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Biomedical subjects

R Guttmann

Publications and source records attributed to R Guttmann.

At least 19 recordsLinked to original sources

Long-term changes in left ventricular hypertrophy after renal transplantation.

BACKGROUND: Concentric and eccentric left ventricular hypertrophy are common progressive disorders in dialysis patients and are associated with cardiac failure and death. Although partial regression of these abnormalities is known to occur during the first post-transplant year, their long-term evolution is unknown. METHODS: A total of 143 of 433 dialysis patients participating in a long-term prospective cohort study received renal transplants. Laboratory parameters were assessed monthly. Echocardiography was performed annually. Left ventricular mass index (LVMI) and cavity volume index were calculated according to standard formulae. Multiple linear regression was used to model change in LVMI as a function of baseline clinical and laboratory variables. RESULTS: LVMI fell from 161 g/m2 at 1 year to 146 g/m2 (P=0.009) g/m2 after 2 years. No further regression was seen in years 3 and 4. Left ventricular volume index showed similar trends, with a decline from year 1 to year 2 (P=0.05) followed by stabilization in years 3 and 4. Older age, long duration of hypertension, need for more than one antihypertensive, high pulse pressure in normal-size hearts, and low pulse pressure in dilated hearts were significantly associated with failure of regression of LVMI between the first and second years (MLR, P<0.000001, r2=0.57). CONCLUSIONS: Regression of left ventricular hypertrophy continues beyond the first year after renal transplantation, reaching a nadir at 2 years and persisting into the third and fourth posttransplant years. Failure to regress was associated with older age, hypertension, high pulse pressure in normal-size hearts and low pulse pressure in dilated hearts.

Adult↗

Long-term knowledge retention following predialysis psychoeducational intervention.

BACKGROUND/AIMS: Early identification and predialysis psychoeducation are gaining acceptance. Although research supports the immediate value of predialysis interventions, long-term benefits remain unknown. We examined long-term knowledge retention following a psychoeducational intervention. METHODS: 47 progressive renal failure patients completed the Kidney Disease Questionnaire at baseline and 18, 30, 42, and 54 months after initiating renal replacement therapy (RRT; the 'longitudinal' sample). A larger cohort provided data at one or more of these points (n = 132, 117, 101, and 70 at 18, 30, 42, and 54 months, respectively; the 'cross-sectional' sample). RESULTS: Initial knowledge gains among psychoeducation recipients were followed by a significant knowledge advantage for three groups throughout follow-up. Patients who received predialysis psychoeducation either before or after starting dialysis demonstrated superior Kidney Disease Questionnaire scores as compared with those identified before the initiation of RRT who received the usual standard of practice. Patients identified after the initiation of RRT and who received standard education, however, demonstrated the same level of knowledge retention as produced by psychoeducation. The results were identical across the longitudinal and cross-sectional samples. CONCLUSIONS: Patient education produces important benefits in end-stage renal disease, but the incremental value of early intervention remains to be demonstrated.

Adult↗

Myoblast transfer in Duchenne muscular dystrophy.

One biceps muscle of 8 patients with Duchenne muscular dystrophy was injected at 55 sites with a total of 55 million viable, purified, and contamination-free normal myoblasts (myoblast transfer). The other biceps of each patient was injected with a placebo to serve as a control. The procedure was blinded to the patients, parents, and investigators. Myoblasts derived from a biopsy specimen of the fathers were cultured and purified under strict conditions and carefully screened for microbial contamination. All patients received cyclophosphamide for immunosuppression for 6 or 12 months. No serious complications were observed after myoblast transfer, indicating that the procedure is safe. The overall therapeutic efficiency of myoblast transfer was poor as judged by the results in maximal voluntary force generation, dystrophin content of the muscle, magnetic resonance imaging of the muscle, and the lack of donor-derived DNA and dystrophin messenger RNA in the injected muscle. An improved efficiency of the take of myoblasts might be achieved by using younger cells and injecting the myoblasts with a myonecrotic agent (to increase the prevalence of regeneration) and a basal laminal fenestrating agent.

Analysis of Variance↗

BioSYNTHESIS: access to a knowledge network of health sciences databases.

