Employing High-Fidelity Simulation for the High-Risk, Low-Frequency Diagnosis and Management of Acute Radiation Syndrome (ARS)

Introduction

Acute radiation syndrome (ARS) is a high-risk, low-frequency diagnosis that can be fatal and is difficult to diagnose without an obvious history of ionizing radiation exposure.

Methods

Twenty-two emergency medicine residents and one pharmacy resident participated in an hour-long simulation session. To accommodate all learners, the simulation was conducted eight times over a block of scheduled time (two to four learners/session). Sessions included a prebriefing, pre/post questionnaires, the ARS case, and a debriefing. Learners evaluated and managed a 47-year-old male (manikin) with the hematopoietic and cutaneous subsyndromes of ARS who presented with hand pain/erythema/edema and underlying signs of infection 2 weeks after an unrecognized radiation exposure. Learners had to perform a history and physical, recognize/manage abnormal vitals, order/interpret labs, consult appropriate disciplines, and initiate supportive care.

Results

There was a mean reported increase in ability to recognize signs and symptoms of ARS (p < .001) and appropriately manage a patient with this condition (p = .03) even after controlling for baseline confidence in ability to make and manage uncommon diagnoses, respectively. Learners rated this simulation as a valuable learning experience, effective in teaching them how to diagnose and treat ARS, and one they would recommend to other health care professionals.

Discussion

This simulation aimed to teach the diagnosis and initial management of the hematopoietic and cutaneous subsyndromes of ARS. It should be used to increase awareness of the potential for ionizing radiation exposure under less obvious conditions and raise the index of suspicion for ARS in the undifferentiated patient.

Feasibility and acceptability of at-home play kits for middle school physical activity promotion during the COVID-19 pandemic

BACKGROUND

Schools are central to providing opportunities for youth physical activity (PA), however such opportunities were limited during the COVID-19 pandemic. Identifying feasible, acceptable, and effective approaches for school-based PA promotion amid pandemic-related barriers can inform resource allocation efforts in future circumstances necessitating remote instruction. The aims of this study were to: (1) describe the pragmatic, stakeholder-engaged and theory-informed approach employed to adapt one school's PA promotion efforts to pandemic restrictions, leading to the creation of at-home "play kits" for students, and (2) assess the feasibility, acceptability, and preliminary effectiveness of this intervention.

METHODS

Intervention activities occurred in one middle school (enrollment: 847) located in a Federal Opportunity Zone in the Seattle, WA area, with control data from a nearby middle school (enrollment: 640). Students at the intervention school were eligible to receive a play kit during the quarter they were enrolled in physical education (PE) class. Student surveys were completed across the school year (n = 1076), with a primary outcome of days/week that the student engaged in ≥ 60 min of PA. Qualitative interviews (n = 25) were conducted with students, staff, parents, and community partners, and focused on play kit acceptability and feasibility.

RESULTS

During remote learning play kits were received by 58% of eligible students. Among students at the intervention school only, students actively enrolled in PE (versus not enrolled) reported significantly more days with ≥ 60 min of PA in the previous week, however the comparison between schools was not statistically significant. In qualitative interviews, most students reported the play kit motivated them to participate in PA, gave them activity ideas, and made virtual PE more enjoyable. Student-reported barriers to using play kits included space (indoors and outdoors), requirements to be quiet at home, necessary but unavailable adult supervision, lack of companions to play outdoors, and inclement weather.

CONCLUSIONS

A pre-existing community organization-school partnership lent itself to a rapid response to meet student needs at a time when school staff and resources were highly constrained. The intervention developed through this collaborative response-play kits-has potential to support middle school PA during future pandemics or other conditions that necessitate remote schooling, however modifications to the intervention concept and implementation strategy may be needed to improve reach and effectiveness.

