Bose-Einstein correlations of charged pion pairs in Au + Au collisions at square root sNN = 200 GeV

Bose-Einstein correlations of identically charged pion pairs were measured by the PHENIX experiment at midrapidity in Au + Au collisions at square root s(NN)=200 GeV. The Bertsch-Pratt radius parameters were determined as a function of the transverse momentum of the pair and as a function of the centrality of the collision. Using the standard core-halo partial Coulomb fits, and a new parametrization which constrains the Coulomb fraction as determined from the unlike-sign pion correlation, the ratio R(out)/R(side) is within 0.8-1.1 for 0.25< <k(T)> <1.2 GeV/c. The centrality dependence of all radii is well described by a linear scaling in N(1/3)(part), and R(out)/R(side) for <k(T)> approximately 0.45 GeV/c is approximately constant at unity as a function of centrality.

The feasibility of telemedicine for the training and supervision of general practitioners performing ultrasound examinations of patients with urinary tract symptoms

Ultrasound examinations were carried out by a general practitioner on patients who presented with lower urinary tract symptoms. To assist in the interpretation of ultrasound anatomy, still images were captured during the ultrasound examination and transmitted to a university expert. In total 15 telemedicine sessions were conducted, using PC-based videoconferencing equipment connected by ISDN at 128 kbit/s. Fifteen patients were randomly selected and both the transmitted and hard-copy images (printed on thermal paper) were graded for technical quality. Data were missing for 13 of the possible 105 paired comparisons, as some images could not be evaluated. Overall agreement between the technical quality scores for the transmitted and hard-copy images was poor (weighted kappa=0.04). The 105 transmitted images were also rated for their diagnostic quality: 90% were classified as diagnostic and 10% were judged to be non-diagnostic. The results show the feasibility of tele-ultrasound in primary care. The general practitioner concerned benefited from regular ultrasound training and supervision, and achieved a satisfactory level of clinical competency in scanning the prostate, bladder and kidneys.

Measurement of nonrandom event-by-event fluctuations of average transverse momentum in square root of (sNN)=200 GeV Au+Au and p+p collisions

Event-by-event fluctuations of the average transverse momentum of produced particles near midrapidity have been measured by the PHENIX Collaboration in square root of (sNN)=200 GeV Au+Au, and p+p collisions at the Relativistic Heavy Ion Collider. The fluctuations are observed to be in excess of the expectation for statistically independent particle emission for all centralities. The excess fluctuations exhibit a dependence on both the centrality of the collision and on the pT range over which the average is calculated. Both the centrality and pT dependence can be well reproduced by a simulation of random particle production with the addition of contributions from hard-scattering processes.

J/psi production from proton-proton collisions at square root of s=200 GeV

J/psi production has been measured in proton-proton collisions at square root of s=200 GeV over a wide rapidity and transverse momentum range by the PHENIX experiment at the Relativistic Heavy Ion Collider. Distributions of the rapidity and transverse momentum, along with measurements of the mean transverse momentum and total production cross section are presented and compared to available theoretical calculations. The total J/psi cross section is 4.0+/-0.6(stat)+/-0.6(syst)+/-0.4(abs) mu b. The mean transverse momentum is 1.80+/-0.23(stat)+/-0.16(syst) GeV/c.

Midrapidity neutral-pion production in proton-proton collisions at square root s = 200 GeV

The invariant differential cross section for inclusive neutral-pion production in p+p collisions at sqrt[s]=200 GeV has been measured at midrapidity (|eta|<0.35) over the range 1<p(T) less, similar 14 GeV/c by the PHENIX experiment at the Relativistic Heavy Ion Collider. Predictions of next-to-leading order perturbative QCD calculations are consistent with these measurements. The precision of our result is sufficient to differentiate between prevailing gluon-to-pion fragmentation functions.

Elliptic flow of identified hadrons in Au+Au collisions at sqrt sNN =200 GeV

The anisotropy parameter (v(2)), the second harmonic of the azimuthal particle distribution, has been measured with the PHENIX detector in Au+Au collisions at sqrt[s(NN)]=200 GeV for identified and inclusive charged particle production at central rapidities (|eta|<0.35) with respect to the reaction plane defined at high rapidities (|eta|=3-4 ). We observe that the v(2) of mesons falls below that of (anti)baryons for p(T)>2 GeV/c, in marked contrast to the predictions of a hydrodynamical model. A quark-coalescence model is also investigated.

Scaling properties of proton and antiproton production in sqrt[s(NN)]=200 GeV Au+Au collisions

We report on the yield of protons and antiprotons, as a function of centrality and transverse momentum, in Au+Au collisions at sqrt[s(NN)]=200 GeV measured at midrapidity by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider. In central collisions at intermediate transverse momenta (1.5<p(T)<4.5 GeV/c) a significant fraction of all produced particles are protons and antiprotons. They show a centrality-scaling behavior different from that of pions. The pmacr;/pi and p/pi ratios are enhanced compared to peripheral Au+Au, p+p, and e(+)e(-) collisions. This enhancement is limited to p(T)<5 GeV/c as deduced from the ratio of charged hadrons to pi(0) measured in the range 1.5<p(T)<9 GeV/c.

