Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 17 de 17
Filter
1.
Head Neck Pathol ; 14(4): 1036-1040, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32451875

ABSTRACT

Amyloidosis is a localized or systemic process where extracellular insoluble plasma protein fibers are deposited into tissues. Localized amyloidosis is rare and curable by surgical resection. While the head and neck region represents 19% of localized amyloidosis cases, only one other case of bilateral involvement of the pharyngeal tonsils has been published in the international literature. We report a case of asymptomatic amyloidosis isolated to the bilateral palatine tonsils and a cervical lymph node in a 59-year-old male. Systemic amyloidosis was ruled out through multidisciplinary consultation, and resection of the masses was performed. This represents the second reported case of bilateral tonsillar amyloidosis.


Subject(s)
Amyloidosis/pathology , Palatine Tonsil/pathology , Humans , Lymph Node Excision , Lymph Nodes/pathology , Male , Middle Aged , Tonsillectomy
2.
Plant Biol (Stuttg) ; 21(6): 997-1007, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31276285

ABSTRACT

Species with rewardless flowers often have low fruit to flower ratios, although wide temporal and spatial variation in fruiting success can occur. We compared floral phenotypes, insect visitors and fruiting success in four populations of the small white (Cypripedium candidum) and yellow (C. parviflorum) lady's slipper orchids and their hybrids near the northern extent of North America's tall grass prairie. Flower and fruit numbers were observed for two seasons on marked individuals (n = 1811). Floral traits were measured on 82-140 individuals per taxon and analysed in relation to fruiting success. All insects found inside flowers were collected, inspected for pollen smears and measured for comparison to floral features. Among orchid taxa, C. candidum had the smallest flowers, lowest number and variety of insect visitors, and lowest fruit to flower ratios. These measures were intermediate in hybrids and highest in C. parviflorum, despite low flower numbers in the latter. Within orchid taxa, fruit number was positively related to flower number, but fruit to flower ratios decreased slightly, as would be expected if pollinators left unrewarding patches. Potential pollinators included the dipteran Odontomyia pubescens and hymenopterans Andrena spp., Apis mellifera and Lasioglossum zonulum. Cypripedium parviflorum had a reproductive advantage over C. candidum across multiple populations and years. Hybrids showed segregation for floral traits, and hybrid fruiting success increased with a deeper intensity of yellow pigment and larger escape routes for floral visitors. These same attributes likely contributed to the relatively high fruit set in C. parviflorum in the study region.


Subject(s)
Fruit/physiology , Orchidaceae/physiology , Pollination/physiology , Animals , Bees/physiology , Flowers/metabolism , Flowers/physiology , Fruit/metabolism , Grassland , Orchidaceae/metabolism
3.
Int J Tuberc Lung Dis ; 20(10): 1309-1313, 2016 10.
Article in English | MEDLINE | ID: mdl-27725040

ABSTRACT

BACKGROUND: The diagnosis of tuberculous meningitis (TBM) in children is often delayed, with disastrous consequences. The Integrated Management of Childhood Illness (IMCI) strategy aims to ensure the accurate assessment of ill children using simple yet reliable clinical signs. METHODS: We conducted a retrospective observational study of 30 consecutive children aged 3 months to 5 years diagnosed with TBM at Tygerberg Hospital, Cape Town, South Africa. Clinical records were reviewed to assess diagnostic delay and identify IMCI indicators that were present at the time of initial presentation. RESULTS: Six patients (20%) presented with stage I, 6 (20%) with stage II and 18 (60%) with stage III TBM. Recent contact with an adult TB source case was recorded in 21 (70%) cases. The median number of health care visits before hospital admission was 4.0 (range 1-6). At the first health care visit, 21 (70%) had potential TB features and recent contact with an adult household TB source case. CONCLUSION: Adequate implementation of IMCI clinical indicators is essential to ensure earlier diagnosis and prompt treatment initiation in children with TBM, as the majority of cases present with advanced disease. Recent contact with an adult TB source case is an important consideration.