Comparison of two pixelated insoles using in-shoe pressure sensors to determine percent offloading: case studies

Objective:

The gold standard for offloading neuropathic forefoot and midfoot wounds is the total contact cast (TCC). However, in practice TCC is rarely used and is contraindicated in patients with fluctuating oedema, poor perfusion, lack of adequate tissue oxygenation and morbid obesity. It can also be too restrictive for patients, inevitably resulting in treatment rejection and delayed healing. This paper examines the role of shoe-based offloading devices as an alternative in reducing plantar pressure and optimising the healing of neuropathic ulcers.

Method:

Healthy subjects were recruited and fitted for two types of pixelated insoles: PegAssist (PA) insole system (Darco International, US) and FORS-15 (FORS) offloading insole (Saluber, Italy). An area of discreet, elevated high pressure was created by adding a 1/4-inch-thick felt pad to the plantar skin under the first metatarsal head. Subjects walked barefoot in surgical shoes with standard insoles (Condition 1), barefoot in pixelated insoles (Condition 2), barefoot with pixels removed (Condition 3). Dynamic plantar pressures were measured using F-Scan and the results were analysed to determine plantar pressure changes in each condition.

Results:

Using PA, the percentage reduction of plantar pressure (kPa) under the first metatarsal between Condition 1 and Condition 2 was 10.54±15.81% (p=0.022), between Condition 2 and Condition 3 was 40.13±11.11% (p<0.001), and between Condition 1 and Condition 3 was 46.67±12.95 % (p<0.001). Using FORS, the percentage reduction between Condition 1 and Condition 2 was 24.25±23.33% (p=0.0029), between Condition 2 and Condition 3 was 23.61±19.45% (p<0.001), and between Condition 1 and Condition 3 was 43.39±18.70% (p<0.001). A notable difference in the findings between the two insoles was the presence of a significant edge effect associated with PA, indicating that the offloading was not entirely successful. No edge effect was detected with FORS.

Conclusion:

Our current analysis shows that pixelated insoles exhibit potential for supplemental offloading in surgical shoes. These devices could provide an alternative way for physicians to offload plantar wounds and expedite closure for patients that cannot tolerate a TCC or other restrictive devices.

Peliosis hepatis following treatment with androgen-steroids in patients with bone marrow failure syndromes

Androgens widely used in the treatment of bone marrow failure syndromes can in rare cases cause hepatic peliosis, a pathological entity characterized by multiple blood-filled cavities in the liver parenchyma. Bone marrow failure syndromes per se are associated with a low coagulation status, which is further magnified by bone marrow transplantation for aplastic anaemia due to deep thrombocytopenia. Both these conditions can cause bleeding; their combination is especially dangerous. We describe two cases of aplastic anaemia due to paroxysmal nocturnal hemoglobinuria and Fanconi syndrome, in which patients developed peliosis hepatis after prolonged treatment with androgens. One patient developed severe subcapsular bleeding, successfully treated with catheterization of the right hepatic artery and embolization of the bleeding site. The second patient bridged over deep post-transplant aplasia with high frequency platelet transfusions, and demonstrated an uncomplicated post-BMT course. We suggest avoiding or interrupting treatment with androgens in patients preparing for BMT.

Capacity building for international tuberculosis control through operations research training

SETTING

In resource-poor countries, few tuberculosis (TB) program staff at the national, provincial, and even district levels have the basic analytical and epidemiological skills necessary for collecting and analyzing quality data pertaining to national TB control program (NTP) improvements. This includes setting program priorities, operations planning, and implementing and evaluating program activities.

OBJECTIVES

To present a model course for building capacity in basic epidemiology and operations research (OR).

DESIGN

A combination of didactic lectures and applied field exercises were used to achieve the main objectives of the 6-day OR course. These were to increase the understanding of quantitative and qualitative research concepts, study design, and analytic methods, and to increase awareness of how these methods apply to the epidemiology and control of TB; and to demonstrate the potential uses of OR in answering practical questions on NTP effectiveness. As a final outcome, course participants develop OR proposals that are funded and later implemented.

