Small vessel disease disrupts EEG postural brain networks in 'unexplained dizziness in the elderly'.

OBJECTIVE: To examine the hypothesis that small vessel disease disrupts postural networks in older adults with unexplained dizziness in the elderly (UDE). METHODS: Simultaneous electroencephalography and postural sway measurements were undertaken in upright, eyes closed standing, and sitting postures (as baseline) in 19 younger adults, 33 older controls and 36 older patients with UDE. Older adults underwent magnetic resonance imaging to determine whole brain white matter hyperintensity volumes, a measure of small vessel disease. Linear regression was used to estimate the effect of instability on electroencephalographic power and connectivity. RESULTS: Ageing increased theta and alpha desynchronisation on standing. In older controls, delta and gamma power increased, and theta and alpha power reduced with instability. Dizzy older patients had higher white matter hyperintensity volumes and more theta desynchronisation during periods of instability. White matter hyperintensity volume and delta power during periods of instability were correlated, positively in controls but negatively in dizzy older patients. Delta power correlated with subjective dizziness and instability. CONCLUSIONS: Neural resource demands of postural control increase with age, particularly in patients with UDE, driven by small vessel disease. SIGNIFICANCE: EEG correlates of postural control saturate in older adults with UDE, offering a neuro-physiological basis to this common syndrome.

A 5-year survival study of general surgical patients aged 65 years and over.

A prospective 5-year survival study of 900 patients, aged 65 years and over, undergoing a general surgical procedure, demonstrated that following an initial high mortality rate the survival of the group as a whole approached that of an age-matched population. Non-elective admissions, age 75 years and over, ASA grade 4-5 and major surgery were associated with a high early mortality. Mortality associated with malignancy extended over 1 year. The study reinforces the conclusion that age alone should be no bar to surgery and anaesthesia, endorses the findings of the National Confidential Enquiry into Peri-operative deaths and emphasises the need to re-examine the provision of anaesthetic and surgical services in District General Hospitals. The benefits of elective admission in the very old are highlighted, along with the potential for extension of day case surgery.

Evolving role of intensive and high-dependency care.

As stratified patient care evolves, and with an increasing population of elderly patients undergoing major surgery there is a growing demand for critical and high-dependency care beds. Results of an audit comparing the activity of a combined Intensive Care and High-Dependency Unit (ITU/HDU) in 1981 with 1991 has shown an increase in the number of patients admitted, particularly for high-dependency care. The overall mortality in 1981 was 12% compared with 9.5% in 1991. The greatest improvement was seen in ventilated patients, where the mortality was reduced from 54% in 1981 to 30% in 1991. An attempt is made to predict the demand for critical care and high-dependency beds for the future in a population of approximately 250,000 based on current trends. It is perceived that it will be necessary to establish a six-bed ITU and eight high-dependency surgical beds in two separate but adjacent units, where there will be a free interchange of skills at the different levels of care.

Leucocyte migration: effects of in vitro exposure to anaesthetic agents: possible potentiation of effects by adrenaline.

The effect on in vitro migration of leucocytes and lymphocytes of various drugs used in anaesthesia have been determined in the concentration range 10(-2) to 10(-6) M. The drugs included, thiopentone, bupivacaine, lignocaine, adrenaline, noradrenaline, hydrocortisone, morphine (with and without preservative), lorazepam, suxamethonium, pancuronium and atropine. Toxicity and effect on random mobility after incubation for 1 and 18 h were also determined. Thiopentone depressed leucocyte function at a concentration of 10(-5) M which is comparable to clinical plasma concentrations. Increasing the duration of exposure of the cells to the drugs significantly lowered the concentrations at which depression of function was observed. At concentrations used during local infiltration in clinical practice, bupivacaine and lignocaine were toxic to both leucocytes and lymphocytes. Adrenaline, whilst having no direct effect on cell function, potentiated the effect of lignocaine. Morphine showed no effect at 10(-4) M, a level 1,000 times greater than the reported toxic plasma levels. However, this level falls within the range reported for drug addicts. No effects were found for the other drugs.

Western blot analysis of serological responses following immunization with vaccinia viral lysates of melanoma cells.

