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Biomedical subjects

W Poser

Publications and source records attributed to W Poser.

At least 19 recordsLinked to original sources
PubMed1999

Specific attentional dysfunction in adults following early start of cannabis use.

RATIONALE AND OBJECTIVE: The present study tested the hypothesis that chronic interference by cannabis with endogenous cannabinoid systems during peripubertal development causes specific and persistent brain alterations in humans. As an index of cannabinoid action, visual scanning, along with other attentional functions, was chosen. Visual scanning undergoes a major maturation process around age 12-15 years and, in addition, the visual system is known to react specifically and sensitively to cannabinoids. METHODS: From 250 individuals consuming cannabis regularly, 99 healthy pure cannabis users were selected. They were free of any other past or present drug abuse, or history of neuropsychiatric disease. After an interview, physical examination, analysis of routine laboratory parameters, plasma/urine analyses for drugs, and MMPI testing, users and respective controls were subjected to a computer-assisted attention test battery comprising visual scanning, alertness, divided attention, flexibility, and working memory. RESULTS: Of the potential predictors of test performance within the user group, including present age, age of onset of cannabis use, degree of acute intoxication (THC+THCOH plasma levels), and cumulative toxicity (estimated total life dose), an early age of onset turned out to be the only predictor, predicting impaired reaction times exclusively in visual scanning. Early-onset users (onset before age 16; n = 48) showed a significant impairment in reaction times in this function, whereas late-onset users (onset after age 16; n = 51) did not differ from controls (n = 49). CONCLUSIONS: These data suggest that beginning cannabis use during early adolescence may lead to enduring effects on specific attentional functions in adulthood. Apparently, vulnerable periods during brain development exist that are subject to persistent alterations by interfering exogenous cannabinoids.

Adolescent↗
PubMed1997

OLITA: an alternative in the treatment of therapy-resistant chronic alcoholics. First evaluation of a new approach.

The Outpatient Long-term Intensive Therapy for Alcoholics (OLITA) is a four-step program of care for severely affected chronic alcoholics which, after inpatient detoxification, extends over a total of 2 years. High-frequency short-term individual therapeutic contacts, initially daily, are followed by a slow tapering of individual contact frequency and resolve in a group session once weekly towards the end of the second abstinent year. Further elements of OLITA are: (a) induction of alcohol intolerance by the application of aldehyde dehydrogenase inhibitors; (b) introduction of control factors, i.e. controlled intake of deterrent medication and regular urine analysis for alcohol; and (c) allocation of responsibility to the patient with respect to the overall success of the therapeutic concept including his own physical rehabilitation. Thus far, 30 male alcoholic patients from two recruitment periods have been treated for 6-26 months with a success rate of 60% abstinent patients. In conclusion, OLITA, based on the gradual tapering of high-frequency therapeutic contacts, thus far unique among outpatient programs for alcoholics, represents a promising advance in the treatment of therapy-resistant chronic alcoholics.

Adult↗
PubMed1997

Sustained elevation of vasopressin plasma levels in healthy young men, but not in abstinent alcoholics, upon expectation of novelty.

The role of vasopressin (AVP) as a stress hormone in man is still a matter of controversy. Thus, the response of plasma AVP, among other hormones, to either intravenously injected human corticotropin releasing factor (hCRF, in the absence or presence of the opioid antagonist naloxone) or a combined 5-minute stress test was compared in healthy men (n = 10) and short-term abstinent alcoholics (n = 11), a group with recognized abnormalities of humoral stress parameters. Stimuli were applied blindly and in random order, one per day, in a 3-day experimental block. A second block using the same standardized protocol was carried out 12 weeks later. Alcoholics entered block I 8 days after the last ethanol ingestion. Up to block II, they were strictly controlled for abstinence. On each experimental day, subjects remained supine from 0700h until 1500h. Stimuli were applied alternatively at 1030h each day. Fourteen blood samples were drawn per day with simultaneous fluid substitution. There were no significant changes in plasma AVP as an acute response to any of the stimuli in either group or block. However, unexpectedly, controls had significantly higher basal AVP levels throughout block I as compared with block II without concomitant changes in plasma osmolality or blood pressure. Further analysis of the data revealed that the dramatically increased AVP levels of the five younger control subjects accounted for this difference. In fact, AVP levels in the five older healthy subjects and in all alcoholics remained low throughout the two blocks. Our data suggest that plasma AVP is continuously elevated in healthy young men upon anticipation of novelty. In contrast, healthy men of the older age group and early abstinent alcoholics seem to lack such a sustained AVP response.

