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PubMed2001

The effect of casting solvent quality on the structure of polymeric Langmuir-Blodgett films.

The effect of casting solvent quality (good vs. [symbol: see text] solvent) on the structure of Langmuir-Blodgett films of a flexible-chain polymer [poly(dimethylsiloxane)] was examined on the basis of differences in the shape of Langmuir-Blodgett isotherms for two solvents, two temperatures, four polymer molecular weights, and three compression rates. The magnitude of a new index that describes the shape characteristics of the isotherm beyond the point of monolayer formation is found to be capable of separating all 48 isotherms studied into two groups, exclusively on the basis of the quality of the casting solvent. Experimental observations are supplemented by qualitative polymer physics interpretations regarding the structure of the films upon casting and compression.

Butanones↗
PubMed1994

Three-dimensional relationships between tumor cells and microcirculation with double cyanine immunolabeling, laser scanning confocal microscopy, and computer-assisted reconstruction: an alternative to cast corrosion preparations.

The morphology of the microcirculation of uveal melanomas is a reliable market of tumor progression. Scanning electron microscopy of cast corrosion preparations can generate three-dimensional views of these vascular patterns, but this technique sacrifices the tumor parenchyma. Formalin-fixed wet tissue sections 100-150 microns thick from uveal melanomas were stained with the lectin Ulex europaeus agglutinin I (UEAI) and proliferating cell nuclear antigen (PCNA) to demonstrate simultaneously the tumor blood vessels and proliferating tumor cells. Indocarbocyanine (Cy3) was used as a fluorophore for UEAI and indodicarbocyanine (Cy5) was used for PCNA. Double labeled sections were examined with a laser scanning confocal microscope. Images of both stains were digitized at the same 5-microns intervals and each of the two images per interval was combined digitally to form one image. These combined images were visualized through voxel processing to study the relationship between melanoma cells expressing PCNA and various microcirculatory patterns. This technique produces images comparable to scanning electron microscopy of cast corrosion preparations while permitting simultaneous localization of melanoma cells expressing PCNA. The microcirculatory tree can be viewed from any perspective and the relationship between tumor cells and the tumor blood vessels can be studied concurrently in three dimensions. This technique is an alternative to cast corrosion preparations.

Antigens, Neoplasm↗
PubMed2003

Shape differences rather than size differences between castes in the Neotropical swarm-founding wasp Metapolybia docilis (Hymenoptera: Vespidae, Epiponini).

BACKGROUND: Swarm-founding epiponine wasps are an intriguing group of social insects in which colonies are polygynic (several queens share reproduction) and differentiation between castes is often not obvious. However, caste differences in some may be more pronounced in later phases of the colony cycle. RESULTS: Using morphometric analyses and multivariate statistics, it was found that caste differences in Metapolybia docilis are slight but more distinct in latter stages of the colony cycle. CONCLUSIONS: Because differences in body parts are so slight, it is proposed that such variation may be due to differential growth rates of body parts rather than to queens being larger in size, similar to other previously observed epiponines.

Animals↗
PubMed2000

Expression profiles during honeybee caste determination.

BACKGROUND: Depending on their larval environment, female honeybees develop into either queens or workers. As in other polyphenisms, this developmental switch depends not on genomic differences between queens and workers but on the differential expression of entire suites of genes involved with larval fate. As such, this and other polyphenic systems can provide a novel tool for understanding how genomes and environmental conditions interact to produce different developmental trajectories. Here we use gene-expression profiles during honeybee caste determination to present the first genomic view of polyphenic development. RESULTS: Larvae raised as queens or workers differed greatly in their gene-expression patterns. Workers remained more faithful than queens to the expression profiles of younger, bipotential, larvae. Queens appeared to both downregulate many of the genes expressed by bipotential larvae and turn on a distinct set of caste-related genes. Queens overexpressed several metabolic enzymes, workers showed increased expression of a member of the cytochrome P450 family, hexameric storage proteins and dihydrodiol dehydrogenase, and young larvae overexpressed two putative heat-shock proteins (70 and 90 kDa), and several proteins related to RNA processing and translation. CONCLUSIONS: Large differences in gene expression between queens and workers indicate that social insect castes have faced strong directional selection pressures. Overexpression of metabolic enzymes by queen-destined larvae appears to reflect the enhanced growth rate of queens during late larval development. Many of the differently expressed genes we identified have been tied to metabolic rates and cellular responses to hormones, a result consistent with known physiological differences between queen and worker larvae.

Animals↗
PubMed1985

A developmental study of reactions to frustration among Scheduled Caste Indians.

