Theoretical & experimental analysis of the Non Markov Parameter to detect low frequency synchronisation in time series analysis

A theoretical investigation into the behaviour of the Non-Markov Parameter is performed from a signal processing perspective in contrast to previous methodologies based on stochastic processes theory. The results indicate that the NMP can be regarded as an informational metric which is indicative of the degree of low frequency synchronisation in a complex system. These results have deep implications for physiological analysis of biological systems where the presence of sychronisation is often a marker of pathological functioning. The NMP measure is then applied to in vivo micro-electrode recordings from the subthalamic nucleus.

Rapid subthalamic nucleus deep brain stimulation lead placement utilising CT/MRI fusion, microelectrode recording and test stimulation

Subthalamic nucleus (STN) deep brain stimulation (DBS) has become an established treatment strategy for patients with medically refractory Parkinson's disease (PD). There are however numerous strategies employed for STN lead placement. Variations include method of STN localisation, use of microelectrode recording, number of microelectrode recording passes and time taken for the procedure. We describe a relatively simple and rapid technique of STN lead placement utilising CT/ MRI image fusion, microelectrode recording and test stimulation. The first 58 consecutive patients undergoing STN DBS were assessed pre- and post-operatively. UPDRS scores, medication use and any surgical complication were assessed. Bilateral STN DBS was an efficacious treatment option for medically refractory PD. We have described a technique which can be performed with effect and low morbidity, and in a time which is well tolerated by patients.

Self-rated quality of life measures: effect of change to a low-fat, high-fiber, fruit and vegetable enriched diet

The Polyp Prevention Trial (PPT) was a multicenter, randomized clinical trial to determine the effect of a low-fat (20% of energy from fat), high-fiber (18 g/1,000 kcal/day), high-fruit/vegetable (3.5 servings/1,000 kcal/day) eatingplan on the recurrence of large bowel adenomatous polyps. The PPT provided an opportunity to examine the impact of dietary changes on quality of life. At baseline and annuallyfor 4 years, participants in the Quality of Life Substudy of PPT completed a Quality of Life Factors (QF) Questionnaire, a modified Block-National Cancer Institute Food Frequency Questionnaire, and a Health and Lifestyle Questionnaire. The 51-item QF Questionnaire assessed changes in nine domains: taste, convenience, cost, self-care, social, health assessment, health belief health action, and life satisfaction. The analysis compared annual changes in domain scores for intervention (n = 194) and control (n = 200) participants. At Year 1, 363 (92%) completed a questionnaire, and 325 (82%) participants completed a Year 4 questionnaire. There were no statistically significant differences between treatment groups in the change from baseline to Year 1 for the convenience, cost, taste, health assessment, and life satisfaction domains. At Year 1, intervention participants rated the self-care (p < .001), health belief (p = .021), and health action (p < .001) domains significantly higher and the social domain significantly lower (p <.001) than control participants. These changes were consistent through Years 2, 3, and 4. This study

Avoidance responding following amphetamine-induced dopamine depletion

The effect of an amphetamine-induced depletion of striatal dopamine on active and passive avoidance responding of rats was examined. Sixteen animals received two sets of 4 injections each of 15 mg/kg d-amphetamine, administered at 2 hr intervals with each set delivered one week apart. One week after the last injection, animals were given 50 consecutive active avoidance trials in a shuttle box. Animals treated with amphetamine exhibited a 50%, depletion of striatal dopamine and showed a slower learning curve, as evidenced by significantly fewer avoidances and a slower escape latency during trials 21-30. Both groups demonstrated a 90% avoidance rate by trials 41-50. A separate group of rats was treated as above and trained for several weeks on the active avoidance procedure. Haloperidol (0.01-0.10 mg/kg intraperitoneally) dose-dependently decreased avoidance number and increased avoidance and escape latency in both groups, an effect that was exaggerated in those animals previously treated with amphetamine. Finally, these animals were tested in the same apparatus using a passive avoidance procedure. The amphetamine treatment produced a significantly higher mean number of avoidances in this procedure compared to saline-treated animals during trials 1-20. These results suggest that the impairment in conditioned avoidance following amphetamine treatment is due to a motoric, rather than a cognitive deficit.

