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PubMed1992

Hemagglutination (fimbriae) and hydrophobicity in adherence of Serratia marcescens to urinary tract epithelium and contact lenses.

The capacity of 59 isolates of Serratia marcescens, obtained from urinary tract infections, wounds, and contact lenses or their paraphernalia, to agglutinate erythrocytes from different animal species was tested. Three main patterns were found: mannose-sensitive agglutination of guinea-pig, fowl or horse erythrocyte; mannose-resistant agglutination of chicken or pigeon erythrocytes alone or in combination with mannose-sensitive agglutination; and no agglutination. Hemagglutination capacity was associated with isolates from urinary tract infection, but not with isolates associated with contact lenses. Adherence to human urinary tract epithelium did not correlate with the hemagglutination patterns nor with the origin of the isolates. Some strains of different hemagglutination pattern were selected for the study of hydrophobicity and adherence to contact lens polymers. Hydrophobicity, as determined by degree of partition in hexadecane and water (BATH-values), correlated neither with degree of adherence to contact lens polymers nor with the hemagglutination pattern. For a representative strain there was an excellent correlation (r2 = 0.98) between adherence and the water content (hydrophobicity) of the lens polymers. These results suggest that, as with tissues, other factors interact with hydrophobicity in causing adherence to plastics.

Alkanes↗
PubMed2004

Characterization of a trinucleotide repeat sequence (CGG)5 and potential use in restriction fragment length polymorphism typing of Mycobacterium tuberculosis.

The genomes of 28 bacterial strains, including mycobacterial species Mycobacterium tuberculosis and Mycobacterium bovis, were analyzed for the presence of a special class of microsatellite, that of trinucleotide repeat sequences (TRS). Results of a search of all 10 possible TRS motifs (i.e., CCT, CGG, CTG, GAA, GAT, GTA, GTC, GTG, GTT, and TAT) with five or more repeating units showed that (CGG)(5) was highly represented within the genomic DNA of M. tuberculosis and M. bovis. Most of the (CGG)(5) repeats in the genome were within the open reading frames of two large gene families encoding PE_PGRS and PPE proteins that have the motifs Pro-Glu (PE) and Pro-Pro-Glu (PPE). (CGG)(5)-probed Southern hybridization showed that some mycobacterial species, such as Mycobacterium marinum, Mycobacterium kansasii, and Mycobacterium szulgai, possess many copies of (CGG)(5) in their genomes. Analysis of clinical isolates obtained from Tokyo and Warsaw with both IS6110 and (CGG)(5) probes showed that there is an association between the fingerprinting patterns and the geographic origin of the isolates and that (CGG)(5) fingerprinting patterns were relatively more stable than IS6110 patterns. The (CGG)(5) repeat is a unique sequence for some mycobacterial species, and (CGG)(5) fingerprinting can be used as an epidemiologic method for these species as well as IS6110 fingerprinting can. If these two fingerprinting methods are used together, the precise analysis of M. tuberculosis isolates will be accomplished. (CGG)(5)-based fingerprinting is particularly useful for M. tuberculosis isolates with few or no insertion elements and for the identification of other mycobacterial species when informative probes are lacking.

Base Sequence↗
PubMed2002

Tuberculum sellae meningiomas: microsurgical anatomy and surgical technique.

OBJECTIVE: Despite Cushing's accurate description of the anatomic origin of tuberculum sellae meningiomas, many subsequent authors have included tumors originating from the neighboring sella region in this classification. This has led to difficulty in evaluating the surgical results and consensus for an optimal surgical technique. We think this confusion has arisen from Cushing's description of these tumors under the heading "suprasellar meningiomas," which referred to their distinctive clinical symptoms and not their anatomic origin. We describe the microsurgical anatomy and tumor growth patterns to reemphasize the original classification of Cushing's tuberculum sellae meningiomas. Additionally, we describe our surgical approach, which decreases the risk of injury to anterior visual pathways and anterior cerebral circulation arteries. METHODS: During a 19-year period, 23 patients with meningiomas arising from the tuberculum and diaphragma sellae underwent craniotomies at New York University Medical Center. The tumor size ranged from 2 to 5 cm. All patients presented with symptoms of visual dysfunction; 15 were asymmetrical. Magnetic resonance imaging with and without gadolinium differentiated these tumors from other suprasellar tumors with a high degree of accuracy. All patients underwent a pterional transsylvian approach. RESULTS: Twenty patients had total tumor removal, and three had subtotal tumor removal. There was one regrowth in the subtotal tumor removal group. Patients were observed for a mean follow-up time of 9.3 years (range, 3.6-18.5 yr). Visual acuity improved in 55%, was unchanged in 26%, and worsened in 19% of patients. Two of the oldest patients died from pulmonary complications, resulting in a mortality rate of 8.7%. CONCLUSION: We think that tuberculum and diaphragma sellae meningiomas are anatomically indistinguishable and should be termed tuberculum sellae meningioma. A pterional craniotomy with microsurgical dissection of the sylvian fissure allows access to these tumors with minimal neurological and ophthalmological morbidity.

