A modified, prefixed, Golgi-rapid technique for the cephalopod retina

A quick and simple method for Golgi staining of neurons and glia in the cephalopod retina is described. The main difference between this method and other Golgi-rapid protocols is that tissue is placed in sachets constructed from dialysis membrane prior to chromation and impregnation. This greatly reduces the amount of surface deposition of silver chromate and can reduce the number of elements impregnated. Together these effects produce improved Golgi staining of the cephalopod retina. Given some modifications to the osmolarity of the solutions employed, the method should be applicable to other, non-cephalopod tissues where superficial structures are obscured by surface precipitation, or neurons are arranged in thin sheets of tissue. The method employs prefixation of tissue in a fixative suitable for light or electron microscopy.     

Effects of castration, testosterone and immobilization on the activities of choline acetyltransferase and cholinesterase in rat limb muscles.

Thirteen months after castration of male rats the weight of their soleus muscles was lowered to 82% and their choline acetyltransferase (ChAc) activity to 83% of control values. The administration of testosterone lasting 5 weeks increased the weight of the soleus muscles of castrated animals by 19% and their ChAc activity bu 37%. Changes in the activity of cholinesterase occurring after castration and testosterone treatment were not statistically significant. It is assumed taht the effect of testosterone on the activity of ChAc was mainly due to an increase in the functional activity of the motoneurones innervating the muscle. Rapid developmental increase of ChAc activity was observed in the muscles of intact rats between the age of 48 and 82 days. During this period of development the activity of ChAc rose faster than the weight of the muscles. Testosterone had no effect on the weight and ChAc activity of the soleus and extensor digitorum longus muscles of non-castrated rats after 1 week's administration; after 5 weeks' administration the weight of the muscles and their ChAc activity were diminished. After the soleus muscles of non-castrated rats had been immobilized for 10 days, their ChAc activity was 56% and their weight 51% of control values. The administration of testosterone did not alter the effect of immobilization on the ChAc and weight of the muscle.     

Topographical distribution of arsenic, manganese, and selenium in the normal human brain

The concentrations of arsenic, manganese and selenium per gram wet tissue weight were determined in samples from 24 areas of normal human brain from 5 persons with ages ranging from 15 to 81 years of age. The concentrations of the 3 elements were determined for each sample by means of neutron activation analysis with radiochemical separation. Distinct patterns of distribution were shown for each of the 3 elements. Variations between individuals were found for some but not all brain areas, resulting in coefficients of variation between individuals of about 30% for arsenic, 10% for manganese and 20% for selenium. The results seem to indicate that arsenic is associated with the lipid phase, manganese with the dry matter and selenium with the aqueous phase of brain tissue.     

Glia cell response to bacterial lipopolysaccharide : Effect on nucleotide synthesis, its genetic control and definition of the active principle

Cell types sensitive to lipopolysaccharides (LPS) include macrophages, polymorphonuclear leukocytes, platelets, B-lymphocytes and fibroblasts. Earlier observations that during endotoxemia or intracerebral injection of LPS morphological and functional alterations of the central nervous system develop, suggest that LPS may also interact with brain cells. The effects of bacterial products on nucleotide synthesis of cultured murine glia cells are examined in this study. LPS extracted from the outer cell wall of gram-negative bacteria were found to cause an increased RNA synthesis and an inhibition of DNA synthesis in the cultured glia cells. The inhibitory effect of LPS on DNA synthesis is not due to an LPS-mediated increase of the cAMP content in the glia cells or contact inhibition of the monolayer culture. Within the structure of LPS lipid A was found to be the active part. On the basis of the LPS-induced increase of RNA synthesis, the glia cells of C3H/HeJ mice are low responders to low doses of LPS. We conclude that in the presence of fetal calf serum glia cells are sensitive to the lipid A part of LPS, the sensitivity being under genetic control.     

Subarachnoid block and enlargement of the spinal canal in hypertrophic neuritis.

