ACS focusing on breast cancer detection.
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American Cancer Society↗
Biomedical subjects
M King
Publications and source records attributed to M King.
Biocompatibility of the Vascugraft: evaluation of a novel polyester urethane vascular substitute by an organotypic culture technique.
To evaluate the biocompatibility of chemically and structurally modified polyurethane elastomers for use as blood vessel replacements, small squares of vascular prostheses were cultured in direct contact with endothelium from chick embryo aorta using an organotypic culture assay. The polyurethane materials tested were: Vascugraft (fibrous, open pore structure); commercial Hydrophilic Mitrathane prosthesis (high porosity, smooth surface, non-permeable, closed pore structure); experimental hydrophobic Mitrathane (less porosity but a fibrous, open pore structure, similar to Vascugraft). The commercial expanded polytetrafluoroethylene prostheses Impra and reinforced GORETEX were included as controls on account of their extensive clinical application in the femoropopliteal position. After 5 d incubation at 37 degrees C biocompatibility was assessed in terms of average area of migrating cells on the biomaterial, total number of cells surrounding the explant and level of adhesion between the cells and the biomaterial. The Vascugraft prosthesis promoted the growth of a continuous monolayer of cells on its surface. This behaviour was equivalent to Impra and reinforced GORETEX materials in terms of cell density and area of cell migration but appeared to be superior for cell adhesion. From a second series of cell culture tests, in which the extractables leached from the biomaterials were added to the nutrient medium, it was concluded that none of the biomaterials tested released cytotoxic contaminants.
Animals↗
Respiratory alterations due to urban air pollution: an experimental study in rats.
In order to assess the adverse effects of urban levels of air pollution, rats were used as biological indicators in a chronic exposure experiment. Animals were housed for 6 months in the center of São Paulo (the largest South American city) and were compared to controls kept for the same period in a clean area. Pollution levels were obtained from a State air pollution monitoring station, 200 m distant from the exposure place, which provided the levels of CO, SO2, particulates, and ozone. The animals were submitted to several tests focusing on the respiratory system, comprising pulmonary function tests, studies on mucociliary clearance and mucus rheology, histochemical evaluation of airways, bronchoalveolar lavage, and ultrastructural studies of the epithelium of the airways. Rats exposed to air pollution developed secretory cell hyperplasia in the airways, ultrastructural ciliary alterations, and a more rigid mucus, changes that caused mucociliary clearance impairment. In addition, nasal resistance and the number of inflammatory cells recovered by bronchoalveolar lavage were increased in air pollution exposed animals. The results obtained in the present investigation suggest that chronic exposure to urban levels of air pollution may cause respiratory lesions in rats.
Air Pollution↗
Aortic saddle embolus presenting with transient lower extremity paresthesia.
We report the case of a 58-year-old woman who developed acute onset of bilateral lower-extremity numbness and difficulty ambulating at home. On presentation to the emergency department, however, the patient's symptoms essentially had resolved. An aortic saddle embolus was suspected based on the patient's cardiac history and the absence of distal pulses in the lower extremities. This case illustrates that even with vague or resolving complaints, a high index of suspicion should be maintained for the diagnosis of aortic saddle embolus based on the patient's medical history and on physical examination.
Aorta, Abdominal↗
A dual level model for speciation by multiple pericentric inversions.
A considerable body of evidence suggests that the deleterious meiotic effects of pericentric inversions in F1 hybrids can be overcome by changes in chiasma location and various means of non-homologous pairing. Such overriding mechanisms may render pericentric inversions benign and increase the likelihood of their fixation in population isolates. It has been argued that overriding mechanisms of this type negate the involvement of pericentric inversions as reproductive isolating mechanisms in speciation. It is suggested, however, that the involvement of pericentric inversions in speciation should be considered on two levels. First, that by reducing meiotic effects in F1 hybrids, overriding mechanisms facilitate the fixation of pericentric inversions. Secondly, when contact hybridization occurs between the chromosomally derived and parental populations second-level effects may be encountered. That is, the recombinational effects of pericentric inversion differences on coadapted gene complexes (sensu Brncic, 1954, Shaw & Coates, 1983) enforce profound inviability barriers in F2 and backcross matings. In this way, multiple pericentric inversions may act as significant post-mating isolating mechanisms, whereas individual inversions with less significant second-level effects may not.
Animals↗
The polyurethane foam covering the Même breast prosthesis: a biomedical breakthrough or a biomaterial tar baby?
Because controversy continues to surround the implantation of the polyurethane foam-covered Même breast prosthesis, in vitro experiments were conducted to determine: (1) whether the polyurethane foam contains extractable toluene diamine isomers (TDAs), and (2) whether the polyurethane foam releases TDAs on exposure to mild hydrolytic conditions. Results confirmed the presence of extractable TDAs and other impurities in the foam covering the unused Même prosthesis, and that the concentrations of these impurities could be significantly reduced by washing the foam in a regular detergent. This washing step was omitted from the manufacturer's production process. Furthermore, on exposure to mild alkalis, the foam exhibited significant degradation, rapid fragmentation, loss of mechanical strength and physical integrity, as well as the release of additional TDAs. Because of the potential long-term risks associated with the release of TDAs in vivo, continued clinical use of the Même prosthesis containing this particular type of foam appears questionable.