Red cell exchange using cell separator (therapeutic erythrocytapheresis) in two children with acute severe malaria

Red cell exchange using a cell separator (therapeutic erythrocytapheresis) has been used successfully in a large number of clinical conditions including acute severe cases of malaria. We report two children suffering from severe malaria (Plasmodium falciparum) with infestation rates of 75% and 67% respectively. They were treated successfully with erythrocytapheresis in combination with antimalarial treatment.

Absence of suppression in particle production at large transverse momentum in sqrt[s(NN)]=200 GeV d+Au collisions

Transverse momentum spectra of charged hadrons with p(T)<8 GeV/c and neutral pions with p(T)<10 GeV/c have been measured at midrapidity by the PHENIX experiment at BNL RHIC in d+Au collisions at sqrt[s(NN)]=200 GeV. The measured yields are compared to those in p+p collisions at the same sqrt[s(NN)] scaled up by the number of underlying nucleon-nucleon collisions in d+Au. The yield ratio does not show the suppression observed in central Au+Au collisions at RHIC. Instead, there is a small enhancement in the yield of high momentum particles.

Suppressed pi(0) production at large transverse momentum in central Au+Au collisions at sqrt[s(NN)]=200 GeV

Transverse momentum spectra of neutral pions in the range 1<p(T)<10 GeV/c have been measured at midrapidity by the PHENIX experiment at BNL RHIC in Au+Au collisions at sqrt[s(NN)]=200 GeV. The pi(0) multiplicity in central reactions is significantly below the yields measured at the same sqrt[s(NN)] in peripheral Au+Au and p+p reactions scaled by the number of nucleon-nucleon collisions. For the most central bin, the suppression factor is approximately 2.5 at p(T)=2 GeV/c and increases to approximately 4-5 at p(T) approximately 4 GeV/c. At larger p(T), the suppression remains constant within errors. The deficit is already apparent in semiperipheral reactions and increases smoothly with centrality.

Flow measurements via two-particle azimuthal correlations in Au + Au collisions at sqrt [s(NN)]=130 GeV

Two-particle azimuthal correlation functions are presented for charged hadrons produced in Au+Au collisions at the Relativistic Heavy Ion Collider (sqrt [s(NN)]=130 GeV). The measurements permit determination of elliptic flow without event-by-event estimation of the reaction plane. The extracted elliptic flow values (v2) show significant sensitivity to both the collision centrality and the transverse momenta of emitted hadrons, suggesting rapid thermalization and relatively strong velocity fields. When scaled by the eccentricity of the collision zone epsilon, the scaled elliptic flow shows little or no dependence on centrality for charged hadrons with relatively low p(T). A breakdown of this epsilon scaling is observed for charged hadrons with pT >1.0 GeV/c.

Measurement of Lambda and Lambda(macro) particles in Au+Au collisions at the square root of S(NN) = 130 GeV

We present results on the measurement of Lambda and Lambda(macro) production in Au+Au collisions at square root of (S (NN) = 130 GeV with the PHENIX detector at the Relativistic Heavy Ion Collider. The transverse momentum spectra were measured for minimum bias and for the 5% most central events. The Lambda;/Lambda ratios are constant as a function of p(T) and the number of participants. The measured net Lambda density is significantly larger than predicted by models based on hadronic strings (e.g., HIJING) but in approximate agreement with models which include the gluon-junction mechanism.

Net charge fluctuations in Au + Au interactions at sqrt[s(NN)]=130 GeV

Data from Au + Au interactions at sqrt[s(NN)]=130 GeV, obtained with the PHENIX detector at the Relativistic Heavy-Ion Collider, are used to investigate local net charge fluctuations among particles produced near midrapidity. According to recent suggestions, such fluctuations may carry information from the quark-gluon plasma. This analysis shows that the fluctuations are dominated by a stochastic distribution of particles, but are also sensitive to other effects, like global charge conservation and resonance decays.

Measurement of analyzing power for proton-carbon elastic scattering in the coulomb-nuclear interference region with a 22-GeV/c polarized proton beam

The analyzing power for proton-carbon elastic scattering in the Coulomb-nuclear interference region of momentum transfer, 9.0x10(-3)<-t<4.1x10(-2) (GeV/c)(2), was measured with a 21.7 GeV/c polarized proton beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory. The ratio of hadronic spin-flip to nonflip amplitude, r(5), was obtained from the analyzing power to be Rer(5)=0.088+/-0.058 and Imr(5)=-0.161+/-0.226.

