Showing papers by "University of Miami published in 1990"

Origins and Functions of Positive and Negative Affect: A Control-Process View.

Abstract: The question of how affect arises and what affect indicates is examined from a feedback-based view-point on self-regulation. Using the analogy of action control as the attempt to diminish distance to a goal, a second feedback system is postulated that senses and regulates the rate at which the action-guiding system is functioning

The American College of Rheumatology criteria for the classification and reporting of osteoarthritis of the hip.

Abstract: Clinical criteria for the classification of patients with hip pain associated with osteoarthritis (OA) were developed through a multicenter study. Data from 201 patients who had experienced hip pain for most days of the prior month were analyzed. The comparison group of patients had other causes of hip pain, such as rheumatoid arthritis or spondylarthropathy. Variables from the medical history, physical examination, laboratory tests, and radiographs were used to develop different sets of criteria to serve different investigative purposes. Multivariate methods included the traditional "number of criteria present" format and "classification tree" techniques. Clinical criteria: A classification tree was developed, without radiographs, for clinical and laboratory criteria or for clinical criteria alone. A patient was classified as having hip OA if pain was present in combination with either 1) hip internal rotation greater than or equal to 15 degrees, pain present on internal rotation of the hip, morning stiffness of the hip for less than or equal to 60 minutes, and age greater than 50 years, or 2) hip internal rotation less than 15 degrees and an erythrocyte sedimentation rate (ESR) less than or equal to 45 mm/hour; if no ESR was obtained, hip flexion less than or equal to 115 degrees was substituted (sensitivity 86%; specificity 75%). Clinical plus radiographic criteria: The traditional format combined pain with at least 2 of the following 3 criteria: osteophytes (femoral or acetabular), joint space narrowing (superior, axial, and/or medial), and ESR less than 20 mm/hour (sensitivity 89%; specificity 91%). The radiographic presence of osteophytes best separated OA patients and controls by the classification tree method (sensitivity 89%; specificity 91%). The "number of criteria present" format yielded criteria and levels of sensitivity and specificity similar to those of the classification tree for the combined clinical and radiographic criteria set. For the clinical criteria set, the classification tree provided much greater specificity. The value of the radiographic presence of an osteophyte in separating patients with OA of the hip from those with hip pain of other causes is emphasized.

Zidovudine in Asymptomatic Human Immunodeficiency Virus Infection: A Controlled Trial in Persons with Fewer Than 500 CD4-Positive Cells per Cubic Millimeter

Abstract: Zidovudine (AZT) is a potent inhibitor of the replication of the human immunodeficiency virus (HIV), and it has been shown to improve survival in advanced HIV disease. We conducted a randomized, double-blind trial in adults with asymptomatic HIV infection who had CD4+ cell counts of fewer than 500 per cubic millimeter on entry into the study. The subjects (92 percent male) were randomly assigned to one of three treatment groups: placebo (428 subjects); zidovudine, 500 mg per day (453); or zidovudine, 1500 mg per day (457). After a mean follow-up of 55 weeks (range, 19 to 107), 33 of the subjects assigned to placebo had the acquired immunodeficiency syndrome (AIDS), as compared with 11 of those assigned to receive 500 mg of zidovudine (P = 0.002; relative risk, 2.8; 95 percent confidence interval, 1.4 to 5.6) and 14 of those assigned to receive 1500 mg of zidovudine (P = 0.05; relative risk, 1.9; 95 percent confidence interval, 1.0 to 3.5). In the three treatment groups, the rates of progression (per 100 person-years) to either AIDS or advanced AIDS-related complex were 7.6, 3.6, and 4.3, respectively. As compared with those assigned to placebo, the subjects in the zidovudine groups had significant increases in the number of CD4+ cells and significant declines in p24 antigen levels. In the 1500-mg zidovudine group, severe hematologic toxicity (anemia or neutropenia) was more frequent than in the other groups (P less than 0.0001). In the 500-mg zidovudine group, nausea was the only toxicity that was significantly more frequent (in 3.3 percent) than in the placebo group (P = 0.001). We conclude that zidovudine is safe and effective in persons with asymptomatic HIV infection and fewer than 500 CD4+ cells per cubic millimeter. Additional study will be required to determine whether such treatment will ultimately improve survival for persons infected with HIV.