Administered the Indian adaptation of the Rosenzweig P-F Study to 144 Scheduled Caste (SC) adolescent and 158 young adult male Indians. The results show that SC adolescents scored significantly higher on ego-defensive (ED) and extragressive (EA) and lower on need-persistive (NP), introgressive (IA) and imgressive (MA) reactions as compared to the Non-Scheduled caste (Non-SC) adolescents while there was no significant difference on any reaction among SC and Non-SC young adults. SC adolescents scored higher on NP and lower on obstacle-dominance (OD) reaction as compared to the SC young adults. Non-SC young adults were higher on EA, ED, and OD and lower on IA and NP as compared to those of adolescents. The pattern of reactions was ED-EA-NP-IA-MA-OD among adolescents and ED-EA-IA-NP-MA-OD among young adults of both the castes.

Adolescent↗
PubMed2007

Growing out of a caste--reproduction and the making of the queen mole-rat.

Naked mole-rats have a eusocial colony structure consisting of non-reproductive workers and a reproductively active caste where a single, dominant queen and 1-3 males produce all of the offspring. Well-established queens have elongated bodies that characterize their caste. Worker females retain the ability to transform into queens, however the trigger and time course for this physical transformation remain a mystery. Here, we show a direct link between periods of pregnancy and vertebral lengthening in nascent queens. Adult female mole-rats were paired with a male and radiographed weekly for two and a half years to track the growth of the lumbar vertebrae as the mole-rats became sexually mature and experienced pregnancies. The lumbar vertebrae of breeding females grew at an increased rate during each pregnancy but growth rates returned to normal between pregnancies and during extended periods without reproduction. The rate of lumbar lengthening was reduced to normal rates in older, established queens experiencing pregnancies. Our results imply that the length of a new queen mole-rat is proportional to the number of pregnancies experienced and suggest that hormones related to pregnancy may play the critical role in bone growth associated with caste transformation.

Age Factors↗
PubMed1979

The treatment of femoral fractures by cast-brace and early walking: a review of seventy-nine patients.

Seventy-nine cases of fracture of the femoral shaft treated by cast-brace and early walking have been reviewed. Discrepancy in femoral length was assessed by scanogram. The cases were analysed to relate the incidence of shortening greater than 2 centimetres to the type and site of the fracture, and the time which elapsed from injury until the cast-brace was applied. Such shortening was encountered most frequently when the cast-brace was applied within the first two weeks from injury or after six weeks and in those patients with comminuted fractures of the middle third of the femoral shaft.

Adult↗
PubMed2001

Tracheobronchial tumor cast formation and pneumothorax.

A 34-year-old white man was admitted to the hospital for progressive respiratory difficulty, recurrent left pneumothorax, and a diagnosis of aplastic left lung. Further evaluation, including bronchoscopy and CT scan, demonstrated a cast-forming tracheobronchial obstructing tumor. Surgical resection of the tumor through the left chest with left lower lobectomy resolved his symptomatology. Improved ventilation with an open airway led to expansion of the left upper lobe. The pathologic diagnosis remained controversial as to a definite designation and was primarily descriptive: spindle cell proliferation with myxoid and collagenized stromal benign tumor. However, the extent of this rubbery tumor cast and the ability to remove it intact illustrate the tenacity of the structure and the very unusual nature of a cast of the entire tracheobronchial system on the left side.

Adult↗
PubMed1988

Improving the cementation of complete cast crowns: a comparison of static and dynamic seating methods.

This study measured the effect of static and dynamic forces, during cementation, on the retention and seating of complete cast crowns made for extracted human teeth prepared with a diamond bur. Under a static load, the castings failed to seat by a mean value of 203 micron. When dynamically loaded, the castings seated an average of 14 micron beyond the point of precementation measurement. No statistically significant differences were found in the retention of the crowns cemented by the two different methods.

Cementation↗
PubMed1996

The coming demise of the cast gold restoration?

Cast gold restorations have overall characteristics unavailable in any other restorative procedure for inlays and onlays, including low restoration wear; low wear of opposing teeth; lack of breakage; burnishability-malleability; and proven long-term service. Bonding cast gold restorations with resin cement improves their characteristics even more. However, they are not tooth-colored, which eliminates them from consideration for many patients. Although tooth-colored inlays and onlays, both ceramic and filled polymer, are increasing in use, and their serviceability is acceptable at a moderate level, cast gold restorations remain the standard of care for long-term indirect restorative service.

Composite Resins↗
PubMed1993

Vascular architecture of 3-methyl choranthrene-induced rat fibrosarcoma demonstrated by scanning electron microscopy of resin casts.