Centrality dependence of pi(+/-), K(+/-), p, and (-)p production from sqrt[s(NN)] = 130 GeV Au + Au collisions at RHIC

Identified pi(+/-), K(+/-), p, and (-)p transverse momentum spectra at midrapidity in sqrt[s(NN)] = 130 GeV Au+Au collisions were measured by the PHENIX experiment at RHIC as a function of collision centrality. Average transverse momenta increase with the number of participating nucleons in a similar way for all particle species. Within errors, all midrapidity particle yields per participant are found to be increasing with the number of participating nucleons. There is an indication that K(+/-), p, and (-)p yields per participant increase faster than the pi(+/-) yields. In central collisions at high transverse momenta (p(T) > or =2 GeV/c), (-)p and p yields are comparable to the pi(+/-) yields.

Transverse-mass dependence of two-pion correlations in Au+Au collisions at square root[s(NN)] = 130 GeV

Two-pion correlations in square root[s(NN)] = 130 GeV Au+Au collisions at RHIC have been measured over a broad range of pair transverse momentum k(T) by the PHENIX experiment at RHIC. The k(T) dependent transverse radii are similar to results from heavy-ion collisions at square root[s(NN)] = 4.1, 4.9, and 17.3 GeV, whereas the longitudinal radius increases monotonically with beam energy. The ratio of the outwards to sidewards transverse radii (R(out)/R(side)) is consistent with unity and independent of k(T).

Measurement of single electrons and implications for charm production in Au+Au collisions at square root[s(NN)] = 130 GeV

Transverse momentum spectra of electrons from Au+Au collisions at square root[s(NN)] = 130 GeV have been measured at midrapidity by the PHENIX experiment at the Relativistic Heavy Ion Collider. The spectra show an excess above the background from photon conversions and light hadron decays. The electron signal is consistent with that expected from semileptonic decays of charm. The yield of the electron signal dN(e)/dy for p(T) > 0.8 GeV/c is 0.025+/-0.004(stat)+/-0.010(syst) in central collisions, and the corresponding charm cross section is 380+/-60(stat)+/-200(syst) microb per binary nucleon-nucleon collision.

Suppression of hadrons with large transverse momentum in central Au+Au collisions at root square[s(NN)] = 130 GeV

Transverse momentum spectra for charged hadrons and for neutral pions in the range 1 GeV/c<p(T)<5 GeV/c have been measured by the PHENIX experiment at RHIC in Au+Au collisions at root square[s(NN)] = 130 GeV. At high p(T) the spectra from peripheral nuclear collisions are consistent with scaling the spectra from p+p collisions by the average number of binary nucleon-nucleon collisions. The spectra from central collisions are significantly suppressed when compared to the binary-scaled p+p expectation, and also when compared to similarly binary-scaled peripheral collisions, indicating a novel nuclear-medium effect in central nuclear collisions at RHIC energies.

Use of general-purpose negation detection to augment concept indexing of medical documents: a quantitative study using the UMLS

OBJECTIVES

To test the hypothesis that most instances of negated concepts in dictated medical documents can be detected by a strategy that relies on tools developed for the parsing of formal (computer) languages-specifically, a lexical scanner ("lexer") that uses regular expressions to generate a finite state machine, and a parser that relies on a restricted subset of context-free grammars, known as LALR(1) grammars.

METHODS

A diverse training set of 40 medical documents from a variety of specialties was manually inspected and used to develop a program (Negfinder) that contained rules to recognize a large set of negated patterns occurring in the text. Negfinder's lexer and parser were developed using tools normally used to generate programming language compilers. The input to Negfinder consisted of medical narrative that was preprocessed to recognize UMLS concepts: the text of a recognized concept had been replaced with a coded representation that included its UMLS concept ID. The program generated an index with one entry per instance of a concept in the document, where the presence or absence of negation of that concept was recorded. This information was used to mark up the text of each document by color-coding it to make it easier to inspect. The parser was then evaluated in two ways: 1) a test set of 60 documents (30 discharge summaries, 30 surgical notes) marked-up by Negfinder was inspected visually to quantify false-positive and false-negative results; and 2) a different test set of 10 documents was independently examined for negatives by a human observer and by Negfinder, and the results were compared.

RESULTS

In the first evaluation using marked-up documents, 8,358 instances of UMLS concepts were detected in the 60 documents, of which 544 were negations detected by the program and verified by human observation (true-positive results, or TPs). Thirteen instances were wrongly flagged as negated (false-positive results, or FPs), and the program missed 27 instances of negation (false-negative results, or FNs), yielding a sensitivity of 95.3 percent and a specificity of 97.7 percent. In the second evaluation using independent negation detection, 1,869 concepts were detected in 10 documents, with 135 TPs, 12 FPs, and 6 FNs, yielding a sensitivity of 95.7 percent and a specificity of 91.8 percent. One of the words "no," "denies/denied," "not," or "without" was present in 92.5 percent of all negations.

