Search PubMed⌕ Search

Biomedical subjects

J Jolles

Publications and source records attributed to J Jolles.

At least 127 records · Page 7Linked to original sources
PubMed1994

The relationship between plasma osmolality and plasma vasopressin concentration is altered in old male Lewis rats.

Kidney dysfunction has been observed in aged humans and rats, the primary cause of which may reside in the kidney itself or in the hypothalamus. The latter possibility is suggested by the increased release of AVP in response to salt infusion in humans. The effect of age on the relationship between plasma osmolality and plasma AVP concentration has never been verified in an animal model. Therefore, in the present study, 9% salt solution was infused into adult and aged Lewis rats, and plasma AVP concentration and osmolality were measured. Basal plasma AVP concentration, osmolality and total water intake were not altered in aged Lewis rats as compared with adult animals, indicating the absence of overt disturbances in water homeostasis. Infusion of 9% salt solution resulted in a linear increase in plasma osmolality in both adult and aged rats. Plasma osmolality increased more with time in aged animals than in adult animals, suggesting an age-related difference in kidney function during salt infusion. Plasma AVP concentration increased 50% less with osmolality at relatively low osmolalities, but not at relatively high osmolalities. The altered relationship between plasma osmolality and plasma AVP concentration in rats with age may be related to changes in neurons monitoring osmolality or to changes in baroreflex regulation. The data suggest that reduced kidney function with age does not result from an altered relationship between plasma osmolality and plasma AVP concentration.

Aging↗
PubMed1994

The effect of age on phosphatidylinositol kinase, phosphatidylinositol phosphate kinase and diacylglycerol kinase activities in rat brain cortex.

A previous study, in which a lysed fraction was used with endogenous phospholipids as substrate, revealed age-related changes in PA and PIP2 formation but not in PIP formation (Bothmer et al., Neurochem. Int. 21, 223-228, 1992). To rule out the influence of substrate availability in the present study, the effect of age on PI kinase, PIP kinase and DAG kinase activities was studied with exogenous phospholipids as substrate in the cerebral cortex from 8-month-old, 14-month-old and 26-month-old Brown Norway rats. PI kinase activity was predominantly located in a tight membrane-bound protein fraction, DAG kinase activity in cytosolic and loosely membrane-bound protein fractions, and PIP kinase activity was present in all three protein preparations. The effects of age were limited to a small increase in kinase activity in the tight membrane-bound protein fraction in 14-month-old and 26-month-old rats compared to 8-month-old rats, and a 10% decrease in PIP kinase activity in the cytosolic protein fraction in 14-month-old and 26-month-old rats compared to 8-month-old rats. DAG kinase activity showed no age-related changes. In conclusion, one should take care in comparing rat aging with human aging as PI kinase activity shows an age-related decline in human brain cortex (Jolles et al., J. Neurochem. 58, 2326-2329, 1992). Furthermore, previously reported decreases in PA formation rates in rat brain are probably not due to changes in DAG kinase itself but to changes in DAG availability, although further experimental evidence is needed to confirm this conclusion.

1-Phosphatidylinositol 4-Kinase↗
PubMed1994

[Education about dementia and forgetfulness in daily and weekly press].

In the period March 1990-March 1991 the attention for dementia increased in the Dutch printing press in comparison with the period 1987-1990. Despite this increase, the average number of articles on dementia in daily and weekly news magazines is less than one article per two months. This is extremely little for such an enormous medical and social problem. Furthermore, there is a relative decrease in the number of articles on general aspects of dementia. As expected, the number of articles on research in the field of dementia has increased considerably. In contrast with our hypothesis, it appears that in the printing press there is still hardly attention to memory and normal forgetfulness. In future education programs more explicit information should be given not only about dementia (symptoms, progress, consequences, etc), but also about memory complaints and normal forgetfulness. The printing press could make an important contribution towards achieving these goals. An important condition for this is a better cooperation with experts on the subject.

Aged↗
PubMed1993

[Psychiatric disorders in patients of a memory outpatient clinic].

