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Biomedical subjects

M Adams

Publications and source records attributed to M Adams.

At least 145 records · Page 8Linked to original sources

Magnetic source imaging evidence of sex differences in cerebral lateralization in schizophrenia.

BACKGROUND: It has been postulated that schizophrenia represents a disorder of anomalous cerebral lateralization. This study is a replication of earlier preliminary findings using a multichannel neuromagnetometer, suggesting altered lateralization in schizophrenia in male subjects, with an extension of the findings to female subjects. METHODS: We used magnetoencephalography-based magnetic source imaging to estimate the intracranial location of the 100-millisecond latency auditory-evoked field component (M100) in both left and right hemispheres of 20 patients with paranoid schizophrenia and 20 controls without schizophrenia. Neuroanatomical data were obtained by means of magnetic resonance imaging, from which we segmented and computed volumes of both total brain and left and right superior temporal gyri. RESULTS: Locations of M100 source were compatible with neuronal generators located in the transverse gyri of Heschl on the superior temporal gyri in both study groups; M100 sources were asymmetric in all the control subjects. The male patient subgroup exhibited significantly less asymmetry than the control group, while the female patient subgroup actually showed significantly more asymmetry. The male patient subgroup generally had smaller superior temporal gyri than the control group. No evidence of total brain volume differences was observed. CONCLUSIONS: Our findings support previous magnetoencephalography-based studies suggesting anomalous cerebral lateralization in schizophrenia. Further, in extending our studies to female patients, our data suggest that the nature of this anomaly is sex specific, a finding that, to our knowledge, has not previously been reported.

Adult↗

Oxaprozin and piroxicam, nonsteroidal antiinflammatory drugs with long half-lives: effect of protein-binding differences on steady-state pharmacokinetics.

The nonsteroidal antiinflammatory drugs (NSAIDs) oxaprozin and piroxicam have long elimination half-lives (t 1/2 approximately 55 hours), permitting once-daily dose regimens. The protein-binding characteristics of these drugs, however, vary widely. This study examines the effect of these binding differences on the drugs' disposition kinetics at steady state. A total of 52 participants (26 young healthy volunteers, and 26 elderly osteoarthritic patients, 15 men and 37 women (2 of them poor metabolizers of debrisoquine [CYP2D6]) completed the two-period, two-treatment, randomized, single-dose and 21-day, once-daily multiple-dose, cross-over study. Doses of oxaprozin and piroxicam were 1,200 mg once daily and 20 mg once daily, respectively. Mean single-dose kinetic parameters of oxaprozin versus piroxicam did not differ more than +/-14% (t1/2, 53.0 versus 57.4 hours; apparent oral clearance adjusted for 70-kg body weight [Clpo], 0.139 versus 0.121 L/hr; apparent volume of distribution adjusted for 70-kg body weight [Vd/F]; 10.2 L versus 9.13 L). Protein binding was plasma-concentration dependent with oxaprozin (range, 10-400 mg/L) but not with piroxicam (range, 1-30 mg/ L). Steady-state conditions were established within 3 days with oxaprozin but took almost 12 days with piroxicam. Compared with the single-dose values, steady-state Clpo (Clpo,ss) and Vd/F of total drug increased with oxaprozin by almost 127% but remained within +/-10% with piroxicam. Post-steady-state apparent t 1/2 of the total and unbound drugs of approximately 62 hours were similarly prolonged with piroxicam but differed substantially with oxaprozin (50.6 hours [total drug] versus 23.8 hours [unbound drug]). Single dose Clpo (Clpo,sd) values of both NSAIDs were significantly correlated in the study populations. With both NSAIDs, Clpo in the two poor metabolizers of debrisoquine was within +/-20% of mean values for the population. Clinically important age- and gender-dependent decreases were not observed in the weight-adjusted, Clpo,sd or Vd/F values of the total drug for either NSAID. Clearances of the two NSAIDs were significantly correlated, suggesting that a common P450 isozyme (most likely CYP2C9, in that piroxicam is a known substrate of this isozyme) may be at least partly involved in the oxidative metabolism of these NSAIDs.

Adult↗

Collaborative use of informatics among hospitals to benchmark medication use processes.