RESULTS

Since 1997, this OR course has been conducted nine times in five countries; 149 key NTP and laboratory staff have been trained in OR methods, and 44 OR protocols have been completed or are underway.

CONCLUSION

This low-cost model course can be adapted to a wide range of public health issues.

Clinical utility of computed tomography-guided core needle biopsy in the diagnostic re-evaluation of patients with lymphoproliferative disorders and suspected disease progression

BACKGROUND

Histological transformation is a common clinical event in patients with lymphoproliferative diseases, often requiring a modification in therapy. Minimally invasive biopsy techniques have been used for initial diagnosis of these disorders but their role has not been systematically evaluated in disease progression. The purpose of this study was to evaluate the yield of computed tomography (CT)-guided core needle biopsy in patients with lymphoproliferative disorders and suspected disease progression.

PATIENTS AND METHODS

We performed a retrospective analysis of the records of patients with known lymphoproliferative disorders who underwent CT-guided core needle biopsy during the course of their disease, between 1990 and 2002.

RESULTS

A total of 130 patients with lymphoproliferative disorders (91 patients with non-Hodgkin's lymphoma, 21 with Hodgkin's disease, 10 with chronic lymphocytic leukemia, six with combined malignancies and two with Castleman's disease) underwent CT-guided core needle biopsy 4.7 +/- 5.1 (standard deviation) (range 0-40) years after initial diagnosis. The procedure was diagnostic in 98 cases (75.4%). In 22 patients (17%) a subsequent open biopsy was performed, and in 10 (7.6%) the final diagnosis remained unconfirmed. Histological transformation was found in 20 cases (15.4%), of which 19 were suspected clinically. A new diagnosis (malignant and non-malignant) was apparent in 18 cases (13.9%) and relapsed or ongoing evidence of the original disease was found in 82 (63%).

CONCLUSIONS

CT-guided core needle biopsy is a reliable procedure in patients with suspected histological transformation of lymphoproliferative disorders, and should be used as the initial tool for pathological re-evaluation.

Cue-induced cocaine craving: neuroanatomical specificity for drug users and drug stimuli

OBJECTIVE

Cocaine-related cues have been hypothesized to perpetuate drug abuse by inducing a craving response that prompts drug-seeking behavior. However, the mechanisms, underlying neuroanatomy, and specificity of this neuroanatomy are not yet fully understood.

METHOD

To address these issues, experienced cocaine users (N=17) and comparison subjects (N=14) underwent functional magnetic resonance imaging while viewing three separate films that portrayed 1 ) individuals smoking crack cocaine, 2) outdoor nature scenes, and 3) explicit sexual content. Candidate craving sites were identified as those that showed significant activation in the cocaine users when viewing the cocaine film. These sites were then required to show significantly greater activation when contrasted with comparison subjects viewing the cocaine film (population specificity) and cocaine users viewing the nature film (content specificity).

RESULTS

Brain regions that satisfied these criteria were largely left lateralized and included the frontal lobe (medial and middle frontal gyri, bilateral inferior frontal gyrus), parietal lobe (bilateral inferior parietal lobule), insula, and limbic lobe (anterior and posterior cingulate gyrus). Of the 13 regions identified as putative craving sites, just three (anterior cingulate, right inferior parietal lobule, and the caudate/lateral dorsal nucleus) showed significantly greater activation during the cocaine film than during the sex film in the cocaine users, which suggests that cocaine cues activated similar neuroanatomical substrates as naturally evocative stimuli in the cocaine users. Finally, contrary to the effects of the cocaine film, cocaine users showed a smaller response than the comparison subjects to the sex film.

CONCLUSIONS

These data suggest that cocaine craving is not associated with a dedicated and unique neuroanatomical circuitry; instead, unique to the cocaine user is the ability of learned, drug-related cues to produce brain activation comparable to that seen with nondrug evocative stimuli in healthy comparison subjects.

