Do visual evoked potentials detect neural damage in children treated for cancer?

Abnormal visual evoked potentials (VEPs) have been reported in children treated for acute lymphoblastic leukaemia (ALL), which suggests that VEPs may be useful in screening for toxicity. The authors investigated this by recording flash and pattern VEPs in a control group of 34 siblings of patients, a group of six children studied longitudinally during the early stages of treatment for ALL, and three other follow-up groups. In only three follow-up patients were VEP results outside the normal range and the six ALL patients did not develop new abnormalities during early treatment. Although differences were detected between the groups, there was no evidence of VEPs being a useful means of monitoring the treatment of individual patients.

Dostoevsky's epilepsy: a case report and comparison

The Russian writer Dostoevsky (1821-1881) suffered from a rare form of temporal lobe epilepsy termed "ecstatic epilepsy." Dostoevsky used his epileptic experiences to create Prince Myshkin, the protagonist of The Idiot. The recent case of a patient who experienced ecstatic epilepsy as a result of a temporal lobe brain tumor is presented and compared with that of Prince Myshkin. Reading Dostoevsky can give the contemporary physician an insight into the inner life of an epileptic patient--an example of how art can directly benefit medical practice.

Assessment of students' behavioral interactions during on-task classroom activities

This study was designed to characterize the quality and quantity of interactions between students and significant others in the processing of new information during classroom activities. I wanted to test the hypothesis that black children, from moderate to low income urban environments, tend to have a more socially active cognitive style than their white peers in the performance of classroom tasks. Five different English classes, all 8th graders in a single junior high school (total of 114 black and white boys and girls), were observed in the same environment at different intervals to identify differences in the number of interactions between boys and girls, by racial groups. Classroom lessons and related activities were videotaped. The recorded activity was tabulated and rated by 3 trained observers. Black children more than white, and boys more than girls, initiated interactions with peers in the classroom in performing assigned tasks. This social interaction also showed that (1) 76% of the observed classroom time, subjects as a group were observed on-task and (2) pupils' interactions with their selected targets (classmates and their teacher) were 87% positive, and (3) relatively few interactions could be classified as disruptive.

The accumulation of cadmium by vegetables grown on soils contaminated from a variety of sources

The accumulation of cadmium by four crops (cabbage, carrot, lettuce and radish) grown on soils contaminated from a variety of sources was investigated in greenhouse pot experiments. Stepwise multiple regression analyses of the data revealed that, out of the 23 soil variables determined, only eight were significantly related to cadmium accumulation in the edible plant tissues. The most frequently occurring soil parameter was total cadmium, which was inversely related to plant cadmium accumulation (CdPlant tissue/CdSoil). This implies that, for the heterogeneous group of soils used, as the concentration of cadmium in the soil increases the proportion available to the plant decreases. This may be due to the presence of metallic ore particles and/or the high sorptive capacity of the most contaminated soils. When the data were divided into two groups: sewage sludge amended soils and inorganically contaminated soils, the R-squared values were usually enhanced and some differences occurred in the variables included in the multiple regression equations; this may be indicative of the differences in speciation. Cadmium accumulation by plants grown on sewage sludge amended soils was lower than that for the inorganically contaminated soils. The heterogeneity of the inorganically contaminated group of soils resulted in lower R-squared values for the multiple regression equations; this group of soils exhibited a wide range of soil variables, such as pH, and had been contaminated by a variety of means, such as atmospheric deposition from metal smelters and the dumping of mine wastes.

Polarity-dependent voltage-gated porin channels from Escherichia coli in lipid bilayer membranes

A porin preparation from Escherichia coli 0111:B4 consisting of Omp F and Omp C (with Omp F in excess) was purified by salt extraction procedures and investigated in bilayer lipid membranes formed according to the Montal-Mueller technique. The porin preparation was added to the KCl electrolyte compartment of the Montal-Mueller cell which was connected to the voltage source. As the porin incorporated into the membrane, asymmetric, voltage-gated ion channels were formed. Transmembrane voltages greater than +50 mV (measured with respect to the side of porin addition) caused channel closing, while negative voltages, on the other hand, had no effect on channel behaviour but did increase the rate of porin incorporation at higher voltages. With porin added to both compartments voltage gating no longer occurred. Single-channel conductances corresponded to effective pore diameters of 1.5 nm for opening events and 1.18 nm for channel closing events. The number of charges involved in gating was approximately 2.

Neurophysiological investigation of diabetic impotence. Are sacral response studies of value?

The role of electrophysiologically elicited sacral responses in the detection of the neurological component of diabetic impotence has been evaluated in a detailed study using properly defined diagnostic criteria. The results prove that these tests are not reliable indicators of neuropathy and their relevance in the routine investigation of diabetic impotence is of questionable value.

