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Biomedical subjects

J E Bruce

Publications and source records attributed to J E Bruce.

31 records · Page 2Linked to original sources
PubMed1996

"Colored" noise waveforms and quadrupole excitation for the dynamic range expansion of Fourier transform ion cyclotron resonance mass spectrometry.

Fourier transform ion cyclotron resonance (FTICR) mass spectrometry offers unparalleled analytical performance in most regards but has a dynamic range of typically no better than 10(2)-10(3). This limitation reportedly arises from two opposing constraints, involving the maximum number of ions that can be effectively trapped (10(6)-10(7)) and the minimum number of ions required to produce a detectable signal (10(2)-10(3)). A potential solution to this dynamic range limitation is presented, based on the application of selected-ion accumulation using quadrupole excitation. We show that lower concentration species can be effectively accumulated in the FTICR trapped ion cell, while the more abundant species are continually removed by the application of quadrupolar excitation in the form of band-limited or "colored" noise waveforms. The result is that "room" is made in the cell for lower abundance species, even during extended accumulation periods. This approach was demonstrated with mixtures of the bovine proteins, insulin, ubiquitin, and cytochrome c. For normal accumulation, the dynamic range was approximately 100. The application of selected-ion accumulation in the form of colored noise allowed the extension by 2 orders of magnitude and the detection of species of 1 x 10(-8) M concentration from a solution also containing another component at 9 x 10(-5) M. With this method, a putative new low abundance variant of bovine insulin was observed, and selected-ion accumulation and subsequent collisionally activated dissociation were used for its identification. Dipolar magnetron excitation was also explored to enhance selected-ion accumulation and was found to reduce the amount of buffer gas required for complete removal of the undesired species by a factor of 5. Further possible improvements are discussed, as are the complications due to the required balance between magnetron and cyclotron damping rates.

Amino Acid Sequence↗
PubMed1996

Analysis of double-stranded polymerase chain reaction products from the Bacillus cereus group by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.

The analysis of polymerase chain reaction (PCR) products by electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR) has been achieved. Specifically, a 105 base-pair nucleotide portion of the ribosomal spacer region was amplified in two members of the B. cereus group (i.e. B. thuringiensis and B. cereus) using PCR. These amplified regions were then analyzed by gel electrophoresis and ESI-FTICR. Based on the predicted sequence of the PCR products for each organism, the mass measurement using ESI-FTICR matched the theoretical mass within experimental error and was consistent with gel electrophoresis results. In contrast, for the typical several hour time-scale of the gel electrophoresis experiment, the mass spectrometric analysis was completed in a matter of minutes. To our knowledge, this constitutes the first report demonstrating the ionization and detection of a double-stranded PCR product by ESI-MS. This preliminary result indicates the potential use of ESI-MS to analyze PCR products on a rapid time-scale, with potential for medical and taxonomic applications.

Bacillus cereus↗
PubMed1996

Transrectal ultrasound guided prostatic nerve blockade eases systematic needle biopsy of the prostate.

PURPOSE: We assessed the effect of transrectal ultrasound guided prostatic nerve blockade on the discomfort associated with systematic needle biopsy of the prostate. MATERIALS AND METHODS: A prospective randomized double-blind study was performed of 64 patients requiring systematic biopsy of the prostate. Patients were randomly assigned to receive an injection of 5 ml. 1% lidocaine or 5 ml. saline (0.9% sodium chloride) at the vascular pedicle on 1 side of the prostate only. They were then asked to score the severity of discomfort of the injection and subsequent biopsies on each side. RESULTS: Mean pain scores were significantly lower on the side with than the side without lidocaine injection (1.6 +/- 0.9 versus 2.4 +/- 1.2, p < 0.0001) and not significantly different when saline was injected (2.9 +/- 1.2 versus 3.0 +/- 1.1, p = 0.52). Pain scores were significantly different when the lidocaine injected side was compared to the saline solution injected side (p < 0.0001) but the difference was not significant between the noninjected sides of the 2 groups (p = 0.076). Of the patients in the lidocaine group 68% reported that they would prefer to undergo biopsy with the injection compared to only 41% in the placebo group (p = 0.037). During the study no patient in either group had any adverse effect from the injection. CONCLUSIONS: Transrectal ultrasound guided nerve blockade before prostatic biopsy results in a more comfortable procedure for the patient.

