-selective 'simple cells' if the dark activity of ON (or OFF)-center inputs is best correlated with that of other ON (or OFF)-center inputs at small retinotopic separations and with that of OFF (ON)-center inputs at larger separations. Features of cat and monkey cortical organization emerge, including continuous and periodic arrangement of preferred orientation across the cortex. A new feature, systematic variation of receptive field spatial phase, is predicted. Experimental tests of this hypothesis are proposed.

Animals↗
PubMed1992

AUA1: new immunocytochemical marker for detecting epithelial cells in body cavity fluids.

Further to detailed genetic and biochemical characterisation of AUA1 as a surface glycoprotein present on epithelial cells, the antibody against AUA1 was used as an immunocytochemical marker of epithelial cells in body cavity fluids in an attempt to improve the diagnosis made on routine staining. AUA1 was initially tested in 144 morphologically clear cut effusions. It was positive in 46 of 52 (88%) carcinomas and negative in 82 of 84 (98%) benign effusions, including technically inadequate or poorly cellular preparations. There were no false positive results. AUA1 was subsequently used more selectively--that is, in 42 of 175 (24%) of morphologically difficult fluids. AUA1 provided essential diagnostic information in 15 of 42 (36%) and confirmed diagnosis in 17 of 42 (40%), thus enabling accurate diagnosis in a further 32 of 42 (76%) of the difficult cases. The total diagnostic accuracy was therefore 94.3%. AUA1 is a reliable immunocytochemical marker for detecting epithelial cells in body fluids. Its use improves diagnostic accuracy of morphological assessment in difficult cases.

Antibodies, Monoclonal↗
PubMed1991

Compulsive overeating.

Compulsive overeating is a behavior used in an attempt to numb or nurture feelings that are threatening to the person. Emotional states are soothed by use of food. Treatment is designed to respond to internal, biologic causes of hunger and satiety while simultaneously allowing feelings to surface and be dealt with. Work on the inner child enables the person to identify and deal with unmet needs and correct distortions from childhood. The secondary gain realized from the extra weight is examined, and direct means of dealing with these needs explored. The focus of recovery is on learning to nurture the self, physically and emotionally.

Body Image↗
PubMed1991

Body-image therapy.

Body image is a complex interplay of factors resulting in a sense of the body perceived by that individual. In eating-disorder clients, there is a distortion between their perceived image of their body and its actuality. This is combined with a sense of dissatisfaction and alienation of mind and body. Cognitive, right-brain, and kinesthetic strategies are described that seek to decrease distortion and dissatisfaction and facilitates individuation-separation and a reintegration of the self. These strategies are both therapeutic and evaluative. Cultural expectations of women have had a profound impact on the proliferation of eating disorders, and they account for the fact that body distortion is found in both normal and eating-disordered women.

Body Image↗
PubMed1989

Ocular dominance column development: analysis and simulation.

The visual cortex of many adult mammals has patches of cells that receive inputs driven by the right eye alternating with patches that receive inputs driven by the left eye. These ocular dominance patches (or "columns") form during early life as a consequence of competition between the activity patterns of the two eyes. A mathematical model of several biological mechanisms that can account for this development is presented. Analysis of this model reveals the conditions under which ocular dominance segregation will occur and determines the resulting patch width. Simulations of the model also exhibit other phenomena associated with early visual development, such as topographic refinement of cortical receptive fields, the confinement of input cell connections to patches, monocular deprivation plasticity including a critical period, and the effect of artificially induced strabismus. The model can be used to predict the results of proposed experiments and to discriminate among various mechanisms of plasticity.

Afferent Pathways↗
PubMed1989

Treatment of severe malaria in the United States with a continuous infusion of quinidine gluconate and exchange transfusion.