CONCLUSIONS

Negation of most concepts in medical narrative can be reliably detected by a simple strategy. The reliability of detection depends on several factors, the most important being the accuracy of concept matching.

Simultaneous purification and reversible immobilization of D-amino acid oxidase from Trigonopsis variabilis on a hydrophobic support

Purification and reversible immobilization of D-amino acid oxidase from Trigonopsis variabilis could be simultaneously accomplished by hydrophobic interaction on Phenyl Sepharose CL-4B in the presence of 50 mM pyrophosphate buffer (pH 8.5). The presence of a high salt concentration of 2 M, which is generally required for the hydrophobic interactions, was not essential for the hydrophobic immobilization. The enzyme in free as well as immobilized form was optimally active between pH 7.0 and 9.0. The immobilized preparation could be reused in a batch process for the conversion of D-amino acids to alpha-keto acids. When the activity of the preparation dropped below practical limits, the gel could be regenerated by water wash and recharged with fresh crude extract from yeast.

Measurement of the midrapidity transverse energy distribution from square root of [(s)NN] = 130 GeV Au + Au collisions at RHIC

The first measurement of energy produced transverse to the beam direction at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory is presented. The midrapidity transverse energy density per participating nucleon rises steadily with the number of participants, closely paralleling the rise in charged-particle density, such that <E(T)>/<N(ch)> remains relatively constant as a function of centrality. The energy density calculated via Bjorken's prescription for the 2% most central Au+Au collisions at square root[s(NN)] = 130 GeV is at least epsilon(Bj) = 4.6 GeV/fm(3), which is a factor of 1.6 larger than found at sqrt[s(NN)] = 17.2 GeV ( Pb+Pb at CERN).

Centrality dependence of charged particle multiplicity in Au-Au collisions at square root of (s)NN = 130 GeV

We present results for the charged-particle multiplicity distribution at midrapidity in Au-Au collisions at square root of [s(NN)] = 130 GeV measured with the PHENIX detector at RHIC. For the 5% most central collisions we find dN(ch)/d eta(vertical line eta = 0) = 622+/-1(stat)+/-41(syst). The results, analyzed as a function of centrality, show a steady rise of the particle density per participating nucleon with centrality.

Leiomyosarcoma of third part of duodenum with perforation

Malignant stromal cell tumors of the duodenum present with pain or bleed. We report a patient with leiomyosarcoma of the third part of the duodenum that presented with perforation.

Piloleiomyoma--a report of five cases

Piloleiomyomas are uncommon smooth muscle neoplasms of the skin with a few reproted cases in Indian literature (1,2,3,4,5). They are often misdiagnosed clinically. A correct biopsy report is important because patients may have to be managed medically since surgery is associated with a high rate of recurrence. The classical histologic findings, and Masson's stain to confirm the smooth muscle origin aids in the correct diagnosis.

Determination of enantiomeric excess of alpha-hydroxy-3-phenoxybenzeneacetonitrile and its n-butyl ester by chiral high-performance liquid chromatography

Determination of enantiomeric excess of alpha-hydroxy-3-phenoxybenzeneacetonitrile, an important intermediate in the production of several pyrethroid insecticides, is usually done after derivatization and gas chromatographic analysis on a beta-cyclodextrin-based column. In this communication we report a direct determination of enantiomeric excess of alpha-hydroxy-3-phenoxybenzeneacetonitrile and its n-butyl ester by chiral HPLC on Chiralcel OJ (Daicel, Japan) in a single run without derivatization.

Flow cytometry-based minisequencing: a new platform for high-throughput single-nucleotide polymorphism scoring

Single-nucleotide polymorphisms (SNPs) are the most abundant type of human genetic variation. These variable sites are present at high density in the genome, making them powerful tools for mapping and diagnosing disease-related alleles. We have developed a sensitive and rapid flow cytometry-based assay for the multiplexed analysis of SNPs based on polymerase-mediated primer extension, or minisequencing, using microspheres as solid supports. The new method involves subnanomolar concentrations of sample in small volumes ( approximately 10 microl) which can be analyzed at rates of one sample per minute or faster, without a wash step. Further, genomic analysis using multiplexing microsphere arrays (GAMMArrays), enables the simultaneous analysis of dozens, and potentially hundreds of SNPs per sample. We have tested the new method by genotyping the Glu69 variant from the HLA DPB1 locus, a SNP associated with chronic beryllium disease, as well as HLA DPA1 alleles using the multiplexed method. The results demonstrate the sensitivity and accuracy of flow cytometry-based minisequencing, a powerful new tool for genome- and global-scale SNP analysis.

Granular cell ameloblastoma of the jaw. A report of two cases with fine needle aspiration cytology

BACKGROUND

Fine needle aspiration cytology (FNAC) of jaw tumors has not been studied extensively. Ameloblastomas are jaw tumors that show a wide morphologic spectrum and thus may pose some diagnostic difficulties. Of the many types, granular cell ameloblastoma (GCA) is an uncommon variant that possesses distinctive features. To the best of our knowledge, there have been no previous reports on the cytologic findings of GCA. We present two cases diagnosed by FNAC.