Adult↗
PubMed2003

Are all community methicillin-resistant Staphylococcus aureus related? A comparison of their mec regions.

AIMS: To compare the relationship of community-acquired, methicillin-resistant Staphylococcus aureus (CMRSA) from five Australian States and New Zealand. METHODS: Contour-clamped homogeneous electric field (CHEF) electrophoresis and analysis of the mec complex and ccr gene complex by PCR were used to compare 22 CMRSA isolates from Western Australia (WA), South Australia (SA), Victoria (VIC), New South Wales (NSW) and New Zealand (NZ) and three hospital-acquired epidemic MRSA (EMRSA). RESULTS: Sixteen community isolates were found to carry Class B mec complex and Type 2 ccr gene complex. Two WA isolates carried the Class B1 mec complex and three VIC and one SA isolate carried a previously unreported mec complex, which has been labelled E. The ccr gene type of the Class B1 and Class E isolates could not be determined. These isolates may carry previously unreported ccr gene complexes. The relatedness of the CHEF patterns of the CMRSA was dependent on their geographical origin. A similar CHEF pattern was found in some WA MRSA, VIC and SA isolates. NSW and NZ CMRSA had the same CHEF patterns and were similar to three VIC isolates and EMRSA-16. Two SA CMRSA isolates had CHEF patterns similar to the English EMRSA-15 strain. A multiply resistant, nosocomial EMRSA from Australia had a class A mec complex, and a CHEF pattern, which was unrelated to any of the CMRSA. CONCLUSION: Most of the CMRSA isolated from five Australian states and New Zealand had unrelated CHEF patterns. However, the majority of them carried the Type IV SCCmec cassette (Class B mec and Type 2 ccr gene complexes), which indicates that they may have acquired their mec complex from the same source or that they have evolved from the same progenitor. Some of the CMRSA had a previously undescribed SCCmec cassette.

Australia↗
PubMed1996

Microadenocarcinoma of the pancreas--morphologic pattern or pathologic entity? A reevaluation of the original series.

The term microadenocarcinoma was first proposed for a subtype of pancreatic carcinoma by Cubilla and Fitzgerald in 1975 based largely on the morphological features of 15 cases. Since that time, no independent studies have appeared in the English literature to address whether microadenocarcinoma represents a distinctive tumor or a pattern of growth, and some authors have questioned its existence as a definable entity. Immunohisto-chemistry is now available to allow the identification of lines of differentiation in pancreatic neoplasms, on which their classification is largely based. Reasoning that heterogeneity of differentiation between different cases would not justify the separation of microadenocarcinomas from other better defined pancreatic neoplasms, we reevaluated 12 cases from the original series using antibodies for acinar, endocrine, and ductal differ-entiation. Two distinctive morphological patterns were identified: microglandular and solid cribriform. The microglandular cases (n = 6) were not separable from typical ductal adenocarcinomas either morphologically or immunophenotypically. Of the solid-cribriform cases (n = 6), immunohistochemistry revealed three to be acinar cell carcinomas, one an endocrine carcinoma, one a mixed endocrine-ductal carcinoma, and one a ductal adenocarcinoma. We concluded that with the benefit of further study, most of these cases could be reclassified as other types of pancreatic carcinoma. Microadenocarcinoma is best regarded as a pattern of growth associated with an aggressive clinical course rather than a distinctive entity.

Adult↗
PubMed2002

DNase I sensitive site in the core region of the human beta-globin origin of replication.

HeLa cells were synchronized at late G1, early S, and late S phase of the cell cycle by nocodazole treatment. The cells were permeabilized with Triton X-100, digested with DNAse I, and extracted with 0.2 M ammonium sulfate to remove the digested chromatin. DNA was isolated from the residual chromatin attached to the nuclear matrix, digested with Hind III, and subjected to hybridization with [(32)P] labeled probe located upstream of the core region of the human beta-globin replication origin. The hybridization pattern revealed the existence of a DNase I sensitive site in the core region of the beta-globin replicator. The results suggest that association with the nuclear matrix induce alteration in the chromatin structure of the origin of replication that represents a more open chromatin configuration.