A Randomized, Controlled Trial of Interferon Alfa-2b Alone and after Prednisone Withdrawal for the Treatment of Chronic Hepatitis B

Abstract: Background and Methods. Chronic hepatitis B is a common and often progressive liver disorder for which there is no accepted therapy. To assess the efficacy of treatment with interferon, we randomly assigned patients with chronic hepatitis B to one of the following regimens: prednisone for 6 weeks followed by 5 million units of recombinant interferon alfa-2b daily for 16 weeks; placebo followed by 5 million units of interferon daily for 16 weeks; placebo followed by 1 million units of interferon daily for 16 weeks; or observation with no treatment. Results. Hepatitis B e antigen and hepatitis B viral DNA disappeared from serum significantly more often in the patients given prednisone plus interferon (16 of 44 patients, or 36 percent) or 5 million units of interferon alone (15 of 41; 37 percent) than in the untreated controls (3 of 43; 7 percent; P<0.001); the difference between those given 1 million units of interferon (7 of 41; 17 percent) and the controls was not significant. The strongest indep...

Behavior-State Matching and Synchrony in Mother-Infant Interactions of Nondepressed versus Depressed Dyads.

Abstract: The purpose of the study was to assess the degree to which depressed mother-infant dyads, relative to nondepressed mother-infant dyads,matched behavior states on a continuous scale from negative to neutral to positive affect. Furthermore, interaction synchrony in these two groups was determined by measuring the coherence of the dyads' behavior time series

Islet isolation assessment in man and large animals.

Abstract: Recent progress in islet isolation from the pancreas of large mammals including man, accentuated the need for the development of precise and reproducible techniques to assess islet yield. In this report both quantitative and qualitative criteria for islet isolation assessment were discussed, the main topics being the determination of number, volume, purity, morphologic integrity andin vitro andin vivo function tests of the final islet preparations. It has been recommended that dithizone should be used as a specific stain for immediate detection of islet tissue making it possible to estimate both the total number of islets (dividing them into classes of 50 µ diameter range increments) and the purity of the final preparation. Appropriate morphological assessment should include confirmation of islet identification, assessment of the morphological integrity and of the purity of the islet preparation. The use of fluorometric inclusion and exclusion dyes together have been suggested as a viability assay to simultaneously quantitate the proportion of cells that are intact or damaged. Perifusion of islets with glucose provides a dynamic profile of glucose-mediated insulin release and of the ability of the cells to down regulate insulin secretion after the glycemic challenge is interrupted. Although perifusion data provides a useful guide to islet viability the quantity and kinetics of insulin release do not necessarily predict islet performance after implantation. Therefore, the ultimate test of islet viability is their function after transplantation into a diabetic recipient. For this reason,in vivo models of transplantation of an aliquot of the final islet preparation into diabetic nude (athymic) rodents have been suggested. We hope that these general guidelines will be of assistance to standardize the assessment of islet isolations, making it possible to better interpret and compare procedures from different centers.

The safety and efficacy of zidovudine (AZT) in the treatment of subjects with mildly symptomatic human immunodeficiency virus type 1 (HIV) infection a double-blind, placebo-controlled trial

Abstract: Objective To evaluate the efficacy and safety of zidovudine early in the treatment of human immunodeficiency virus type 1 (HIV) infection. Design A double-blind, randomized, placebo-controlled trial with subject stratification by pretreatment CD4 T lymphocyte counts. Setting Multicenter trial at AIDS Clinical Trial units. Subjects Seven hundred eleven subjects with mildly symptomatic HIV infection. Intervention Three hundred fifty-one subjects were assigned to placebo and 360 to zidovudine, 200 mg orally every 4 hours. The median duration of follow-up was 11 months. Measurements and main results Fifty-one subjects developed the acquired immunodeficiency syndrome (AIDS), advanced AIDS-related complex, or death as a first critical event. For the stratum of subjects with more than 200 but less than 500 CD4 T lymphocytes/mm3 before treatment, 34 events occurred in placebo recipients and 12 in zidovudine recipients (P = 0.0002; relative risk [RR] estimate, 3.23 [95% CI, 1.67 to 6.24]). For the stratum of subjects with 500 to 799 CD4 T lymphocytes/mm3 before treatment, 2 events occurred in placebo recipients and 3 in zidovudine recipients. Candidiasis at study entry independently increased the risk for having an event (P = 0.005; RR estimate, 2.3 [95% CI, 1.29 to 4.12]); HIV antigenemia at study entry also increased this risk (P = 0.01; RR estimate, 2.1 [95% CI, 1.2 to 3.8]). Significant differences between the treatment groups in CD4 T-lymphocyte counts occurred in subjects with more than 200 but less than 500 CD4 T lymphocytes/mm3 after 4 weeks of therapy (P = 0.002). Differences persisted through week 52. Less prominent changes occurred in subjects with 500 or more CD4 T lymphocytes/mm3. Serum levels of HIV antigen decreased significantly in zidovudine recipients. Serious anemia and neutropenia occurred in 5% and 4% of zidovudine recipients, respectively, and in 0% and 1% of placebo recipients, respectively. Conclusion Zidovudine delayed progression of HIV disease and produced little toxicity in subjects with mildly symptomatic HIV disease and less than 500 CD4 T lymphocytes/mm3.

