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Biomedical subjects

L Bayer

Publications and source records attributed to L Bayer.

30 records · Page 2Linked to original sources
PubMed1998

Conversion from Sandimmune to Neoral in organ transplant recipients.

The pharmacokinetic profiles of Sandimmune and Neoral vary considerably among transplant recipients. Cyclosporine exposure is far more consistent with Neoral than it is with Sandimmune. Because intrapatient variability of drug exposure has been demonstrated to be a risk factor for chronic rejection, this difference becomes important. Neoral also has a linear dose response and a stronger correlation between trough level and drug exposure. Dose linearity greatly facilitates accurate dose titration. Results of controlled studies in which kidney, liver, and heart transplant recipients were converted from Sandimmune to Neoral have shown that conversion on a 1:1 mg basis results in more predictable bioavailability and often in reductions in cyclosporine dose. Carefully monitored conversion has not been associated with increased side effects, and any side effects that do emerge can usually be managed by taking Neoral with food, changing the dose from every 12 hours to every 8 hours, or through dose reduction.

Cyclosporine↗
PubMed1997

Immunocytochemical detection of the neurokinin B receptor (NK3) on melanin-concentrating hormone (MCH) neurons in rat brain.

The presence of the neurokinin B receptor (NK3 receptor) in the rat lateral hypothalamus and the zona incerta was previously reported. The aim of the present study was to define its cellular localization in these areas. Investigations, coupling immunocytochemical and in situ hybridization techniques, focussed on two neuron populations: the melanin-concentrating hormone (MCH) neurons and a population of neurons recognized by an ovine prolactin antiserum (PRL-ir neurons). While PRL-ir neurons did not exhibit NK3 immunoreactivity, 57% +/- 6% of MCH neurons were strongly stained by the NK3 antiserum. These results suggest that neurokinin B is involved in the regulation of MCH neuron activity via the NK3 receptor; they provide new bases for further investigations on MCH role in the control of food and water intake.

Animals↗
PubMed1996

Molecular analysis of the replication elements of the broad-host-range RepA/C replicon.

RepA/C is a replicon specific to the IncA/C incompatibility group of plasmids and was isolated recently from plasmid RA1. The sequence of this autoreplicative region was established; it contains 13 repeats, suggesting that the replicon uses iterons to control its copy number. The sequence contains two ORFs, one potentially coding for a 33-kDa protein (ORF1) and a second potentially coding for a 14-kDa protein (ORF2) (Llanes et al., 1994b). In this work, using an in vitro transcription/translation system, we detected a polypeptide whose size corresponded well to that of the deduced product of ORF1. Deletion and insertion mutation analysis showed that ORF1 is essential for replication; it encodes an initiator protein (called RepA). ORF2 was not essential for replication in Escherichia coli and its function remains to be determined. Using complementation experiments, the replication origin (ori) of RepA/C was defined. The ori was located in a 600-bp fragment downstream from repA, containing 10 direct repeats. To study the control of repA expression, a transcriptional fusion PrepA::lacZ was constructed. Its analysis showed that repA is transcriptionally autoregulated as are most repA genes of replicons controlled by iterons.

Cloning, Molecular↗
PubMed1996

Variability in salt sensitivity classifications in black male versus female adolescents.

Salt sensitivity (changes in blood pressure in response to alterations in salt intake) may be a risk factor for hypertension. In the present study, we examined the prevalence of salt sensitivity based on two different classifications in healthy black male and female adolescents (aged 13 to 16 years). A total of 135 black adolescents participated in a 50 mmol/24 h low sodium diet for 5 days and a 150 mmol/24 h NaCl supplement for 10 days. Dietary compliance was defined as sodium excretion less than or equal to 50 mmol/24 h for the low sodium diet and greater than or equal to 165 mmol/24h for the high NaCl supplement. Salt sensitivity was defined by two classifications: (1) as a decrease in mean blood pressure greater than or equal to 5 mm Hg from baseline to the low sodium diet, and (2) as an increase in mean blood pressure greater than or equal to 5 mm Hg from the low sodium diet to the high NaCl supplement. With classification 1, 14% of boys were identified as salt sensitive compared with 22% of girls. With classification 2, however, 31% of boys were identified as salt sensitive compared with 18% of girls. Analyses based on changes in systolic pressure demonstrated similar findings across sex, although overall classifications based on systolic pressure yielded a greater percentage of salt-sensitive subjects. These sex differences in classification patterns were not due to differences in other important variables, such as changes in sodium excretion, potassium excretion, or Quetelet index. These results suggest that the prevalence of salt sensitivity differs by sex depending on the type of protocol used for the classification of salt sensitivity in a black pediatric population.

Adolescent↗
PubMed1987

Community hospital administration of intravenous tissue plasminogen activator in acute myocardial infarction: improved timing, thrombolytic efficacy and ventricular function.