OBJECTIVE: To determine whether psychiatric conditions other than depression are relevant in elder patients with memory disturbances. METHODS: 430 consecutive outpatients (242 males, 188 females; mean age 61.7 years) who visited the Maastricht Memory Clinic were examined, according to a standardised diagnostic procedure, including somatic, neurological, psychiatric and neuropsychological examination. Psychiatric disorders were diagnosed according to DSM-III(-R) criteria. RESULTS: Of 152 patients with dementia, 34 had a secondary depressive syndrome, 19 another secondary psychiatric disorder. Of the 37 patients with a psycho-organic disorder other than dementia, 16 had an organic mood disorder. Of the other 241 patients, 152 had 159 primary psychiatric diagnoses: mood disorders in 100 cases and other psychiatric disorders in 59 cases, especially adjustment disorders, anxiety disorders and personality disorders. Together, only 60% percent of all primary or secondary psychiatric disorders were mood disorders. Various ways in which organic substrate, cognitive problems and psychopathology can be interrelated are discussed. CONCLUSION: Although affective disorders were the most frequent psychiatric disorders, several other psychiatric conditions were related to memory disturbances as well. Psychiatric assessment in patients with memory complaints should not be restricted to the diagnosis of depressive symptoms.

Adolescent↗
PubMed1993

Behavioural and biochemical effects of acute central metabolic inhibition: effects of acetyl-l-carnitine.

In the present study we evaluated a new method to assess the behavioural and biochemical effects of a brief period of acute hypoxia in the brain. In this method, cyanide is injected into the lateral ventricles. Spatial navigation performance in a Morris task was found to be impaired 1 and 5 min after an i.c.v. injection of 5.0 micrograms cyanide but not after 2.5 micrograms cyanide. Increased rate of phosphatidic acid formation, reflecting increased phospholipase C activity, were observed after injection of 5.0 micrograms cyanide, indicating that energy-dependent phosphoinositide metabolism was affected. Chronic treatment with acetyl-l-carnitine attenuated the cyanide-induced behavioural deficit, but had no effect on energy-dependent phosphoinositide metabolism. The results suggest that, in this model, acetyl-l-carnitine may act via free fatty acid metabolism, by increasing the reservoir of activated acyl groups which are involved in the reacylation of membrane phospholipids.

Acetylcarnitine↗
PubMed1993

Primitive reflexes in healthy, adult volunteers and neurological patients: methodological issues.

A study was made to determine whether two experienced clinicians elicited and scored primitive reflexes (PR) differently and whether reliability could be improved by standardization. Three studies were carried out, using a protocol for the examination of 14 PR. In the first study with 31 healthy young subjects, two investigators found virtually no difference in the routine neurological examination. However, the interobserver agreement was very poor, indicating the need for a further improvement of the PR protocol. In the second study, 30 neurological patients were examined with an improved, more explicit and standardized protocol, in which the amplitude and the persistence of the reflex were scored separately. Interobserver agreement improved considerably, and was high for amplitude as well as persistence. In the third study, 36 neurological patients were examined twice by one investigator within 2 weeks. Good to excellent intraobserver agreement was found. No pathognomonic or strictly localizing reflex could be distinguished.

Adolescent↗
PubMed1993

Platelet phosphatidylinositol kinase activity is not altered in Alzheimer disease.

We previously reported a specific decline in phosphatidylinositol (PI) kinase activity in the neocortex of patients with Alzheimer disease (AD) as compared to controls, whereas phosphatidylinositol phosphate (PIP) kinase activity appeared not to be affected (Jolles et al., 1992). In search of a possible systemic effect of AD, in the present study we investigated phosphoinositide kinase activity in platelets from patients with AD and from control subjects. The study was based on the notion that disease-specific abnormalities in the brain could be reflected in blood platelets. PI kinase activity was studied in platelet homogenates and in a salt-solubilized protein fraction of platelets, because of the difference in subcellular localization of the different types of PI kinases. In addition, NADH cytochrome-C reductase was measured in platelet homogenates as a marker for the endoplasmic reticulum, to detect a possible proliferation of the endoplasmic reticulum. AD patients and normal elderly controls showed no difference in PI kinase activity in either enzyme fraction. Furthermore, NADH cytochrome-C reductase activity and the protein/phospholipid ratio per 10(6) platelets were the same for AD patients and controls. This was taken as an indication that platelets in AD patients do not show proliferation of intracellular membranes.

1-Phosphatidylinositol 4-Kinase↗
PubMed1993

Spatial learning deficit and reduced hippocampal ChAT activity in rats after an ICV injection of streptozotocin.