Experimental evidence for high temperature stress as the cause of El Niño-coincident coral mortality

Abstract: High temperature tolerance experiments performed on Pocillopora damicornis, a major reef-building coral in the tropical eastern Pacific, resulted in loss of zooxanthellae, histopathological abnormalities, and mortality similar to that observed during the severe 1982–83 El Nino-Southern Oscillation (ENSO) event. Coral vitality declined significantly at 30–32°C during a 10-week period, but remained high at normal temperatures (26–28°C). Laboratory time courses to coral morbidity and death were similar to those observed in the field. Experimental high temperatures had a greater negative effect on corals from the Gulf of Panama, which experiences seasonally cool upwellings, than on corals from the nonupwelling Gulf of Chiriqui. The condition of obligate symbiotic crustaceans (Trapezia, Alpheus) associated with experimental corals declined with their host's declining condition. All Gulf of Panama corals subjected to 32°C were dead after 5 weeks, and all of their associated crustacean symbionts were dead after 9 weeks. Gulf of Chiriqui corals at 30°C survived for 9 weeks and 42% of their crustacean symbionts were still alive after 10 weeks. Coral mortality in the Gulf of Panama was significantly higher (68.5%) after El Nino warming than after subsequent episodes of unusually intense cool upwellings (10.4%). Low temperature stress (cool currents and upwelling) has been generally suggested as the critical limiting condition that prevents extensive coral reef development in the eastern Pacific. Our results suggest that infrequent but severe ENSO sea warming events also may limit reef development in this region.

The effects of prolonged ``bleaching'' on the tissue biomass and reproduction of the reef coral Montastrea annularis

Abstract: Colonies of Montastrea annularis from Carysfort Reef, Florida, that remained bleached seven months after the 1987 Caribbean bleaching event were studied to determine the long term effects of bleaching on coral physiology. Two types of bleached colonies were found: colonies with low numbers of zooxanthellae with normal pigment content, and a colony with high densities of lowpigment zooxanthellae. In both types, the zooxanthellae had an abnormal distribution within polyp tissues: highest densities were observed in basal endoderm and in mesenteries where zooxanthellae are not normally found. Bleached corals had 30% less tissue carbon and 44% less tissue nitrogen biomass per skeletal surface area, but the same tissue C:N ratio as other colonies that either did not bleach (normal) or that bleached and regained their zooxanthellae (recovered). Bleached corals were not able to complete gametogenesis during the reproductive season following the bleaching, while recovered corals were able to follow a normal gametogenic cycle. It appears that bleached corals were able to survive the prolonged period without nutritional contribution from their zooxanthellae by consuming their own structural materials for maintenance, but then, did not have the resources necessary for reproduction. The recovered corals, on the other hand, must have regained their zooxanthellae soon after the bleaching event since neither their tissue biomass nor their ability to reproduce were impaired.