During the past decade the incidence of Plasmodium falciparum malaria in the United States has increased 10-fold. Treatment may be delayed because the therapy recommended for severe or complicated disease, intravenous quinine dihydrochloride, is available only from the Centers for Disease Control. We studied 17 patients who were treated for severe or complicated P. falciparum malaria in the United States between 1985 and 1987. Five patients were treated with a continuous infusion of quinidine gluconate, 10 with an exchange transfusion in addition to the continuous infusion of quinidine gluconate, and 2 with intermittently administered intravenous quinine dihydrochloride and an exchange transfusion. All 16 patients with P. falciparum malaria (1 patient had P. vivax malaria) had hyperparasitemia at the time of diagnosis (6 to 54 percent of the erythrocytes infected; median, 13 percent). Three patients with marked hyperparasitemia (54, 38, and 30 percent) and multiple other indicators of a poor prognosis, including advanced age, died. The 13 patients who completed their courses of quinidine with or without exchange transfusion had a parasitemia level of 1.1 percent or less 28 to 72 hours (mean, 44.4 hours) after the start of therapy. Side effects of quinidine treatment were observed in only two patients, one of whom had a serum quinidine concentration above the toxic level. We conclude that the continuous infusion of quinidine gluconate is well tolerated alone and with exchange transfusion and is effective in the treatment of severe and complicated malaria.

Adult↗
PubMed1989

An animal model of hearing loss from alpha-difluoromethylornithine.

alpha-Difluoromethylornithine is a new antineoplastic and antiparasitic drug that inhibits the synthesis of polyamines. It causes a sensorineural hearing loss in humans. We have established an animal model for alpha-difluoromethylornithine-induced hearing loss. The time course for onset and recovery of the hearing loss in animals was similar to that seen in humans. Electrophysiologic and histologic data suggest that the anatomic site of alpha-difluoromethylornithine-induced hearing loss is the organ of Corti. Unlike other drugs with ototoxic effects, the specific enzymatic site of action of alpha-difluoromethylornithine is known, making it a potentially important tool in auditory research.

Animals↗
PubMed1989

Visual responses in adult cat visual cortex depend on N-methyl-D-aspartate receptors.

We have investigated the role of the N-methyl-D-aspartate (NMDA) receptor, a subtype of glutamate receptor, in the responses of cells in adult cat visual cortex. After intracortical infusion of the NMDA receptor antagonist DL-2-amino-5-phosphonovalerate (DL-APV) for one day, iontophoretic responses to NMDA, to kainate, and to quisqualate revealed a receptor blockade specific to NMDA receptors and extending several millimeters from the cannula. In this region, neuronal responses to visual stimulation were profoundly suppressed, in a manner strongly correlated with the degree of NMDA receptor blockade. Neither NMDA receptor blockade nor activity suppression was caused by the inactive stereoisomer L-APV. Hence, we conclude that NMDA receptors make a major contribution to normal excitatory transmission in adult visual cortex.

2-Amino-5-phosphonovalerate↗
PubMed1989

MRI of soft tissue vascular malformations.

Magnetic resonance imaging (MRI) is constantly progressing as an important imaging modality for the evaluation of the cardiovascular system and vascular malformations. Due to its superior contrast resolution and sensitivity, MRI is able to differentiate between fat, muscle, bone, and vascular structures. It provides three-dimensional information without the use of ionizing radiation or invasive procedures. We evaluated 11 vascular malformations by MRI using Spin Echo T1 and T2 weighted images. MRI provided more information than computerized tomography, and, in many instances, obviated the need for angiography.

Adolescent↗
PubMed1988

Chloroquine treatment of severe malaria in children. Pharmacokinetics, toxicity, and new dosage recommendations.