BACKGROUND: In spring 1995 pharmacists representing each of the 23 member hospitals in Synernet, a hospital cooperative in Maine, decided to collaborate in developing a multihospital medication use evaluation (MUE) program. The committee set up task forces for adverse drug reaction reporting and prevention, MUE plans, and medication error reporting and prevention, for exploration of opportunities to eliminate duplication of efforts, compare performance, and share best practices. PLANNING THE PROGRAM: The members retained a consulting firm to manage the SynRx medication use program from conceptualization through implementation. Modules--on individual drug dosing, switching from intravenous to oral administration, pharmacists' clinical recommendations, and surgical antibiotic prophylaxis--were designed so that participants could adopt the entire plan as a turnkey procedure by inserting their hospital name in the appropriate blanks, modify it to more closely fit their own organizations, use portions of it for inclusion in their current plans, or not use it at all. The goal was to build in maximum flexibility to accommodate the variations in the participating hospital pharmacies and their respective hospitals. RESULTS: Early program benefits include improvements in medication event reporting, documentation of the measured aspects of medication use, delivery of care processes, and administrative efficiency. LESSONS LEARNED AND CONCLUSIONS: The participants, consultants, and programmers involved in the SynRx program learned firsthand the complexity and magnitude of hospital medication use processes. Yet it is possible to overcome the wide variability in systems among hospitals to create standards that allow for more meaningful comparisons of medication use.

Adverse Drug Reaction Reporting Systems↗

Alcohol-history taking by nurses and doctors--how accurate are they really?

The aim of this study was to look at how nurses and doctors record alcohol histories on the patients under their care and the frequency and appropriateness of the way they use an alcohol withdrawal scale in the acute hospital setting. To achieve these aims patient records were audited and compared at two points in time, in 1992 and 1994. Results of the study showed that nurses and doctors took alcohol histories from patients on approximately three-quarters of occasions and that this level of recording has not changed over time. The adequacy of alcohol-history taking has, however, increased for both nurses and doctors since 1992. At that time, 71% of the alcohol histories taken by nurses and 74% of alcohol histories taken by doctors were judged to be adequate. By 1994, however, 79% of alcohol histories taken by nurses and 77% of histories by doctors were rated as adequate. The increase in the adequacy of history taking by nurses was significant (chi 2 = 5.05; d.f. = 1; P < 0.05) and the increase by doctors was not significant (chi 2 = 1.03; d.f. = 1; P > 0.05). These results are seen as being positively associated with the major governmental nursing initiative in New South Wales, Australia, the New South Wales Strategic Plan for the Nursing Management of Alcohol and Other Drugs.

Aged↗

Potential risk factors associated with progressive renal damage in childhood urological diseases: the role of angiotensin-converting enzyme gene polymorphism.

PURPOSE: Experimental as well as human studies have established an important role for the renin-angiotensin system in the progressive deterioration of renal function. Recently genetic polymorphism in components of the renin-angiotensin system has been associated with several cardiovascular diseases, particularly variations in the angiotensin-converting enzyme gene that involve insertion (I) or deletion (D) of a 287 bp fragment. The D variant has been associated with myocardial infarction and cardiac hypertrophy. MATERIALS AND METHODS: To assess whether this genetic variant is associated with worse prognosis in renal disorders we evaluated 70 children with congenital urological abnormalities, since a substantial number have progressive renal deterioration even after early corrective intervention. Renal deterioration was assessed by the presence or absence of radiographic evidence of parenchymal damage and serum creatinine. RESULTS: Among patients with no radiographic renal parenchymal damage angiotensin-converting enzyme genotype distribution of II, ID and DD was 24, 67 and 9%, respectively. In contrast, a significantly different angiotensin-converting enzyme genotype distribution was observed in patients with evidence of parenchymal damage, that is 10, 49 and 41% for II, ID and DD, respectively (p < 0.05, chi-square 5.0). Mean serum creatinine plus or minus standard error in the former group was normal at 0.6 +/- 0.1 mg./dl., while in those with scarring it was elevated at 1.1 +/- 0.1 mg./dl., as expected. In patients with the DD genotype an overwhelming frequency of parenchymal damage was observed, that is of all 22 with that genotype 20 (91%) had parenchymal damage. CONCLUSIONS: Considered together, these studies suggest that there are differences in the distribution of angiotensin-converting enzyme gene polymorphism in patients with congenital urological abnormalities who have evidence of renal parenchymal damage versus those who do not have such damage. Given that this genetic variation activates the renin-angiotensin system and this activation may be particularly robust in the kidney, we propose that the genotype of an individual independent of other factors modifies the likelihood of parenchymal loss in this setting.

Adolescent↗

Purification and Characterization of Two Functional Forms of Intracellular Protease PfpI from the Hyperthermophilic Archaeon Pyrococcus furiosus.