Subject(s)
Primary Health Care , Tuberculosis, Meningeal/diagnosis , Tuberculosis, Meningeal/epidemiology , Antitubercular Agents/therapeutic use , Child, Preschool , Delayed Diagnosis , Early Diagnosis , Female , Follow-Up Studies , Humans , Infant , Lost to Follow-Up , Male , Retrospective Studies , South Africa/epidemiology , Tuberculosis, Meningeal/drug therapy
4.
J Anim Ecol ; 77(5): 974-83, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18624739

ABSTRACT

1. In long-lived animals with delayed maturity, the non-breeding component of the population may play an important role in buffering the effects of stochastic mortality. Populations of colonial seabirds often consist of more than 50% non-breeders, yet because they spend much of their early life at sea, we understand little about their impact on the demographic process. 2. Using multistate capture-mark-recapture techniques, we analyse a long-term data set of individually identifiable common guillemots, Uria aalge Pont., to assess factors influencing their immature survival and two-stage recruitment process. 3. Analysis of the distribution of ringed common guillemots during the non-breeding season, separated by age classes, revealed that all age classes were potentially at risk from four major oil spills. However, the youngest age class (0-3 years) were far more widely spread than birds 4-6 years old, which were more widely spread than birds aged 6 and over. Therefore the chance of encountering an oil spill was age-dependent. 4. A 2-year compound survival estimate for juvenile guillemots was weakly negatively correlated with winter sea-surface temperature, but was not influenced by oil spills. Non-breeder survival did not vary significantly over time. 5. In years following four oil spills, juvenile recruitment was almost double the value in non-oil-spill years. Recent work from Skomer Island showed a doubling of adult mortality associated with major oil spills, which probably reduced competition at the breeding colony, allowing increased immature recruitment to compensate for these losses. We discuss the implications of compensatory recruitment for assessing the impact of oil pollution incidents.


Subject(s)
Accidents , Charadriiformes/physiology , Climate , Petroleum , Water Pollutants, Chemical , Animals , Breeding , Ecology , Models, Biological , Population Dynamics , Seasons , Survival Analysis
6.
Nature ; 411(6839): 775-9, 2001 Jun 14.
Article in English | MEDLINE | ID: mdl-11459051

ABSTRACT

Many living organisms contain biominerals and composites with finely tuned properties, reflecting a remarkable level of control over the nucleation, growth and shape of the constituent crystals. Peptides and proteins play an important role in achieving this control. But the general view that organic molecules affect mineralization through stereochemical recognition, where geometrical and chemical constraints dictate their binding to a mineral, seems difficult to reconcile with a mechanistic understanding, where crystallization is controlled by thermodynamic and kinetic factors. Indeed, traditional crystal growth models emphasize the inhibiting effect of so-called 'modifiers' on surface-step growth, rather than stereochemical matching to newly expressed crystal facets. Here we report in situ atomic force microscope observations and molecular modelling studies of calcite growth in the presence of chiral amino acids that reconcile these two seemingly divergent views. We find that enantiomer-specific binding of the amino acids to those surface-step edges that offer the best geometric and chemical fit changes the step-edge free energies, which in turn results in macroscopic crystal shape modifications. Our results emphasize that the mechanism underlying crystal modification through organic molecules is best understood by considering both stereochemical recognition and the effects of binding on the interfacial energies of the growing crystal.


Subject(s)
Amino Acids/chemistry , Calcium Carbonate/chemistry , Aspartic Acid/chemistry , Crystallization , Isomerism , Microscopy, Atomic Force , Molecular Conformation , Spectrum Analysis , Thermodynamics , X-Ray Diffraction
7.
Skeletal Radiol ; 30(1): 57-9, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11289637

ABSTRACT

This case report describes a patient with severe back pain and radiculopathy. She was found to have a facet cyst within the lumbar spine that appeared to contain calcium on MRI and CT. Upon aspiration the cyst was found to contain calcium ammonium phosphate (struvite) and calcium phosphate (hydroxyapatite). Ammonia production in the presence of urease-producing bacteria is responsible for the production of struvite in the human body. We postulate that there was a prior infection of the facet with urease-producing bacteria, thus accounting for the production of the struvite within the facet cyst.