A detailed knowledge of the vascular system of tumors is requisite to a clear understanding of tumor physiology and pathology. Accordingly, in this study, examination was made of the vascular architecture of rat fibrosarcomas induced by 3-methyl choranthrene by scanning electron microscopy of resin casts to observe the three-dimensional vascular pattern of the sarcoma. The results were compared with those of corresponding serial sections of India ink-injected tissue. The major arteries in and around tumors appeared devoid of intra-arterial cushions which regulate blood flow. The arterial lining of resin casts was smooth just at the site where it entered the tumor. This may possibly be indication of degeneration and loss of the smooth muscle layer in the vascular wall. Casts of capillaries were very thin from 4 to 6 microns in diameter and very few sprouts could be seen. Capillaries, frequently present in superficial regions of the tumor, formed a rich irregular fine polygonal network. In fibrous tissue in deeper regions of the tumor, this network was coarse. The absence of intra-arterial cushions and degeneration of muscle cells may thus possibly be the reason for the characteristic haemodynamics of tumors.

Animals↗
PubMed2004

Three-dimensional analysis of maxillary dental casts using Fourier transform profilometry: precision and reliability of the measurement.

OBJECTIVE: Fourier transform profilometry was used for the three-dimensional measurement of maxillary dental casts to analyze the size and shape of the palate. The objective of this study was to test the accuracy of the measuring system and determine the precision and reliability of the measurement METHODS: Images of dental casts were analyzed using newly developed measuring software. Based on five landmarks located on the alveolar ridge, the measuring software constructed 10 transversal sections of the palate. In each section profile, the width, area, and 23 height variables were assessed. SUBJECTS: Maxillary dental stone casts of 25 healthy girls, 14.1 to 15.3 years of age, were studied. RESULTS: The technical error of measurement exceeded 5% of the size of the measurement only in variables with means less than approximately 3 mm. In fact, such small absolute dimensions were exhibited only by the palate height in anterior profile 2 and the palate height at the margins of other profiles. Reliability of the measurements was found to be very high for the width and area of the profiles. For height measurements, the coefficient of reliability was slightly lower at the profile margins than near the midline. Nevertheless, only three height variables showed a coefficient of reliability lower than 0.90. The coefficients of reliability of other height measurements of profiles 3 through 10 were only sporadically lower than 0.97. CONCLUSION: With regard to the accuracy of the measuring system as well as the precision and reliability of the measurement, this method proved to be a suitable tool for studying palatal morphology.

Adolescent↗
PubMed1999

A multicenter retrospective 3D study of serial complete unilateral cleft lip and palate and complete bilateral cleft lip and palate casts to evaluate treatment: part 1--the participating institutions and research aims.

OBJECTIVE: To compare the multicenter retrospective and prospective spatiotemporal (4D) serial analyses of complete unilateral (CUCLP) and complete bilateral (CBCLP) cleft lip and palate casts that had undergone different treatment procedures. The involved institutions are Miami Craniofacial Anomalies Foundation, South Florida Cleft Palate Clinic; University Hospital of Nijmegen Cleft Palate Center; Free University of Amsterdam Cleft Palate Center; Academic Hospital (Dijkzigt/Sophia) Rotterdam Cleft Palate Center; Center for Craniofacial Anomalies, University of Illinois College of Medicine; Cleft Palate Center, Sahlgrenska University Hospital, Göteborg, Sweden; and Children's Memorial Medical Center, Northwestern University Cleft Palate Institute. DESIGN: Using serial casts of the upper jaw and an electromechanical digitizer with special Cad-Cam software (CadKey), the occlusal relationships and morphometric palatal growth changes that occur under the influence of presurgical orthopedics and various surgical procedures will be studied. It is anticipated that 3D geometric data extracted from serial casts will identify the important geometric palatal parameters present before cleft surgical closure, which will supply objective criteria for establishing a scientific basis for improved surgical therapy. This research study will test three hypotheses: (1) Conservative (varying the timing of surgical cleft closure according to the size of the cleft space) lip and palatal surgery will permit "catch-up" palatal growth and normalize palatal growth and development. (2) The amount of mucoperiosteal tissue relative to the size of the cleft space is important in determining the timing of palatal surgery, as it influences the degree of scarring and ultimately the palate's adult size and form. (3) Presurgical orthopedics (the use of appliances soon after birth) can stimulate palatal growth beyond its normal growth potential. RESULTS: In a previous project and again after reviewing the data already collected during the first year of this study, it has been shown that incremental changes in size of palatal segments in CUCLP and CBCLP cases prior to surgery vary slightly. The CBCLP cases grow slightly faster than CUCLP cases before surgery, but growth of the CBCLP cases decreases in acceleration after surgery. Reasons for these differences will be determined when more cases are analyzed and subjected to biostatistical analysis.

Adolescent↗
PubMed1988

Blood vascular organization of the human appendix: a scanning electron microscopic study of corrosion casts.