Adult↗
PubMed1997

Endocrine and hemodynamic effects of stress versus systemic CRF in alcoholics during early and medium term abstinence.

In alcoholics, disturbances of the autonomic nervous system as well as of the hypothalamic-pituitary-adrenal axis (HPA) are known. However, these two systems have never been analyzed, under stimulated conditions, in parallel in the same patients. Moreover, studies using intravenous (i.v.) corticotropin releasing factor (CRF) to assess neuroendocrine function bypass the hypothalamic component of the HPA axis. Therefore, i.v. human (h) CRF (pituitary stimulation/exogenous CRF) and a multifaceted stress test (hypothalamic activation/endogenous CRF) were compared with respect to their effects on hemodynamics as well as plasma norepinephrine (NE), epinephrine (E), ACTH, and cortisol in abstinent alcoholics (n = 11) versus healthy men (n = 10). Each stimulus was tested twice, 12 weeks apart, in two separate experimental blocks (I and II). Alcoholics entered block 18 days after the last ethanol ingestion and were controlled for abstinence up to block II. hCRF caused a fall in mean arterial pressure (MAP), most pronounced in alcoholics, particularly in block II. In contrast, stress testing raised MAP in both groups and blocks. A sustained increase in ACTH, cortisol, and NE occurred after hCRF, although the ACTH response in alcoholics was blunted in both blocks. Stress testing elevated NE in both groups and blocks, while raising plasma ACTH and cortisol during block I only in controls. However, unlike the persistently blunted ACTH response to i.v. CRF, a normalization of the stress-induced ACTH output occurred in alcoholics after 12 weeks of abstinence. During block I, basal E levels were elevated in alcoholics whereas NE levels tended to be lower than in controls, resulting in a significantly decreased NE/E ratio that returned to near control values in block II. Neither CRF nor stress had any effect on circulating E in either group or block. To conclude: (1) Normalization of the ACTH response to stress, but not to i.v. CRF, after 12 weeks of abstinence, suggests that other ACTH secretagogues may be compensating for CRF dysfunction in alcoholics. (2) Despite the dramatically lowered plasma NE/E ratio in alcoholics, the NE response to stimuli was unaffected. (3) The exaggerated hypotensive reaction and blunted ACTH response to i.v. CRF may reveal a long-term dissociative dysregulation of CRF actions in alcoholics.

Adrenocorticotropic Hormone↗
PubMed1996

Effects of chronic treatment with methadone and naltrexone on sleep in addicts.

Previous studies have described sleep disturbance secondary to chronic opiate use and abuse. Drug-dependency insomnia is of interest because chronic sleep disturbances can promote depressive symptoms which could lead to a drug relapse. For the first time we compared the polysomnographic parameters of 10 methadone-substituted outpatients and 10 naltrexone-treated outpatients. Methadone (mu-opioid agonist) produced a marked fragmentation of the sleep architecture with frequent awakenings and a decrease in EEG arousals. In comparison with methadone and controls, the naltrexone (mu-opioid antagonist) group showed the shortest sleep latency and the longest total sleep time. These data indicate that mu-agonists and mu-antagonists have different effects on sleep. The implications, especially the involvement of opioid-dopamine interactions on sleep and movements during sleep, are discussed.

Adult↗
PubMed1992

Mortality in patients with dependence on prescription drugs.

In 1974 we started a follow-up of patients with different psychoactive substance use disorders (PSUD) according to DSM-III; 2082 cases out of 2127 were analyzed; 1370 patients had taken legal drugs (i.e. prescription drugs and/or over-the-counter drugs); 444 patients suffered from abuse or dependence of legal drugs alone; 678 combined legal drugs and ethanol, and 248 cases combined legal and illegal drugs, often together with ethanol. A group of 712 alcoholics were included for comparison. Mean time under observation was 6.5 +/- 5.4 years, and 269 patients died. Mortality and survival were calculated and compared with expected survival from the normal population of the former Federal Republic of Germany. Mortality in all subgroups of PSUD was increased, the standardized mortality ratio (SMR) for patients on legal drugs alone being 2.1. Patients with legal plus illegal drugs had a SMR as high as 20.7; those with legal drugs plus ethanol 3.4; and alcoholics 4.2. The increased mortality seemed to be constant over the years. Mortality decreased in patients with stable abstinence. There was no clear sex difference. Abuse had a better prognosis than dependence. An estimation of potential life lost by the different PSUDs was attempted. Patients on legal drugs died from suicides, malignancies or accidents (including intoxication). In alcoholics or patients on legal drugs plus ethanol malignoma, liver cirrhosis, accident and suicide were the most prominent causes of death.