Generalized joint laxity and its relation with oral habits and temporomandibular disorders in adolescent girls

A group of 248 girls, aged 15-16 years, were randomly selected and examined both clinically and by questionnaire with regard to the signs and symptoms of temporomandibular disorders (TMD), generalized joint laxity (GJL), range of mandibular opening, temporomandibular joint (TMJ) hypermobility and presence of oral parafunctions. The prevalence of GJL was 43% and that of TMJ hypermobility (TMJH) was 27.3%. A significant, albeit weak, correlation was found between the two. In the presence of joint click, both active and passive opening were significantly larger. When either muscle or joint sensitivity to palpation was present, the difference between the active and passive range of mouth opening increased significantly. The presence of reported clicks was negatively associated with GJL. This association was not valid in the presence of parafunction. Some of the signs and symptoms of TMD affected the range of mouth opening. In the presence of joint clicks, the mean active and passive mandibular opening were significantly larger. In the presence of joint and muscle sensitivity to palpation, the difference between passive and active mouth opening was larger. This was possibly because of the effect of pain on the full active range of opening, which was invalid in the registration of the passive mandibular opening. GJL, when present, did not seem to jeopardize the health of the stomatognathic system as expressed in the signs and symptoms of TMD. There was a negative association between GJL and the presence of reported joint clicks and catch. When a parafunction was present in addition to GJL, this association was invalid but not reversed, as has been previously reported.

Identification of surface residues of the monocyte chemotactic protein 1 that affect signaling through the receptor CCR2

The CC chemokine, monocyte chemotactic protein, 1 (MCP-1) functions as a major chemoattractant for T-cells and monocytes by interacting with the seven-transmembrane G protein-coupled receptor CCR2. To identify which residues of MCP-1 contribute to signaling though CCR2, we mutated all the surface-exposed residues to alanine and other amino acids and made some selective large changes at the amino terminus. We then characterized the impact of these mutations on three postreceptor pathways involving inhibition of cAMP synthesis, stimulation of cytosolic calcium influx, and chemotaxis. The results highlight several important features of the signaling process and the correlation between binding and signaling: The amino terminus of MCP-1 is essential as truncation of residues 2-8 ([1+9-76]hMCP-1) results in a protein that cannot stimulate chemotaxis. However, the exact peptide sequence may be unimportant as individual alanine mutations or simultaneous replacement of residues 3-6 with alanine had little effect. Y13 is also important and must be a large nonpolar residue for chemotaxis to occur. Interestingly, both Y13 and [1+9-76]hMCP-1 are high-affinity binders and thus affinity of these mutants is not correlated with ability to promote chemotaxis. For the other surface residues there is a strong correlation between binding affinity and agonist potency in all three signaling pathways. Perhaps the most interesting observation is that although Y13A and [1+9-76]hMCP are antagonists of chemotaxis, they are agonists of pathways involving inhibition of cAMP synthesis and, in the case of Y13A, calcium influx. These results demonstrate that these two well-known signaling events are not sufficient to drive chemotaxis. Furthermore, it suggests that specific molecular features of MCP-1 induce different conformations in CCR2 that are coupled to separate postreceptor pathways. Therefore, by judicious design of antagonists, it should be possible to trap CCR2 in conformational states that are unable to stimulate all of the pathways required for chemotaxis.

