Visuomotor skill learning on serial reaction time task in patients with early Parkinson's disease

This study tested the role of basal ganglia in visuomotor skill learning. Thirty-nine patients early in the course of Parkinson's disease (PD) and 30 patients after operation for an aneurysm of the anterior communicating artery (ACoA) were compared with 31 matched control subjects on a Serial Reaction Time test (SRTt). The patients with PD showed impaired visuomotor skill learning across the repeating blocks, in the presence of preserved declarative knowledge of embedded sequences, in contrast to the ACoA group in whom the reverse pattern was observed. The significant correlation in patients with PD between the standard neuropsychological and motor measures and the performance observed in the skill acquisition test, in the ACoA group and control subjects was not observed. The suggestion that this learning impairment could not be attributed to a motor deficit per se was also confirmed more directly for patients with PD. Accuracy of performance after the initial learning phase on the SRTt in patients with PD was associated predominantly with visual span capacity measures. Declarative knowledge of the embedded sequence of the SRTt was correlated to general cognitive and verbal span abilities in the PD group. The impairment observed in the PD group was not the result of a general decline in cognitive functioning, mood disturbances, or the severity of the motor symptoms.

Reappraisal of the quantity and nature of renal calcifications and mineral metabolism in the magnesium-deficient rat. Effects of treatment with potassium citrate or the combination magnesium citrate and potassium citrate

There is an urgent need for drugs capable of inhibiting renal calcifications, nephrocalcinosis and stones included, in humans. Current anticalcification medication is based mainly on alkalinization of the metabolism using potassium-containing citrate alone, despite the fact that calcium stone patients suffer marginally from both magnesium and potassium deficiency. We investigated the anticalcification efficacy of oral potassium citrate versus the combined administration of this drug and magnesium citrate in the magnesium-deficient rat developing corticomedullary nephrocalcinosis and luminal microliths in the long term. Among other things we employed specific stains for calcium and oxalate, light microscopy and element analysis for renal tissue and calcifications, respectively. In addition, minerals in renal tissue, urine and plasma were determined, as well as the state of extracellular calcium homeostasis. Magnesium deficiency caused pure calcium phosphate tissue deposits, containing no magnesium, but no deposition of calcium oxalate in the tubular lumen; tissue magnesium, calcium and phosphorus were increased, and there was marked potassium wastage via urine; despite mild hypercalcemia other signs of hyperparathyroidism were not found. Alkalinization with the two kinds of medication evoked an increase in urinary pH, citrate, and potassium; however, potassium citrate alone tended to aggravate renal concretions, whereas the combination of this drug with magnesium citrate completely prevented concretions. It was concluded that: (1) magnesium deficiency-induced calcifications are oxalate-free and are not sensitive to mobilization by alkalinization with potassium citrate, which might explain the failure of the drug to prevent stone recurrence in clinical stone patients, and (2) the combination of potassium citrate and magnesium citrate, which shows enormous anticalcification efficacy, deserves high priority in clinical trials aimed at evaluating strategies for the prevention of stones.

From theory to perioperative practice with Parse

The operating room nurse today is often thought of as a task skilled, highly technical, process oriented, and efficient member of the operating room team. Too often her/his nursing education and preparation in practice, theory and discipline are overlooked. Perioperative nursing as a specialty is an important, vital factor in the success of the planned surgical intervention. Perioperative nursing practice involves caring for the patient; it is patient-centered rather than task oriented. The RN combines both the physiologic and psychosocial aspects of nursing in delivery of care. This is reflective of the theoretical model used to plan effective nursing care. The RN interacting with the preoperative patient has a focus on being in true presence with the patient (Parse, 1987). The interrelationship sets in motion utilization of theory, reflecting nursing knowledge and practice.

Thermophysical properties of some pharmaceutical excipients compressed in tablets

PURPOSE

Thermophysical properties of three tableting excipients; microcrystalline cellulose, lactose and dicalcium phosphate dihydrate were observed to evaluate their ability to resist temperature induced changes in tablet form.

METHODS

Two thermophysical parameters, thermal diffusivity and specific heat, were measured by a pulse heating method. The materials were also evaluated by differential scanning calorimetry (DSC).