As an investigational fibrinolytic agent for acute myocardial infarction, intravenous recombinant tissue-type plasminogen activator (rt-PA) has been administered primarily in tertiary care and university centers. To determine the value of early initiation of such therapy, two satellite community hospital emergency rooms were established for use of rt-PA and the experience was compared among 142 consecutive patients who were transferred to a regional center for acute cardiac catheterization after intravenous rt-PA therapy. In Group I (n = 19), patients received rt-PA after interhospital transport to the regional center, but before cardiac catheterization. In Group II (n = 70), rt-PA therapy was initiated by the helicopter physician and nurse team after their arrival at the local community hospital emergency room. Group III patients (n = 53) had rt-PA administered in the local community hospital by the emergency room physician. Group III patients had earlier initiation of therapy (2.1 +/- 0.8 hours in Group III versus 3.8 +/- 1.2 hours in combined Groups I and II, p less than 0.001) and an increased rate of infarct vessel recanalization on the 90 minute coronary angiogram (81 in Group III versus 67% in combined Groups I and II, p = 0.057). The patients in Group III had a higher acute left ventricular ejection fraction (54 +/- 8% versus 50 +/- 9.5% in combined Groups I and II, p less than 0.01) and a trend toward an increased 7 day ejection fraction (55.5 +/- 9% versus 51.7 +/- 9.5%, respectively, p = 0.08).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1977

Clinical significance of ventricular ectopic beats in the early posthospital phase of myocardial infarction.

The clinical significance of ventricular ectopic beats in the posthospital phase of myocardial infarction was studied in 272 patients aged 65 years or less who were followed up for 1 year after the infarction. Ventricular ectopic beats, identified in 6 hour electrocardiographic tape recordings, obtained before hospital discharge (study 1) and 5 months after discharge (study 2) increased in frequency and complexity in the 5 month interval. Ventricular ectopic beats at a rate of 20 or more per hour recorded before discharge were associated with complex ventricular ectopic patterns in the same 6 hour recording and with frequent (20 or more per hour), early cycle and bigeminal patterns in recordings mad 5 months later. Analysis with log-linear modeling indicated that the occurrence of complex ventricular ectopic beats at follow-up examination was associated with the concomitant use of antiarrhythmic agents,but not with use of digitalis, propranolol or tranquilizers. A ventricular ectopic beat frequency of 20 or more per hour at discharge was associated with increased (P less than 0.05) cardiac mortality in the initial 0 to 4 months after discharge but not in the subsequent 8 months; ectopic beats recorded in the 5 month follow-up study were not associated with increased cardiac mortality in the subsequent 5 to 12 months. The prognostic significance of ventricular ectopic beats is discussed in the light of these findings.

Aged↗
PubMed1976

The early posthospital phase of myocardial infarction. Prognostic stratification.

Prognostic stratification was carried out on 518 patients less than or equal to 65 years of age who were discharged from the hospital following a definite or probable acute myocardial infarction and followed for four months. The total population was made up of 272 patients hospitalzed in 1973 and 246 patients hospitalized in 1974; one hundred and forty-two variables were collected on each patient. The clinical characteristics of the 1973 and 1974 populations were remarkably similar, and both groups had a four-month posthospital cardiac mortality rate of 4%. Two prognostic stratification schemes were developed on the 1973 population which identified low and high risk groups with meaningfully different four-month cardiac death rates. Both stratification schemes were tested on the 1974 population, and one of the two schemes was validated as identifying a significantly increased cardiac mortality rate in the high as opposed to the low risk group. The four-month posthospital cardiac mortality rate was 3% in the low and 14% in the high risk group (Z = 2.70, P less than 0.003). The high risk group was characterized by two or more of the following characteristics: 1) history of angina at ordinary levels of activity or at rest; 2) CCU hypotension and/or congestive heart failure; 3) ventricular premature beat frequency greater than or equal to 20/hr on a six-hour electrocardiographic tape recording. The low risk group had none or only one of the above characteristcis. The prognostic power of this stratification scheme is such that sixteen percent of the posthospital population can be identified as high risk, and this subgroup contains forty-six percent of the patients who die of cardiac cause in the four-month posthospital interval.

Aged↗
PubMedDate not supplied

[C-reactive protein, Il-6 and procalcitonin as infection parameters in children with oncologic diseases].

BACKGROUND: Due to anti-neoplastic therapy, there is a high incidence of infections and fever in pediatric patients with malignant disease. We have searched for parameters that may be of value in the early diagnosis of infection, in discriminating between bacterial and non-bacterial causes and for monitoring the response to antimicrobiotic therapy. PATIENTS: 46 febrile episodes in 33 children with malignant diseases under anti-neoplastic therapy, aged 0.5 to 17 years, were included. Each patient was supplied with a central venous catheter (Hickman catheter). METHODS: Blood was taken for the evaluation of C-reactive-protein (CRP), Interleukin-6 (IL-6) and Procalcitonin (PCT). Laboratory data included WBC, blood cultures, as well as microbiologic and serologic tests for important infectious agents. Patients were grouped as follows: 1. Patients with febrile diseases and positive blood cultures, 2. Patients with localized bacterial or mycotic infections and negative blood cultures, 3. Patients with fever of unknown origin, 4. Patients with viral infections, 5. Control group. RESULTS: CRP and IL-6 were more sensitive than PCT in detecting bacterial and mycotic diseases in leukopenic children, because of low PCT-levels in patients with localized infections. IL-6 values were high shortly after onset of fever and decreased under sufficient antimicrobiotic therapy until day three. CONCLUSIONS: Because of the quick response, IL-6 may be helpful in monitoring antimicrobiotic therapy. Using Procalcitonin-levels, we were not able to distinguish between localized bacterial and viral infection in leukocytopenic patients.

Adolescent↗