CASES

Two cases of GCA were diagnosed on cytology and subsequently confirmed on histology. Both patients presented with a large, lytic jaw tumor. FNAC smears showed characteristic granular cells along with spindle and basaloid cells.

CONCLUSION

Although GCAs are rare tumors, they possess distinctive features that permit an accurate diagnosis, provided that this entity is kept in mind. This tumor has to be differentiated from cystic odontogenic lesions, epulis and granular cell myoblastoma. An accurate preoperative diagnosis also helps the surgeon to plan more extensive surgery as these tumors show a great propensity for malignant change and metastases.

Shouldice's herniorrhaphy versus Moloney's darn herniorrhaphy in young patients (a prospective randomised study)

AIMS

Shouldice's repair (SR) and Moloney's darn repair (DR) are commonly practised repairs for hernias in the young age group with acceptably low recurrence rates. The SR is considered technically challenging and difficult, while the DR is gaining popularity in recent years. Therefore, there is a need to compare these repairs.

MATERIAL AND METHODS

To compare these techniques a total of 50 cases (age group 18-40 years) were randomised to two groups (SR 25, DR 25). These were well matched for age, the side and the type of hernia. Both groups were studied with respect to operative time; postoperative pain at 6,12 and 24 hours (evaluated by pain scale 1-10) need for analgesia, ambulation (evaluated by a four-point scale), complications and return to work.

RESULTS

The SR required a longer time (average 81 minutes) compared to DR (average 43 minutes). Patients undergoing SR complained of pain of a higher scale at 6, 12 and 24 hours post surgery and had a significant higher need for analgesia on day 1 and 2 (p < 0.05). Ambulation grades were significantly better in the DR group on the first postoperative day (p < 0.05). There was no significant difference in the two groups with respect to postoperative complications, return to work, and recurrences rate (2-year follow-up).

CONCLUSION

The SR and DR are comparable for young patients having a primary hernia. However, DR is superior in terms of the time taken, post-operative pain, need for analgesia and early ambulation.

Endovascular repair of an aortoenteric fistula in a high-risk patient

PURPOSE

To describe the endovascular repair of an aortoenteric fistula in a high-risk patient.

METHODS AND RESULTS

A Vanguard tube stent-graft was deployed at the upper anastomotic suture line of a secondary aortoenteric fistula, successfully sealing the communication between the aorta and the third part of the duodenum without occlusion of the renal arteries.

CONCLUSIONS

Endovascular stent-graft repair of aortoenteric fistulae is possible, but further evaluation of this technique will determine its role in the management of this complication.

Prognostic significance of the 1997 TNM classification of renal cell carcinoma

PURPOSE

The TNM classification of renal cell carcinoma was recently revised in 1997. The most significant change from the previous edition (1987) is an increase in the size cutoff between T1 and T2 tumors from 2.5 to 7.0 cm. We compared the 1997 and 1987 TNM staging classifications in predicting patient outcome.

MATERIALS AND METHODS

A total of 381 patients who underwent nephrectomy for renal cell carcinoma at our hospital between 1968 and 1994 were identified. Mean patient age was 61 years (range 15 to 89) and mean followup was 64.5 months. All pathological slides were re-reviewed in uniform manner and staged using the 1987 and 1997 TNM classifications. The impact of numerous pathological factors and each staging classification on disease specific survival and freedom from progression were statistically analyzed, and Kaplan-Meier survival curves were generated and compared.

RESULTS

The 1997 TNM classification resulted in a redistribution of 170 cases previously classified as stage II (T2N0M0) to stage I (T1N0M0) under the new system. Both classifications were strong predictors of survival on univariate and multivariate analyses, and essentially equivalent in the ability to predict patient outcome. However, comparison of survival curves on Kaplan-Meier life tables revealed better separation of survival for stage I (T1N0M0) and stage II (T2N0M0) cases under the 1997 TNM classification, with survival for TNM stage I essentially remaining unchanged.

CONCLUSIONS

The 1997 TNM classification of renal cell carcinoma appears to be equivalent to the previous classification in predicting outcome but permits better stratification of cases according to survival and, therefore, may have improved clinical usefulness.

Calcinosis cutis: diagnosis by aspiration cytology--a case report

Calcinosis cutis is characterized by the deposition of calcium salts in the subcutaneous tissues of the body. Metastatic calcifications can occur in the body in hyperparathyroidism and end-stage renal disease. Calcifications can also occur in a variety of other clinical settings and can be subjected to fine-needle aspiration (FNA). Calcinosis cutis was diagnosed by FNA in a 20-yr-old male who presented with a solitary subcutaneous nodule near the ankle, on the lateral malleolus. Smears showed amorphous granular material consistent with calcium, and occasional histiocytes. The presence of amorphous calcium salts along with histiocytes in the appropriate clinical setting is diagnostic of calcinosis cutis. The diagnosis was confirmed on histology. Diagn. Cytopathol. 1999;21:200-202.

