Post-Partum Spontaneous Coronary Artery Dissection with Occluded Left Anterior Descending Artery.

Presentation We present a case of spontaneous coronary artery dissection (SCAD) in a 35-year-old lady who was 4 months post-partum. Despite a lack of typical risk factors, initial presentation and investigations were strongly suggestive of ACS. Diagnosis Coronary angiography revealed an occluded proximal left anterior descending (LAD) artery with TIMI 0 flow. Angiographic appearances and intravascular ultrasound (IVUS) were consistent with SCAD. Treatment A single drug-eluting stent was deployed, successfully restoring good flow, without extending the dissection flap. Discussion SCAD should be considered as an important and underdiagnosed cause of ACS, predominantly in young women without other apparent risk factors.

Hypokalaemia in ibuprofen and codeine phosphate abuse.

Ibuprofen abuse may be more prevalent than generally considered. Although normally benign, serious complications have been documented. We report an unusual presentation of hypokalaemia and its associated symptoms as a result of Nurofen Plus (200 mg ibuprofen + 12.8 mg codeine phosphate) abuse. Ibuprofen is generally not included in a standard toxicology screen, but should be considered as a rare cause of hypokalaemia.

Eyelid reconstruction: an oculoplastic surgeon's perspective.

The eyelids provide structural support for the globe and play an essential role in protecting and lubricating the eye. Trauma, tumor resection, or congenital defects may compromise eyelid function. The goals of eyelid reconstruction are to restore the function of the eyelids and lacrimal drainage apparatus, provide adequate protection for the globe, and achieve reasonable cosmetic results.

Comparative culture and toxicity studies between the toxic dinoflagellate Pfiesteria piscicida and a morphologically similar cryptoperidiniopsoid dinoflagellate.

A series of fish bioassays using cultures of the toxic dinoflagellate, Pfiesteria piscicida and a cryptoperidiniopsoid dinoflagellate indicated various degrees of toxicity for Pfiesteria piscicida and no toxicity by the cryptoperidiniopsoid. P. piscicida maintained toxicity in the presence of live fish, and this toxicity was perpetuated following a series of inoculations to other culture vessels. Differences in the onset and magnitude of the fish deaths occurred, requiring 16 days for the initial fish death when using P. piscicida from a culture that had previously been maintained on algal cells, to kills within hours when using a culture that had recently (previous day) killed fish. Autopsies of moribund fish from the test and control fish bioassays indicated a general lack of bacterial infection, which ensued following death of other autopsied fish. Moreover, bacterial comparisons of waters in the fish bioassay and control fish cultures indicated that similar bacterial concentrations were present. Neither oxygen or ammonia levels were determined to be factors in the fish death. Life stages of a cryptoperidiniopsoid dinoflagellate from Virginia estuaries were also identified, including motile zoospore, gametes, planozygote, amoebae, and cyst stages. The cryptoperidiniopsioid did not initiate fish deaths in bioassays conducted over a 14-week period at zoospore concentrations of ca. 700-800 cells ml(-1). Elemental X-ray analysis of the scales from cysts of this dinoflagellate and P. piscicida indicate that they both contain silicon. Overall, the data from this study demonstrate that the cryptoperidiniopsoid possesses several similar life stages and feeding patterns as P. piscicida, but was not toxic to fish.

An annotated catalog of inverted repeats of Caenorhabditis elegans chromosomes III and X, with observations concerning odd/even biases and conserved motifs.

We have taken a computational approach to the problem of discovering and deciphering the grammar and syntax of gene regulation in eukaryotes. A logical first step is to produce an annotated catalog of all regulatory sites in a given genome. Likely candidates for such sites are direct and indirect repeats, including three subcategories of indirect repeats: inverted (palindromic), everted, and mirror-image repeats. To that end we have produced a searchable database of inverted repeats of chromosomes III and X of Caenorhabditis elegans, the first completely sequenced multicellular eukaryote. Initial results from the use of this catalog are observations concerning odd/even biases in perfect IRs. The potential usefulness of the catalog as a discovery tool for promoters was shown for some of the genes involved with G-protein functions and for heat shock protein 104 (hsp104).

