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Biomedical subjects

H J Sagar

Publications and source records attributed to H J Sagar.

At least 55 records · Page 3Linked to original sources
PubMed1989

Nonverbal recognition and recency discrimination deficits in Parkinson's disease and Alzheimer's disease.

In a study of verbal temporal ordering, patients with Parkinson's disease (PD) were impaired in making judgements of the relative recency of serially-presented words but were normal in word recognition; by contrast, patients with Alzheimer's disease (AD) were impaired on both verbal tasks (Sagar et al., 1985, 1988b). The present study used a nonverbal analogue of the verbal temporal ordering task to examine whether the deficit in recency discrimination of the PD patients transcended material-specific bounds or was specific to verbal material. The nonverbal task was administered to the patients with PD, patients with AD and normal control subjects studied with the verbal task. The results showed that the retention functions for the recognition of verbal and nonverbal material differed qualitatively from each other and this difference was present in all three subject groups. For verbal and nonverbal recency discrimination and verbal content recognition, performance declined with increasing retention intervals; for nonverbal content recognition, however, performance was essentially unchanging across retention intervals. As on the verbal test, recency discrimination on the nonverbal test was impaired in both patient groups. In contrast to the results with the verbal task, both groups were impaired on content recognition. The patterns of impairment, however, differed between the two patient groups in a parallel way to those of the verbal task: performance of the AD group was impaired at the longest retention intervals but not at the shortest intervals, whereas the performance of the PD group was impaired at the shortest but not at the longest intervals. This deficit in nonverbal short-term recognition memory was present even in PD patients who scored within the normal range on a quantitative test of dementia. These results show that deficits in recency discrimination and short-term memory processing in PD extend to nonverbal as well as verbal material and imply bilateral frontal lobe dysfunction in the genesis of these deficits.

Aged↗
PubMed1988

Remote memory function in Alzheimer's disease and Parkinson's disease.

Remote memory for public and personal events was evaluated in Alzheimer's disease (AD) and Parkinson's disease (PD), using a series of recall and recognition tests. Information related to content and date of past events was assessed separately. In recall of the content of personal and public events, both groups showed a gradient of deficit in which remote events were affected less than recent ones; the magnitude and temporal extent of the retrograde loss was related to severity of dementia. By contrast, gradient effects were not evident in the recall of date and were less marked in the recognition of content or date. In public and personal events tests, patients with PD showed a relative impairment in dating capacity, compared with their memory for the content of events, which was independent of dementia. These results suggest that dementia affects the recall of distant events less than recall of recent ones. Furthermore, the selective gradient effects in recall of content suggest that memory for date is served by cognitive processes independent of memory for event content. In PD, dating capacity is a sensitive measure of remote memory function that may be disrupted independently of dementia.

Alzheimer Disease↗
PubMed1988

Temporal ordering and short-term memory deficits in Parkinson's disease.

Previous studies of remote memory function have indicated a dissociability between memory for the content and date of past events and suggested selective deficits of dating capacity in Parkinson's disease (PD). The present study examined the hypothesis that poor dating in PD is linked to a specific deficit in temporal contextual memory which also affects new learning. Patients with PD and patients with Alzheimer's disease (AD) were compared in their ability to perform tasks of content recognition and recency discrimination of words presented sequentially. Compared with AD patients, PD patients were disproportionately impaired in recency discrimination relative to content recognition. When performance was analysed as a function of retention interval, AD patients showed impairment in both tasks at all intervals. PD patients, by contrast, showed deficits in content recognition at the short stimulus-test intervals only, possibly reflecting the clinical phenomenon of bradyphrenia. These results suggest that recency discrimination deficits and impaired short-term memory processing are specific cognitive deficits in PD that may be linked to subcortical deafferentation of the frontal lobes.

Alzheimer Disease↗
PubMed1987

IgG synthesis within the central nervous system. Comparison of three formulas.

IgG synthesis within the central nervous system is the expression of a local pathologic immune reaction. Its detection is of great importance in a large number of neurologic diseases, especially multiple sclerosis (MS). The results obtained from the study of 115 neurologic patients (52 patients with MS and 63 patients with other neurologic diseases) using three different mathematic formulas (Tourtellotte's formula, the index of Tibbling and coworkers, and Schuller and Sagar's formula) are presented and statistically analyzed. Despite their obvious differences, the results from these three formulas are in accordance in 76% of the patients observed. The clinical correlations of these formulas are discussed; none of them allows a specific diagnosis of MS. The formula of Schuller and Sagar seems the most sensitive, detecting local central nervous system IgG synthesis in 79% of patients with MS, compared with 54% of patients with MS utilizing the index of Tibbling and coworkers and 50% of patients with MS utilizing Tourtellotte's formula. No correlation was established between serum and cerebrospinal fluid albumin concentrations, nor between serum albumin and IgG levels in cerebrospinal fluid. Thus, no evidence exists to support the inclusion of variations in serum albumin levels in the calculation of intrathecal IgG synthesis. Furthermore, Schuller and Sagar's formula allows classification of neuroimmunologic diseases and the evaluation of antibody-specific activity (ASA) in locally produced IgG. The comparison of intrathecal IgG ASA with serum IgG ASA, which reflects local and general immunity, respectively, seems potentially important.

Albumins↗
PubMed1987

Hippocampal neuron loss in temporal lobe epilepsy: correlation with early childhood convulsions.