Formation of carbonyl compounds from UV‐induced photodegradation of humic substances in natural waters: Fate of riverine carbon in the sea

Abstract: Low-molecular-weight (LMW) carbonyl compounds, e.g. formaldehyde, acetaldehyde, and the a-keto acid glyoxylate, were produced in a wide variety of natural waters upon irradiation with sunlight. Production rates were linearly related (r2 > 0.98) to initial absorbance at 300 nm and initial fluorescence (360/460 nm) in all waters tested. Photochemical production was also linearly related to loss (photobleaching) of absorbance and fluorescence during irradiation, irrespective of irradiation time and prior photobleaching history of the sample. These results were attributed to absorption of light by humic substances in the waters, as determined by experiments where purified humic and fulvic extracts were added to open-ocean water. The wavelengths in the solar spectrum responsible for photoproduction of LMW carbonyl compounds and bleaching of dissolved organic matter light absorbance are in the UV-B region (280-320 nm). These results, plus results from time-course irradiations, suggest that photoproduction of carbonyl compounds from humic substances is closely related to photobleaching of absorbance. Based on our photoproduction rates of LMW carbonyl compounds, we estimate that the half-life of humic-rich riverine dissolved organic C in the oceanic mixed layer is 5-l 5 yr.

Hydroxyl radical photoproduction in the sea and its potential impact on marine processes.

Abstract: Photochemical production rates and steady-state concentrations of hydroxyl radicals (.OH) were measured in sunlight-irradiated seawater. Values ranged from 110 nanomolar per hour and 12 x 10(-18) molar in coastal surface water to 10 nanomolar per hour and 1.1 x 10(-18) molar in open ocean surface water. The wavelengths responsible for this production are in the ultraviolet B region (280 to 320 nanometers) of the solar spectrum. Dissolved organic matter (DOM) appears to be the main source for .OH over most of the oceans, but in upwelling areas nitrite and nitrate photolysis may also be important. DOM in the deep sea is degraded more readily by .OH (and its daughter radicals), by a factor of 6 to 15, than is DOM in open-ocean surface water. This finding may in part bear on major discrepancies among current methods for measuring dissolved organic carbon in seawater.

Relationship of oxygen dose to angiogenesis induction in irradiated tissue.

Abstract: This study was accomplished in an irradiated rabbit model to assess the angiogenic properties of normobaric oxygen and hyperbaric oxygen as compared with air-breathing controls. Results indicated that normobaric oxygen had no angiogenic properties above normal revascularization of irradiated tissue than did air-breathing controls (p = 0.89). Hyperbaric oxygen demonstrated an eight- to ninefold increased vascular density over both normobaric oxygen and air-breathing controls (p = 0.001). Irradiated tissue develops a hypovascular-hypocellular-hypoxic tissue that does not revascularize spontaneously. Results failed to demonstrate an angiogenic effect of normobaric oxygen. It is suggested that oxygen in this sense is a drug requiring hyperbaric pressures to generate therapeutic effects on chronically hypovascular irradiated tissue.

Influence tactics used by subordinates: A theoretical and empirical analysis and refinement of the Kipnis, Schmidt, and Wilkinson subscales.

Abstract: The research of Kipnis, Schmidt, and Wilkinson (1980) is critiqued and their subordinate influence subscales examined in four studies. In the first, the subscale items were given to 34 judges, who rated each item for dimensionality. In the second, the 27 items plus several additions were administered to a sample of 251 employed MBA students, and exploratory and confirmatory factor analyses were conducted. A third study used a similar sample (N=281) and the same analyses

Sleep disorders and sleep effect in Parkinson's disease

Abstract: It has been suggested that sleep may have a positive effect on morning motor symptoms in Parkinson's disease (PD). We examined this possibility and also looked at common sleep disorders in PD. Seventy-eight PD patients and 43 normal elderly subjects answered a questionnaire. Of the PD patients, 43.6% reported improved motor symptoms in the morning, 37.2% worse, and 19.2% unchanged compared to the rest of the day. No difference was found between morning-better and -worse groups with respect to age, duration or stage of PD; antiparkinsonian medications utilized, and predominant motor symptoms. However, the morning-same group had a shorter duration of PD and less severe disease and required fewer dopaminergic medications. Sleep disorders were seen with equal frequency in the morning-better and -worse groups. Our results suggest that sleep does not have a direct effect on morning motor function. Alterations in morning motor symptomatology probably represent a manifestation of motor fluctuations. Sleep fragmentation and spontaneous daytime dozing occurred much more frequently in PD patients than controls. In addition, nocturnal vocalizations and daytime hallucinations occurred only in the PD group.