A case of Dejerine-Sottas hypertrophic neuritis is reported. The patient, a 45-year-old male, suffered from chronic hypertrophic polyneuropathy, abnormal pupils, fasciculations, tremor, back pain, impotence, sphincter disorders, cramps, and lightning pains in the lower extremities. Besides extensive subarachnoid block, there was X-ray evidence of enlargement of the bony spinal canal with scalloping of the lumbar vertebrae. Surgical exploration showed these abnormalities to be due to extreme hypertrophy of the cauda equina. Histologic findings in peripheral nerve and lumbar root biopsies were typical of hypertrophic neuropathy of the onion bulb type. Vertebral changes secondary to hypertrophied nerve roots appear not to have been described before in hypertrophic neuritis; however, knowledge of their possible occurrence may be of practical importance in the management of similar future cases. A simple way of visualizing enlarged peripheral nerves is briefly described.     

Membrane desmosterol and the kinetics of the sarcolemmal Na,K-ATPase in myotonia induced by 20,25-diazacholesterol

The kinetics of the sarcolemmal Na⁺,K⁺-ATPase were studied in rats made myotonic by treatment with 20,25-diazacholesterol (20,25-D; 200 mg/kg every 14 days). Overall Na⁺,K⁺-ATPase activity in purified sarcolemma increased from 44.6 ± 8.7 nmol P_i/mg protein⁻¹ min⁻¹ in controls to 77.7 ± 7.9 nmol mg⁻¹ min⁻¹ in treated animals whose membrane desmosterol concentrations exceeded 70% of total membrane sterol. In general the activity of this enzyme paralleled the desmosterol content of the sarcolemma. The total number of enzyme units, however, was not changed as evidenced by [³H]ouabain binding and by measurements of steady-state phosphorylated intermediate in the absence of K⁺. Independent measurements of the Na⁺,K⁺-ATPase dephosphorylation partial reaction in 20,25-D sarcolemma revealed no change from control rats at any temperature between 5 and 40°C; the K⁺ dependence of this reaction was also unchanged. Rates of phosphoprotein formation inferred from measurements of steady-state phosphorylated intermediate under various ionic conditions were also not altered by increasing desmosterol. Kinetic analysis suggests that the increase in overall Na⁺,K⁺-ATPase activity in membranes with high concentrations of desmosterol may reflect an increase in the rate of conformational interchange between two states of the enzyme during its activity cycle.     

Action of chloroquine on in vivo RNA and protein biosynthesis in the retina and the optic pathway of the rabbit

The in vivo action of chloroquine on RNA and protein metabolism in the optic pathway of the albino or pigmented rabbit was examined. To study the acute effects, chloroquine in a dose of 500 μg was injected into the vitreous body of one eye. The following day the animals were injected into both eyes with [³H]uridine or [³H]leucine. At various time intervals following the isotope injections the retinal synthesis and the axonal transport of labelled RNA or protein was studied. The results showed no significant difference between the drug-treated and the control side with respect to synthesis and axonal transport of RNA or protein. Nor was any selective effect noticed on the synthesis of different RNA fractions from the retina.

In long-term experiments chloroquine (100 mg/kg body weight) was administered via their drinking water 3 days a week for a period of 6 or 8 months. Following an intraocular injection of [³H]leucine no significant change in rapid axonal transport could be found in those chronically treated rabbits.     

Differences among humans in steady-state evoked potentials: Evaluation of alpha activity,attentiveness and cognitive awareness of perceptual effectiveness

We examined some of the variables that were possible sources of the wide variability among and within human subjects in their steady-state visual evoked potentials (VEP) in response to continuously counter-phased visual stimuli (vertical bars).We found that within a given subject the magnitude of VEP was reasonably consistent during replicate trials under comparable conditions. However, across subjects there were enormous differences (as much as 17-fold) in the VEP magnitude (i.e. in the spectral power developed at the stimulus reversal frequency). These differences could not be explained by differences among subjects in arousal (alpha activity before or during stimulation), attentiveness (as indicated by reaction times to random cueing), or by a person's subjective impression of his responsiveness to stimulation.     