Phototoxicity of argon laser irradiation on biofilms of Porphyromonas and Prevotella species.

Species of Prevotella (Pr.) and Porphyromonas (Po.) and other microorganisms were cultivated as biofilms on agar medium and examined for their susceptibility to argon laser irradiation (continuous mode; wavelengths, 488-514 nm; fluences, 20-200 J cm(-2)). Fluences of 35 to 80 J cm(-2) inhibited biofilm growth in Po. endodontalis, Po. gingivalis, Pr. denticola, Pr. intermedia, Pr. melaninogenica and Pr. nigrescens. A fluence of 70 J cm(-2) did not affect biofilm growth in species of Bacillus, Candida, Enterobacter, Proteus, Pseudomonas, Staphylococcus and Streptococcus. The phototoxic effects of argon laser irradiation against Prevotella and Porphyromonas species were: (1) caused by the radiation alone; (2) modified by biofilm age; (3) dependent on the presence of atmospheric oxygen; (4) influenced by medium supplements of hemin, hemoglobin and blood; (5) greater when compared with other microbial species; (6) demonstrated without augmentation with an exogenous photosensitizer; and (7) apparently unrelated to the protoporphyrin content of the cells. Overall, these in vitro findings suggest that low doses of argon laser radiation may be effective in the treatment and/or prevention of clinical infections caused by biofilm-associated species of Prevotella or Porphyromonas.

PDGF-B producing cells and PDGF-B gene expression in normal gingival and cyclosporine A-induced gingival overgrowth.

It has been proposed that healthy gingiva is in a continuous state of wound repair. Thus, one might expect to find cells in normal gingiva producing growth factors associated with wound healing such as platelet-derived growth factor B chain (PDGF-B). One might also expect to find increased numbers of these cells or increased amounts of these growth factors in conditions which involve increased tissue volume such as drug-induced gingival overgrowth (DGO). The purpose of this study was to quantify PDGF-B gene expression and identify cells producing PDGF-B in normal gingiva and DGO. Cyclosporine A (CSA) was selected as a prototype of the overgrowth condition. Twelve patients with clinical CSA DGO and 12 patients with no DGO or history of drugs known to cause DGO were selected for study. Frozen sections of gingival specimens from these patients were subjected to in situ hybridization for PDGF-B mRNA. Positive cells were counted and expressed as mean +/- SEM cells/mm2 of lamina propria. Morphometric analysis revealed 6.2 +/- 1.9 cells/mm2 for control gingiva and 10.3 +/- 3.4 cells/mm2 for CSA DGO samples. There was no statistically significant difference between groups. PDGF-B gene expression was measured in these cells and expressed as mean +/- SEM silver grains/cells. There was a significant upregulation of PDGF-B gene expression in cells from the CSA DGO group (39.5 +/- 14.7 silver grains/cell for normal gingiva vs. 255.3 +/- 77.1 silver grains/cell for CSA DGO samples; P < 0.001). The presence of PDGF-B in these cells was confirmed in all cases by immunocytochemical localization. Additionally, PDGF-B producing cells were identified as macrophages in sections taken from an additional patient with CSA DGO by double immunofluorescence labeling of the CD51 membrane marker for macrophages and intracellular PDGF-B. These findings are consistent with the concept that healthy gingiva is in a continuous state of wound repair and support the hypothesis that CSA DGO is associated with enhanced macrophage PDGF-B gene expression rather than an increase in the number of PDGF-B producing macrophages.

Central venous catheters in the emergency department: access, utilization, and problem solving.

As the number of children with central venous catheters cared for at home continues to escalate, the physician is increasingly confronted with a wide variety of devices in the emergency setting. The most common presenting complaints are fever (infection), occlusion (thrombus), breakage, and dislodgement. Familiarity with the basic characteristics of these devices and their variations, as well as the approaches to specific complaints, will lead to prompt, efficient, and definitive emergency care for these patients.

Sensitivity of Porphyromonas and Prevotella species in liquid media to argon laser.