The importance of brain temperature in alterations of the blood-brain barrier following cerebral Ischemia

Abstract: We studied whether small variations in intraischemic brain temperature influence the response of the blood-brain barrier (BBB) to transient forebrain global ischemia. Six animal subgroups included rats whose brain temperature was maintained at 30, 33, 36 or 39 degrees C during 20 minutes (min) of 4-vessel occlusion. Control rats without ischemia had brain temperature maintained between 30 and 39 degrees C for a 20 min period. After a 45 min postischemic recirculation period, rats were injected with the protein tracer, horseradish peroxidase (HRP), and perfusion fixed 5 or 15 min later. Control rats showed no leakage of the tracer protein. Postischemic rats in which brain temperature was controlled at either 30 or 33 degrees C failed to demonstrate consistent BBB alterations. In contrast, foci of cortical HRP extravasation were consistently documented in rats whose intraischemic brain temperature was 36 degrees C. Permeability alterations were more widespread in the 39 degrees C ischemic group and occurred in cortical, thalamic, hippocampal and striatal regions. The HRP extravasation frequently involved arterioles surrounded by perivascular spaces. Routes of increased permeability to HRP included endothelial pinocytosis, opening of the interendothelial tight junctions and diffuse leakage through damaged endothelial cells. These results demonstrate that brain temperature is a critical factor in determining whether BBB dysfunction is an acute consequence of a transient cerebral ischemic insult.

Determinants of Variation in Tropical Forest Primate Biomass: New Evidence from West Africa

Abstract: To explore sources of variation in tropical forest primate biomass, and, in particular, to test the hypothesis that soil conditions are a major ultimate determinant of the biomass of colobine monkeys and other primates, we compared data on the soils, vegetation, and primate community at a site in West Africa (Tiwai Island, Sierra Leone) with information from other sites, especially two other African sites (Douala-Edea in Cameroon, and Kibale Forest in Uganda). The biomass of eight anthropoid primate species in old secondary high forest on Tiwai was estimated from data on population densities assessed by transect samples combined with data on social group densities and individual body masses. Samples of soil and tree foliage were collected at the same site, and subjected to a variety of chemical and mechanical analyses. Our estimate of anthropoid biomass at Tiwai is 1229-1529 kg/kM2, including 682-889 kg/km2 of colobines. This is one of the highest primate biomasses recorded anywhere. The soils at Tiwai were found to be relatively high in sand content and low in pH, and to have low levels of mineral nutrients. Levels of condensed tannins in the mature foliage of the trees comprising a major part of the forest canopy were higher than at other sites, but the ratio of protein to fiber in this foliage was also higher than at any other site except Kibale. It is argued that a wide range of environmental factors affect primate population densities, and that nutrient-poor soils and high tannin levels in tree foliage do not necessarily produce a low primate (or colobine) biomass, as some earlier studies had suggested. Fur-

Cerebrovascular complications of the use of the "crack" form of alkaloidal cocaine.

Abstract: Background and Methods. The use of cocaine, especially one of its alkaloidal forms ("crack"), has been increasingly associated with cerebrovascular disease. To clarify the clinical, radiologic, and pathological features of the events associated with cocaine use, we identified 28 patients at four medical centers who had stroke temporally related to the use of alkaloidal cocaine (during or within 72 hours of use). Results. The 28 patients had the following types of cerebrovascular event: cerebral infarction (n = 18[2hemorrhagic; 1 fatal]) in the areas supplied by the middle cerebral artery (n = 10), anterior cerebral artery (n = 3), posterior cerebral artery (n = 1 ), and vertebrobasilar arteries (n = 4); subarachnoid hemorrhage (n = 5); intraparenchymal hemorrhage (n = 4); and primary intraventricular hemorrhage (n = 1). Eighteen patients (64 percent) had acute neurologic symptoms immediately or within one hour of using cocaine. Fifteen patients (45 percent) with either occlusive or hemorrhagic st...

Corticosteroids as adjunctive therapy for severe Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome. A double-blind, placebo-controlled trial.