Binding Sites↗
PubMed1977

Origin of the translocated segment of the 14q+ marker in non-Burkitt lymphomas.

The cytogenetic findings by G-banding in two histiocytic lymphomas are described. Both tumors had a stemline with a 14q+ marker. The origin of the extra segment on No. 14 was determined, and it was different in the two cases. These observations, and those from non-Burkitt lymphomas with 14q+ markers reported in the literature, indicate an inconsistent pattern for the origin of the extra material on No. 14. The only feature in common for all cases is instability of the distal region of the long arm of No. 14, and liability of this region to be involved in structural rearrangements, particularly translocations.

Biopsy↗
PubMed2001

Signal decomposition method of evaluating head movement to measure induced forelimb lameness in horses trotting on a treadmill.

In horses at a trot, the head moves up and down twice in one stride. In horses with unilateral forelimb lameness this movement is asymmetric. Computer-assisted kinematic analysis of vertical head movement can be used to quantify objectively lameness in horses in clinical trials. However, in mild lameness, absolute measurements of vertical head height may not be sensitive enough to detect small differences in lameness, and extraneous head movement by the horse due to curiosity, excitement or nervousness interferes with the accurate measurement of vertical head movement asymmetry. We describe a simple, signal-decompensation method of evaluating vertical head movement using a model of induced mild foot lameness in 9 horses. The technique assumes that the vertical head movement pattern can be broken down into 3 components; the vertical head movement caused by forelimb lameness (A1), the amplitude of the natural biphasic vertical head movement (A2) and extraneous head movement. Extraneous head movement is mathematically removed from the vertical head movement pattern. A1 and A2 are then calculated. After induction of lameness, mean A1 increased by 1.63 cm (range 0.10-3.33 cm, P = 0:005). Mean A2 did not significantly change after lameness induction. Error in reproduction of the original head movement pattern was 0.3-0.5%. We calculated that a hypothetical clinical trial would require 12 subjects for testing to be 80% certain that this difference would be successfully detected using this method of lameness evaluation.

Animals↗
PubMed1982

Acid phosphatase and alpha-naphthyl acetate esterase in neoplastic and non-neoplastic lymphocytes. A statistical analysis.

Acid phosphatase and alpha-naphthyl acetate esterase reaction patterns were evaluated in lymphocytes from patients with a variety of neoplastic and non-neoplastic conditions: leukemia, 59; NHL, 53; and reactive follicular hyperplasia, 23. Fifteen individuals with normal peripheral blood were also studied. For both enzymes, statistical analysis showed a strong correlation between a globular reaction pattern and T lymphocytic origin in both non-neoplastic lymph nodes and normal peripheral blood specimens (P less than 0.0001). A similarly strong correlation was found between a granular acid phosphatase pattern and T lymphocytic origin in cell isolated from non-neoplastic lymph nodes (P less than 0.0001) but not in those obtained from normal peripheral blood where this pattern was observed with equal frequency in B, T, and "null" lymphocytes (P = 0.415). A granular alpha-naphthyl acetate esterase pattern was correlated with non-T lymphocytes from normal peripheral blood (P less than 0.0001), but was observed with equal frequency in B, T, and "null" lymphocytes fron non-neoplastic lymph nodes (P = 0.76). In the eight T cell neoplasias studied, a globular pattern was evident in the majority of cells for both enzymes. In the majority of the B cell neoplasias, however, a granular pattern was observed for both enzymes.

Acid Phosphatase↗
PubMed1976

Structure of beef heart mitochondrial F1-ATPase. Arrangement of subunits as disclosed by cross-linking reagents and selective labeling by radioactive ligands.