RESULTS

Microcrystalline cellulose in tablet form was found to be rather insensitive to heating and cooling treatments, even though the tablets seemed to remain in a stressed state four weeks after tableting. This stress, indicated by low temperature anomalies, was observed by the pulse method, but not by DSC. When magnesium stearate was incorporated as a lubricant within the microcrystalline cellulose powder, the thermophysical parameters indicated that the internal structure of the tablets changed with heating and cooling. Magnesium stearate eliminated the low temperature anomalies as well. The heat treatment changed the thermophysical properties of tablets made of the crystalline excipients lactose and dicalcium phosphate dihydrate, permanently causing irreversible structural changes.

CONCLUSIONS

The melting of the lubricant together with enhanced stress relaxation in the structure of microcrystalline cellulose most probably caused the improved thermal diffusivity. The observed thermophysical changes with the crystalline excipients were due to changes in tablet's structure and material. The combination of methods used was found to be an accurate and reliable way to obtain useful information on the structural changes and material relaxations of intact tablets during temperature treatment and age-related changes in material properties.

Liposome-entrapped superoxide dismutase reduces ischemia/reperfusion 'oxidative stress' in gerbil brain

Bilateral common carotid artery occlusion (15 min.) followed by two hours of recirculation reduced mitochondrial superoxide dismutase (SOD) and glutathione reductase (GR) activities, and increased susceptibility of mitochondrial membranes to in vitro lipid peroxidation in brain regions (i.e., cortex, striatum and hippocampus) of Mongolian gerbil. Intraperitoneal bolus injection (2 mg/kg b.w.) of liposome-entrapped CuZn superoxide dismutase (1-SOD) increased the endogenous SOD activity in normal brain tissue and, when given at the end of ischemia, counteracted both the ischemic reduction of endogenous SOD and the increased peroxidation of mitochondrial membranes. 1-SOD treatment was ineffective in reducing brain swelling, suggesting that superoxide radicals are not a main participant in the process of (post)ischemic brain edema formation.

'Therapeutic window's for multiple drug treatment of experimental cerebral ischemia in gerbils

The effects of the following drugs: nimodipine (1 mg/kg b.w., i.p.), 2-amino-5-phosphonovaleric acid (4 mg/kg b.w., i.p.) and propentofylline (25 mg/kg b.w., i.p.), administered (alone or in combination) at the end of 15 min bilateral ischemia in gerbils were evaluated on mitochondrial superoxide dismutase (SOD), glutathione reductase (GR), glucose-6 phosphate dehydrogenase (G6PD), monoamine oxidase (MAO) activities, and thiobarbituric acid reactive material (TBARM), and brain water content at 1 hour of reperfusion. The combined treatment virtually abolished early postischemic brain edema (4.1% v.s. 0.6%) and efficiently counteracted ischemia-induced changes [decreased SOD (79% v.s. 98%), GR (52% v.s. 105%) and MAO (25% v.s. 79%), and increased TBARM (198% v.s. 108%)]. The same combination of drugs administered 15 min before ischemia had a similar effect (e.g., reduced brain swelling and lipid peroxidation) as when given at the end of ischemia, whereas a limited or absent impact was seen when the drugs were given 15 min or 1 hour after ischemia, respectively. The data suggest that (post)ischemic brain swelling and mitochondrial dysfunction can be reduced by drugs which synchronously prevent processes induced in the early stages of reperfusion.

Microbial growth in clinically used enteral delivery systems

Potential contamination of enteral formulas has led to the development of policies limiting formula hangtimes. However, enteral administration bags can easily become contaminated during formula refilling. We prospectively studied enteral formula contamination when the hangtime of a prefilled 1000 ml pouch was compared with the standard 4-hour hangtime of a refilled enteral administration bag. Samples of formula collected from different locations along the enteral delivery system were cultured during 57 days of enteral hyperalimentation in 19 patients. The overall enteral formula contamination rate was 61%, where the greatest microbial growth occurred in reconstituted enteral formulas. The presence of microbial growth did not differ between canned formulas administered according to a 4-hour hangtime and the prefilled pouch. Greatest growth in all cases was at the distal tubing hub, where contamination during system manipulation or from the patient probably occurred. Use of prefilled enteral administration bags may delay formula contamination in the administration reservoir. A change in equipment design that would decrease the need to manipulate feeding sets or feeding tube connections should be further investigated.