Blood vascular beds of the human appendix were reproduced with a methacrylate casting medium and observed with a scanning electron microscope. The appendix received some small afferent arterial branches of the appendicular artery. These small arterial branches pierced the muscular layer and reached the submucosal plexus. Small arterioles arising from this plexus, climbed the mucosa and formed honeycomb-like capillary meshes at the luminal surface level. These capillaries were drained by the collecting veins, which descended the mucosa and joined the submucosal plexus. The large efferent veins arising from the submucosal plexus passed through the muscular layer and continued with the appendicular vein. In the mucosal and submucosal layers, several spherical basket-like casts of the germinal center (lymphoid follicle) were seen. In the parafollicular region (primary follicle), casts of postcapillary venules with prominent surface undulations were relatively frequently observed.

Adult↗
PubMed1999

A resuscitated case from asphyxia by large bronchial cast.

A 62-year-old woman with bronchiectasis suffered from asphyxia due to a large bronchial cast that obstructed the bronchial tree. Immediate bronchoscopic suction of a bronchial cast of 17 cm in length through the intubated tube relieved the patients without any complications. Large bronchial casts appear to be rare in this century but it should be considered in patients with acute exacerbation of excessive sputa not only in patients with asthma or allergy but also in patients with respiratory tract infection.

Airway Obstruction↗
PubMed1985

Three-dimensional organization of lymphatics and their relationship to blood vessels in rabbit small intestine. A scanning electron microscopic study of corrosion casts.

Casts of small intestinal blood vessels and lymphatics in the rabbit were made with methacrylate and observed under a scanning electron microscope (SEM). In casting the lymphatics, a specially diluted low viscosity medium was injected intraparenchymally into the intestinal submucosa. This parenchymal injection allowed good reproduction of fine lymphatics, including the initial lacteals in the villi. The central lacteals were completely surrounded externally by the subepithelial blood capillary networks of the intestinal villi. Individual villi in the lower intestine contained only one central lacteal that drained through a thin lymphatic in the glandular layer into the submucosal lymphatic plexus. Villi in the upper small intestine were broader than those in the lower small intestine, and contained two to five lacteals. They anastomosed with each other at the villous base and formed a markedly expanded sinus. The cast submucosal lymphatics frequently showed constrictions strongly suggestive of valves. It was constantly observed that well-developed lymphatics in the submucosa ran in pairs and held an arteriole or artery between them. This close association of the lymphatics with arteries suggests that arterial vasomotion might provide an important hydrodynamic energy source for lymph formation and transport.

Animals↗
PubMed1976

Corrosion casts of lymphatics.

After direct injection of Mercox into the thyroid parenchyma we obtained the corrosion casts of lymphatics to be observed by scanning electron microscopy. It seems reasonable to deduce from the following points that these corrosion casts were of the lymphatic system: 1) variable size of columnar vessels, 2) their three-dimensional anastomoses, 3) occurrence of blind endings, 4) V-shaped reliefs on parts of the columns, certainly indicative of valves, 5) bead-like structures formed by closure of valves, 6) depressions and surrounding saw-toothed figures on the surfaces of the casts, probably corresponding to the nuclei and boundaries of endothelial cells. The method described in this study seems useful in the study of the structures and changes of lymphatics in various organs.

Animals↗
PubMed2006

Behavioral regulation of genetic caste determination in a Pogonomyrmex population with dependent lineages.

The fate of a social insect colony is partially determined by its ability to allocate individuals to the caste most appropriate for the requirements for growth, maintenance, and reproduction. In pairs of dependent lineages of Pogonomyrmex barbatus, the allocation of individuals to the queen or worker caste is constrained by genotype, a system known as genetic caste determination (GCD). In mature GCD colonies, interlineage female eggs develop into sterile workers, while intralineage eggs become reproductively capable queens. Although the population-level consequences of this system have been intensively studied, the proximate mechanisms for GCD remain unknown. To elucidate these mechanisms, we brought newly mated queens into the laboratory and allowed them to establish colonies, nearly half of which unexpectedly produced virgin queens only seven months after colony founding. We genotyped eggs, workers, and the virgin queens from these colonies. Our results showed that queens in young colonies produce both interlineage and intralineage eggs, demonstrating that queens of GCD colonies indiscriminately use sperm of at least two lineages to fertilize their eggs. Intralineage eggs were more frequent in colonies producing virgin queens. These findings suggest that intralineage eggs are predetermined to become queens and that workers may cull these eggs when colonies are not producing queens. Virgin queens produced by young GCD colonies were smaller than field-caught virgin queens, and often had developmental problems. Hence, they are probably nonfunctional and represent an intense resource drain for developing colonies, not a contribution to colony fitness.

Animals↗