Outcomes following treatment of metastatic spine tumors

Fifty seven consecutive patients with metastatic spine tumors were assessed for their suitability for operative treatment or radiotherapy and/or chemotherapy using a modified version of the Nihon University scoring system. Using this scoring system 29 patients underwent surgery and 28 received radiotherapy/chemotherapy. The outcomes were assessed to determine if a modified scoring had any effect on patient survival. No statistical difference was found between the two groups, though a trend was noted--the group receiving surgery had a mean survival of 30 weeks compared to a mean survival of 16 weeks found in the non-surgical group.

Effect of dietary ribonucleic acid on bacterial translocation and survival following blood transfusion and thermal injury

Ribonucleic acid (RNA) has been shown to have a key role in the maintenance of normal cellular function and host resistance to infection. The effect of experimental diets containing RNA on microbial translocation, killing of translocated bacteria and the survival rate of the host was studied in a burn animal model which included immunosuppression. Balb/c mice were fed for 10 days with an RNA supplemented diet (AIN/76A). Control groups were fed with two commercial diets: AIN-76A or Purina chow 5001 (chow). After 10 days of feeding, all animals received an allogenic transfusion. On day 15 the animals were gavaged with 10(10)(14)C radiolabeled or unlabeled Escherichia coli, and given a 20% total body surface area (TBSA) burn injury. Animals gavaged with unlabeled bacteria were observed for survival (n = 60) and animals gavaged with labeled bacteria were sacrificed 4 h post-burn (n = 30) and the mesenteric lymph nodes, liver and spleen were harvested. Slightly less translocation was observed in the liver and spleen of animals fed on RNA diet. Bacterial counts were measured and the percentages of translocated organisms that survived in the tissues were calculated and showed no statistical differences between the three groups. Survival was 45% in RNA group versus 55% in the non-supplemented AIN-76A and 50% in the chow group. It is concluded that a diet enriched in RNA slightly affects bacterial translocation but does not affect survival after severe injury.

The validity of classification for the clinical presentation of intracranial dural arteriovenous fistulas

A number of classification schemes for intracranial dural arteriovenous fistulas (AVFs) have been published that claim to predict which lesions will present in a benign or aggressive fashion based on radiological anatomy. We have tested the validity of two proposed classification schemes for the first time in a large single-institution study. A series of 102 intracranial dural AVFs in 98 patients assessed at a single institution was analyzed. All patients were classified according to two grading scales: the more descriptive schema of Cognard, et al. (Cognard) and that recently proposed by Borden, et al. (Borden). According to the Borden classification, 55 patients were Type I, 18 Type II, and 29 Type III. Using the Cognard classification, 40 patients were Type I, 15 Type IIA, eight Type IIB, 10 Type IIA+B, 13 Type III, 12 Type IV, and four Type V. Intracranial hemorrhage (ICH) or nonhemorrhagic neurological deficit was considered an aggressive presenting clinical feature. A total of 16 (16%) of 102 intracranial dural AVFs presented with hemorrhage. Eleven of these hemorrhages (69%) occurred in either anterior cranial fossa or tentorial lesions. When analyzed according to the Borden classification, none (0%) of 55 Type I intracranial dural AVFs, two (11%) of 18 Type II, and 14 (48%) of 29 Type III intracranial dural AVFs presented with hemorrhage (p < 0.0001). After exclusion of visual or cranial nerve deficits that were clearly related to cavernous sinus intracranial dural AVFs, nonhemorrhagic neurological deficits were a feature of presentation in one (2%) of 55 Type I, five (28%) of 18 Type II, and nine (31%) of 29 Type III patients (p < 0.0001). When combined, an aggressive clinical presentation (ICH or nonhemorrhagic neurological deficit) was seen most commonly in intracranial dural AVFs located in the tentorium (11 (79%) of 14) and the anterior cranial fossa (three (75%) of four), but this simply reflected the number of higher grade lesions in these locations. Aggressive clinical presentation strongly correlated with Borden types: one (2%) of 55 Type I, seven (39%) of 18 Type II, and 23 (79%) of 29 Type III patients (p < 0.0001). A similar correlation with aggressive presentation was seen with the Cognard classification: none (0%) of 40 Type I, one (7%) of 15 Type IIA, three (38%) of eight Type IIB, four (40%) of 10 Type IIA+B, nine (69%) of 13 Type III, 10 (83%) of 12 Type IV, and four (100%) of four Type V (p < 0.0001). No location is immune from harboring lesions capable of an aggressive presentation. Location itself only raises the index of suspicion for dangerous venous anatomy in some intracranial dural AVFs. The configuration of venous anatomy as reflected by both the Cognard and Borden classifications strongly predicts intracranial dural AVFs that will present with ICH or nonhemorrhagic neurological deficit.