The role of the orthodontist in the treatment of adolescents with orofacial clefts

In the orthodontic treatment of patients with clefts the main aim is to maximize the growth and development of the maxillary complex and, at the same time, to improve functional efficiency and facial aesthetics. The commonest malocclusions found in adolescents with lip and palate clefts are: frontal or anterior crossbite; posterior or buccal crossbite which is either unilateral or bilateral; retrusion of the middle third of the face to a greater or a lesser degree; open bite; and finally malformation and displacement of the teeth adjacent to the cleft. Treatment may be divided into: correction of malocclusions in the transverse plane; correction in the antero-posterior plane; vertical corrections; and correction of misplaced individual teeth. Posterior (lateral) crossbite can be corrected by both gradual and rapid (forced) expansion using various removable appliances. Following this, correction of anterior crossbite and restoration of vertical occlusal relationships will be necessary. Finally, misplaced individual teeth will need to be repositioned. Traumatic surgery and consequent scar tissue affects the growth of the maxillary arch and the development of the occlusion. This was demonstrated in a comparative analysis of monozygotic and dizygotic twins discordant for clefts as well as in twin pairs whose clefts were non-identical in type and extent. The adolescents who still have unoperated clefts have special problems.

Microbial growth comparisons of five commercial parenteral lipid emulsions

The ability of parenteral lipid emulsions to support microbial growth was compared using commercially available brands of lipid emulsion. Both 10 and 20% concentrations of soybean and safflower oil emulsions were used. Washed cultures of six gram-negative, three gram-positive, and one yeast, in concentrations of 1 x 10(4) to 2 x 10(4) colony-forming units/ml, were inoculated into lipid emulsion aliquots and stored at room temperature. There were than subcultured at 0, 6, 12, 24 and 48 hr. After 48 hr at 37 degrees C, growth was recorded as colony-forming units/ml. Normalized growth curves were expressed as mean +/- SEM. ANOVA demonstrated no difference in growth patterns due to the nature of the oil or its concentration. Gram-negative organisms multiplied faster when compared to gram-positive (p less than 0.05 at 12 hr, p less than 0.01 at 24 hr, and p less than 0.005 at 48 hr). Yeast grew as well as bacteria. The Center for Disease Control's recommendation of a 12-hr hang time for parenteral lipid emulsions should be observed until correlation of laboratory microbial growth patterns and clinical use are studied further.

A comparative occlusal and cephalometric study of dental and skeletal anteroposterior relationships

Anteroposterior dental relationships (Class I, II or III) were assessed from study plaster models and skeletal relationships were determined on the basis of the ANB angle of 585 orthodontic patients. It was found that there was no agreement between dental and skeletal anteroposterior relationships in about 25 per cent of the cases investigated.

Twins with clefts

The concurrence of two experiments of nature, twins and congenital birth defects, provides a unique population for the elucidation of nature-nurture questions. Although the concurrence of twins with clefts is not common, their frequency in the aggregate of international reporting is sufficient to allow for meaningful studies.

In a recent conference on the genetics of cleft lip and palate, Fraser (1968) summarized the state of knowledge regarding etiology. The following quotation from his report is pertinent to the present paper:

1) In the majority of cases, cleft lip or cleft lip and palate [CL(P)] represents a quasi-continuous variant, or threshold character of multifactorial etiology. For cleft palate [CP] there is less convincing information;

2) Observations on arch form, face shape, body asymmetries and developmental variables suggest that such variants may underly the predisposition to clefts;

3) Twin studies may be useful in identifying the physiognomic factors predisposing to facial clefts.

With these concepts in mind, we initiated an analysis of 19 twin pairs selected from the continuing longitudinal growth study which began at our Center in 1949 (Pruzansky and Lis, 1958).