The hyperthermophilic archaeon Pyrococcus furiosus grows optimally at 100(deg)C by the fermentation of peptides and carbohydrates. From this organism, we have purified to homogeneity an intracellular protease, previously designated PfpI (P. furiosus protease I) (S. B. Halio, I. I. Blumentals, S. A. Short, B. M. Merrill, and R. M. Kelly, J. Bacteriol. 178:2605-2612, 1996). The protease contains a single subunit with a molecular mass of approximately 19 kDa and exists in at least two functional conformations, which were purified separately. The predominant form from the purification (designated PfpI-C1) is a hexamer with a molecular mass of 124 (plusmn) 6 kDa (by gel filtration) and comprises about 90% of the total activity. The minor form (designated PfpI-C2) is trimeric with a molecular mass of 59 (plusmn) 3 kDa. PfpI-C1 hydrolyzed both basic and hydrophobic residues in the P1 position, indicating trypsin- and chymotrypsin-like specificities, respectively. The temperature optimum for Ala-Ala-Phe-7-amido-4-methylcoumarin (AAF-MCA) hydrolysis was (symbl)85(deg)C both for purified PfpI-C1 and for proteolytic activity in P. furiosus cell extract. In contrast, the temperature optimum for PfpI prepared by incubating a cell extract of P. furiosus at 98(deg)C in 1% sodium dodecyl sulfate for 24 h at 95 to 100(deg)C (I. I. Blumentals, A. S. Robinson, and R. M. Kelly, Appl. Environ. Microbiol. 56:1255-1262, 1990), designated PfpI-H, was (symbl)100(deg)C. Moreover, the half-life of activity of PfpI-C1 at 98(deg)C was less than 30 min, in contrast to a value of more than 33 h measured for PfpI-H. PfpI-C1 appears to be a predominant serine-type protease in cell extracts but is converted in vitro, probably in part by deamidation of Asn and Gln residues, to a more thermally stable form (PfpI-H) by prolonged heat treatment. The deamination hypothesis is supported by the differences in the measured pI values of PfpI-C1 (6.1) and PfpI-H (3.8). High levels of potassium phosphate (>0.5 mM) were found to extend the half-life of PfpI-C1 activity towards AAF-MCA by up to 2.5-fold at 90(deg)C, suggesting that compatible solutes play an important role in the in vivo function of this protease.

Journal Article↗

Characterization of Di-myo-Inositol-1,1(prm1)-Phosphate in the Hyperthermophilic Bacterium Thermotoga maritima.

Di-myo-inositol-1,1(prm1)-phosphate (DIP) is present at a significant concentration ((symbl)160 nmol/mg of protein) in the cytoplasm of the hyperthermophilic bacterium Thermotoga maritima. The concentration of DIP was independent of the pH of the growth medium or the cell growth phase but increased with increasing concentrations of NaCl in the growth medium, reaching a maximum ((symbl)450 nmol/mg of protein) at 0.4 to 0.6 M NaCl. A large-scale purification procedure for DIP which yields approximately 18 g of DIP per kg of cells (wet weight) is described. Purified DIP was stable at 90(deg)C for at least 5 h. The presence of DIP (50 mM) did not increase the stability at 90(deg)C of pure forms of the hydrogenase or pyruvate ferredoxin oxidoreductase of T. maritima, suggesting that DIP is not a general thermoprotectant.

Journal Article↗

Predisposing factors for individuals' Lyme disease prevention practices: Connecticut, Maine, and Montana.

OBJECTIVES: This study examined factors that predispose individuals to protect against Lyme disease. METHODS: Knowledge, attitude, and practice questions concerning Lyme disease prevention were included in the Behavioral Risk Factor Surveillance surveys in Connecticut, Maine, and Montana. A total of 4246 persons were interviewed. RESULTS: Perceived risk of acquiring Lyme disease, knowing anyone with Lyme disease, knowledge about Lyme disease, and believing Lyme disease to be a common problem were significantly associated with prevention practices. CONCLUSIONS: Predisposing factors differ substantially between states and appear related to disease incidence. Personal risk, knowing someone with Lyme disease, and cognizance about Lyme disease and acting on this information are consistent with social learning theories.

Adult↗

Coagulation and fibrinolytic profile of paediatric patients undergoing cardiopulmonary bypass.