1. The following bifunctional reagents, dimethylsuberimidiate, dimethyladipimidate, methylmercaptobutyrimidate have been used to produce dimers between the neighboring subunits of beef heart F1-ATPase. 2. Treatment of beef heart F1-ATPase with dimethylsuberimidate or dimethyladipimidate resulted in the formation of four cross-linked products. Their molecular weights determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were 11 500, 105 000, 95 000 and 80 000, respectively. The products of molecular weight 115 000 and 105 000 were predominant and could be detected at the early stage of the cross-linking reaction. Treatment of beef heart F1-ATPase with methylmercaptobutyrimidate resulted in the accumulation of the product of molecular weight 115 000 and in traces of products of lower molecular weight. When the cross-linked products obtained with methylmercaptobutyrimidate were cleaved by beta-mercaptoethanol, the original gel electrophoresis pattern was restored. 3. Cross-linking of beef heart F1-ATPase by dimethylsuberimidate, dimethyladipimidate and methylmercaptobutyrimidate was accompanied by a loss of the ATPase activity. Cleavage of the cross-linked products obtained with methylmercaptobutyrimidate did not restore the original ATPase activity. 4. Identification of subunits A and B in the products of molecular weight 115 000 and 105 000 was achieved by specific labeling of subunit A with N-[14C]ethylmaleimide and of subunit B by chloronitro [14C]benzooxodiazole. Both products were able to bind N-[14C]ethylmaleimide; only the 105 000 dalton product was able to bind chloronitro [14C]benzooxodiazole. 5. The product of molecular weight 115 000 obtained by treatment of beef heart ATPase with methylmercaptobutyrimidate could bind N-[14C]ethylmaleimide. Its cleavage, following N-[14C]ethylmaleimide binding, yielded one labeled peptide identified with subunit A by polyacrylamide gel electrophoresis. 6. The above results indicate that the product of molecular weight 115 000 is a dimer containing two subunits A and that the product of molecular weight 105 000 is a dimer containing one subunit A and one subunit B. It can therefore be concluded that, in beef heart F1-ATPase, the A subunits are close to each other and that subunit A is close to subunit B. In contrast the B sublnits are probably too far from each other to be cross-linked by dimethylsuberimidate, dimethyladipimidate or methylmercaptobutyrimidate.

Adenosine Triphosphatases↗
PubMed2003

Origin of directionality in the fish stripe pattern.

The formation of stripe patterns in animal skin has been explained by the reaction-diffusion (RD) system, a hypothetical chemical reaction proposed by A. Turing. Although animal stripes usually have directionality, the RD model alone cannot explain how the direction is specified. To investigate the mechanism regulating the direction of stripes, we studied stripe pattern formation in two species of Genicanthus during sexual conversion. These species share almost identical morphologic properties, except for their stripe direction. In both species, spots transiently arise at random positions and then combine and rearrange to form directional stripes. Computational analysis has shown that diffusion anisotropy is very effective at specifying the direction of stripes formed by the RD system. Model simulations reproduce the transient dynamics of directional pattern formation observed in fish as well as the resulting stripes. In cases where the magnitude and direction of diffusion anisotropy of the substances are identical, the resulting stripes are not directional. However, if they differ, stripes become directional. As only a small difference in anisotropy is required for this effect, any kind of structure with directional conformation might cause a marked change in stripe direction. Scales are the most likely candidate structure for generating anisotropic interactions in skin.

Animals↗
PubMed2006

The origin of the diversity of leaf venation pattern.

The leaf venation pattern of plants shows remarkable diversity and species-specificity. However, the mechanism underlying the pattern formation and pattern diversity remains unclear. We developed a mathematical model that is based on the positive feedback regulation between plant hormone auxin and its efflux carrier. This system can generate auxin flow pathways by self-organization from an almost homogeneous state. This result explains a well-known experimental phenomenon referred as to "polar auxin transport." The model can produce diverse leaf venation patterns with spatial regularity under similar conditions to those of leaf development, that is, in the presence of leaf expansion and auxin sink. Final venation patterns are strikingly affected by leaf shape and leaf expansion. These results indicate that the positive feedback regulation between auxin and its efflux carrier is a central dynamic in leaf venation pattern formation. The diversity of leaf venation patterns in plant species is probably due to the differences of leaf shape and leaf expansion pattern.

Algorithms↗
PubMed1995

Heartbeat control in the medicinal leech: a model system for understanding the origin, coordination, and modulation of rhythmic motor patterns.

We have analyzed in detail the neuronal network that generates heartbeat in the leech. Reciprocally inhibitory pairs of heart interneurons form oscillators that pace the heartbeat rhythm. Other heart interneurons coordinate these oscillators. These coordinating interneurons, along with the oscillators interneurons, form an eight-cell timing oscillator network for heartbeat. Still other interneurons, along with the oscillator interneurons, inhibit heart motor neurons, sculpting their activity into rhythmic bursts. Critical switch interneurons interface between the oscillator interneurons and the other premotor interneurons to produce two alternating coordination states of the motor neurons. The periods of the oscillator interneurons are modulated by endogenous RFamide neuropeptides. We have explored the ionic currents and graded and spike-mediated synaptic transmission that promote oscillation in the oscillator interneurons and have incorporated these data into a conductance-based computer model. This model has been of considerable predictive value and has led to new insights into how reciprocally inhibitory neurons produce oscillation. We are now in a strong position to expand this model upward, to encompass the entire heartbeat network, horizontally, to elucidate the mechanisms of FMRFamide modulation, and downward, to incorporate cellular morphology. By studying the mechanisms of motor pattern formation in the leech, using modeling studies in conjunction with parallel physiological experiments, we can contribute to a deeper understanding of how rhythmic motor acts are generated, coordinated, modulated, and reconfigured at the level of networks, cells, ionic currents, and synapses.

