Biomedical subjects
Publications and source records attributed to J B Murphy.
We report the first experimental results on a high-gain harmonic-generation (HGHG) free-electron laser (FEL) operating in the ultraviolet. An 800 nm seed from a Ti:sapphire laser has been used to produce saturated amplified radiation at the 266 nm third harmonic. The results confirm the predictions for HGHG FEL operation: stable central wavelength, narrow bandwidth, and small pulse-energy fluctuation.
An experiment has been carried out at the Brookhaven Accelerator Test Facility to investigate the effect of a surface-roughness wakefield in narrow beam tubes with artificially created bumps. The measurements show that the synchronous modes decay significantly due to the randomization of the roughness pattern. It is pointed out that this decay mechanism has not been investigated in the previous experiment at DESY and the investigators' conclusion does not apply for surface-roughness wakefields in real surfaces.
A 17-year-old boy presented with Fournier gangrene associated with previously undiagnosed Crohn ileocolitis. Fournier gangrene was managed by débridement, broad-spectrum antibiotics, and hyperbaric oxygen. A diverting ileostomy was performed before skin grafting and scrotal reconstruction. Microscopy of a full-layer surgical sample from the terminal ileum revealed granulomas with multinucleated histiocytes, consistent with Crohn disease. Crohn disease was treated with mesalamine, metronidazole, 6-mercaptopurine, and infliximab. The patient was discharged on hospital day 32. At 6-month follow-up, reconstruction of his scrotum had completely healed. Ostomy output was normal.
A lectin isolated from the roots of the legume, Dolichos biflorus, binds to Nod factors produced by rhizobial strains that nodulate this plant and has a deduced amino acid sequence with no significant homology to any lectin reported to date. This lectin also is an enzyme that catalyzes the hydrolysis of phosphoanhydride bonds of nucleoside di- and triphosphates; the enzyme activity is increased in the presence of carbohydrate ligands. This lectin-nucleotide phosphohydrolase (LNP) has a substrate specificity characteristic of the apyrase category of phosphohydrolases, and its sequence contains four motifs characteristic of this category of enzymes. LNP is present on the surface of the root hairs, and treatment of roots with antiserum to LNP inhibits their ability to undergo root hair deformation and to form nodules on exposure to rhizobia. These properties suggest that this protein may play a role in the rhizobium-legume symbiosis and/or in a related carbohydrate recognition event endogenous to the plant.
Pre-inoculation of plants with a pathogen that induces necrosis leads to the development of systemic acquired resistance (SAR) to subsequent pathogen attack [1]. The phenylpropanoid-derived compound salicylic acid (SA) is necessary for the full expression of both local resistance and SAR [2] [3]. A separate signaling pathway involving jasmonic acid (JA) is involved in systemic responses to wounding and insect herbivory [4] [5]. There is evidence both supporting and opposing the idea of cross-protection against microbial pathogens and insect herbivores [6] [7]. This is a controversial area because pharmacological experiments point to negative cross-talk between responses to systemic pathogens and responses to wounding [8] [9] [10], although this has not been demonstrated functionally in vivo. Here, we report that reducing phenylpropanoid biosynthesis by silencing the expression of phenylalanine ammonialyase (PAL) reduces SAR to tobacco mosaic virus (TMV), whereas overexpression of PAL enhances SAR. Tobacco plants with reduced SAR exhibited more effective grazing-induced systemic resistance to larvae of Heliothis virescens, but larval resistance was reduced in plants with elevated phenylpropanoid levels. Furthermore, genetic modification of components involved in phenylpropanoid synthesis revealed an inverse relationship between SA and JA levels. These results demonstrate phenylpropanoid-mediated cross-talk in vivo between microbially induced and herbivore-induced pathways of systemic resistance.
Reducing phenylpropanoid biosynthesis in transgenic tobacco compromises systemic acquired resistance (SAR) to tobacco mosaic virus, while increasing phenylpropanoid biosynthesis enhances SAR. Surprisingly, transgenic tobacco plants compromised in SAR exhibit more effective grazing-induced systemic resistance to larvae of Heliothis virescens, whereas induced insect resistance is compromised in transgenic plants with elevated phenylpropanoid levels. Levels of the phenylpropanoid-derived signal salicylic acid are directly correlated with overall phenylpropanoid biosynthesis in this series of transgenic plants. Moreover, while pathogen-induced SAR is almost completely compromised in salicylic acid-deficient plants expressing the bacterial nahG salicylate hydroxylase gene, these plants show enhanced grazing-induced insect resistance compared to wild-type. Hence, suppression of grazing-induced insect resistance is mediated at least in part by salicylic acid and likely reflects salicylic acid inhibition of the synthesis and action of the wound signal jasmonic acid. We propose that the dual functions of salicylic acid contribute to a signal poise which constrains constitutive expression of disease and insect resistance mechanisms, and reciprocally switches their selective activation.