Bacterioopsin-triggered retinal biosynthesis is inhibited by bacteriorhodopsin formation in Halobacterium salinarium

Factors regulating retinal biosynthesis in halobacteria are not clearly understood. In halobacteria, events leading to the biosynthesis of bacteriorhodopsin have been proposed to participate in stringent regulation of retinal biosynthesis. The present study describes a novel approach of in vivo introductions of mRNA and membrane proteins via liposome fusion to test their role in cellular metabolism. Both the bacterioopsin-encoding mRNA and the liposome-encapsulated bacterioopsin (apoprotein) are independently introduced in spheroplasts of the purple membrane-negative strain Halobacterium salinarium that initially contain neither bacterioopsin nor retinal. Isoprenoid analyses of these cells indicate that the expression/presence of bacterioopsin triggers retinal biosynthesis from lycopene, and its subsequent binding to opsin generates bacteriorhodopsin. When bacteriorhodopsin and excess retinal were independently introduced into spheroplasts of purple membrane-negative cells, the introduction of bacteriorhodopsin resulted in an accumulation of lycopene, indicating an inhibition of retinal biosynthesis. These results provide direct evidence that the formation of bacterioopsin acts as a trigger for lycopene conversion to beta-carotene in retinal biosynthesis. The trigger for this event does not lie with either transcription or translation of the bop gene. It is clearly associated with the folded and the membrane-integrated state of bacterioopsin. On the other hand, the trigger signaling inhibition of retinal biosynthesis does not lie with the presence of excess retinal but with the correctly folded, retinal-bound form, bacteriorhodopsin.

Endovascular treatment of a posttraumatic femoral vein-profunda femoris artery fistula

PURPOSE

To describe successful endovascular management of a posttraumatic arteriovenous fistula (AVF) when a covered stent is unavailable.

METHODS AND RESULTS

An AVF developed between the profunda femoris and the femoral vein in a 59-year-old man undergoing a total hip revision procedure. No covered stent being available, a Dacron plug was inserted on top of scaffolding created by a conventional stent and embolization coils. Successful control of hemorrhage and resolution of the AVF was documented. Pulmonary embolization was avoided by using this scaffolding technique.

CONCLUSIONS

Dacron can be used for occlusion of a medium-sized artery in an emergency situation in selected cases.

Reactivity of trypsin in reverse micelles: pH-effects on the W0 versus enzyme activity profiles

pH-Dependence of hydrolytic activity of trypsin has been studied in cationic reverse micellar system of cetyltrimethylammonium bromide (CTAB) in (50% v/v) chloroform/isooctane using a positively charged substrate N(alpha)-benzoyl-L-arginine ethyl ester (BAEE). The pH of the medium was varied from 4.0 to 8.5 with addition of 0.025 M citrate-phosphate buffer containing 1 mM CaCl2. Optimum pH for maximum enzyme activity, pH(opt) in reverse micelles is found to be similar to that observed in bulk aqueous solution (8.0-8.5). However, changes in activity of trypsin (k(cat)) as a function of water content W0 (W0 = [H2O]/[CTAB]) in reverse micelles are found to be pH dependent. At low pH (4.0) and low water content (W0 = 5) the enzyme is more active in reverse micelles than in bulk aqueous solution by a factor of 2. This 'superactivity' is lost at higher W0 values and the k(cat) in reverse micelles is found to be similar to that observed in aqueous bulk. At pH 5, the enzyme activity is found to be independent of W0 while at pH 6.0-6.5 the enzyme activity is low at W0 5 and increases with water content to a constant value which is still 50% lower than that in aqueous buffer. Above pH 7, the W0-activity profile becomes distinctly bell shaped with W0 optimum around 10-15. The enzyme activity at optimum W0 is close to that observed in aqueous bulk.

Functional popliteal entrapment syndrome

BACKGROUND

Classic popliteal artery entrapment is caused by the abnormal relationship between the popliteal artery and the medial head of the gastrocnemius, resulting in repetitive arterial compression and trauma. There is, however, a distinct subset of calf claudicants who have an anatomically normal popliteal fossa but can occlude the popliteal artery by repetitive vigorous exercise which involves active plantar flexion with or without extension at the knee joint.

METHODS

Eight patients who led a vigorous athletic lifestyle were evaluated with duplex scan and biplane angiogram after being referred for bilateral calf claudication. They were found to have significant stenosis or occlusion of the popliteal artery with active plantar flexion. All patients had transection of the medial head of the gastrocnemius muscle with release of any vascular bands tethering the popliteal artery.