The phototoxicity of argon laser irradiation was studied in aqueous suspensions of Porphyromonas endodontalis (American Type Culture Collection [ATCC] 35406), Porphyromonas gingivalis (ATCC 33277), Prevotella denticola (ATCC 33184) and two strains of Prevotella intermedia (ATCC 15033 and 49046), all "black-pigmented bacteria," BPB, that accumulate cellular porphyrins. Several of these species have been implicated in the etiology of periodontal disease. Non-black-pigmented bacteria were also studied to test the specificity of irradiation as a potential photodynamic treatment for periodontal infections. Cell suspensions were irradiated with an argon laser at fluences of 20-200 J/cm2. When cultured in hemin-supplemented media, ATCC 15033 was the most sensitive to irradiation. However, a second strain of the same species (ATCC 49046) was resistant. The photosensitivity of other species ranked ATCC 33277 > 35406 = 33184 = 35496. When hemin was replaced in media by hemoglobin, ATCC 33277 became resistant to irradiation. Protoporphyrin IX content in BPB cells was shown not to be a major factor determining photosensitivity. Oxygen was required during irradiation for BPB species to be affected. Non-black-pigmented bacteria were much less sensitive to irradiation than BPB.

Decline in number of Na-K pumps on low-K+ sheep reticulocytes during maturation is modulated by Lp antigen.

The number of the Na-K pumps on sheep red blood cells declines markedly during cell maturation. In addition, in red blood cells of the low-K+ (LK) phenotype, there is an increase during maturation in the affinity of the pumps for intracellular K+. This increase does not occur in cells of the high-K+ (HK) phenotype. This HK/LK polymorphism is associated with the M/L blood group antigen system. The Lp antigen, which is on only LK cells, promotes the increase in affinity for K+ [Am. J. Physiol. 265 (Cell Physiol. 34): C99-C105, 1993]. Mature LK cells have fewer pumps than mature HK cells. The present study shows that the Lp antigen also promotes the loss of pumps in LK cells. The evidence was that modification of the Lp antigen of immature LK red blood cells either with anti-Lp antibody or by trypsinization diminished the loss of pumps during culture in vitro (numbers determined from [3H]ouabain binding). Confirmation came from demonstration of the decline during maturation of the amount of the alpha-subunit of the Na-K pump (measured by immunoblotting), which was also retarded by pretreatment with anti-Lp or trypsin. Comparisons of the relative amounts of Lp antigen on immature and mature LK cells showed that there is little decline in number of antigens during maturation. Therefore there is an increase in the antigen-to-pump ratio during maturation even though an association between pumps and antigens is necessary for the loss of pumps.

Synthesis of platelet-derived growth factor by cells of splenic red pulp in normal rats.

A population of cells in the spleens of normal rats was found to contain platelet-derived growth factor (PDGF) B chain mRNA. These cells were found predominantly in the red pulp and nuclear morphology of some was consistent with that of macrophages. Similar cells were also shown by immunocytochemical staining to contain PDGF-AB/BB. These PDGF-positive cells were also found almost exclusively in the red pulp. It has been suggested by others that PDGF plays an important role in the function of the lymphohemopoietic microenvironment.

Guided tissue regeneration with dentin biomodification.

This study was undertaken to provide histologic observations on the effectiveness of citric acid and tetracycline HCl root surface demineralization when used in conjunction with guided tissue regeneration (GTR) procedures. Eight beagle dogs with naturally-occurring periodontitis were initially treated with scaling and root planing. Four weeks later, 12 mandibular quadrants were treated surgically with modified Widman flap and expanded polytetrafluoroethylene (ePTFE). The teeth in 4 of the quadrants were randomly root conditioned with tetracycline HCl, while those in 4 additional quadrants were randomly treated with citric acid. ePTFE membranes were sutured in place. The beagles received prophylaxis (chlorhexidine and toothbrushing) 3 times a week. After 6 weeks, the membranes were removed; prophylaxes continued for 4 months. Histological evaluation revealed new cementum on the root surfaces. A new periodontal ligament with fibers inserting into the new cementum was noted. Statistical evaluation of the buccolingual measurements demonstrated membranes alone resulted in significantly more new connective tissue and new bone formation than membranes with root conditioning agents. Within the furcation, no significant differences were found. However, there was a trend for more bone formation with membranes alone. Within the limits of this study it may be concluded that GTR utilizing an ePTFE membrane results in new connective tissue attachment and bone regeneration in the beagle dog. Root surface demineralization with citric acid or tetracycline HCl does not enhance the results achieved with GTR when used alone.