Identification of residues in the monocyte chemotactic protein-1 that contact the MCP-1 receptor, CCR2

The CC chemokine, MCP-1, has been identified as a major chemoattractant for T cells and monocytes, and plays a significant role in the pathology of inflammatory diseases. To identify the regions of MCP-1 that contact its receptor, CCR2, we substituted all surface-exposed residues with alanine. Some residues were also mutated to other amino acids to identify the importance of charge, hydrophobicity, or aromaticity at specific positions. The binding affinity of each mutant for CCR2 was assayed with THP-1 and CCR2-transfected CHL cells. The majority of point mutations had no effect. Residues at the N-terminus of the protein, known to be crucial for signaling, contribute less than a factor of 10 to the binding affinity. However, two clusters of primarily basic residues (R24, K35, K38, K49, and Y13), separated by a 35 A hydrophobic groove, reduced the level of binding by 15-100-fold. A peptide fragment encompassing residues 13-35 recapitulated some of the mutational data derived from the intact protein. It exhibited modest binding as a linear peptide and dramatically improved affinity when the region which adopts a single turn of a 3(10)-helix in the protein, which includes R24, was constrained by a disulfide bond. Additional constraints at the ends of the peptide, corresponding to the disulfide between the first and third cysteines in MCP-1, yielded further improvements in affinity. Together, these data suggest a model in which a large surface area of MCP-1 contacts the receptor, and the accumulation of a number of weak interactions results in the 35 pM affinity observed for the wild-type (WT) protein. The receptor binding site of MCP-1 also is significantly different from the binding sites of RANTES and IL-8, providing insight into the issue of receptor specificity. It was previously shown that the N-terminus of CCR2 is critical for binding MCP-1 [Monteclaro, F. S., and Charo, I. F. (1996) J. Biol. Chem. 271, 19084-92; Monteclaro, F. S., and Charo, I. F. (1997) J. Biol. Chem. 272, 23186-90]. Point mutations of six acidic residues in this region of the receptor were made to test their role in ligand binding. This identified D25 and D27 of the DYDY motif as being important. On the basis of our data, we propose a model in which the receptor N-terminus lies along the hydrophobic groove in an extended fashion, placing the DYDY motif near the basic cluster involving R24 and K49 of MCP-1. This in turn orients the signaling residues (Y13 and the N-terminus) for productive interaction with the receptor.

Correlation of viral RNA, alanine aminotransferase, and histopathology in hepatitis C virus-associated hepatitis

BACKGROUND

Hepatitis C virus (HCV) infection is usually monitored by the level of alanine aminotransferase (ALT) and histopathological changes in liver biopsy specimens. However, accumulating data indicate these parameters are not always correlated with disease progression or the response of HCV infection to therapy.

MATERIALS AND METHODS

Using the Amplicor PCR Monitor Test Kit (Roche Diagnostic Systems, Branchburg, NJ), HCV RNA level was measured in 38 patients with positive anti-HCV antibodies and in 21 of those patients after interferon treatment. The grade and stage of histological changes on hematoxylin and eosin-stained sections of liver biopsy specimens were evaluated on a scale of 1 to 4. In each case, the HCV RNA level was compared with the histological grade or stage and level of ALT and statistically analyzed by Student's t-test.

RESULTS

ALT level did not correlate with pretreatment and posttreatment levels of HCV RNA or histopathological changes. However, there was a statistically significant correlation between HCV RNA and histological grade (P,.05).

CONCLUSION

HCV RNA measurement is a better means of determining and monitoring HCV infection than either ALT level or histopathological characteristics and may provide insight into hepatic injury caused by HCV infection even without an invasive liver biopsy.

Monomeric monocyte chemoattractant protein-1 (MCP-1) binds and activates the MCP-1 receptor CCR2B

