Biomedical subjects
Publications and source records attributed to J H Anderson.
Gravimetric sampling over a three year period indicates that birch, alder and poplar pollen and fungus spores are the major aeroallergens from early May to September in the Fairbanks area, Alaska. Of less importance are willows, the grasses, lamb's-quarters, plantain, goldenrod, and wormwood pollen. A standard pollen calendar is presented.
It has been postulated that otosclerosis may produce vertigo by several mechanisms. One mechanism is by causing endolymphatic hydrops. We present six temporal bones in which otosclerosis and endolymphatic hydrops coexist. We consider that there is a spectrum-like interrelationship between these two entities. At one end of the spectrum the relationship is coincidental, while at the other end of the spectrum we consider the massive amount of active otosclerosis to be a causative factor in the development of the endolymphatic hydrops.
A syndrome closely resembling acquired immunodeficiency syndrome (AIDS) in man has been identified in a group of 64 rhesus monkeys (Macaca mulatta) maintained outdoors at the California Primate Research Center. The syndrome is characterised by generalised lymphadenopathy, severe opportunistic infections including cytomegalovirus, chronic wasting, and high mortality. In 1 animal a multifocal cutaneous fibrosarcoma developed. This syndrome in monkeys may provide an animal model for human AIDS.
A live dengue 2 vaccine was tested in 38 volunteers in an evaluation of the safety, infectivity, and immunogenicity of doses of 10(1.8)-10(5.5) plaque-forming units. Twenty yellow fever-immune and 18 yellow fever-nonimmune individuals received 0.5 ml of vaccine sc. Immunization was dose related in yellow fever-immune volunteers, with a 50% immunizing dose of 10(3.3) plaque-forming units. In the group not immune to yellow fever, some but not all recipients of each vaccine dilution were immunized, and no 50% immunizing dose could be estimated. Volunteers immune to yellow fever developed adequate titers of neutralizing antibody to dengue 2 virus and maintained them for at least three years; those not immune to yellow fever developed lower antibody titers that disappeared within six months in half of the cases. More than 40 isolates of dengue 2 virus from 12 volunteers retained the in vitro growth characteristics of the vaccine virus; this result affirmed the genetic stability of the virus. Common clinical signs in immunized individuals were leukopenia (55%), macular rash (15%), and fever (10%).
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Stimulations or inhibitions by various agents of 45Ca efflux from prelabeled cells or tissues display distinct and reproducible profile patterns when the results are plotted against time as fractional efflux ratios (FER). FER is the fractional efflux of 45Ca from stimulated cells divided by the fractional efflux from a control unstimulated group. These profile patterns fall into three categories: peak patterns, exponential patterns, and mixed patterns. Each category can be positive (stimulation) or negative (inhibition). The interpretation of these profiles is difficult because 45Ca efflux depends on three variables: the rate of calcium transport out of the cell, the specific activity of the cell compartment from which the calcium originates, and the concentration of free calcium in this compartment. A computer model based on data obtained by kinetic analyses of 45Ca desaturation curves and consisting of two distinct intracellular pools was designed to follow the concentration of the traced substance (40Ca), the tracer (45Ca), and the specific activity of each compartment before, during, and after the stimulation or the inhibition of calcium fluxes at various pool boundaries. The computer model can reproduce all the FER profiles obtained experimentally and bring information which may be helpful to the interpretation of this type of data. Some predictions of the model were tested experimentally, and the results support the views that a peak pattern may reflect a sustained change in calcium transport across the plasma membrane, that an exponential pattern arises from calcium mobilization from an internal subcellular pool, and that a mixed pattern may be caused by a simultaneous change in calcium fluxes at both compartment boundaries.
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Partial splenic arterial embolization (50% reduction in flow) was evaluated in dogs using polyvinyl alcohol foam or microspheres (20-500 mu) made of dextran, polystyrene, or silicone. Dextran and polystyrene were found to be superior for several reasons: they were easier to use, did not shatter when agitated, and produced permanent, homogeneous, peripheral occlusion with only one administration. Partial embolization with dextran or polystyrene increased platelet levels within 1 week and markedly reduced splenic size with minimal if any collateral filling within 6 weeks. Microscopically, no acute infarction or necrosis was seen at 6 weeks; there was some fibrosis, but the remaining parenchyma appeared normal.