Subject(s)
Durapatite/analysis , Lumbar Vertebrae , Magnesium Compounds/analysis , Phosphates/analysis , Spinal Diseases/diagnosis , Synovial Cyst/diagnosis , Female , Humans , Lumbar Vertebrae/diagnostic imaging , Lumbar Vertebrae/pathology , Magnetic Resonance Imaging , Middle Aged , Radiography , Spinal Diseases/diagnostic imaging , Spinal Diseases/metabolism , Spinal Stenosis/diagnosis , Spinal Stenosis/etiology , Struvite , Synovial Cyst/complications , Synovial Cyst/diagnostic imaging , Synovial Cyst/metabolism
8.
J Clin Rheumatol ; 4(3): 159-61, 1998 Jun.
Article in English | MEDLINE | ID: mdl-19078279
9.
Abdom Imaging ; 23(6): 633-5, 1998.
Article in English | MEDLINE | ID: mdl-9922200

ABSTRACT

Littoral cell angioma (LCA) is a rare benign vascular tumor of the spleen. LCA most commonly presents with constitutional symptoms (low grade fever and fatigue) and signs of hypersplenism (anemia and thrombocytopenia). Radiographically and at gross pathology an enlarged spleen containing multiple nodules is most commonly seen. Currently the radiological findings are nonspecific and correlation with clinical findings is necessary to narrow the differential while tissue is required for a definitive diagnosis.


Subject(s)
Hemangioma/diagnostic imaging , Splenic Neoplasms/diagnostic imaging , Tomography, X-Ray Computed , Adult , Diagnosis, Differential , Female , Hemangioma/pathology , Hemangioma/surgery , Humans , Splenectomy , Splenic Neoplasms/pathology , Splenic Neoplasms/surgery
10.
Am J Hum Genet ; 51(6): 1265-76, 1992 Dec.
Article in English | MEDLINE | ID: mdl-1463010

ABSTRACT

In the present report, we summarize studies aimed at examining the reliability of chromosome heteromorphisms in analyses of chromosome 21 nondisjunction. We used two cytogenetic approaches--fluorescent in situ hybridization (FISH) to repetitive sequences on 21p and traditional Q-banding--to distinguish chromosome 21 homologues and then compared the results of these studies with those obtained by DNA markers. Using a conservative scoring system for Q-banding and FISH heteromorphisms, we were able to specify the parental origin of trisomy in 10% of cases; in contrast, DNA marker studies were informative for parental origin in almost all cases. The results of the molecular and cytogenetic studies of parental origin concurred in all cases in which assignments were made independently using both techniques. However, in 4 of 13 cases in which the molecular studies contributed to the interpretation of the cytogenetic findings, the two results did not agree with respect to the meiotic stage of nondisjunction. A relatively high frequency of crossing-over on either the short arm or proximal long arm of chromosome 21 could explain these results and may be a mechanism leading to nondisjunction.


Subject(s)
Chromosomes, Human, Pair 21 , Meiosis/genetics , Nondisjunction, Genetic , Chromosome Aberrations , Chromosome Banding , Chromosome Disorders , Down Syndrome/genetics , Female , Heterozygote , Humans , In Situ Hybridization, Fluorescence , Karyotyping , Male , Parents
11.
Am J Hum Genet ; 49(3): 608-20, 1991 Sep.
Article in English | MEDLINE | ID: mdl-1831960

ABSTRACT

To assess the association between recombination and nondisjunction of chromosome 21, we analyzed cytogenetic and DNA markers in 104 trisomy 21 individuals and their parents. Our DNA marker studies of parental origin were informative in 100 cases, with the overwhelming majority (94) being maternal in origin. This value is significantly higher than the 75%-80% maternal nondisjunction rate typically observed in cytogenetic studies of trisomy 21 and illustrates the increased accuracy of the molecular approach. Using the maternally derived cases and probing at 19 polymorphic sites on chromosome 21, we created a genetic map that spans most of the long arm of chromosome 21. The map was significantly shorter than the normal female linkage map, indicating that absence of pairing and/or recombination contributes to nondisjunction in a substantial proportion of cases of trisomy 21.