Plasma levodopa,dopamine and therapeutic response following levodopa therapy of Parkinsonian patients

In a double blind placebo controlled study of 6 Parkinsonian patients given a single dose of oral levodopa, the plasma levodopa and dopamine as measured by a radioenzymatic method both correlated with clinical improvement. There was a closer correlation with plasma dopamine than with plasma levodopa and it is proposed that peripheral decarboxylation may reflect central decarboxylation.     

Relationships between triggered seizures, spontaneous seizures, and interictal spiking in the kindling model of epilepsy

Cats were kindled in the amygdala. After completion of kindling, their EEG was monitored almost continuously by a computer system which allowed the detection of spontaneous seizures and the quantification of interictal spikes. The relationships between seizures triggered by stimulation, spontaneous seizures, and interictal spikes in kindled and contralateral amygdalas were examined. Very few spontaneous seizures were observed; their occurrence appeared facilitated by a few triggered seizures after a long seizure-free interval. Stimulation-triggered seizures were followed first by a decrease in spiking activity during a few hours and then by an increase which could take 3 to 8 days to return to baseline. Spontaneous seizures were also, but less systematically, followed by such a sequence. Spontaneous seizures could occur when the interictal spiking rate was high as well as when it was low. It is concluded that, in the fully kindled cat, interictal spiking appears to be mainly regulated by the occurrence of seizures; the rate of spiking appears to have no bearing on the probability of occurrence of spontaneous seizures. Hence, seizures and interictal spiking could be generated by separate pathophysiologic mechanisms, the seizure-generating mechanism influencing the spike-generating mechanism but not the reverse.     

The prevalence of emotional and cognitive dysfunction in a general medical population: using the MMSE, GHQ, and BDI

The Mini Mental Status Examination, General Health Questionnaire-30, and Beck Depression Inventory were administered to 335 randomly selected hospitalized medical patients. Twenty-eight percent of the population had evidence of cognitive dysfunction on the Mini Mental Status Examination, 61% showed emotional dysfunction on the General Health Questionnaire-30, and 36% were depressed as measured by the Beck Depression Inventory. Only 29% of the patients had no evidence of emotional or cognitive dysfunction. Medical resident diagnostic concordance with these tests was poor. The effects of demographic variables on these test scores were also determined.     

Relationships between anxiety, depression self-ratings and CHD risk factors among obese, normal and lean individuals.

Psychosomatic interactions leading to the development of Coronary Heart Disease (CHD) have yet to be clarified. This study explores further whether and how an important CHD risk factor, relative weight, affects the relationships between psychological and bioclinical parameters. A principal factorial components solution (linear procedure) and an extension of the median test (non-linear procedure) were run on the scores of self-reported anxiety (IPAT Anxiety Scale) and depression (Zung Self-rating Scale), the indices of anxiety expression style, and the bioclinical measures (systolic and diastolic blood pressure, fasting blood glucose, urea and lip concentrations). The statistical procedures were carried out separately in the six subgroups which subdivide 1,694 male volunteers to a CHD detection examination, according to age (under- and over-45 yr) and relative weight (obese, normal and lean subjects). Results indicate that the relationship between psychological and bioclinical measures are specific to the subgroup considered: they are recurrent in obese and lean individuals, and more frequent in older than in younger subjects. The composition of the first factorial component is psycho-bioclinical in the under-45 obese subgroup; the second factorial component is biopsychological in the obese and lean, under- as well as over-45-yr old, subgroups. The expression style indices and the lipid concentrations are associated when the statistical method does not presuppose linearity. Present theories on psychological and bioclinical determinants of relative weight are reported, since the experimental data upon which these theories are based parallel interestingly the results of our correlational study. Indeed, both approaches suggest that cognitive factors, operationally defined by response tendencies and anxiety expression style, are different in obese and nonobese humans, and that these differences determine psycho-bioclinical relationships which are specific to these relative weight groups. Could these mechanisms of action be specified, an important step would be made in the understanding of the CHD etiology.     

