Biomedical subjects

S Wetter

Publications and source records attributed to S Wetter.

6 recordsLinked to original sources

PubMed2000

Mitral repair in patients with a ruptured papillary muscle.

BACKGROUND: The objective of this study was to evaluate the feasibility of a modified papillary muscle repair procedure for a group of patients with ischemic mitral regurgitation when ischemia/infarction has resulted in the rupture of a papillary muscle. From January 1997 to January 1999, 843 patients underwent mitral valve surgery in our hospital. Mitral reconstruction was performed in 520 (61.7%) patients, and 6 (1.2%) of these patients were found to have a rupture of a papillary muscle at initial examination. METHODS AND RESULTS: A modified papillary muscle repair procedure to reimplant the tip of the ruptured papillary muscle "height- and/or length-adjusted" into a corresponding papillary muscle, with the use of a sandwiched pericardium pledget-reinforced polytetrafluoroethylene suture, was performed in 6 patients. Although the underlying cause in this group of patients was ischemic, concomitant coronary artery bypass grafting was performed in only 3 patients, with 1.3 grafts per patient. Of these 6 patients, 3 (50%) were men; the mean age was 60.2 +/- 12.8 years. All patients had in addition to the papillary muscle repair procedure an annuloplasty with a Carpentier-Edwards Physio-Ring. There was no early death in this group of patients. Postoperative Doppler echocardiography showed satisfactory mitral valve function in all patients and a significant postoperative ventricular remodeling: The left ventricular end-diastolic diameter decreased from 72.8 +/- 3.1 mm before surgery to 54.6 +/- 9.3 mm (P <.1) after surgery; left ventricular systolic diameter also decreased (48.5 +/- 4.9 mm vs 38. 4 +/- 9.8 mm; P <.1), and a substantial reduction of left atrial diameter (58.8 +/- 1.5 mm vs 49.7 +/- 4.1 mm; P <.1) was observed. Within the short mean follow-up period of 8.6 +/- 7.5 months (2 to 26 months), there were no late deaths, reoperations, or thromboembolic or bleeding complications. All patients were in New York Heart Association functional class I or II at the time of follow-up. CONCLUSIONS: Our results indicate that our modified papillary muscle reimplantation procedure is a valuable surgical tool with good survival results in patients with ischemic mitral regurgitation caused by papillary muscle rupture.

Adult↗

PubMed2000

Olfactory event-related potentials and aging: normative data.

Unlike the clinical usages of evoked potentials (e.g. brain stem auditory evoked potentials for the assessment of auditory function), normative data for the olfactory event-related potential (OERP) have been unavailable. The principal objective was to establish normative data across the human life span for OERPs with a given set of parameters. Participants were 140 persons from seven age groups (16-19, 20-29, 30-39, 40-49, 50-59, 60-69 and 70-79 years of age), with equal numbers of males and females, screened for nasal health and dementia. The odor stimulus was amyl acetate, presented at nasal temperature in a humidified airstream delivered by an air-dilution olfactometer at a constant flow rate, using a 60-s inter-stimulus interval. OERPs were recorded at Fz, Cz, and Pz electrode sites, amplified and averaged over trials. Amplitudes of the N1/P2 and P3 and latencies of the P2 and P3 were analyzed. Processing speed decreased at a constant rate over decades for the sensory (P2 latency) as well as cognitive (P3 latency) components. Decline in amplitude over decades was also apparent. Normative data will be useful in research on olfactory function and in clinical assessment of olfactory functional status.

Adolescent↗

PubMed1999

Individuals with Down's syndrome demonstrate abnormal olfactory event-related potentials.

OBJECTIVE: Recent research has demonstrated that individuals with Down's syndrome (DS) develop plaques and tangles in the brain similar to people with Alzheimer's disease. As a result, they show increased dementia and decreased olfactory functioning compared to healthy individuals. The olfactory event-related potential (OERP) has been used as an objective quantitative measure of olfactory functioning in normal and clinical populations. The present study investigated the utility of the latency and amplitude of the OERP components in examining olfactory dysfunction in DS individuals. METHODS: OERPs were recorded monopolarly at the Fz, Cz and Pz electrode sites, using amyl acetate at a 60 s inter-stimulus interval, from individuals with DS (mean age 26.0 years) and age-matched normal controls. Participants were screened for nasal health and odor thresholds were assessed. Dementia was assessed using the dementia rating scale (DRS). RESULTS: Results indicate that DS subjects have significantly longer latencies in the sensory (N1, P2, and N2) and cognitive (P3) components of the OERP than normal controls. Odor threshold was significantly associated with sensory OERP components. In addition, DS subjects with a higher level of dementia showed significantly longer P3 latencies than those with lower dementia levels. CONCLUSIONS: The study suggests that the OERP may be a useful measure of olfactory dysfunction in DS which may precede developing dementia in this population.