ICV injections of streptozotocin (STREP) lower the glucose utilization of the brain and affect the cholinergic system. The present study was designed to evaluate whether STREP-treated rats have an impaired spatial discrimination performance in the Morris spatial navigation task. Performance in this task is sensitive to treatment with cholinergic antagonists. In contrast to young rats, middle-aged STREP-treated rats tended to have an impaired spatial discrimination performance in the Morris task at the end of training. In middle-aged STREP-treated rats, but not in control rats, spatial discrimination performance was associated with hippocampal choline acetyltransferase (ChAT) activity. The correlation between spatial discrimination performance in the Morris task and the decrease in hippocampal ChAT activity resembles the relation between cognitive and biochemical changes observed in Alzheimer's disease. Our findings suggest that STREP treatment of middle-aged rats may provide a relevant model for dementia.

Animals↗
PubMed1993

Primitive reflexes in Parkinson's disease.

A standardised protocol for the examination of 15 primitive reflexes in which the amplitude and the persistence were scored separately, was applied to 25 patients with Parkinson's disease and an equal number of healthy matched control subjects. Most reflexes were found considerably more often in the patients than in the control subjects, especially the snout, the glabellar tap, and its variant, the nasopalpebral reflex. Only the mouth open finger spread reflex was present more often in the control subjects. For all reflexes except this last, the scores for amplitude and persistence of the reflexes for the control group never exceeded the scores for the patient group. Reflexes persisted more often in the patients than in the control subjects. Parkinsonism alone can explain a large number of primitive reflexes, irrespective of the severity or duration of the disease. In contrast, the number of reflexes was related more closely to cognitive scales. It is concluded that such reflexes may be helpful in diagnosing Parkinson's disease. In addition, a standardised protocol for eliciting and scoring is essential for the study of these reflexes in parkinsonism and other neuropsychiatric conditions.

Adult↗
PubMed1993

Water metabolism and postconcussional symptoms 5 weeks after mild head injury.

Posttraumatic diabetes insipidus has been reported as a sequela to head injury. It is unknown whether subclinical types of diabetes insipidus, or other types of water metabolism disorders, occur after mild head injury (MHI) and, if so, whether they are related to the persistence of postconcussional symptoms. MHI patients (n = 38) were screened for disturbances of water metabolism by comparing plasma and urine osmolalities at about 5 weeks after the trauma. Eight patients had evidence of an increased plasma osmolality together with a relatively decreased urine osmolality after an overnight fast. The presence of this disturbance was significantly related to the persistence of postconcussional symptoms. The results suggest that subclinical disturbances of water metabolism may, among other factors, be related to the persistence of symptoms after MHI.

Adolescent↗
PubMed1993

Diagnosing dementia: a comparison between a monodisciplinary and a multidisciplinary approach.

Discrepancies were examined in diagnostic outcome between a monodisciplinary approach and a multidisciplinary, criteria-based approach in patients referred to a university memory clinic. Of 278 patients not fulfilling dementia criteria, 19 had been previously diagnosed as demented (specificity: 0.93). In 60 of 152 demented patients, dementia had not been diagnosed before (sensitivity: 0.61). Underreporting was frequent for mildly demented patients and for patients with coexisting depressive symptoms. In patients referred by psychiatrists, sensitivity rates for dementia and Alzheimer's disease were low; in patients referred by neurologists, depression often went unreported. Results underscore the need for more frequent use of integrated multidisciplinary services for cognitively disturbed patients.

Aged↗
PubMed1993

A controlled trial with vasopressin analogue (DGAVP) on cognitive recovery immediately after head trauma.

Recent evidence suggests that the vasopressin analogue desglycinamide-arginine8-vasopressin (DGAVP) might specifically benefit mild brain trauma patients. We investigated the effect of intranasal DGAVP treatment in 32 patients who had sustained a mild head injury for 3 months in a double-blind, placebo-controlled, matched-pairs study. DGAVP did not have a positive effect on cognitive recovery in this group of mildly affected patients.

Adolescent↗
PubMed1993

Age-related decline of psychomotor speed: effects of age, brain health, sex, and education.

A cross-sectional study into age-related decline of psychomotor speed is reported. A newly introduced choice response task was used, involving three conditions: simple reaction time (SRT), choice reaction time (CRT), and CRT with stimulus-response incompatibility. Subjects were 247 volunteers, aged 20 to 80 yr. in seven age levels. Although all subjects thought themselves to be normal and healthy, a post hoc division could be made based on biological life events (BLE, mild biological or environmental factors that can hamper optimal brain functioning, such as repeated general anesthesia). Performance was poorer by subjects who had experienced one or more such event: slowing was comparable to the effect of age, especially in the more difficult task conditions. There were significant effects of sex and education, men being consistently faster than women, and more highly educated subjects performing better than subjects with only low or medium education. These findings replicate observations from other test methods. They are also in line with several other studies giving interactions between the effects of aging and physical fitness. This study questions the validity of much research on aging, as the data suggest that a more rigorous health screening for biological life events in subjects recruited from the normal, healthy population can reduce performance effects normally ascribed to aging.