Nutrition intervention program of the Modification of Diet in Renal Disease Study: a self-management approach

OBJECTIVE

To characterize the Modification of Diet in Renal Disease (MDRD) Study nutrition intervention program by determining the frequency of intervention strategies used by the dietitians and the usefulness of program components as rated by participants.

DESIGN

Dietitians recorded which of 32 intervention strategies they used at each monthly visit. Participants rated the usefulness of 19 program components.

SUBJECTS

840 adults with renal insufficiency.

INTERVENTION

Participants were assigned randomly to usual-, low-, or very-low-protein diet groups. Each eating pattern also specified a phosphorus intake goal. Each participant met monthly with a dietitian for an average of 26 months.

STATISTICAL ANALYSES

Analyses of variance and chi 2 analyses.

RESULTS

Dietitians used the following intervention strategies most often in all groups: providing feedback based on self-monitoring and/or food records, reviewing adherence or biochemistry data, providing low-protein foods, and reviewing graphs of adherence progress. In general, the dietitians used feedback, modeling, and support strategies more often, and knowledge and skills strategies less often, with participants who had to make the greatest reductions in protein intake and those with more advanced disease. In all groups, the dietitians' use of knowledge and skills, feedback, and modeling strategies decreased over time (P < .001), whereas use of support strategies was maintained. The type and frequency of intervention strategies used by dietitians and the usefulness ratings of participants did not vary by educational level of the participant. Both self-monitoring and dietitian support were rated as "very useful" by 88% of the participants.

CONCLUSIONS

Three features were central to the MDRD Study nutrition intervention program: feedback, particularly from self-monitoring and from measures of adherence; modeling, particularly by providing low-protein food products; and dietitian support. We recommend the self-management approach.

Factors associated with adherence to the dietary protein intervention in the Modification of Diet in Renal Disease Study

OBJECTIVE

To determine the characteristics and behaviors associated with adherence to dietary protein interventions among participants with chronic renal disease in the Modification of Diet in Renal Disease (MDRD) Study.

DESIGN

Participants were categorized as consistent adherers or nonadherers on the basis of urinary urea nitrogen excretion and dietary protein intake data from self-reports. Psychosocial and behavioral factors were compared between groups.

SUBJECTS

Subgroups of consistently adherent and non-adherent participants in the MDRD Study.

SETTING

15 clinical centers in the United States.

INTERVENTION

In the nutrition intervention program, participants were assigned randomly to a usual-, low-, or very-low-protein diet group. Each eating pattern also specified a phosphorus goal.

STATISTICAL ANALYSIS

Analysis of variance.

RESULT

Psychosocial factors significantly related to adherence included participant knowledge, attitude, support, satisfaction, and self-perception of success. Behavioral strategies including participant self-monitoring of protein intake and the provision of feedback by the dietitian were also significantly related to adherence.

APPLICATION

Nutrition interventions for patients with renal disease should focus on psychosocial factors and behavioral approaches. Such approaches can be successfully incorporated into treatment programs and will assist the dietitian in promoting adherence to usual-, low-, and very-low-protein eating patterns.

Dietary satisfaction correlated with adherence in the Modification of Diet in Renal Disease Study

OBJECTIVE

To measure satisfaction with modified protein eating patterns and the relationship of satisfaction to adherence and sociodemographic factors in a clinical trial.

DESIGN

Participants completed the Dietary Satisfaction Questionnaire at baseline, at 6-month follow-up visits, at annual visits, and at the final visit. Satisfaction with diet was rated on a visual analog scale from 1 (dislike extremely) to 5 (like very much). Adherence to protein goals was assessed using urine urea nitrogen excretion from monthly 24-hour urine samples.