RESULTS

Seven of the eight patients had complete relief. One patient noticed return of claudication at long distances, but a postoperative angiogram was normal. In all patients postoperative duplex scan showed no stenosis or occlusion of the popliteal vessels with the foot in active plantar flexion and the knee in extension.

CONCLUSIONS

Functional popliteal artery entrapment is becoming a significant cause of disabling claudication in young athletic individuals and needs to be diagnosed accurately for appropriate treatment. This condition is becoming well known with the incorporation of sports in the daily routine of most young people.

Pancreatic leiomyosarcoma in a middle-aged lady

Leiomyosarcoma is an uncommon malignant tumour of the pancreas. Many retroperitoneal leiomyosarcomas grow silently and are extremely large when diagnosed. We report a 45 year old lady who presented with abdominal lump and haemoptysis. Ultrasound guided biopsy of the mass revealed a pancreatic leiomyosarcoma. The patient had lung metastasis and received chemotherapy. She is alive with disease at last followup.

Treatment of traumatic false aneurysm of the thoracic aorta with endoluminal grafts

PURPOSE

Traumatic false aneurysms of the thoracic aorta presenting at a time remote from the original injury are a rare but complex problem. The treatment of a traumatic false aneurysm by endovascular techniques may offer many advantages over conventional open surgery.

METHODS AND RESULTS

Two male patients presented with traumatic false aneurysm of the thoracic aorta after being treated emergently for visceral injuries from a gunshot wound in one and an automobile accident in the other. In both cases, the aneurysm was situated so that only the T11 intercostal artery would be sacrificed by endoluminal exclusion. Commercially available endoluminal stent-grafts (Talent) were deployed successfully. Recovery in both patients was rapid and uneventful with no neurological sequelae. Spiral computed tomographic scans at 1 year indicated sustained aneurysm exclusion and satisfactory endograft position.

CONCLUSIONS

A customized endoluminal stent-graft can be used with great accuracy to exclude thoracic false aneurysms, avoiding the potential complexity and morbidity of an open thoracic approach.

Fetus in fetu

Fetus in fetu occurs due to aberration of monozygotic twinning. A 16-year-old boy presented with abdominal pain and mass. Laparotomy revealed an anencephalic fetus within an encapsulated retroperitoneal mass. Pathologic examination confirmed rib formation with a primitive vertebral column with bone marrow. There was no other organogenesis.

Wandering spleen causing splenic flexure volvulus and obstruction

A 48-year-old woman presented with symptoms of distal bowel obstruction. On examination she had abdominal distension and a lump in the left lumbar and iliac regions. X-ray revealed distension of the colon with dilated small bowel. Exploration revealed an enlarged ptotic spleen whose pedicle caused obstruction of the colon. There was concomitant partial volvulus of the splenic flexure around the splenic pedicle. The splenic vein was thrombosed. Splenectomy was performed.

Significance of serum ferritin and lactate dehydrogenase in benign and malignant disease of breast

Serum ferritin (SF) and lactate dehydrogenase (LDH) was estimated in 117 patients presenting with a breast lump and in 40 controls. Both pre and post treatment values were determined. Both the values were significantly higher in breast malignancies (p = 0.00) and also corresponded with the clinical stage and bulk of the tumour. The fall in post treatment values was proportional to the response to therapy. Persistent rise in values in the post treatment period was indicative of local recurrence of metastasis.

Extracellular factor(s) following exposure to alpha particles can cause sister chromatid exchanges in normal human cells

The mechanism(s) by which alpha particles like those emitted from inhaled radon and radon progeny cause their mutagenic and carcinogenic effects remains unclear. Although direct nuclear traversals by alpha particles may be involved in mediating these outcomes, increasing evidence indicates that alpha particles can cause alterations in DNA in the absence of direct "hits" to cell nuclei. Using the occurrence of excessive sister chromatid exchanges (SCEs) as an index of DNA damage in human lung fibroblasts, we investigated the hypothesis that alpha particles may induce DNA damage via the generation of extracellular factors. We have found that a relatively low dose of alpha particles indeed results in the generation of extracellular factors, which, upon transfer to unexposed normal human cells, can cause excessive SCEs to an extent equivalent to that observed when the cells are directly irradiated with the same irradiation dose. A short-lived, SCE-inducing factor(s) was generated in alpha-irradiated culture medium containing serum in the absence of cells; it was found that the activity of this factor can be promptly inhibited by superoxide dismutase. A more persistent SCE-inducing factor(s), which can survive freeze-thawing, is heat labile and also can be inhibited by superoxide dismutase, was produced by fibroblasts after exposure to alpha particles. These results indicate that the initiating target for alpha-particle-induced genetic changes can be larger than the nuclear compartment alone and even larger than the cytoplasmic compartment. How transmissible factors like those observed here in vitro may extend to the in vivo condition in the context of alpha-particle-induced carcinogenesis in the respiratory tract and elsewhere remains to be determined.