To address the role of dimerization in the function of the monocyte chemoattractant protein-1, MCP-1, we mutated residues that comprise the core of the dimerization interface and characterized the ability of these mutants to dimerize and to bind and activate the MCP-1 receptor, CCR2b. One mutant, P8A*, does not dimerize. However, it has wild type binding affinity, stimulates chemotaxis, inhibits adenylate cyclase, and stimulates calcium influx with wild type potency and efficacy. These data suggest that MCP-1 binds and activates its receptor as a monomer. In contrast, Y13A*, another monomeric mutant, has a 100-fold weaker binding affinity, is a much less potent inhibitor of adenylate cyclase and stimulator of calcium influx, and is unable to stimulate chemotaxis. Thus Tyr13 may make important contacts with the receptor that are required for high affinity binding and signal transduction. We also explored whether a mutant, [1+9-76]MCP-1 (MCP-1 lacking residues 2-8), antagonizes wild type MCP-1 by competitive inhibition, or by a dominant negative mechanism wherein heterodimers of MCP-1 and [1+9-76]MCP-1 bind to the receptor but are signaling incompetent. Consistent with the finding that MCP-1 can bind and activate the receptor as a monomer, we demonstrate that binding of MCP-1 in the presence of [1+9-76]MCP-1 over a range of concentrations of both ligands fits well to a simple model in which monomeric [1+9-76]MCP-1 functions as a competitive inhibitor of monomeric MCP-1. These results are crucial for elucidating the molecular details of receptor binding and activation, for interpreting mutagenesis data, for understanding how antagonistic chemokine variants function, and for the design of receptor antagonists.

Objective markers of condom failure

BACKGROUND

Studies of condom efficacy rely on self-reported behavior. Objective markers of exposure to semen may provide a more valid assessment of condom failure and failure to use condoms.

GOALS OF THIS STUDY

To compare three semen biomarkers: acid phosphatase (AP) activity, prostate specific antigen (PSA), and the human seminal plasma antigen (MHS-5).

STUDY DESIGN

Twenty women were intravaginally inoculated with six measured, increasingly larger amounts of their partners' semen. Vaginal fluid was collected by the participant using swabs and tested.

RESULTS

Background levels of PSA were low (0.00-1.25 ng/ml), background levels of AP were variable (0-350 U/l), and all preinoculation samples were negative for MHS-5. All postinoculation samples were positive for PSA, 64 of 117 (55%) for AP, and 14 of 120 (12%) for MHS-5.

CONCLUSION

The PSA immunoassay was the best semen biomarker under these sampling and testing conditions.

Lack of bioeffects of ultrasound energy after intravenous administration of FS069 (Optison) in the anesthetized rabbit

The current study was designed to provide a sensitive in vivo model to maximize the potential bioeffects (measured by hemolysis) of B-mode ultrasound energy in combination with FS069 (Optison). B-mode ultrasound energy was delivered to anesthetized male New Zealand white rabbits with a phased array 5 MHz transducer on a Hewlett-Packard Sonos 1500 ultrasonograph, with transmit level set to maximum (40 dB, approx 135 W/cm2). FS069 (Optison), latex particles in human albumin, or human albumin alone (vehicle) was infused via an ear vein at 0.6 mL/kg. No statistically significant changes were noted in serum free hemoglobin or lactate dehydrogenase either over time or between groups.

Pancreaticojejunostomy versus controlled pancreaticocutaneous fistula in pancreaticoduodenectomy for periampullary carcinoma

BACKGROUND

Anastomotic leak of the pancreaticojejunostomy is a major cause of morbidity and mortality following pancreaticoduodenectomy. Reports have described a large variety of techniques for performing this anastomosis and managing the pancreatic stump. In an attempt to obviate the pancreaticojejunostomy, we prospectively studied the technique of ligating the pancreatic duct and using external drains to create a temporary controlled pancreaticocutaneous fistula.

PATIENTS AND METHODS

Thirty-five consecutive patients who were to undergo pancreaticoduodenectomy for periampullary carcinoma were prospectively randomized to one of two groups: pancreaticojejunostomy (PJ) (n = 18) or controlled pancreaticocutaneous fistula (CPF) (n = 17). The groups were well matched for age, sex, coexisting medical illnesses, type of tumor, and preoperative condition. Except for the management of the pancreatic remnant, all patients in both groups underwent an identical procedure. Major morbidity, length of hospitalization, duration of the controlled pancreatic fistula, and mortality were analyzed over a mean follow-up interval of 26 months (range 5 months to 7.5 years).