Animals↗
PubMed1986

Diurnal rhythms in neurotransmitter receptor binding and choline acetyltransferase activity: different patterns in two rat lines of Wistar origin.

Diurnal cycles for 8 ligand receptor pairs and choline acetyltransferase (ChAT) activity in 3 brain regions differed markedly in two rat lines, both of Wistar origin. Statistically significant differences between diurnal cycles in the two rat lines were found in the following parameters: 24 h means in 6 of 11 measurements, magnitude of cycle amplitudes, and phase position in 6 of 11 measurements, up to complete reversal of the acrophases in the case of ChAT activity in hippocampus. The importance of these findings--such major differences in two closely related rat lines--is obvious in any attempt to compare receptor-binding studies per se between laboratories using the same strain but not line, in studies of receptor rhythm characteristics, and in particular, for analysing the effects of brain-reactive drugs. While there are some reports on strain-dependency of cyclic functions, we are not aware that line-dependency has previously been described.

Animals↗
PubMed1986

DC potential shift preceding repetitive perceptually relevant stimuli and its possible origin.

The Necker cube pattern was flashed repetitively with regular, 5.12 s interstimulus intervals and EEG activity was recorded by means of non-polarizable Ag/AgCl electrodes and averaged. The subjects reported the actual subjective interpretation of the pattern by pushing one of two buttons, i.e. they were motivated to interpret each stimulus. A negative potential shift (lasting about 2.5 s increasing in a more or less linear way and, reaching the final amplitude of about 11 mV), developed gradually before the stimulus onset. Positive correlation was found between the duration and amplitude of DC shift. The phenomenon described might reflect cortical processes related to expectation of a regularly repeated perceptually relevant stimulus and may be considered a version of CNV. A hypothesis interpreting the DC shift as the consequence of neuroglial processes is presented.

Adult↗
PubMed1999

Angioedema due to ACE inhibitors: increased risk in patients of African origin.

AIMS: To determine patterns in presentation, risk factors, management and outcome of patients with ACE inhibitor associated angioedema in one British teaching hospital. METHODS: Cases of ACE inhibitor associated angioedema in patients presenting to the City Hospital, Birmingham between 1993 and 1999 were collected and entered prospectively onto a computerised register. RESULTS: A total of 20 cases (mean age 60 years, range 42-82 years) of ACE inhibitor associated angioedema were reported (11 female and 9 male) with 65% (n=13) of patients being black/Afro-Caribbean. In 70% of cases (n=14), angioedema occurred within 4 weeks of starting therapy, although three patients presented following long-term treatment (24-48 months). ACE inhibitors were continued in 50% (n=10) patients, despite at least one documented episode of angioedema. Admission to hospital was necessary in 40% (n=8) patients, with three of these admitted to the intensive care unit, and one of these died as a result of severe laryngeal obstruction. CONCLUSIONS: ACE inhibitor related angioedema is a serious and potentially fatal complication which is relatively rare in the general population, but is more common amongst black/Afro-Caribbean patients. ACE inhibitors are frequently continued following an episode of angioedema and it is important that these episodes are minimised by prompt cessation of the drug, careful patient counselling and heightened awareness in all clinicians who prescribe this common group of drugs.

Adult↗
PubMed2000

Origin and Significance of the Cyclic Alternating Pattern (CAP). REVIEW ARTICLE.

This article reviews the 15 years of studies conducted on the cyclic alternating pattern (CAP), the electro- encephalogram (EEG) marker of arousal instability during sleep. Starting from the limits and drawbacks of conventional sleep parameters (macrostructure), investigation of the underground world (microstructure) is extensively carried out with particular attention to K-complexes and other arousal-related phasic events of non-rapid eye movement (NREM) sleep. The continuity between conventional and non-conventional arousals is stressed in the light of autonomic function and motor activity evidence. The similarities and differences between CAP and arousals are thoroughly illustrated as well as the putative biological bases of these phenomena. The oscillatory nature of CAP, the involvement of CAP in the modulation of EEG synchrony, the sleep-maintenance properties of CAP in response to arousing stimuli, the clinical applications of CAP parameters and the promising availability of automatic scoring systems are highlighted.

Journal Article↗