Adult↗
PubMed1993

[Public information on normal forgetfulness and dementia: effectiveness of a systematically developed information pamphlet].

Previous research revealed that many elderly people are worried about their memory and are afraid of falling victim to dementia. An information brochure was developed in 1991 for this target group. After reading the brochure, 63% of all respondents who were worried about dementia beforehand (n = 307), said that their anxiety had decreased or disappeared. Approximately 3% of the total group of 400 respondents became more worried. A cognitive test battery was used to determine whether people's increased or decreased anxiety was justifiable. This test battery gave an indication of the severity of cognitive problems. A sample of 104 people was tested. Thirty subjects achieved a low test score and sixteen of them were inappropriately reassured by the brochure. Approximately 64% of fifty-four subjects who performed well on cognitive test and were worried about dementia beforehand, were rightly reassured, but the other 36% were (still) unnecessarily worried. The occurrence of dementia in a close relative covaried with worries about possible dementia in people with good test results. In conclusion, it appeared that an information brochure about normal forgetfulness and dementia may reduce the anxiety for dementia.

Aged↗
PubMed1993

[Forgetful or demented? Who worries and why?].

Many elderly people complain about their memory or are afraid to become demented. Research shows that in most cases this worry is unsubstantiated. Anxiety and uncertainty are primarily caused by a lack of proper information about the differences between normal forgetfulness and dementia. In order to be able to effectively inform the general public, more insight and a better understanding are needed about level of knowledge, needs and characteristics of the target group. For this reason, a survey was carried out among 500 elderly people who ordered an information brochure on memory and dementia. Approximately 32% of the respondents worry very much about their forgetfulness and 57% worry somewhat. Among other things, respondents ascribe their memory complaints to bad concentration (61%), stress and tension (45%) and the medication they use (30%). Almost 22% indicate that they worry a lot about possible dementia and 47% worry somewhat about dementia. The main predictors for respondents' concern about dementia are the extent to which people are hindered by their forgetfulness in daily life and the fact that someone in the near family has or has had dementia. Of all respondents who worry about their memory, 26% consulted their general practitioner to discuss their complaints. Important reasons for not seeking help despite being worried, are that many subjects do not want to bother their general practitioner (48%) and feel that they are not taken seriously by their social environment (27%).

Adult↗
PubMed1993

Persistent neuropsychological deficits in cervical whiplash patients without direct headstrike.

Persistent cognitive and neurasthenic complaints can be the consequence of a cervical whiplash injury. In contrast to otoneurological and orthopedic reports, neuropsychological studies on whiplash patients are scarce. We report disturbances of information processing and memory functions in two patients with a pure cervical whiplash injury with demonstrated central otoneurological abnormalities, whereas there was no evidence of intellectual deterioration or focal cortical deficits. The results suggest that the cognitive disturbances and neurasthenic symptoms may be part of one syndrome which appears to manifest itself under conditions of time pressure and distraction.

Adult↗
PubMed1992

Evidence for a new inositol phospholipid in rat brain mitochondria.

Phosphorylation of phosphatidylinositol (PI), phosphatidylinositol monophosphate (PIP) and diacylglycerol (DAG) was studied in rat brain cortex myelin, synaptosomal and mitochondrial fractions, with ATP as phosphate donor and endogenous phospholipids as substrate. All fractions had PI, PIP and DAG phosphorylating activity with their own characteristic subcellular distribution. However, in the mitochondrial fraction an unidentified lipid was phosphorylated, which had a slower Rf value than PIP2 on TLC. After hydrolysis of the polar head group of the lipid and separation on anion exchange columns, it appeared to be a phosphoinositide. The elution profile showed that it was not phosphatidylinositol trisphosphate, or a lyso-compound. The available evidence suggests that the unknown inositol phospholipid in rat brain mitochondria is a phosphatidylinositol 4,5-bisphosphate isomer, although the possibility of it being a glycosyl-phosphoinositide cannot be excluded.

Adenosine Triphosphate↗