Western blot analysis was used to characterize the antibody response of melanoma patients during immunization with vaccinia-virus-induced melanoma cell lysates (VMCL). Strong antibody responses were detectable within 4 weeks from commencement of immunization against different fractions (from 3 to 10) in blots of VMCL. The approximate MW of the main fractions identified were 100, 91, 85, 77, 64-66, 49, 46, 43 and 34-36 kDa. Comparison of the reactivity of the sera with extracts of vaccinia virus suggested that the reactivity against VMCL was not against viral antigens in the lysates. Studies on autologous extracts from 7 patients immunized with VMCL indicated that the majority of the fractions identified in extracts of VMCL were also identified in autologous extracts of melanoma cells. This indicated vaccine-induced responses against the patients' tumor cells and not merely against alloantigens in the vaccine. Sera from the immunized patients appeared to identify a number of fractions of similar MW in extracts of colon and glioma cells, suggesting that the responses were not specific for melanoma. Possible exceptions were reactivity against melanoma fractions of 85, 64-66 and 36 kDa. Our studies provide evidence for the effectiveness of VMCL in inducing antibody responses against autologous melanoma cells and form a basis for subsequent biochemical and genetic analysis of the antigens identified by antibody responses in immunized patients.

Lectin-stimulated lymphocyte responses: use and misuse in clinical research.

The use of mitogen stimulation assays in clinical research has increased rapidly during the last 25 years. However, little is understood about the mechanisms of action of mitogens. This, coupled with the complexity of the mitogen stimulation assay, has led to much misuse and abuse of this assay system. Data are presented that demonstrate the inherent variability of the assay system due to diurnal variation in the response of human lymphocytes to mitogen stimulation and to the variation in response between patients. It is argued that the use of the assay should be confined to rigorously controlled studies using either animal lymphocytes or paired samples from humans, one of which should be treated in vitro with test material.

The effects of three differing anaesthetics on the immune response.

A clinical study was undertaken to investigate changes in the immune response in patients undergoing three differing anaesthetic techniques for inguinal hernia repair. No significant differences between anaesthetic groups were demonstrated in the haematological parameters. The value of mitogen stimulation tests was questioned in the clinical setting. The migratory component of neutrophil function was shown to be preserved following conduction anaesthesia compared to the other anaesthetic groups and its possible advantage noted.

Time perception and hemodialysis.

Subtle alterations in neurological function are often difficult to identify and even harder to quantitate. The identification of a neurotoxic state existing before overt behavioral changes occur has eluded quantification. It was hypothesized that a challenging signal-detection procedure would be used to assess neurological function of dialysis patients and other subjects, the degree of uremic toxicity occuring during an interdialytic interval, and the effects of neuroactive drugs. A vigilance task demanding the detection of an irregularly flashing light from a matrix of regularly flashing lights was administered to 3 groups of 15 men: patients undergoing maintenance hemodialysis, patients with chronic illness and no kidney disease, and healthy subjects. The procedure was found to yield a reliable measure; average test-retest correlation was 0.93, which differentiated not only within the hemodialysis cycle (p less than 0.001), between groups (p less than 0.001), but was also related to the recency of neuroactive drugs ingested (p less than 0.01).

Personality correlates of male sexual arousal and behavior.

This study explores the relationship between male sexual behavior and personality factors, as measured by the MMPI and Sensation Seeking Scale. Subjects were 20 male volunteers, ages 19-58, with a history of long-term sexual relationships. Subjects kept a daily record of sexual behaviors. Frequency of these behaviors was correlated with MMPI and Sensation Seeking (SSS) subscales. Results indicate that both introversion and depression show significant correlations with autoerotic stimulation and arousal, but not with heterosexual activity. There is no significant correlation demonstrated between hypomania and sexual activity. The Boredom Susceptibility subscale of the SSS correlated significantly with the number of sexual partners.

Pruritic skin diseases, psychological stress, and the itch sensation. A reliable method for the induction of experimental pruritus.

A method of inducing controlled levels of terminable itching was developed. This method consists of administering constant monophasic pulsations of electric current by means of noninvasive electrodes. Once experimental pruritus had been reliably reproduced, two variables, hypothesized to be relevant to the perception of itching, were investigated, viz, the presence of a positive or a negative history of a pruritic dermatosis, and the presence of a high or low level of psychological stress. Both variables were found to be related to the perception of itching, but in different manners. A positive history of a pruritic dermatosis lowered the threshold for the perception of itch stimuli, while a high level of psychological stress enhanced the ability to discriminate among the more intense itch stimuli, with no effect on the itch threshold.