Biopsy, Needle↗
PubMed1996

Efficacy of radiographic imaging in pediatric blunt renal trauma.

PURPOSE: We sought to determine whether radiographic imaging can effectively detect significant renal injuries in children with blunt trauma who do not have significant hematuria. MATERIALS AND METHODS: We reviewed the records of 180 children who presented to our hospital for suspected renal trauma between 1977 and 1995. Results of excretory urography or abdominal computerized tomography were correlated with urinalysis findings and clinical outcome. RESULTS: Of 147 patients with microscopic hematuria after blunt trauma 77 underwent imaging. Only 1 patient had a significant renal injury (grade 2 or greater) and 76 had normal findings or renal contusions only, including 11 with microscopic hematuria and shock. Of the 74 patients who did not undergo imaging a clinical diagnosis of renal contusion was made and followup was available for 57 (77%). All patients healed without adverse sequelae. Of 33 patients with gross hematuria significant renal injuries were found in 9, including 3 who required immediate surgical repair of a major renal laceration or vascular injury. Combining our results with those of other reported series revealed significant renal injuries in only 11 of 548 children (2%) with less than 50 red blood cells per high power field on presenting urinalysis after blunt abdominal trauma. These patients were likely to have multiple associated injuries. CONCLUSIONS: Significant renal injuries are unlikely in pediatric patients with blunt renal trauma but no gross or substantial microscopic hematuria. Shock does not appear to be a clinically useful indicator.

Algorithms↗
PubMed1995

Bio-affinity characterization mass spectrometry.

A new approach, bio-affinity characterization mass spectrometry (BACMS), aimed at providing a more rapid, sensitive and potentially more flexible alternative to techniques presently employed for the characterization of noncovalent interactions in mixtures, such as would be encountered in combinatorial chemistry, in presented. BACMS avoids some of the difficulties and potential artifacts associated with affinity chromatography since the noncovalent associations occur in solution; thus, BACMS avoids the requirement of solid support media and the development of non-interfering linker species. This paper describes the conceptual basis for the methodology and its potential use in applications which include the screening of high affinity ligands in support of new drug development. BACMS exploits new Fourier-transform ion cyclotron resonance (FTICR) mass spectrometry technologies which, when coupled to electrospray ionization (ESI), allow the investigation of specific noncovalent complexes formed in solution. BACMS utilizes the well-known attributes of FTICR, such as the high resolution mass analysis and (MS)n (n > or = 2) capabilities; however, it is even more directly a result of recently developed techniques involving quadrupolar excitation, such as selected-ion accumulation. These tools are demonstrated and the results illustrate the extraordinary sensitivity achievable (solution concentration of 1 x 10-9 M without the use of separations prior to ESI). Thus, the new capabilities demonstrated here, in conjunction with ESI, will be useful for the investigation of very low relative concentration noncovalent association directly from solution, and promote a faster alternative for combinatorial mixture screening and analysis.

Animals↗
PubMed1995

Nephrectomy for traumatic renal injuries.

During a 16-year period 2,521 patients presented to our institution with renal trauma. Renal exploration was performed in 195 patients (202 renal units), with 31 units requiring exploration alone, 145 repair and 26 nephrectomy, yielding an overall nephrectomy rate of 13%. A detailed review of these 26 patients identified them as a unique population: all had major renal injuries, and as a group they demonstrated significantly higher rates of shock, injury severity scores, transfusion requirements and death rates than those in whom exploration with renal salvage was possible. In no case was nephrectomy required as a complication of exploration or attempted repair. In the properly staged patient undergoing surgery for appropriate indications with early vascular control exploration of renal injuries is safe. It is not the exploration that results in the nephrectomy but the injury itself.