RESULTS

The CPF group experienced lower overall operative morbidity rates than the PJ group (24% versus 56%, P < 0.01). Two patients (11%) in the PJ group and none in the CPF group died (P = NS). Half the morbidity in the PJ group and both mortalities were related to anastomotic leak. The CPF and PJ groups left the hospital after mean stays of 26.4 and 42.2 days respectively (< 0.01).

CONCLUSIONS

Compared to pancreaticojejunal anastomosis, creation of a temporary controlled pancreaticocutaneous fistula in patients who undergo pancreaticoduodenectomy for periampullary malignancy has no appreciable risk. It is associated with reduced morbidity and shorter length of hospitalization.

Human health and the environment in eastern and central Europe. Report of the conference Prague, Czech Republic, 12-15 April 1993

A group of 46 leading environmental health scientists from 15 nations unanimously agreed to join forces in a new scientific effort to protect human health around the world from the potentially harmful effects of environmental chemicals and radioactive materials. The scientists agreed to establish a non-political European-based, not-for-profit organization whose objectives will be to promote, coordinate and fund environmental health research in order to provide a scientific basis for environmental remediation. The organization will be affiliated with the Conte Institute. The research priorities decided upon for Eastern and Central Europe were as follows: 1. Research into the effects of toxic metals, such as lead, cadmium, arsenic, and beryllium. 2. Research in the populations of the region on cancer, birth defects, and other diseases, with emphasis on data sharing across national boundaries, on quality control, and on use of biomarkers of reproductive and other effects. 3. Studies on the molecular, biochemical, and chromosomal bases for varying genetic susceptibilities to environmentally-induced diseases. 4. Coordination of research on radiation effects, especially on radiation-exposures resulting from nuclear power and weapons plants. 5. Research on approaches to bioremediation. 6. Education and training of professionals and nonprofessionals in environmental health issues, on an international basis. These and other issues will be taken up over time by this new, cooperative scientific research organization, as decided at the Prague Conference.

Physician credentialing in managed care

The managed care industry is increasingly using physician credentialing when seeking health care providers. The credentialing process must be conducted in a manner that meets the goals of the managed care program.

Antireflection coatings for germanium IR optics: a comparison of numerical design methods

Refinement and thin film synthesis methods were used by members of six different institutions to design antireflection coatings for germanium substrates. The solutions are based on the use of zinc sulfide and germanium layers only. Several systems were found with an average reflectance that is less than 1% in the 7.7 to 12.3 microm spectral region.

Pulmonary infection due to methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) are now causing severe clinical infection on a worldwide basis. Pulmonary infection due to MRSA although widely reported is poorly documented. We report the predisposing factors, underlying diseases, treatment and outcome in 4 patients with pneumonia, 3 patients with empyema thoracis, 1 patient with pneumonia and empyema thoracis, 1 patient with pneumonia plus lobectomy wound infection and 2 patients with lung abscess. Vancomycin was highly effective in treatment, a finding compatible with experience treating other severe MRSA infections.

Evidence against a platelet cyclooxygenase defect in uraemic subjects on chronic haemodialysis

Defective platelet thromboxane synthesis has been described in uraemia and attributed to a 'functional cyclooxygenase defect'. We have studied platelet aggregation and generation of immunoreactive thromboxane B2 (TXB2) in 11 subjects on a chronic haemodialysis programme. The platelet function abnormality of uraemia was confirmed, maximal aggregation in response to collagen (2 and 4 micrograms/ml) and sodium arachidonate (1.5 and 3.0 mM) being significantly depressed. However, increased platelet aggregation in response to sodium arachidonate 0.75 mM was noted. Due to the reduced haematocrit, the platelet concentration in platelet-rich plasma (PRP) of uraemic subjects was significantly lower than that of controls; when TXB2 generation in PRP adjusted to 200 X 10(9) platelets/l was assessed, no evidence for a defect of cyclooxygenase was found, although reduced synthesis of TXB2 in response to thrombin was noted. Furthermore, increased thromboxane generation by uraemic PRP in response to sodium arachidonate 0.75 mM was detected. We conclude that the mild platelet abnormality in uraemic subjects treated by haemodialysis is not explained by a 'functional cyclooxygenase defect', although an abnormality of thrombin-induced thromboxane synthesis may be present. Furthermore, the tendency to increased aggregation and thromboxane synthesis in response to a low concentration of arachidonic acid may contribute to the thrombotic tendency which is also described in such subjects.