Phenotypic characterization of cellular components of cardiac myxoma: a light microscopy and immunohistochemistry study

Cardiac myxoma is the most common primary tumor of the heart. A detailed evaluation of cell types in 41 cardiac myxomas by light microscopy and in 30 cases by immunohistochemistry was made. Reactivity to the various antisera were observed in the surface lining cells, the stromal myxoma cells and the cells in the perivascular location. Factor VIII-related antigen (FVIIIR-Ag) and Ulex europaeus agglutinin (UEA-1), both endothelial markers, were positive in 23 cases each. UEA-1 was found to be a more sensitive marker than factor VIII. Desmin and myoglobin were positive in 16 and 24 cases, respectively. Reactivity for cytokeratin was noted in ten cases, one of which showed glandular differentiation. Vimentin and S-100 positivity was obtained in 16 and 14 cases respectively. Thus, cardiac myxoma appears to arise from multipotent cells which have the potential to differentiate along several mesenchymal cells or epithelial cells and may also concurrently exhibit reactivity for both mesenchymal and epithelial markers.

Alpha-particle-induced sister chromatid exchange in normal human lung fibroblasts: evidence for an extranuclear target

We investigated the relationship between nuclear hits by alpha particles and the subsequent occurrence of sister chromatid exchanges (SCEs) in normal human diploid lung fibroblasts (HFL1). Cells were exposed to 238Pu alpha particles at doses ranging from 0.4-12.9 cGy and subsequently analyzed for SCEs. A significant increase in SCE frequency was observed even at the lowest dose examined. The extent of induction of SCEs in the HFL1 cells showed dose dependency in the very low dose range, i.e. 0.4-2.0 cGy. Thereafter, induction of SCEs was independent of dose. Based on measurements of the nuclear areas of the HFL1 cells in conjunction with target theory calculations, the lowest dose resulted in an approximately 8.6-fold increase in the percentage of cells showing excessive SCEs over the theoretically expected percentage of cells whose nuclei were calculated to be traversed by one or more alpha particles. The extent of the discrepancies between theoretically expected and experimentally observed frequencies of SCEs became progressively reduced with increasing radiation dose. We additionally determined that SCEs induced by the alpha particles have no significant dependency on the time of cell collection after exposure to a selected dose of alpha particles, thereby confirming that the differences between the theoretically predicted and observed SCE frequencies were not due to an artifact of the time of cell sampling for the SCE measurements. These results obtained with normal human cells are similar to those of other investigators who observed excessive SCEs in immortalized rodent cells beyond that which could be attributed exclusively to nuclear traversals by alpha particles. Such consistent findings point to the existence of an alternative, extranuclear target through which alpha particles cause DNA damage, as detected by SCE analysis. The existence of an extranuclear compartment as a target for alpha particles may have important implications for the susceptibility of lung cells to the DNA-damaging effects of alpha-particle exposure due to the inhalation of radon progeny.

Variant Max protein, derived by alternative splicing, associates with c-Myc in vivo and inhibits transactivation

Max (Myc-associated factor X) is a basic helix-loop-helix/leucine zipper protein that has been shown to play a central role in the functional activity of c-Myc as a transcriptional activator. Max potentiates the binding of Myc-Max heterodimers through its basic region to its specific E-box Myc site (EMS), enabling c-Myc to transactivate effectively. In addition to the alternatively spliced exon a, several naturally occurring forms of alternatively spliced max mRNAs have been reported, but variant protein products from these transcripts have not been detected. Using Western blot (immunoblot) and immunoprecipitation analysis, we have identified a variant form of Max protein (16 to 17 kDa), termed dMax, in detergent nuclear extracts of murine B-lymphoma cells, normal B lymphocytes, and NIH 3T3 fibroblasts. Cloning and sequencing revealed that dMax contains a deletion spanning the basic region and helix 1 and the loop of the helix-loop-helix region, presumably as a result of alternative splicing of max RNA. S1 nuclease analysis confirmed the presence of the mRNA for dMax in cells. The dMax protein, prepared via in vitro transcription and translation, associated with bacterially synthesized Myc-glutathione S-transferase. Coimmunoprecipitation of dMax and c-Myc indicated their intracellular association. In vitro-synthesized dMax failed to bind EMS DNA, presumably because of the absence of the basic region. Coexpression of dMax inhibited EMS-mediated transactivation by c-Myc. Thus dMax, which can interact with c-Myc, appears to function as a dominant negative regulator, providing an additional level of regulation to the transactivation potential of c-Myc.

Squamous cell carcinoma in thyroglossal duct cyst

Although a thyroglossal duct cyst (TDC) is a common cyst occurring in the neck, carcinomas arising in the TDC are a rare event. To date, approximately 100 cases have been reported, the majority of them being papillary carcinomas. Squamous cell carcinomas (SCC) are very rare, and only nine cases have been reported so far in the literature. We present a 55-year-old female patient with a SCC in a TDC to highlight the clinical and pathological features of this condition.