Abstract: Background. Preliminary reports suggest that patients with the acquired immunodeficiency syndrome (AIDS) and Pneumocystis carinii pneumonia may benefit from the addition of corticosteroid treatment to antibiotic therapy. Methods. We conducted a double-blind, placebo-controlled trial to assess the efficacy of adjunctive corticosteroids in patients with AIDS and severe P. carinii pneumonia. Patients with marked abnormalities in gas exchange who had been treated with antibiotics for less than 72 hours were randomly assigned to receive either methylprednisolone (40 mg) or placebo every 6 hours for 7 days, in addition to treatment for 21 days with trimethoprim–sulfamethoxazole. The primary outcome measures were survival until hospital discharge and the development of respiratory failure. Results. Twenty-three patients were enrolled in the study; there were no significant differences in base-line clinical or laboratory measures between the two treatment groups. Of 12 patients treated with corticosteroi...

Effects of normothermic versus mild hyperthermic forebrain ischemia in rats.

Abstract: We compared the neuropathological consequences of global forebrain ischemia under normothermia versus mild hyperthermia. Twenty-one rats underwent 20 minutes of four-vessel occlusion during which brain temperature was maintained at either 37 degrees C (normothermia, n = 9) or 39 degrees C (hyperthermia, n = 12). Quantitative neuropathological assessment was conducted 1 or 3 days later. At 1 day following the ischemic insult, normothermic rats demonstrated neuronal injury mainly confined to the most dorsolateral striatum. By 3 days, ischemic cells were present throughout the striatum and CA1 hippocampus in normothermic animals. Compared with normothermic rats, intraischemic hyperthermia significantly increased the extent and severity of brain damage at 1 day after the ischemic insult. Areas of severe neuronal necrosis and frank infarction included the cerebral cortex, CA1 hippocampus, striatum, and thalamus. Morphologic damage was also detected in the cerebellum and pars reticulata of the substantia nigra. An overall mortality rate of 83% was demonstrated at 3 days in the hyperthermic ischemic group. We conclude that intraischemic hyperthermia 1) markedly augments ischemic brain damage and mortality compared with normothermia, 2) transforms ischemic cell injury into frank infarction, and 3) accelerates the morphological appearance of ischemic brain injury in regions usually demonstrating delayed neuronal necrosis. These observations on mild hyperthermia may have important implications for patients undergoing cardiac or cerebrovascular surgery as well as patients following cardiac arrest or those with stroke-in-evolution.

Recombinant human erythropoietin for patients with AIDS treated with zidovudine.

Abstract: Bone marrow suppression and anemia are frequent side effects of treatment of the acquired immunodeficiency syndrome (AIDS) with zidovudine (formerly azidothymidine [AZT]). We conducted a randomized, double-blind, placebo-controlled clinical trial of recombinant human erythropoietin (100 U per kilogram of body weight thrice weekly by intravenous bolus) in 63 patients with AIDS treated with zidovudine (29 in the erythropoietin group and 34 in the placebo group). Reductions in the number of units of red cells transfused and the number of patients given transfusions per month became apparent in the second and third months of the trial. The reductions were observed in patients with endogenous erythropoietin levels ≤500 IU per liter at base line, but not in patients whose levels were >500 IU per liter at the beginning of the study. Although the hematocrit and hemoglobin level were not used as the primary criteria of efficacy because the patients received transfusions when their physicians decided that ...

A Randomized Controlled Trial of a Reduced Daily Dose of Zidovudine in Patients with the Acquired Immunodeficiency Syndrome

Abstract: Background. The initially tested dose of zidovudine for the treatment of patients with advanced disease caused by the human immunodeficiency virus type 1 (HIV) was 1500 mg. Although this dose is effective, it is associated with substantial toxicity. Methods. To evaluate the efficacy and safety of a reduced dose, we conducted a randomized controlled trial in 524 subjects who had had a first episode of Pneumocystis carinii pneumonia. The subjects were assigned to receive zidovudine in either a dose of 250 mg taken orally every four hours (the standard-treatment group, n = 262) or a dose of 200 mg taken orally every four hours for four weeks and thereafter 100 mg taken every four hours (the low-dose group, n = 262). Results. The median length of follow-up was 25.6 months. At 18 months the estimated survival rates were 52 percent for the standard-treatment group and 63 percent for the low-dose group (P = 0.012 by the log-rank test). At 24 months the estimated survival rates were 27 percent for the st...