Hemoperitoneum from ruptured omental varices

We report a patient with hemoperitoneum from rupture of intraperitoneal varices. Hemoperitoneum is rare. Nevertheless, it should be easily recognized in a patient with abdominal pain and distension, a falling hematocrit in the absence of external blood loss, and gross blood in the abdominal fluid. The syndrome is another justification for early paracentesis in patients with abdominal fluid. Mortality remains high despite surgical correction of the bleeding and reflects the severity of the underlying liver disorder.

Visualization of the human periodontium using serial thin section contact radiography

A method is described to produce radiographs of thin sections of human teeth and periodontal structures. These high resolution contact x-rays allow for visualization of the microscopic details of the mineralized components of these tissues in a dimension heretofore not examined. Twenty-five blocks of human jaws containing teeth affected by periodontal disease were obtained from cadavers. Sagittal, transverse and cross-sectional serial slices were cut using a rotary instrument (1500 rpm) with a water-cooled 3-inch jewelers slot saw. Five hundred-micron sections were made of jaw specimens containing 2 or 3 teeth. The radiographs were taken with a Faxitron low voltage x-ray machine on Kodak-Ortho, Type 3 film. Films were exposed at a distance of 12 inches from the x-ray source at 35 kVp and 1.0 mA for 3 minutes with the specimen in direct contact with the film. Spatial representation of the internal structure of the alveolar bone was obtained using this technique and the detailed anatomy of the vascular channels within the cancellous and cortical compartments of the jaws was studied. Mineralization patterns of plaque and calculus, calcifications in the periodontal ligament, pulp calcifications, accessory root canals, caries and detailed structural changes in the enamel and cementum were also viewed on these films with the aid of microscopy. Magnifications of up to 30 times were used without excessive image distortion resulting from film grain.

Hemolytic-uremic syndrome: demonstration of abnormalities of platelet reactivity and insensitivity to prostaglandin I2

Platelet aggregation and thromboxane synthesis and platelet sensitivity to the antiaggregatory action of prostaglandin I2 were studied serially in a subject suffering from adult hemolytic-uremic syndrome. Platelet aggregation in vitro was defective during the acute phase of the disease and recovered during the convalescent phase. Defective aggregation was not associated with a failure of thromboxane synthesis although it was related to an intrinsic platelet defect rather than an inhibitor in the plasma. The platelets were insensitive to prostaglandin I2, even in the recovery phase of the disease. Furthermore, plasma from the patient rendered normal platelets insensitive to prostaglandin I2 and more sensitive to aggregating agents. It is concluded that the platelet abnormality in hemolytic-uremic syndrome is complex and it combines both an intrinsic platelet abnormality and a plasma component.

Hemoglobin Miyada: DNA analysis of the anti-Lepore beta delta fusion gene

Hemoglobin Miyada, an anti-Lepore hemoglobin, represents the protein product of a nonhomologous crossover between beta and delta genes. The mutant globin is beta-like from the N terminus to amino acid 12, and delta-like from amino acid 22 through the C terminus, thus predicting a crossover site in the first coding region of the gene. DNA analysis, using multiple restriction endonucleases and hybridization to delta and beta globin gene-specific probes, confirms that the beta delta hybrid gene 1) is located on a single chromosomal fragment between normal delta and beta genes, and 2) has 5' beta promoter sequences, delta IVS 1 and 2, and 3' coding and flanking sequences.