Recent studies from our laboratory have found that a root lectin from the legume Dolichos hifloris is present on the root surface, binds rhizobial Nod factor and has apyrase activity. To assess the broader significance of this lectin/nucleotide phosphohydrolase (Db-LNP), we have cloned a second related cDNA (Db-apyrase-2) from D. hiflorus, as well as related cDNAs from the legumes Lotus japonicus and Medicago sativa, and from Arabidopsis thaliana, a non-legume. The deduced amino acid sequences of these apyrases were aligned with one another and with the sequences of other apyrases from plants, animals, yeast and protozoa. Phylogenetic analysis shows that Db-LNP has closely related orthologs only in other legumes, while Db-apyrase-2 is more closely related to apyrase sequences from non-leguminous plants. We also show that the orthologs of Db-LNP from M. sativa and Pisum sativum have carbohydrate binding activity. The results suggest that legume LNPs may represent a special class of apyrases that arose by gene duplication and subsequent specialization.
OBJECTIVE: The hypothesis that decreased growth hormone (GH) secretion contributes to the functional decline that occurs with aging is far from substantiated. There have been few studies addressing the distribution and correlates of IGF-I, an indicator of GH activity, in nonclinical populations. As part of a growth hormone intervention trial, we examined the cross-sectional relations between IGF-I levels and multiple measures of physical function, body composition, and strength in a group of older men and women exhibiting mild to moderate reductions in measured physical performance. METHODS: Using a variety of advertising techniques, 155 older subjects were recruited from a metropolitan area to participate in a growth hormone and exercise intervention study. At baseline, all subjects had blood drawn for IGF-I and underwent testing of body composition using dual X-ray absorptiometry, muscle strength using isokinetic dynamometry, and functional assessment using timed performance measures and self-report. Associations between levels of IGF-I, body composition, strength, and physical function were assessed after dividing men and women separately into tertiles of IGF-I as well as treating IGF-I as a continuous variable. RESULTS: Men had higher IGF-I levels than women, and a significant inverse correlation was observed between age and IGF-I in men (r=-0.29, P=.009). There were no clear trends for associations between tertiles of IGF-I, and any of the variables tested. Linear regression models with IGF-I treated as a continuous measure were not associated significantly with any of the measures of physical function, body composition, or strength (all P > 0.05). CONCLUSIONS: In conclusion, although IGF-I levels declined with age in men, these data did not demonstrate an association between IGF-I and measures of muscle strength, body composition, or physical functioning. These findings support the growing body of evidence that IGF-I levels may not be an indicator of growth hormone activity in older persons.
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We report on 2 cases of an adrenocortical carcinoma with vena caval involvement. Preoperative evaluation included a magnetic resonance imaging (MRI) scan confirming the presence of vena caval involvement. Extremely precise detail of the vena caval tumor thrombus was very helpful in preparing for the surgical extirpation. MRI detail far outweighed what was seen on the computed tomography scan and venacavogram. The MRI scan correlated exactly with what was found surgically. Although MRI scanning has been used to evaluate renal tumors with vena caval extension, few cases have been reported with similar adrenal tumors.
A functionally oriented approach to acute stroke care should take place in parallel with traditional medical management, since the medical care provided during the first days and weeks after a stroke affects the patient's ultimate disability status. The components of the functionally oriented approach include a comprehensive history and physical examination, through which information is obtained on current disabilities and abilities, risk factors for common poststroke complications, psychologic and social resources, and environmental barriers that preclude maximal functioning.
To evaluate the effect of immediate reconstruction on the incidence, location, detection, and treatment of recurrent breast cancer, a review of 306 patients operated on according to a standard protocol during the 10-year period 1979 through 1988 was performed. Reconstruction techniques included submuscular implants (207), tissue expanders (84), and musculocutaneous flaps (15). During a minimum follow-up period of 3 years with a mean of 6.4 years, 60 patients (19.6 percent) developed recurrent disease, at a mean interval to recurrence of 31 months. The first locations of recurrences were local (16), regional (11), and systemic (33). Recurrence rates by stage included stage I, 7 patients (5.2 percent); stage II, 45 patients (32.1 percent); and stage III, 8 patients (40 percent). It was not possible to include comparisons with internal control groups of patients in our institution who were not reconstructed or who had delayed reconstructions, thereby preventing conclusions based on such comparisons. Our recurrence data are similar to literature reports of recurrence rates in patients who were not reconstructed after mastectomy. Detection and treatment of recurrences were not inhibited by the reconstructions. When radiation therapy was used in the treatment of local recurrences, the development of symptomatic capsular contracture was recorded in 58 percent of the patients.