SUBJECTS

840 adults with chronic renal disease.

INTERVENTION

Individual participants, randomly assigned to a usual-protein, low-protein, or very-low-protein group, received monthly counseling from a dietitian for an average of 26 months.

STATISTICS

Analyses of variance and two-sample t tests compared, among study/diet groups, satisfaction with diet, its relationship to adherence and sociodemographic characteristics, and changes in satisfaction over time. Paired t tests compared changes within diet groups from baseline to final visit.

RESULTS

From the baseline visit to the final visit, satisfaction with the prescribed eating pattern increased slightly in the usual-protein group, declined slightly in the low-protein group, and declined significantly in the very-low-protein group. Participants in all of the eating pattern groups who were more satisfied at the final visit had mean protein intakes closer to their assigned protein goals. This relationship was significant in the low-protein group (P < .05). In men, satisfaction with diet declined significantly from baseline to the final follow-up visit in the very-low-protein group.

APPLICATIONS

The Modification of Diet in Renal Disease Study Dietary Satisfaction Questionnaire may be useful in other research and clinical settings to assess and enhance dietary adherence.

Recruitment experience in the full-scale phase of the Modification of Diet in Renal Disease Study

The Modification of Diet in Renal Disease (MDRD) Study is a randomized, multicenter clinical trial testing the effects of three different levels of dietary protein and phosphorus intake and two levels of blood pressure control on the rate of loss of kidney function in persons with various chronic kidney diseases. During a 27-month recruitment period, 2507 persons who had objective evidence of impaired kidney function were screened at 15 centers. Eight hundred and forty men and women aged 18-70 with a glomerular filtration rate between 13 and 55 ml/min/1.73 m2 were randomized. Medical record review was the primary means of identifying study participants at the beginning of recruitment. Later, use of mass media was instrumental in alerting both the public and the medical community of the need for MDRD Study participants. Overall, the most important sources of randomized participants were referral by personal physician (45.4%) and relative/friend (5.6%), and self-referral after hearing about the trial from newspapers (23.9%) and television (5.2%). Review of medical records from defined patient populations was the source of 22.3% of the randomized study participants. A total of 9.4% of the randomized participants called a toll-free (800) telephone number before contacting the centers.

A survey of interhospital transfer of head-injured patients with inadequately treated life-threatening extracranial injuries

A 12 month prospective study was undertaken to determine the frequency of untreated life-threatening extracranial injuries in patients transferred to a major trauma centre because of head injury. Of the 43 patients transferred (15 with isolated head injury and 28 with multiple injuries), four (9%) had an untreated life-threatening extracranial injury, which caused death in two. All four patients with untreated extracranial injuries were transferred from hospitals with general surgical staff and facilities. In three of the patients (none with a major head injury), the extracranial injuries were recognized at the referring hospital, but were left untreated in the rush to transfer the patient to a neurosurgical facility. In the fourth patient, who had a severe head injury, recurrent hypotension from a ruptured spleen was mistakenly ascribed to a scalp wound. The series shows that the dangerous practice of hurriedly transferring patients to trauma centres because of actual or perceived head injuries, while leaving major extracranial injuries untreated, continues despite warnings in the literature and the efforts of the Royal Australasian College of Surgeons through the Early Management of Severe Trauma programme.

Evaluation of preschool meals programmes on the nutritional health of Aboriginal children

One hundred and sixteen three to five year old Aboriginal children were included in an evaluation of the effect of preschool meals programmes on their nutritional health. Sixty-one children attending preschools in five communities were examined at the beginning and end of the school year. Fifty-five control children in five matched communities had two examinations, 38 weeks apart. Height, weight and haemoglobin concentrations were determined on all children and serum levels of ascorbic acid, ferritin, iron, total protein, albumin, cholesterol and triglycerides were determined on a subsample. Aboriginal children in both groups had initial measurements and nutrient levels below acceptable levels. The 61 children who received preschool meals had consistently better growth than the control children. A negative correlation was found between gains in weight and height and serum levels of ferritin, haemoglobin and ascorbic acid, indicating that more rapidly growing children may have been rapidly utilizing nutrients for growth.