The VX2 carcinoma was used to create a rabbit brain tumor model. VX2 tumors were chemically dissociated and suspended in liquid medium. Twenty-five microliters of the tumor suspension containing 3 X 10(3), 3 X 10(4), or 3 X 10(5) viable tumor cells were injected through cranial burr holes 6 mm into the right frontoparietal lobes of 17 rabbits. Fifteen of these developed histologically documented nodular intraparenchymal tumors. Tumors were demonstrable with cerebral computed tomographic scans and by cerebral angiography. The feasibility of surgical resection of lesions using the fluorescein staining technique was also demonstrated. This animal brain tumor model is suitable for neuro-oncology research focusing on imaging and therapeutic techniques.
A transcatheter technique for administering drugs preferentially to the canine left coronary circulation is described. The method involves pulsed, diastolic, small-volume (0.2 ml) injections through a specially designed aortic cusp catheter. In order to evaluate preferential delivery to the coronary circulation, papaverine was administered using this technique and compared to intravenous delivery. Left circumflex and carotid arterial blood flow, as well as systemic arterial pressure, were simultaneously measured. In eight of ten animals studied, diastolic aortic cusp administration of the drug for periods of up to 30 minutes increased circumflex flow an average of 136%, increased carotid arterial flow 22%, and decreased systemic arterial pressure 18%. Intravenous delivery increased circumflex flow an average of 34%, increased carotid flow 41%, and decreased systemic arterial pressure 13%. The technique has immediate research and potential clinical application as a means of preferentially delivering diagnostic or therapeutic agents, such as thrombolytics, to the coronary circulation.
Large intraosseous arteriovenous malformations (AVM) of the mandible are rare lesions. A review of the American literature has revealed sixty cases involving the mandible. This article presents a case of left mandibular AVM in which the initial treatment was embolization. Eventually, however, an emergency hemimandibulectomy became necessary. Postoperative physiotherapy is considered an important part of the treatment in patients who have undergone hemimandibulectomy. An unusual feature in this case has been the amount of spontaneous regeneration of bone in the surgical site.
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Six male volunteers, previously immunized with yellow fever vaccine, were inoculated subcutaneously with a live, attenuated dengue-2 virus (PR-159/S-1) candidate vaccine. Five recipients developed viremia 8 or 9 days after vaccination, which lasted 1 to 10 days. The onset of viremia was followed by fever in three people, transient leukopenia in four, and an erythematous rash in one. One volunteer developed an oral temperature of 38.8 degrees C with headache, myalgia, fatigue, and photophobia suggestive of mild dengue fever. All five viremic volunteers developed fourfold or greater rises in serum neutralizing antibody. The sixth volunteer, who had a low titer of preexisting dengue-2 neutralizing antibody, had no viremia, no symptoms, and a modest rise in hemagglutination inhibiting antibody. Virus isolates obtained from plasma retained the small-plaque and temperature-sensitive growth characteristics of the vaccine virus in vitro. In this study, the vaccine virus genetically stable and immunogenic and seemed sufficiently attenuated for additional testing in humans.
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Embolus radiolabelling with 131I fibrinogen was studied in a canine model of internal carotid artery embolization. The dog was chosen as the experimental animal because of its maxillocarotid artery which permits collateral flow round the occlusion and helps to prevent strokes. Clot was prepared by incubating blood at room temperature to inactivate plasminogen activators and then refrigerating it to promote clot retraction. Emboli persisting 48 hours were seen in 80% of animals. Major strokes were not seen when 0.25 to 0.30 cm3 were used. Autoradiography and well counting revealed uptake of isotope. The test, when refined, should provide a tool for the investigation of thromboemboli.
Nuclear medicine imaging techniques are being more widely applied to study a variety of lung injuries. Ventilation and perfusion imaging is often superior to other roentgenographic techniques for establishing the diagnosis and demonstrating the extent of such injuries. At several large burn centers, the Xe-133 washout technique has become the cornerstone for diagnosing early inhalation injury. The overall accuracy of this procedure is 92%. Regional decreases in ventilation and perfusion can reliably localize aspirated radiolucent foreign bodies. Disproportionate perfusion changes are often the earliest indicator of radiation pneumonitis and other forms of vascular injury. Other types of injury, such as gastropulmonary aspiration, blunt trauma, and near-drowning, require further evaluation before the ultimate role of nuclear imaging is defined. An imaging technique to assess capillary permeability in the adult respiratory distress syndrome would be of great clinical benefits.
Microscopic examination of stool samples from captive nonhuman primates with diarrhea for the presence or absence of leukocytes or erythrocytes or both as a means of predicting the presence of Shigella spp. was performed. Analysis of the data multivariately by means of a log linear model did not show a three-way association between diarrhea, Shigella, and the presence or absence of cells.