Adult↗

PubMed1998

Age effects on central nervous system activity reflected in the olfactory event-related potential. Evidence for decline in middle age.

A series of studies in this laboratory using the olfactory event-related potential (OERP) have examined the underlying central nervous system activity associated with age-related changes in olfactory functioning. Early (sensory) components of the OERP showed reduced amplitude and longer latency in elderly subjects, with larger effects in males. Amplitudes are already decreased in middle age. The late cognitive component, P3, showed a longer latency as well as a decreased amplitude in the elderly, with effect sizes for age significantly larger for the late component than for the early components. We report here the significantly longer latency, particularly for the P3, in middle-aged persons, suggesting age-related slowing of olfactory information processing as early as the 50s. Results suggest that the elderly brain, and indeed, the middle-aged brain shows smaller responses to odors, is less able to allocate attentional resources and slows in its olfactory cognitive processing. The OERP is a potent reflection of these changes.

Adult↗

PubMed1994

Carotid artery stenosis and tachyarrhythmias: regional cerebral blood flow during high-rate ventricular pacing after one vessel occlusion in rats.

The aim of the present study was to investigate the effect of hypotensive tachycardias on cerebral blood flow (CBF) in the presence of significant carotid stenosis. The experiments were performed in 57 spontaneously breathing rats during arterial normoxia and normocapnia anesthetized with thiobarbital. CBF was determined with radiolabeled microspheres during control conditions (normofrequent sinus rhythm, normotension; group A; n = 15), during high-rate left ventricular pacing (660-840 ppm) at normotension (group B1; n = 13), borderline hypotension (group B2; n = 15) and severe hypotension (group B3; n = 7). In addition, CBF measurements were performed during borderline hypotension induced by hemorrhage (group C; n = 7). Global CBF was 1.09 +/- 0.29 ml g-1 min-1 in group A, 0.93 +/- 0.40 in group B1, 0.68 +/- 0.31 in group B2 (P < 0.05 vs. A), 0.42 +/- 0.16 in group B3 (P < 0.05 vs. A) and 0.83 +/- 0.2 in group C. The highest CBF values were found in the cerebellum (A; 1.43 +/- 0.5 ml g-1 min-1) and the lowest in the postocclusive tissue of the ipsilateral hemisphere (A; 0.74 +/- 0.2 ml g-1 min-1). In all groups a 15% mean CBF reduction in the right hemispherical cerebrum in comparison to the left hemisphere was observed (P < 0.01). In contrast, hemispherical CBF of the cerebellum did not differ. The CBF blood pressure relationship shifted to lower CBF values, the threshold of CBF regulation shifted to higher blood pressure values in the tissue regions distal to the occluded vessel during hypotensive tachycardias.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Apolipoprotein E epsilon4 positive individuals demonstrate delayed olfactory event-related potentials.

Apolipoprotein E epsilon4 positive individuals have deficits in the ability to identify and remember odors, as demonstrated by psychophysical measures of olfactory function. The purpose of the present study was to identify olfactory deficits in this population using an objective electrophysiological measure: the olfactory event-related potential (OERP). Olfactory and auditory ERPs were recorded from the Fz, Cz, and Pz electrode sites in 10 epsilon4 positive individuals and 10 age and gender-matched epsilon4 negative individuals in a single-stimulus paradigm. The results indicate: (1) individuals who are positive for the apolipoprotein E epsilon4 allele demonstrated delays (of approximately 100 ms) in the processing of olfactory information compared to those who are epsilon4 negative; (2) OERP latency is more sensitive than psychophysical measures of olfactory function; (3) delays in the cognitive P3 component of the OERP are associated with deficits in the ability to identify an odor; and (4) unlike the moderate ranges found in auditory ERP, OERP latency showed high sensitivity and specificity in classifying epsilon4 positive and negative individuals.

Aged↗