Users of the IAIMS Knowledge Network at the Georgetown University Medical Center have access to multiple in-house and external databases from a single point of entry through BioSYNTHESIS. The IAIMS project has developed a rich environment of biomedical information resources that represent a medical decision support system for campus physicians and students. The BioSYNTHESIS system is an information navigator that provides transparent access to a Knowledge Network of over a dozen databases. These multiple health sciences databases consist of bibliographic, informational, diagnostic, and research systems which reside on diverse computers such as DEC VAXs, SUN 490, AT&T 3B2s, Macintoshes, IBM PC/PS2s and the AT&T ISN and SYTEK network systems. Ethernet and TCP/IP protocols are used in the network architecture. BioSYNTHESIS also provides network links to the other campus libraries and to external institutions. As additional knowledge resources and technological advances have become available. BioSYNTHESIS has evolved from a two phase to a three phase program. Major components of the system including recent achievements and future plans are described.

Academic Medical Centers↗

Medical Facts File: a self service database of reference information.

The Dahlgren Memorial Library, Georgetown University Medical Center, will demonstrate Medical Facts File, a newly developed in-house database of general medical information. The file content emerged from the library's experience with commonly asked reference questions and the need to develop a database as an online source for users seeking quick answers to medical queries. Medical Facts File joins a growing family of over 18 databases which comprise Georgetown's IAIMS Knowledge Network. Use scenarios will demonstrate how an online search is initiated, either directly or as a prompt from one of the other online databases. The design of Medical Facts File at the Dahlgren Memorial Library began in late 1989 with a publishing section on instructions for authors planning to submit manuscripts to a variety of prominent medical journals. Since then, seven sections have been identified for the database. Three sections are highlighted for presentation, although work on the project is on-going. Medical Facts File is an easy-to-use, time saving system that facilitates tedious searching through a multitude of library sources. It provides users with a self-service, information look-up system.

Databases, Factual↗

Prospective study of predictors of beta-cell survival in type I diabetes.

We conducted a prospective study to describe the course of the pancreatic beta-cell function from the time of clinical diagnosis of insulin-dependent (type I) diabetes to determine whether DR type, presence of islet cell antibodies (ICA), presence of insulin antibodies (IA), age at onset, and sex could help in the prediction of residual endogenous insulin secretion. A cohort of 68 children was followed for 18 mo after diagnosis of type I diabetes. The outcome variables selected for analysis were 1) serum C-peptide peak concentration after a Sustacal meal, 2) time of disappearance of the serum C-peptide response, and 3) time after diagnosis at which the maximal serum C-peptide response was observed. After institution of insulin therapy, serum C-peptide peak concentrations rose temporarily for 1-6 mo and declined thereafter. Multivariate analysis of the data showed that DR type (P = .2488) and presence of IA (P = .1604) had no effect on serum C-peptide over time, but sex (P = .0146), age at onset (P = .0002), and presence of ICA (P = .0147) significantly contributed to the variation of serum C-peptide over time. Furthermore, age at onset, presence of ICA, and sex were also the only significant predictors of the time of disappearance of the beta-cell function. The relative risks of beta-cell-function disappearance were 0.87 (P = .0015), 9.43 (P = .0181), and 2.25 (P = .0468), respectively. In conclusion, there are distinct variations in the natural course of the beta-cell function in type I diabetes. beta-Cell-function survival is significantly shortened the younger the subject is at disease onset, if ICA are present at diagnosis, and if the subject is male.

Adolescent↗

Partitioning of airway responses to inhaled methacholine in the rat.

We measured the changes in upper and lower airway resistance after inhalation of aerosols of methacholine (MCh) in doubling concentrations (16, 32, 64, and 128 mg/ml) in 11 anesthetized nonintubated spontaneously breathing rats. Upper airway resistance (Ru) increased from a control value of 0.48 +/- 0.04 cmH2O X ml-1 X s (mean +/- SE) to 0.85 +/- 0.15 after 128 mg/ml MCh, whereas lower airway resistance (Rlo) increased from 0.11 +/- 0.03 to 0.21 +/- 0.04. However, there was no correlation between the magnitudes of the changes in Ru and Rlo. In a further seven anesthetized spontaneously breathing rats aerosols of MCh were delivered into the lower airways via a tracheostomy and resulted in increases in Rlo from a control value of 0.20 +/- 0.03 to 0.66 +/- 0.12 after 128 mg/ml MCh. Ru also increased to approximately double its control value. We conclude that inhaled MCh causes narrowing of both Ru and Rlo in the anesthetized rat, the changes in Ru and Rlo are not correlated, and changes in Ru can occur when MCh deposition occurs only in the lower airways.

Aerosols↗