Adult↗
PubMed1989

Survival in multiple sclerosis.

Survival from onset of symptoms was calculated for two series of MS patients, a population-based epidemiologic series from southern Lower Saxony of 224 cases, and a revised hospital series of 1429 cases from 11 neurologic centers throughout the Federal Republic of Germany. Median survival for the epidemiologic series was 35-42 years, with no finer estimate possible. Observed survival was 3/5 expected survival after 35 years of illness. Survival in this series was similar to that from two other population-based reports. No significant difference was found between the sexes, though patients with onset at age 35 + had a significantly shorter survival than those with onset at age under 35 years. The much larger hospital series, where median survival was 30 years, demonstrated significant differences separately favoring females and young onsets. However, the ratios of observed to expected survival from population life tables were strikingly similar among all four subgroups defined by sex and age at onset. While overall there is a substantial reduction in the expectation of life in MS, the differential survival by sex and age appears to be a reflection of the expected survival by sex and age per se, and not that of the disease.

Adult↗
PubMed1986

Prognostic indicators in multiple sclerosis.

The influence of sex, age at onset, course of the disease and initial symptomatology on the mortality of patients with multiple sclerosis is analysed. A sample of 1926 patients was followed up prospectively over 4.9 years. Both, the mortality ratio (number of observed to expected deaths) and the excess death rate are calculated. Whereas the mortality ratio as a parameter of overall mortality is influenced by a variety of factors, such as age and sex; the excess death rate represents the number of extra deaths per 1000 exposed to risk in an indicated year and is, therefore, a parameter of the mortality which is attributed to MS. The excess death rate was comparable for the sexes, it was slightly higher for patients with a higher age at onset and it was clearly higher for the progressive course. Patients with initial diplopia and sensory signs and symptoms had the lowest excess death rate, whereas patients with pareses, cerebral and sphincter disturbances at onset showed the highest excess death rate.

Adult↗
PubMed1986

Mortality of patients dependent on benzodiazepines.

For patients dependent on benzodiazepines alone, or in combination with alcohol and/or other legal and illegal drugs, observed mortality rates were compared with the average population, and, in cases of isolated benzodiazepine dependence, also with a control group of non-dependent patients chosen to match each dependent not only in sex and date of birth, but also in pre-existing psychiatric illness besides dependence. For patients with an isolated benzodiazepine dependence, the mortality rate was increased, when compared with the average population, by a ratio of observed to expected numbers of deaths of about 3. However, this mortality rate did not differ from that of the control group (non-dependent patients with comparable psychiatric illnesses). For patients combining benzodiazepines with alcohol among other addictive drugs, and for patients combining benzodiazepines with illegal drugs among other addictive substances, the ratio of observed to excepted numbers of deaths was 6.2 resp. 21, thus corresponding well with other studies on mortality rates associated with alcoholism and dependence on illegal drugs. We conclude that our study does not give evidence of higher risk of early death correlated with dependence on benzodiazepines alone. However, it confirms the well-known fact of increased mortality rates in patients with psychiatric illnesses, especially with dependence on alcohol or illegal drugs.

Adult↗
PubMed1986

Chronic enteral poisoning caused by potassium permanganate: a case report.

To our knowledge, this is the first case report of a multiple, low dosage ingestion of manganese. A 66-year-old male patient is presented, who ingested 125 ml of a 8% solution of potassium permanganate (10 g) within 4 weeks. As early as 2 weeks after the beginning of poisoning, psychological alterations were noted. Neurological examination revealed disturbances of many subsystems of the CNS. Visually evoked potentials showed prolongation of the P2-latency, not reported in earlier publications. Levels for manganese were elevated in peripheral blood as well as in hair samples. Treatment with calcium trisodium pentetate decreased serum levels and increased urine excretion of manganese. Nine months after poisoning, the first signs of progressive Parkinson disease became evident. The time-course of neurological symptoms seems to depend on a critical dose of manganese.

Aged↗