Adult↗
PubMed1995

Sono-urethrography in the evaluation of anterior urethral strictures.

During a 7-year period 123 paired urethrographic and sono-urethrographic studies were performed on 101 patients with 110 urethral strictures. In all but 3 cases the urethra was subsequently evaluated either cystoscopically or at open operation. Sono-urethrography readily identified urethral calculi, diverticula and false passages. It correctly identified the stricture and its site in every case. There was a significant difference between stricture length as measured by urethrography compared to that measured by sono-urethrography (p < 0.003). However, if the strictures were grouped based on anatomical location, there was good correlation and no significant difference in the penile urethra (correlation coefficient = 0.94, p = 0.74) but poor correlation and the significant difference remained in the urethral bulb (correlation coefficient = 0.64, p < 0.007). Similarly, when urethrographic and sono-urethrographic stricture lengths were compared with operative lengths, in the penile urethra the correlation coefficients were close (correlation coefficient = 0.91 versus 0.98) but in the urethral bulb the poor correlation persisted (correlation coefficient = 0.69 versus 0.89). Although sono-urethrography certainly identifies periurethral tissue, it was unreliable in predicting the depth of spongiofibrosis when compared with full depth biopsies in 36 patients with histopathological correlation. Finally, in 16% of the patients sono-urethrography correctly indicated a reconstructive procedure different from that originally suggested by conventional urethrography. Sono-urethrography is a dynamic 3-dimensional study that accurately identifies stricture site, number and caliber. Compared with conventional urethrography, it more accurately measures stricture length and diameter, and identifies periurethral tissue, making it a valuable adjunct in the evaluation of patients with suspected anterior urethral strictures.

Biopsy↗
PubMed1975

The influence of intrauterine transfusion upon birthweight in rhesus hemolytic disease.

A study of the birthweight of 876 babies affected by rhesus hemolytic disease has shown that this is reduced in the most severely affected cases, when intrauterine transfusion is not required. However, in 259 very severely affected babies where intrauterine transfusion was necessary, the birthweight was similar to that of the mildly affected and unaffected babies.

Birth Weight↗
PubMed1975

Blood in amniotic fluid following intrauterine transfusion and its effect on premature onset of labor.

The most frequent cause of perinatal death following intrauterine transfusion in cases of severe rhesus hemolytic disease remains premature onset of labor and the resulting newborn so delivered. In the present study, 70% of all perinatal deaths were directly related to immaturity. A factor of decisive importance as an initiator of labor before the intended time is the leakage of blood into the amniotic fluid at the time of the procedure. (Mostly, this blood seems to originate from the fetal abdomen into which it was injected for therapeutic reasons.) The effect of blood-contaminated amniotic fluid on uterine activity is demonstrated on the material from Lewisham Hospital of London, where between 1 and 5 intrauterine transfusions were performed on 517 patients during a period between November 1963 and the end of March 1973. The presence of blood in the amniotic fluid was proved either by means of amniocentesis performed 2 days after intrauterine transfusion, or at the time of membrane rupture in labor. Patients who received a self-retaining catheter for any length of time were excluded from the material since the additive influence of the catheter on labor could not be assessed. Out of a total of 452 cases receiving single-use catheters, there were 208 cases (46%) with premature onset of labor. In 2-thirds of the cases this happened within the first week after the last intrauterinetransfusion. Further investigation of 332 case-histories with complete records was carried out. In 61.6% of the patients with labor before the intended time within 21 days after the last intrauterine transfusion, blood contaminated amniotic fluid was found, whereas this occurred in only 34.8% of the cases without premature onset of labor (p less than 0.001). From the same material, corresponding percentages for livebirths and stillbirths were calculated. As a consequence of these results, it is recommended that patients be kept under intensive hospital care following intrauterine transfusion whenever blood can be proved to be present in the amniotic fluid. Prophylactic measures to prevent premature onset of labor should also be considered.

Amniotic Fluid↗