Hippocampal neuron densities in three areas (H1 zone, end folium, and dentate gyrus) were counted in each of 32 temporal lobectomy excision specimens using the technique of Mouritzen Dam. The association between severe neuronal loss in all three areas and early childhood convulsions that were prolonged and/or lateralized was highly significant. Lesser degrees of neuron loss in H1 and/or end folium were common and were not associated with early childhood convulsions, but were most often found in older patients with a particularly long history of epilepsy.

Adolescent↗
PubMed1987

Seizure characteristics, pathology, and outcome after temporal lobectomy.

We analyzed the histories of 58 patients who had temporal lobectomy for seizure control. A good outcome was more likely if a definite lesion was removed. Unlike other pathologies, including nonspecific hippocampal sclerosis (NSHS), Ammon's horn sclerosis (AHS) was strongly related to a history of a prolonged childhood convulsion as the first epileptic event. Partial seizures developed at a younger age in patients with AHS than with NSHS or nonspecific changes. Epigastric rising sensations were associated with a greater chance of a good outcome than were other forms of simple partial seizure.

Adolescent↗
PubMed1987

Clinical similarities and differences between Alzheimer's disease and Parkinson's disease.

Dementia and extrapyramidal signs combine in both Alzheimer's disease (AD) and Parkinson's disease (PD) to produce various degrees of clinical overlap between the two diseases. Rest tremor, positive motor response to dopaminergic drugs, bradyphrenia and disproportionate deficits in visuospatial function, dating capacity, recency discrimination, sequencing and set-shifting are specific features of PD; myoclonus, orofacial dyskinesia, aphasia and rapidly progressive global dementia favours AD. A clearer analysis of the underlying brain-behaviour relationships is necessary to advance our understanding of the origin of cognitive and motor impairment and its treatment.

Alzheimer Disease↗
PubMed1984

Herpes simplex type 2 meningitis treated with acyclovir.

A case of meningitis due to a primary genital herpes simplex type 2 infection, and its prompt response to therapy with intravenous acyclovir is reported. This complication of genital herpes is probably underdiagnosed and it is worthwhile searching for evidence of genital herpetic lesions in a young patient presenting with viral meningitis.

Acyclovir↗
PubMed1983

Central nervous system IgG synthesis in multiple sclerosis. Application of a new formula.

A new formula for the determination of local central nervous system IgG synthesis has been applied to a group of 191 patients with multiple sclerosis. There were no correlations with sex, age, duration of disease, or clinical status but local IgG synthesis was significantly greater in patients with high levels of disability and a progressive clinical course than those with lower degrees of disability or a relapsing/remitting course. Significant correlations were found between oligoclonal aspect and local IgG synthesis; this synthesis was higher in CSF containing anti-viral and anti-nucleic acid antibodies than in CSF without such antibodies. There was also a lower local IgG synthesis when C-reactive protein (CRP) was present in serum.

Adult↗
PubMed1982

Multiple sclerosis with clinical and radiological features of cerebral tumour.

Three cases of multiple sclerosis, all confirmed pathologically, are described in whom both the unusual clinical features and the CT scan appearances suggested cerebral tumours. The failure of mass effect reliably to differentiate plaques and tumours on a CT scan is stressed and the literature relating to CT scanning in multiple sclerosis is reviewed.

Adult↗
PubMed1981

Local synthesis of CSF immunoglobulins. A neuroimmunological classification.

The relationship between serum and CSF IgG has been analysed: (1) In patients with a normal CSF concentration of albumin, no correlation can be demonstrated between serum IgG and CSF IgG. (2) In cases where the CSF albumin concentration is elevated (i.e. transudation), local synthesis of IgG can be determined by reference of the degree of transudation of albumin and the serum IgG concentration. The combination of local IgG synthesis and transudation (meningitic pattern) is common. Most pure transudates are of "non-inflammatory" type. A very simple formula is proposed which evaluates the relationship between local and general immunity in all neurological diseases.

Antibody Formation↗
PubMed1981

Cell-mediated immunity to viral antigens and tuberculin in multiple sclerosis.

Lymphocyte transformation responses to measles, mumps, herpes simplex and parainfluenza virus antigens and purified protein derivative of tuberculin were determined in both 78 normal controls and 40 patients with multiple sclerosis, 16 of whom were studied serially. Patients with multiple sclerosis showed significantly reduced responses to all antigens except herpes simplex. Impaired responses occurred at all stages of clinical activity, but were lowest during recovery from an acute exacerbation or in patients with chronic disease. The transformation responses to measles, mumps and parainfluenza virus antigens correlated significantly with the numbers of circulating T cells, which, similarly, showed parallel fluctuations with disease activity.

Adult↗
PubMed1981

Cell-mediated immunity in acute idiopathic optic neuritis and multiple sclerosis.

Lymphocyte transformation responses to phytohaemagglutinin, measles antigen and tuberculin and the absolute numbers of circulating T and SIg+ cells were determined in 16 patients with acute idiopathic optic neuritis (ON), 42 patients with multiple sclerosis (MS) and 78 healthy controls. Patients with acute ON showed impaired lymphocyte transformation responses in both autologous plasma and AB serum similar in extent to those seen in MS patients in relapse. They were not associated with a reduced total number of circulating T cells.

Acute Disease↗
PubMed1980

Clinical and immunological associations in myasthenia gravis. 1: Autoantibodies.

Associations between female sex, HLA B8, positive anti-thyroid microsomal antibody and, to a lesser extent, antinuclear antibody were seen in 34 patients with myasthenia gravis. This supports the concept that the disease is heterogeneous. Anti-DNA antibodies, which were present in 62% of the patients, did not show such associations.

Adult↗