Although empirical regimens of parenteral chloroquine have been used extensively to treat severe malaria for 40 years, recent recommendations state that parenteral chloroquine should no longer be used because of potential toxicity. We studied prospectively the pharmacokinetics and toxicity of seven chloroquine regimens in 58 Gambian children with severe chloroquine-sensitive falciparum malaria. In all regimens the total cumulative dose was 25 mg of chloroquine base per kilogram of body weight. Chloroquine was rapidly absorbed after either intramuscular or subcutaneous administration (5 mg of base per kilogram every 12 hours), producing high peak blood concentrations but transient hypotension in 5 of 18 patients (28 percent). Intermittent intravenous infusion (5 mg of base per kilogram over 4 hours, repeated every 12 hours) also produced wide fluctuations in chloroquine levels, suggesting incomplete distribution from a small central compartment. Continuous infusion (0.83 mg of base per kilogram per hour for 30 hours) and smaller, more frequent intramuscular or subcutaneous injections of chloroquine (3.5 mg of base per kilogram every 6 hours) produced smoother blood-concentration profiles with lower early peak levels and no adverse cardiovascular or neurologic effects. Chloroquine given by nasogastric tube (initial dose, 10 mg of base per kilogram) was absorbed well, even in comatose children. We conclude that simple alterations in dosage and frequency of administration can give parenteral chloroquine an acceptable therapeutic ratio and reinstate it as the treatment of choice for severe malaria in areas where chloroquine resistance is not a major problem.

Animals↗
PubMed1988

Diethylcarbamazine prophylaxis for human loiasis. Results of a double-blind study.

To determine whether infection with Loa loa could be prevented in temporary residents of endemic areas, we conducted a randomized, double-blind, placebo-controlled trial of diethylcarbamazine as a chemoprophylactic agent. Diethylcarbamazine (300 mg) or placebo was taken orally once a week by Peace Corps volunteers serving in Gabon, Cameroon, and the Central African Republic. The participants were assessed clinically and with serologic and parasitologic testing before and yearly during their two years of service. One hundred one persons satisfactorily completed the study. In Gabon (where exposure to the parasite was heaviest), 6 of 20 volunteers (30 percent) in the placebo group had clinical disease, as compared with none of 16 (0 percent) in the diethylcarbamazine-treated group (P less than 0.02). Of those taking placebo, 10 of 20 (50 percent) became seropositive for antifilarial IgG antibody, as compared with 2 of 16 (12 percent) in the drug-treated group (P less than 0.02). Exposure to the parasite appeared to be much lower among the 65 Peace Corps volunteers in Cameroon and the Central African Republic. No volunteer in either group in these countries had overt loiasis; 2 of 40 (5 percent) in the placebo groups in Cameroon and the Central African Republic seroconverted, as compared with none of 25 (0 percent) of those receiving diethylcarbamazine. Occasional nausea was the only symptom significantly associated with the prophylactic drug regimen. We conclude that diethylcarbamazine given orally once weekly can be an effective, acceptable chemoprophylactic agent to prevent loiasis in temporary residents of regions of Africa where Loa loa is endemic.

Adult↗
PubMed1988

A review of applications of MRI in soft tissue and bone tumors.

Due to excellent soft tissue contrast and multiplanar imaging capability, MRI is assuming a major role in recognition, staging, and treatment planning of soft tissue and bone tumors. Direct sagittal, coronal, and axial images permit assessment of intraosseous and extraosseous extension of tumors and their relationship to the joints and neurovascular structures, and detection of "skip" lesions. MRI allows improved detection of recurrent tumors in the presence of non-ferromagnetic metallic implants as compared to CT. In the evaluation of soft tissue tumors, MRI is more sensitive than CT and allows differentiation among fat, muscle, tendon, bone, and vascular structures based on signal characteristics. Over a period of 18 months, 100 soft tissue masses and bone tumors were evaluated using MRI. Spin echo sequences with T1 and T2 weighted images were most valuable in differentiating normal and abnormal tissues. Calculated comparative measurements of relaxation times showed no reliable difference between benign and malignant tumors.

Adolescent↗
PubMed1988

Selected public health observations derived from Multicenter AIDS Cohort Study.

Selected findings from the Multicenter AIDS Cohort Study (MACS) of homosexual/bisexual men are reviewed. High risk sexual behaviors, the use of drugs/alcohol, condom use, and behavior change are addressed in a public health context. The potential significance of education/behavior modification programs as strategies for public health intervention emerges from these findings. Until there is a realistic timetable for vaccine availability and more effective chemotherapy, the MACS provides the opportunity to continue to study the effects of behavior change on the AIDS epidemic.

Acquired Immunodeficiency Syndrome↗