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Biomedical subjects

T Wolf

Publications and source records attributed to T Wolf.

At least 73 records · Page 4Linked to original sources
PubMed1996

Mortality of patients who dropped out from regular lithium prophylaxis: a collaborative study by the International Group for the Study of Lithium-treated patients (IGSLI).

Excess mortality has repeatedly been found in patients with recurrent affective disorders. In previous studies our group has shown that during long-term lithium treatment the mortality of such patients is not significantly higher than that of the general population. In the present study, we extended our investigation to 273 patients from the earlier IGSLI cohort who subsequently dropped out from regular lithium prophylaxis. The standardized mortality ratio (SMR) for the whole group was 2.5, significantly higher (P < 0.01) than 1.0, which is the SMR of the general population. Furthermore, the SMR of the patients from each of the participating countries, namely Denmark, Germany and Austria, was significantly higher than 1.0. These findings strengthen the evidence accumulated in previous investigations that regular long-term lithium treatment does in fact markedly reduce the excess mortality of patients with recurrent affective disorders.

Antimanic Agents↗
PubMed1996

Cerebral oxygenation changes in response to motor stimulation.

We studied cerebral hemodynamic response to a sequential motor task in 56 subjects to investigate the time course and distribution of blood oxygenation changes as monitored by near-infrared spectroscopy (NIRS). To address whether response is modulated by different performance velocities, a group of subjects (n = 12) was examined while performing the motor task at 1, 2, and 3 Hz. The results demonstrate that 1) the NIRS response reflects localized changes in cerebral hemodynamics, 2) the response, consisting of an increase in oxygenated hemoglobin concentration [oxy-Hb] and a decrease in deoxygenated hemoglobin concentration ([deoxy-Hb]), is lateralized and increases in amplitude with higher performance rates, and 3) changes in [oxy-Hb] and [deoxy-Hb] differ in time course. Changes in [oxy-Hb] are biphasic, with a fast initial increase and a pronounced poststimulus undershoot. The stimulus-associated decrease in [deoxy-Hb] is monophasic, and response latency is greater. We conclude that NIRS is able to detect even small changes in cerebral hemodynamic response to functional stimulation.

Adult↗
PubMed1996

Validation of the doubly labelled water technique for bumblebees Bombus terrestris (L.)

The doubly labelled water (DLW) technique was validated for the bumblebee Bombus terrestris (L.) using respirometry (RESP) from tethered roundabout flights. We injected small volumes (1 &micro;l) of a mixture containing low concentrations of deuterium and 18O and withdrew 1-2 &micro;l of haemolymph to determine initial 18O concentration. The injected isotopes were equilibrated with the body water pool after 10 min, and high material turnover allowed the analysis of final blood isotope concentrations after 5-7 h. On average (n=16), values measured using the DLW technique exceeded values measured using RESP by 3.1&plusmn;9.9 %, a difference that was not statistically significant at the 99 % confidence level. The absolute error was 7.4&plusmn;7.1 % (mean &plusmn; s.d.). Isotope dilution spaces of both deuterium and 18O were almost identical with the body water pool. We corrected for isotope fractionation, using a slightly higher value than usual for one of the fractionation factors. The single most important variable to influence DLW results, which could not be measured with the desired accuracy, was the volume of the final body water pool N. An overestimate of final N possibly resulted in the DLW overestimate.

Journal Article↗
PubMed1995

Suicide attempts, age and duration of illness in recurrent affective disorders.

One of the strongest predictors of suicide is a suicide attempt in the history of the patient. The question, however, is to what extent age and duration of the illness affects the risk of a suicide attempt. In this study, we examined the course of 310 patients with primary affective disorders before lithium prophylaxis and compared the clinical data of those with and without suicide attempts in their history. In a subgroup of 98 patients with suicide attempts, measures for both suicide attempts and inpatient episodes were investigated. Comparing patients with suicide attempts and those without, we found no difference between duration of illness and number of previous episodes between the two groups. However, those with a suicide attempt in their history had an earlier onset of the illness. In the group of 98 suicide attempters, we found no significant correlation between age and rates for both episodes and suicide attempts, which indicates that these rates were not declining as the illness progressed and the patient aged. Dividing the sample into three different age groups, episode rates and rates of attempted suicide were found to be positively correlated in all age groups, again indicating that as long as episodes occur, the suicide risk does not decline. The results are not in favor of findings which suggest that the risk of attempting suicide might manifest itself primarily in the early course of the illness or that suicide attempts in the early course of illness provide a 'cathartic effect' which leads to a lower risk in the later course of the illness. Rather, the findings support the view that the risk of suicide attempts in recurrent affective disorders is unchanged in all age groups and throughout all stages of untreated illness.