Graft rejection following HLA matched T-lymphocyte depleted bone marrow transplantation

Bone marrow graft rejection following HLA-matched bone marrow transplantation (BMT) for leukaemia has been a rare problem. However, with the introduction of T-lymphocyte depleted BMT, graft rejection is recognized as a new complication. At the Royal Free Hospital (RFH) in London T-depletion is achieved using two monoclonal antibodies with complement mediated lysis. The methodology was extended to other centres and in total 56 patients have received T-depleted, HLA matched BMT. Twelve of 56 patients have had graft rejection. At the RFH three of 41 (7%) patients have had rejection whereas at collaborating centres nine of 15 (60%) patients have had rejection. We have investigated these rejections in order to identify factor(s) responsible. Rejection was not restricted by patient or donor characteristics, nor disease status. Patient management, chemotherapy conditioning, efficiency of T-depletion, graft versus host disease (GvHD), and infection post BMT, were not consistently implicated. The major difference between the RFH and all other centres was in the radiotherapy (RT) conditioning: The RFH prescribed a single fraction of 7.5 Gy total body irradiation (TBI) whilst collaborating centres gave 10 or 12 Gy fractionated TBI. We conclude that the different incidence of rejection (7% v. 60%) relates primarily to the RT conditioning although the mechanisms(s) of rejection remain unknown. We conclude that where T-depleted BMT is used, compensation by more intensive RT conditioning is required in order to avert graft rejection.

Conformation therapy: a method of improving the tumour treatment volume ratio

Restriction of the volume irradiated is a fundamental tenet of radiotherapy. Conventional two-dimensional treatment results in geometrically shaped high-dose regions, the sizes of which are defined by the greatest dimensions of a tumour mass. Conformation therapy permits a tumour to be considered for treatment as multiple short segments, and the radiation field to be tailored to fit each segment accurately. This paper demonstrates that this results in a reduction of the treatment volume of between 10% and 80%, depending on the shape of the tumour. Also, it is shown that a greater proportion of the high-dose region is occupied by tumour, thus reducing the volume of normal tissue treated to a high dose. Smaller treatment volumes allow the prescription of tumoricidal doses and improve the tolerance of radiation by patients.

Cadmium intake and cadmium in the human kidney

The diet and cigarette smoking are the main sources of cadmium intake in people not occupationally exposed to cadmium. Using data gathered from the literature, it is shown that there is a statistically significant relationship between the average cadmium intake in various countries and the average kidney cadmium concentration in 40-60 year old people living in those countries. It is estimated that a regular dietary intake of cadmium of 175 micrograms/day would cause the concentration of cadmium in the renal cortex to reach the critical level in 50 years.

The clinical significance of antisperm antibodies in male subfertility

Sera from 591 men attending Fertility Clinics have been tested for agglutinating, immobilising and immunofluorescent antisperm antibodies. There was good correlation between the presence of high titres (more than 1/32) of agglutinating and immobilising antibodies which were found in 50 patients (8.5%). 27 of these men had normal sperm counts, but crossed hostility testing showed that in 21 of 22 couples the sperms were unable to penetrate the cervical mucus, apparently because of the antibodies. 17 patients were treated with prednisone for an average of 6 months and 1 pregnancy was produced. 17 patients were treated with methylprednisolone for 7 days and 1 pregnancy resulted. No correlation was found between the present of immunofluorescent antibodies and the other antibodies of impaired sperm penetration of cervical mucus.

Sperm/cervical-mucus crossed hostility testing and antisperm antibodies in the husband

The behaviour of sperms has been investigated in preovulatory cervical mucus in 44 infertile couples. In 22 couples, immobilising and agglutinating autoantibodies were detected in the husband's sera in high titres. In 10 couples, antisperm antibodies were detected in the husbands by indirect immunofluorescent testing. In 12 couples, no evidence of antisperm antibodies was found in either husbands or wives. The results obtained with husband and wife were compared with the behaviour of the husband's sperms in cervical mucus from fertile donors, and with the behaviour of sperms from fertile donors in the wives' mucus. This crossed hostility test indicated that high tires of immobilising and agglutinating antisperm antibodies in the husband effectively prevented the sperms from penetrating the cervical mucus, even though the sperms appeared normal on seminal analysis. Antibodies detected by indirect immunofluorescence did not have this effect. Poor penetration was also observed with low sperm motility or poor cervical mucus. It is concluded that this test, taken with the postcoital test, could provide a useful screen for immunological causes of infertility and an accurate test for the clinical relevance of antisperm antibody tests.