Biocompatible Materials↗
What you should know about H.I.V. testing.
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AIDS Serodiagnosis↗
Is there a seasonal variation in mucus transport and nutrient absorption in the leopard frog?
We postulated that as a hibernating species, frogs might have variable demands for nutrients at different seasons of the year and that this must be reflected in seasonal variations of physiologic processes related to nutrient transport and absorption. We examined the rate of mucus transport on the ciliated palate and the movement of nutrients across the intestinal lumen of leopard frogs, Rana pipiens. Mucus transport on the frog palate was strongly influenced by season, with maximal transport occurring in late June (Julian day 178, p = 0.0001; r = 0.58). This increased transport rate was associated with a summertime increase in mucus recoil (lower tangent delta) and a decrease in mucus hydration (increase in percent solids composition). Intestinal transport of leucine, lysine, and galactose did not appear to exhibit seasonal variability. These data suggest that different mechanisms may operate in determining seasonal variability in physiologic responses.
Animals↗
Respiratory mucus from asymptomatic smokers is better hydrated and more easily cleared by mucociliary action.
We compared the physical and transport properties of tracheal mucus collected from 16 asymptomatic smokers and from 18 nonsmokers. The smokers produced a larger volume of mucus (wet weight 18.6 versus 11.2 mg; p = 0.04) with a lower solids content (11.5 versus 16.3%; p = 0.02) and a lower modulus of rigidity (log G* 2.37 versus 2.62; p = 0.04). Although the smokers mucus had a 40% faster mucociliary transport rate on the frog palate (p = 0.04), the cough clearability was nearly identical to the mucus from nonsmokers. The differences are similar to those observed in rats or dogs chronically exposed to cigarette smoke. These data suggest both a quantitative and a qualitative difference in the composition of mucus from asymptomatic smokers. The increased volume of a watery mucus with increased mucociliary clearability may help to protect the airways from the injurious effects of inhaled smoke.
Adult↗
Homosexuals who are twins. A study of 46 probands.
Forty-six homosexual men and women who were twins took part in a study of their sexuality and that of their co-twin. Discordance for sexual orientation in the monozygotic pairs confirmed that genetic factors are insufficient explanation of the development of sexual orientation. There was a high level of shared knowledge of sexual orientation between members of twin pairs, and a relatively high likelihood of sexual relations occurring with same sex co-twins at some time, particularly in monozygotic pairs. The implications of these results for the study of the origins of sexual orientation and for twin research are discussed.
Adolescent↗
Mucus rheology and transport in neonatal respiratory distress syndrome and the effect of surfactant therapy.
BACKGROUND: Neonatal respiratory distress syndrome (RDS) is caused by a deficiency of pulmonary surfactant. Alveolar collapse and obstruction of conducting airways leads to mismatch of ventilation and perfusion and profound hypoxemia. We postulated that surfactant deficiency could alter the properties of respiratory mucus in such a way that it would be poorly cleared from airways and promote airway luminal obstruction and that these changes might be reversed by the exogenous administration of a synthetic surfactant preparation. METHODS: Respiratory mucus coating an endotracheal tube (ETT) or suction catheter was collected from 14 neonates (gestational age, 24 to 36 weeks; birth weight, 600 to 2,400 g) with RDS who required tracheal intubation and ventilation. Eight of these neonates received 5 ml/kg of an intratracheal artificial surfactant preparation (Exosurf), given between 2 and 10 h of age and six neonates received 5 ml/kg of air. Mucus viscoelasticity, hydration (percentage of solid composition of mucus), and mucociliary clearability (NFPTR) were measured for each specimen. RESULTS: The total volume of mucus collected from the surfactant-treated and control infants was similar, but mucus hydration was significantly less in babies with RDS who did not receive Exosurf (percentage of solid composition of mucus 18.7 vs 11.4; p = 0.013). Ciliary transportability was also less in the untreated babies (NFPTR 0.39 vs 0.86; p = 0.018) and this mucus was more rigid (increased viscoelasticity: log G* 1 rad/s 2.28 vs 1.50; p = 0.0001). CONCLUSIONS: These data suggest that airway obstruction in RDS may be due, in part, to abnormal mucus properties and impaired ciliary transport. Surfactant therapy appears to improve mucus clearability. Exogenously administered surfactant may also be beneficial for the treatment of other selected respiratory conditions associated with impaired mucus clearance.
Drug Combinations↗
Trends in tans and skin protection in Australian fashion magazines, 1982 through 1991.