Adult↗
PubMed1995

Excess cardiovascular and suicide mortality of affective disorders may be reduced by lithium prophylaxis.

The mortality of patients suffering from affective disorders is much higher than that of the general population; this excess is due to both suicides and cardiovascular disease. During long-term lithium treatment, the overall mortality has not been found to differ significantly from that of the general population but the question remains whether this lowering, if it is in fact caused by lithium, is due to a reduction in suicide frequency or cardiovascular mortality, or both. We analysed data from 827 previously studied patients and used a procedure that estimated both overall mortality and cause-specific mortalities by single-case analysis. For overall mortality, the ratio of observed deaths (among the patients) to expected deaths (in the general population) was 1.14, which is not significantly different from 1.0; this was also found in our previous analysis. In the whole patient group, comprising 5600 patient years under lithium treatment, seven suicides were observed and 1.3 expected, resulting in a standard mortality ratio of 5.22; this is significantly > 1.0, but markedly lower than that found in patients with affective disorders not given lithium. Cardiovascular mortality was not found to be higher in our patients than in the general population. In view of the fact that a placebo-controlled mortality study under long-term conditions is neither ethically nor practically feasible, our findings cannot prove definitively that long-term lithium treatment counteracts factors responsible for the excess suicide and cardiovascular mortality of affective disorders. However, our observations are compatible with such a notion.

Cardiovascular Diseases↗
PubMed1995

Extended survival of patients on long-term lithium treatment.

OBJECTIVE: Findings from a recent international multi-centre trial are compatible with the idea that long-term lithium treatment extends the survival of patients suffering from affective disorders to match the general population. A similar reduction of mortality was found in Canadian patients, although important questions remained to be answered about cardiovascular and suicide mortality, and patient selection. METHOD: Based on data collected in a study (1) from lithium clinics in Canada, Denmark, Germany and Austria, an analysis was carried out of suicide and cardiovascular mortality in patients who received prophylactic lithium treatment. RESULTS: In patients given lithium for two years or longer (n = 641), both suicide and cardiovascular mortality were the same as, or only slightly higher than, in the general population; in patients given lithium for less than two years (n = 186), both mortalities remained high. The reduced mortality is not likely to be the result of selection because the patients who were treated briefly and those treated for a longer time did not differ in important mortality variables. CONCLUSIONS: In addition to its ability to prevent recurrences, prophylactic lithium treatment appears capable of reducing both the excess suicide risk and excess cardiovascular mortality of affective illness.

Adult↗
PubMed1994

Modeling adherence to colorectal cancer screening.

BACKGROUND: An explanatory framework referred to as the Preventive Health Model was used to identify factors associated with prospective adherence to colorectal cancer screening. METHODS: Data on sociodemographic, psychosocial, social influence, and program factors were collected via telephone survey for 501 older adult members of an independent practice association-type health maintenance organization. Subjects were later mailed fecal occult blood tests for completion and return. Adherence was defined as the return of the tests within 90 days. RESULTS: Structural analysis shows that for men (N = 145), perceived self-efficacy (OR = 1.4), salience and coherence of testing (OR = 2.3 for a 5-point increment on a 30-point scale), and exposure to health education interventions (OR = 6.8) were significant independent predictors of intention to adhere and of adherence. Among women (N = 185), predictors were age (OR = 1.8) and salience and coherence of testing (OR = 1.8 for a 5-point increment on a 30-point scale). CONCLUSIONS: These findings indicate that for both men and women, adherence is influenced strongly by the extent to which the behavior is judged to make sense in everyday life. It also appears that additional education and encouragement may persuade men and younger women to participate in screening.

Age Factors↗
PubMed1994

Mortality during initial and during later lithium treatment. A collaborative study by the International Group for the Study of Lithium-treated Patients.

We have previously shown that the mortality of patients with recurrent affective disorders in long-term lithium treatment is not higher than that of the general population. In the present study on 471 patients from Denmark and Germany, we examined mortality during the initial year of lithium treatment and during later lithium treatment. During initial lithium treatment, the total mortality was twice as high as in the general population (difference not significant) and the mortality due to suicide 16 times higher. During later lithium treatment, the mortality rates did not differ from those in the general population. Our results indicate that patients with frequent, often severe recurrences, those chosen for prophylactic lithium treatment, are at risk of high mortality, which then diminishes as the prophylactic action of the treatment takes effect.

Adult↗