Subject(s)
Chromosomes, Human, Pair 21 , Down Syndrome/genetics , Nondisjunction, Genetic , Recombination, Genetic/genetics , Adult , Chromosome Mapping , Crossing Over, Genetic/genetics , Down Syndrome/etiology , Female , Genetic Markers/genetics , Humans , Male , Maternal Age
12.
J Med Genet ; 28(3): 159-62, 1991 Mar.
Article in English | MEDLINE | ID: mdl-2051452

ABSTRACT

The origin of the additional chromosome in 26 trisomy 16 spontaneous abortions was studied using DNA probes for chromosome 16, including a probe for centromeric alpha sequences. We were able to determine the parent and meiotic stage of origin of trisomy in 22 cases, with all being attributable to maternal meiosis I non-disjunction. Furthermore, in each of the remaining four cases the results were compatible with this origin. Thus, it is likely that the high incidence of trisomy 16 results from an abnormal process acting at maternal meiosis I which more frequently involves chromosome 16 than other similar sized chromosomes. In studies of recombination, we found little evidence for an association between reduced or absent recombination and chromosome 16 non-disjunction; however, we were unable to rule out an effect of hyperrecombination.


Subject(s)
Chromosomes, Human, Pair 16/ultrastructure , Meiosis/genetics , Nondisjunction, Genetic , Trisomy , Cells, Cultured , DNA Probes , Female , Fetus , Genetic Markers , Humans , Pregnancy
13.
Can J Nurs Adm ; 3(3): 25-9, 1990.
Article in English | MEDLINE | ID: mdl-2268663

ABSTRACT

Frequently, clinically competent nurses leave direct patient care for non-clinical positions or other careers to achieve greater professional advancement and recognition. The drain of clinical nursing expertise away from the patient prompted the development and evaluation of a clinical promotion program to appraise and recognize clinical nursing competence. At the beginning of the evaluation period, 205 nurses were appraised for clinical competence and categorized as: Level 1--a beginning practitioner or a nurse returning to service; Level 2--a skilled clinical practitioner; and Level 3--an advanced clinical practitioner. Nurses volunteered information related to demographic characteristics, education, clinical experience, and attitudes to their work and work environment. Reassessments were completed after one year. Evaluation of the program employed a longitudinal comparative design. The major finding shows significant shift in clinical nurses' competence over time with a greater percentage of nurses at higher levels of ability. Further evaluation of the program is in process.


Subject(s)
Career Mobility , Clinical Competence , Employee Performance Appraisal/methods , Nursing Staff, Hospital/standards , Adult , Humans , Middle Aged , Nursing Staff, Hospital/psychology
14.
Can J Nurs Adm ; 2(2): 8-10, 1989 Jun.
Article in English | MEDLINE | ID: mdl-2486680

ABSTRACT

A career advancement program for nurses has been developed and implemented at the Victoria General Hospital, Halifax, as part of a manpower planning strategy for recruitment and retention of clinical nurses. A competency based performance appraisal system was developed and implemented as part of the program. This system identifies four levels of clinical expertise. Progression through each level indicates that a nurse has achieved a certain level of skill, knowledge and abilities. Demonstrated competence in one level is a prerequisite to promotion to the next level of practice. Implementation of this system provides clinical career opportunities for nurses in direct patient care. This article will provide the nurse administrator with an insight into the development and implementation of a clinical career advancement program. Future articles will described the research evaluation of the Clinical Performance Appraisal System and clinical nurses' reactions to the new system.


Subject(s)
Career Mobility , Clinical Competence , Nursing Staff, Hospital/supply & distribution , Personnel Selection/methods , Hospitals, General , Humans , Nova Scotia , Nursing Staff, Hospital/standards
17.
J Nurs Adm ; 14(7-8): 23-7, 1984.
Article in English | MEDLINE | ID: mdl-6565036

ABSTRACT

The value of research to the practice of nursing has been well documented. The difficult question today is how to establish a formal research component into the nursing division when funding sources are scarce or nonexistent. The process that one large tertiary-care hospital used to accomplish this goal is analyzed. The authors discuss design, resources, implementation, financing, and program maintenance.


Subject(s)
Nursing Service, Hospital , Research , Education, Nursing, Continuing , Faculty, Nursing , Humans , Nova Scotia , Quality Assurance, Health Care , Research Support as Topic/economics , Schools, Nursing
SELECTION OF CITATIONS
SEARCH DETAIL