Relationship Between Mood,Thinking, and Walking: A Systematic Review Examining Depressive Symptoms,Executive Function,and Gait

Prior literature has proposed that the coexistence of late-life depression, executive dysfunction and impaired gait speed may constitute a specific phenotype in older adults with a possible shared brain mechanism. All three conditions are independently associated with negative health outcomes including impaired function, risk of falling, and reduced quality of life. However, the existence, etiology, and implications of having all three conditions as a unitary triad remain unclear. This systematic review examined the literature to assess the consistency of this triad and to explore the possible role of frontal-subcortical circuitry in its etiology. English language literature that assessed mood, executive function, and gait speed using a validated tool in human participants over age 65 were included for this review. Following the PRISMA guidelines, 15 studies including 11,213 participants met criteria for inclusion in this study. The triad's existence was supported by 12 of the 15 studies (80%), including 4 longitudinal studies involving 368 participants. A prevalence of 17% was reported in one population study. The three included intervention studies provided mixed results regarding the benefit of pharmacologic and exercise interventions. Two studies assessed the association between presence of white matter hyperintensities and the triad, with one study finding a significant longitudinal relationship with periventricular white matter hyperintensities. Vascular risk factors were also commonly associated with this triad. Taken together, the relationship between this triad, the vascular depression hypothesis, and frontal-subcortical pathology is suggested. Further longitudinal research is needed to further clarify the etiology and clinical relevance of this concomitant prescence oflate-life depression, executive dysfunction and impaired gait speed.     

Clinical data and the identification of special forms of multiple sclerosis in 1271 cases studied with a standardized documentation system

In a multicenter study the clinical data of 1271 patients with multiple sclerosis (MS) were recorded in a standardized manner and analysed by a computer program.

Some of the retrospective data are compared with previous reports. The frequency of optic nerve involvement in the present series was close to the Japanese figures.

The development of signs and symptoms during the course of MS was given for the 1271 patients and differences in the reversibility of symptoms are presented.

In this study, one of the chief purposes was the selection of groups of MS patients with particular symptomatology and course of the disease for prospective, detailed study.

The following groups were selected and are under further investigation: 109 patients with an exclusively spinal symptomatology throughout the course of their disease; 441 patients with optic neuritis as initial symptom; 110 patients with early brain-stem involvement; 64 benign cases (duration of the disease more than 14 years and disability not more than 3 according to Kurtzke); 35 malignant cases (duration of the disease under 5 years and disability grade of 7 or more); 83 families with more than one member with MS; 289 females with a history of pregnancy, childbirth and/or use of oral contraceptives.

In 339 patients a lumbar puncture was performed at the present examination. The parameters determined constitute a pathognomonic pattern highly indicative of the diagnosis of MS.     

The Construction and Evaluation of Executive Attention Training to Improve Selective Attention,Focused Attention,and Divided Attention for Older Adults With Mild Cognitive Impairment: A Randomized Controlled Trial

ObjectivesTo examine the immediate and long-term effects of executive attention training on selective attention, focused attention, and divided attention in older adults with mild cognitive impairment.MethodsA double-blind, multisite randomized controlled trial at five sites. Seventy participants (mean age: 78.19 ± 7.22 years) were assigned to an experimental group (executive attention training, n = 35) or an active control group (n = 35). The training duration was the same for both groups (45 minutes per session, 3 times per week, 18 sessions in total). Primary outcome measure was selective attention (Digit Span Task). Secondary outcome measures included focused attention (Stroop Color Word Test) and divided attention (Trail-Making Test Part B). Data were collected at pretest, post-test, 3-month follow-up, and 6-month follow-up.ResultsIn GEE analysis, findings indicated a significant improvement in selective attention at post-test, whereas divided attention showed significant reducing omission error at 3-month follow-up. There was no significant effect of group in focused attention associated with the executive attention training compared with active control group.ConclusionThe executive attention training significantly improved selective attention and divided attention performance. Future studies should identify transfer effects of attention training, and that can employ early screening to provide integrated attention training, and decrease its relevant risks on competency in performing daily activities, such as falling and driving.