The haemostatic system and the use of heparin during cardiopulmonary bypass (CPB) have been studied extensively in adults but not in children. Results from adult trials cannot be extrapolated to children because of age-dependent physiologic differences in haemostasis. We studied 22 consecutive paediatric patients who underwent CPB at The Hospital for Sick Children, Toronto. Fibrinogen, factors II, V, VII, VIII, IX, XII, prekallikrein, protein C, protein S, antithrombin (AT), heparin cofactor II, alpha 2-macroglobulin, plasminogen, alpha 2-antiplasmin, tissue plasminogen activator (tPA), plasminogen activator inhibitor, thrombin-AT complexes (TAT), D-dimer, heparin (by both anti-factor Xa assay and protamine titration) and activated clotting time (ACT) were assayed perioperatively. The timing of the sampling was: pre heparin, post heparin, after initiation of CPB, during hypothermia, post hypothermia, post protamine reversal and 24 h post CPB. Plasma concentrations of all haemostatic proteins decreased by an average of 56% immediately following the initiation of CPB due to haemodilution. During CPB, the majority of procoagulants, inhibitors and some components of the fibrinolytic system (plasminogen, alpha 2 AP) remained stable. However, plasma concentrations of TAT and D-dimers increased during CPB showing that significant activation of the coagulation and fibrinolytic systems occurred. Mechanisms responsible for the activation of haemostasis are likely complex. However, low plasma concentrations of heparin (< 2.0 units/ml in 45% of patients) during CPB were likely a major contributing etiology. ACT values showed a poor correlation (r = 0.38) with heparin concentrations likely due to concurrent haemodilution of haemostatic factors, activation of haemostatic system, hypothermia and activation of platelets. In conclusion, CPB in paediatric patients causes global decreases of components of the coagulation and fibrinolytic systems, primarily by haemodilution and secondarily by consumption.

Adolescent↗

[Pre- and intraoperative localization of neuroendocrine tumors].

Previous studies of the intraoperative use of a hand-held gamma probe to localize metastases and primary tumors of colorectal cancer have shown improved assessment of tumor spread and changes in surgical management based on added information gained by radioimmunoguided surgery. Following the injection of 180 MBq [111In-DTPA-D-Phe1]-pentetreotide and/or 500 MBq 99mTc-dimercaptosuccinic acid (both for dual-radionuclide scintigraphy) preoperative somatostatin receptor imaging [11 patients with GEP tumors] and dual-radionuclide scintigraphy. (8 patients with relapsing medullary thyroid carcinomas) was performed. One patient with a metastasizing pheochromocytoma underwent 123]-MIBg scintigraphy. Results were combined with the information obtained from conventional imaging modalities. Intraoperative radiodetection was performed 24 hours after administration of [111In-DTPA-D-Phe1]-pentetreotide or 4 hours following the injection of 99mTc(V)DMSA using a hand-held gamma probe (Tec Probe 2000. Stratec, FRG). Intraoperative gamma counting localized 39 somatostatin receptor positive lesions of GEP tumors whereas preoperative receptor imaging visualized 81%, surgical palpation 41% and radiological imaging modalities localized only 31%. In 8 patients with recurrent medullary thyroid carcinoma the surgeon was successful in localizing and removing 18 tumor lesions by the help of the gamma probe. Dual-radionuclide scintigraphy revealed 77% (Octreoscan 5/18; 99mTc-V-DMSA 9/18), surgical palpation 55% and conventional imaging methods (CT, sonography) only 38% of all lesions detected intraoperatively by the hand-held gamma probe. In summary, this preliminary data show that intraoperative hand-held gamma probe detection of microscopic and occult endocrine tumors is feasible and more sensitive than external scintigraphy and conventional imaging.

Adrenal Gland Neoplasms↗

Practicing implant dentistry profitably.

The success of dental implants has opened up countless treatment possibilities for restorative dentists to offer to their patients. Just as our clinical paradigms have had to change because of this new technology, so too must our paradigms concerning the way we communicate with our patients change if we are to get them to say "yes" to treatment that we know that they need. Success in clinical treatment using implants requires a systematic approach. A systematic approach to communicating with your patients will allow you to have the same high degree of success with treatment acceptance that is possible with dental implants. The key to the systems we have discussed is Relationship Centered Care. A relationship is fostered and enhanced through a Comprehensive Examination Process, a structured Consultation Process utilizing the influencing process and Financial Arrangements that allow the patient to receive what they want while the office maintains the profitability that it needs. A system for calculating rational fees can be utilized that allows the practice to have control over an area that traditionally was controlled by anecdotal factors. The Pride Institute has developed this material and is presenting it to the profession so that restorative dentists can truly practice implant dentistry profitably.

Dental Implantation↗