Differentiation of Na(+)-K+ pumps of low-K+ sheep red blood cells is promoted by Lp membrane antigens.

Na(+)-K+ pumps of red blood cells from sheep of the low-K+ (LK) phenotype undergo differentiation during circulation, manifested in part by a striking increase in sensitivity to inhibition by intracellular K+ (Ki). Pumps of red blood cells from sheep from the allelic phenotype, high K+ (HK), do not undergo this type of maturation. The hypothesis was tested that the Lp antigen, found on LK but not HK cells, is responsible for the maturation of LK pumps. Lp antigens have been shown to inhibit LK pumps because anti-Lp antibody stimulates the pumps by relieving inhibition by the antigen. Lp antigens were recently shown to be molecular entities separate from Na(+)-K+ pumps [Xu, Z.-C., P. Dunham, J. Munzer, J. Silvius, and R. Blostein. Am. J. Physiol. 263 (Cell Physiol. 32): C1007-C1014, 1992]. The test of the hypothesis was to modify the Lp antigens of immature LK red blood cells with two kinds of treatments, anti-Lp antibody and trypsinization (which cleaves Lp), and to observe the effects of these treatments on maturation of pumps during culture of the cells in vitro. Both of these treatments prevented the maturation of the kinetics of the pumps to the Ki-sensitive pattern, supporting the hypothesis that interaction of the pumps with Lp antigens is responsible for the maturation of the pumps. Strong supportive evidence came from experiments on Na(+)-K+ pumps from rat kidney delivered into immature LK sheep red blood cells by microsome fusion.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of antibodies to subunit V of cytochrome oxidase on cyanide inhibition of electron transfer.

Binding of antibodies raised against subunit V of mammalian cytochrome oxidase to the intact membranous enzyme is redox-sensitive, suggesting the existence of 'open' and 'closed' protein conformers (Freedman, J.A., Cooper, C.E., Leece, B., Nicholls, P. and Chan, S.H.P. (1988) Biochem. Cell Biol. 66, 1210-1217). Similar open and closed states for the oxygen-reacting site have been proposed to explain cyanide binding kinetics (Jensen, P., Wilson, M.T., Aasa, R. and Malmström, B.G. (1984) Biochem. J. 224, 829-837). We therefore examined cyanide inhibition of oxidase activity polarographically and spectrophotometrically using soluble oxidase preincubated with and without anti-subunit V or non-immune rabbit gamma-globulin. The subunit-specific antibody decreased the cyanide 'on' rate and essentially eliminated the rapid phase of cyanide binding. We conclude that (i), bound antibody blocks HCN binding; (ii), antibody and HCN probably bind to the same conformation of the oxidase and (iii), the 'open'-'closed' conformation change that modulates binding of HCN may be similar to that which modulates antibody binding. The results are consistent with some reciprocating models of electron transfer and energy transduction by the oxidase (cf., Wikström, M.K.F., Krab, K. and Saraste, M. (1981) Cytochrome Oxidase: A Synthesis).

Surface bacteria of Streblomastix strix are sensory symbionts.

Streblomastix strix, a protist living in the hindguts of Zootermopsis sp. (termites) is covered with pseudomonad-like rod-shaped bacteria. These bacteria were demonstrated to be sensory (chemotactic) symbionts for S. strix. S. strix moved toward a source of sodium acetate, a presumed food molecule, when its bacteria were intact. If the bacteria were removed by antibiotic (carbenecillin) treatment, S. strix was unable to orient efficiently in a sodium acetate gradient. The mechanism of this interaction was not determined. This is the first case documented of a sensory symbiosis involving a surface layer of bacteria. However, it may not be an exceptional case given the large numbers of organisms with surfaces covered with symbionts. The assays for chemotaxis used in this research may be applied in other cases in which motile organisms are covered with symbionts.