Brainstem auditory evoked potentials in dizziness

To investigate the role of brainstem dysfunction in patients with dizziness, Brainstem Evoked Responses were recorded, and results of 100 such cases are presented. The present study further emphasizes the fact that dizziness is a symptom complex and careful evaluation of these patients is necessary. If a systematic approach is used, then a correct diagnosis can be achieved in over 95% of the cases. Vascular insufficiency of the brainstem can present as dizziness and may precede a catastrophic vascular infarction by weeks and months. Early recognition of the problem is of paramount importance, since anticoagulation therapy can be started early or other surgical correctable measures can be undertaken to prevent catastrophic infarction.

Radiosensitization in vivo: a study with an homologous series of 2-nitroimidazoles

An homologous series of 1-(omega-morpholino)alkyl-2-nitroimidazoles, previously reported to be more efficient hypoxic cell radiosensitizers than misonidazole (MIS) in vitro, were evaluated in vivo using the murine Lewis Lung carcinoma. When given i.p. the compounds were 3-20 times more acutely toxic (LD50/2d) than MIS and this toxicity increased with both the number of methylene groups (n) in the side chain and the lipophilicity of the compounds. The compounds sensitized the tumour to single doses of X-rays. On the basis of equimolar administered dose, the most effective compounds, n = 2, 4 and 5, were as efficient as MIS. However, on the basis of the measured concentration of drug in the tumour at the optimum time of irradiation the compounds with n = 4 and n = 5 were less efficient than expected from previously published data in vitro. This is attributed to the basicity of the morpholino nitrogen in these compounds such that at physiological pH the compounds are primarily in an ionized form and hence poorly able to penetrate hypoxic cells.

Studies on the photostability of reserpine in parenteral solutions

The photostability of reserpine in several parenteral formulations has been studied and the effects of some commonly used stabilizers have been evaluated. The kinetic data indicate that the photodegradation of reserpine follows zero order kinetics in all the formulations at pH = 2 and 3. The stability of reserpine appears to be higher at pH = 3 than at pH = 2. 3-dehydroreserpine, isoreserpine and lumireserpine were identified as the major photodegradation products by TLC, suggesting that the photodegradation in acidic solutions occurs initially via an oxidative mechanism. The combined effect of EDTA and PABA on the photostability of reserpine was more significant than their individual effect. The formulations in which benzyl alcohol was used as vehicle were found to be more stable than those having propylene glycol. Polyethylene glycol was found to be a better surfactant than Tween 80. The degree of stabilization in the presence of surface active agents has been explained in terms of micellar theory and the degree of hydration of micelles. A stable formula for parenteral solution of reserpine has been suggested.

Visual evoked potentials in alcoholics

Visual evoked potentials were obtained in nineteen patients during the early phase of alcohol intoxication. Out of the thirty-eight responses recorded in the nineteen patients, 13% were found to be abnormal (5 responses). Repeated testing was done in all patients with abnormal responses at three to four week intervals following treatment with vitamins and balanced diets. In three patients the major positive peaks returned to normal after treatment.

Neurotoxicity of radiation sensitizers in the mouse

The neurotoxicity of a homologous series of 1-substituted, 2-nitroimidazole compounds, synthesized in this laboratory, has been studied in mice. This involves measurement of the enzyme beta-glucuronidase in the distal sciatic, tibial and common peroneal nerves. The amount of compound required to give a known neurotoxic response, in terms of elevated beta-glucuronidase (arbitrarily set at 60% increase) has been determined. A correlation between increased number of methylene groups (N) in the side chain and neurotoxicity has been shown. A correlation between increased neurotoxicity and effective octanol; water coefficient, at pH 7.4, was also established. A more soluble version of the n = 4 member of the homologous series, that is the compound RSU 1047 (NSC 328897), and misonidazole also fit this correlation of partition coefficient and dose.

Treatment of sleepwalking: a controlled study

A single-blind, rater-blind, modified crossover design was used to evaluate a simple, practical method of clinical treatment of sleepwalking. Subjects who had severe somnambulism, but were otherwise free of psychiatric illness, responded well to six brief sessions of specialized hypnotherapy. Follow-up at one year has revealed lasting improvement of both subjective and objective symptoms. A brief review of the subject of sleepwalking, as well as detailed information concerning histories of sleep symptoms and emotional problems in these and other sleepwalkers, is presented.

Structure-activity relationships in the development of hypoxic cell radiosensitizers. III. Effects of basic substituents in nitroimidazole sidechains

The effects of substituting 2-nitroimidazoles with groups carrying basic functions were studied. Prototropic, redox, lipophilicity and protein-binding properties were compared with the efficiency in radiosensitizing hypoxic Chinese hamster V79-379A cells in vitro and the cytotoxicities of the compounds after chronic aerobic exposure. Seventeen compounds were (2-nitro-1-imidazolyl)alkylamines in which the effects of changes in the terminating base and of alkyl chain length were investigated. About an order of magnitude increase in sensitization efficiency could be observed in some compounds without any increase in the aerobic cytotoxicity compared to simple, uncharged 2-nitroimidazoles such as misonidazole. The behaviour of five hydrazones was similar to that of uncharged analogues. The methiodide quaternary salts of two of the (2-nitro-1-imidazolyl)alkylamines showed that quaternization considerably reduced sensitization efficiency. (Nitro-1-imidazolyl)alkylamines appear worthy of further investigation as hypoxic cell radiosensitizers in vivo.

F-wave conduction velocity in alcoholic polyneuropathy

We used the F-wave conduction velocities to estimate the motor nerve conduction along the proximal segment (spinal cord to knee) of the axon of tibial and common peroneal nerves in ten patients with alcoholic polyneuropathy and compared these to the motor nerve conduction velocities in ten normal subjects. All the studies so obtained showed a normal conduction in the proximal segments even though in three patients the distal nerve conduction values (knee to ankle) revealed moderate to severe neuropathy. These data support the hypothesis that in alcoholic polyneuropathy, motor conduction in proximal segments is not involved even though distal nerves show moderate to severe neuropathy.

Bilateral epileptiform discharges in multiple sclerosis

A case of multiple sclerosis is presented here with bilateral epileptiform discharges which were associated with acute demyelination. The abnormality changed to slow wave activity with the passage of time and as the acute phase of demyelination was over.

Brainstem auditory evoked potentials in transtentorial herniation

Brainstem auditory evoked responses (BAER's) were recorded in patients exhibiting brainstem compression from supratentorial lesions. BAER's were altered in the early stages of herniation. In two cases the latencies returned to normal on treatment with steroids.

Leukomalacia with ruptured saccular aneurysm

A 42-year-old woman with a ruptured saccular aneurysm of the internal carotid artery developed large areas of cerebral leukomalacia, resulting in hemiparesis and an obtunded mental state. A significant factor in the development of the white matter lesions was episodic hypotension, leading to reduced cerebral blood flow in a patient whose cerebral circulation was already compromised by vasospasm secondary to the subarachnoid hemorrhage. This case illustrates yet another clinical situation associated with the development of white matter necrosis.