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Our screening recommendations for older individuals are outlined in Figures 1 and 2. Our recommendations are parsimonious for two reasons. First, we are concerned about the potential harm of using unproven screening strategies. Second, when there are effective screening strategies, many of the target group are not being adequately screened. We agree with Clayman that it is much wiser to invest our scarce resources on improving the screening rates for clearly efficacious interventions before investing in strategies where efficacy is in question.
Since the establishment of the scientific LTR, the frequency of OLTX has been increasing. Between 1988 and 1991, the number of procedures performed on pediatric patients increased by 28.2%, and among adult patients OLTX increased 84.8%. During this same period, the number of transplant centers performing OLTX rose 62.5% for children, and 54.7% for adult recipients. In 1991 there was a larger proportion of recipients under 1 year of age than in previous years. The effect was to lower the median age at transplantation from over 2 to between 1 and 2. In pediatric recipients of initial transplantation in 1991, compared with earlier recipients, the functional status at time of liver transplantation was improved. Fewer children were in the ICU while awaiting transplantation, and more were able to wait at home. Multiorgan transplantations in pediatric patients remained relatively rare, but a larger portion of these procedures in 1991 than was seen previously included the small intestine. Biliary atresia remained the most common indication for liver transplantation among children, accounting for over 55% of all OLTX procedures in 1991. There was a significant change in the racial distribution among adult recipients. Compared with previous years, there were greater proportions of Hispanic and Asian recipients in 1991. Adult recipients were older in 1991 than previously, and the median age increased from 46 to 49. As with pediatric recipients, adult recipients had better functional status in 1991 than earlier recipients. The increase in positive CMV serology was likely to be a function of older age. Among multiorgan recipients, the combination of liver and pancreas only was much less common in 1991 than previously. As was found previously (1), alcoholic cirrhosis continued to be the most common reason for OLTX, with the proportion of patients diagnosed with this condition increasing in 1991. Twice as many patients with cystic fibrosis were recipients in 1991 as in the prior 3 years. There were decreases in the proportion of patients receiving OLTX due to fulminant liver failure, metabolic disease, and malignant neoplasms. The cumulative probability of surviving (without retransplantation) 4 years after initial transplantation was 0.74 (0.61) for pediatric recipients. Univariate (unadjusted) analyses detected significant differences in survival for age (the youngest recipients had the worst survival), UNOS description (poorer functional status just prior to transplantation led to poorer survival), and primary liver disease (survival was worst for recipients transplanted due to fulminant liver failure, and best for patients with alpha-1 antitrypsin deficiency).(ABSTRACT TRUNCATED AT 400 WORDS)
Careful analysis of electrocautery smoke produced during breast surgery has found organic compounds that are unidentifiable with current analytical techniques. The purpose of this study was to determine the potential mutagenicity of the smoke produced by the electrocautery knife during reduction mammaplasty. Multiple air samples were collected in the operating room during two reduction mammaplasty procedures. Airborne smoke particles were tested for mutagenic potential in both tester strains of Salmonella typhimurium (TA98 and TA100) using the standard Salmonella microsomal test (Ames test). All testing was performed by the Hazard Evaluations and Technical Assistance Branch of the National Institute of Occupational Safety and Health. The smoke produced with the electrocautery knife during reduction mammaplasty was found to be mutagenic to the TA98 strain. The Ames test, an established technique for evaluating the mutagenicity of a substance, was convincingly positive for the smoke collected during the breast surgery. Whether the smoke represents a serious health risk to operating room personnel is not known. Development of techniques to limit electrocautery smoke exposure in the operating room appears to be needed, and surgeons should attempt to minimize their exposure.
This study constitutes a follow-up of a study completed in March 1988, involving 18 patients receiving bone plate stabilization for the repair of surgical defects after mandibular resection. An additional 11 cases are presented with follow-up periods of 3 to 23 months. Of the original study of 18 patients, follow-up was available for 13. Of these 13, five patients died, three as a result of their tumors. One patient was previously reported to have had recurrent disease and loss of the stabilization plate. One patient lost the plate in an area of recurrent tumor just before succumbing to his malignancy. The remaining three died with their stabilization plates in place and functioning. The eight remaining patients with long-term follow-up and 11 additional patients with shorter-term results are now described.
Physical activity has been recognized as an important aspect of patient care for nearly 50 years. Yet, deconditioning and functional decline of hospitalized elderly patients continue to be reported. Such outcomes suggest that a good system for providing activity in hospitals is lacking. In this retrospective study we assessed the provision of physical activity to 500 elderly patients (100 in each of five hospitals) during the first 7 days of hospitalization. No activity order was in effect on 13% of the 3500 patient days reviewed. When activity was ordered, patient activity was different from the activity permitted by the physician orders on 41% of the days. Patients who remained in bed or in a chair rarely received physical therapy, never had physician orders for exercises, and never performed exercises with the nurses. These findings demonstrate that the current practices for the provision of physical activity in hospitals are ineffective.