We rated 3971 photographs of models from midsummer editions of six Australian fashion magazines from 1982-1983 to 1990-1991 for tan on a 9-point scale, for the presence of hats, for sun-protective clothing, and for shade setting. With the exception of the 1990-1991 sample, there was an increasing proportion of light tans over the years. Men were more likely to be deeply tanned than were women. The proportion of models wearing hats followed an increasing linear trend across the five periods. Three quarters of the outdoor photographs were taken in unshaded settings. In unshaded settings, 17% of the women and 5% of the men wore hats.
Australia↗
Biological versus psychosocial.
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Antipsychotic Agents↗
Early diagnosis of holoprosencephaly.
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Adult↗
Intrapartum asphyxia in term and post term infants.
Many attempts have been made to identify infants at risk of suffering asphyxial brain damage. In a retrospective review of records at the Rotunda Hospital over a five year period all infants who died or suffered seizures, presumed secondary to asphyxia, were compared with the general hospital population. Out of 28,655 deliveries reviewed, there were 13 deaths in infants at or after term associated with perinatal asphyxia, and 32 surviving infants had asphyxial seizures. Seizures were regarded as asphyxial in origin if they occurred in the first forty eight hours of life and were associated with other clinical evidence of asphyxia. The incidence of abnormal presentations, assisted breech deliveries, instrumental deliveries and emergency caesarean sections was all increased in the asphyxial categories compared to the control population. Referral to the fetal assessment unit was associated with a seizure rate of 0.16/1000 live births compared with a rate of 1.4/1000 in the remaining non referred hospital population. Nineteen percent of the infants who seized subsequently developed cerebral palsy. It would appear from our data that referral to the fetal assessment unit and the consequent assignment to "high risk" status is associated with low risk in terms of asphyxial outcome.
Asphyxia Neonatorum↗
Phase II evaluation of iproplatin in patients with advanced gastric and pancreatic cancer.
A total of 48 patients with measurable advanced gastric adenocarcinoma (n = 16) or adenocarcinoma of the exocrine pancreas (n = 32) were prospectively treated with iproplatin at a starting dose of 270 mg/m2 intravenously over 2 hours. The dose was repeated every 28 days, and dose escalations or reductions were made on the basis of toxicity in the preceding course. No patient with gastric carcinoma achieved either a complete or partial response. One partial response and two complete responses were seen with pancreatic adenocarcinoma for an overall response rate of 10%. One patient has remained free of disease for more than 2 years. The major toxicities were granulocytopenia, thrombocytopenia, nausea, vomiting, and diarrhea. All toxicities were reversible upon discontinuation of the drug. On the basis of this trial, we conclude that iproplatin has no substantive activity in advanced gastric or pancreatic carcinomas.
Adenocarcinoma↗
Does lithium dose prediction improve treatment efficiency? Prospective evaluation of a mathematical method.
An attempt was made to determine whether an algorithm for lithium dose prediction allows earlier or more economical attainment of a therapeutic steady state than does the usual "clinical titration." Twelve patients were treated using an algorithm developed by Zetin and associates and compared with 21 patients treated by clinical titration. Ten of the 12 algorithm-treated patients (83%) had reached the desired lithium blood level by the seventh day, whereas only 8 of the 21 clinical titration patients (38%) had done so. This difference is significant. In addition, the Zetin algorithm performed safely: the 2 dose prediction errors led to underdosing. Some of the relevant literature is reviewed.
Adult↗
Characterization of Fc gamma receptors on a human erythroleukemia cell line (HEL).
It has been established that human platelets express a single class of Fc gamma receptors that has been designated Fc gamma RII. However, the function of this receptor on these cells and its regulation are less certain. Studies to further investigate Fc gamma RII on platelets are limited by the inability to culture platelets in vitro. Therefore, identification of a human cell line that expresses Fc gamma RII as its only Fc gamma receptor as well as other platelet characteristics would be of potential importance. To this end, we examined Fc gamma receptor expression by the human erythroleukemia (HEL) cell line, which expresses platelet/megakaryocyte surface proteins. Flow cytometry studies on HEL cells with anti-Fc gamma receptor monoclonal antibodies revealed that, similar to platelets and megakaryocytes, Fc gamma RII is the only Fc gamma receptor expressed on the cell surface. Furthermore, Northern blot analysis revealed that Fc gamma RII is the only Fc gamma receptor mRNA present. Stimulation with dimethylsulfoxide (DMSO) or 12-O-tetradecanoylphorbol-13-acetate (TPA) did not alter Fc gamma RII protein or mRNA expression. Ligand binding studies with [125I]IgG trimer indicated that HEL cells express 92,240 +/- 5030 binding sites per cell, with a kd of 1.94 +/- 0.31 x 10(-8) M. Similar to human platelets, HEL cells preferentially bound oligomeric IgG, and this binding was ionic strength dependent. These observations are similar to those previously observed with Fc gamma RII on human platelets and suggest that the HEL cell Fc gamma receptor is similar, if not identical to the platelet Fc gamma RII receptor. HEL cells may serve as a model for the study of platelet/megakaryocyte Fc gamma RII.
Humans↗