A 28-day feeding study with methyl isoeugenol in rats.

Methyl isoeugenol was administered in rodent diet for a minimum of 28 consecutive days to groups of 16 male and 16 female rats (Sprague-Dawley strain) at levels of approximately 30, 100 and 300 mg/kg body weight/day. A further group of 16 male and 16 female rats was given the rodent diet as a control. The administration of methyl isoeugenol in the diet did not adversely affect the growth or general health of the animals or their food intakes. Although high dose animals of both sexes had increased lymphocyte and total white blood cell counts, these are not considered, in isolation, to be an adverse effect of treatment. None of the minor variations observed in the serum chemical analyses or urine analyses is considered to be indicative of a treatment-related toxic effect. An increase in liver weight, adjusted for body weight, was seen in male and female rats receiving 300 mg methyl isoeugenol/kg body weight. Few histopathological abnormalities were observed. Although the incidence of kidney and Harderian gland lesions was higher for high dose animals compared with the controls, the lesions are of a type that occurs spontaneously and are thus not considered to be attributable to treatment with methyl isoeugenol. While the increased liver weight and white blood cell counts of rats given 300 mg methyl isoeugenol/kg body weight may represent effects of treatment, it is not considered that there is any reason to regard these as adverse effects.     

Staged bilateral thalamic electrode implantation utilizing frameless stereotactic guidance.

Deep brain stimulation (DBS) for medically intractable Parkinson's disease (PD) is well established, but carries the inconveniences of frame-based neurosurgery. Previous reports have demonstrated that ventricular shunt placement and some functional procedures can be accurately performed using frameless stereotaxy. We present a report indicating that staged deep brain electrode placement can be accurate and efficacious using a frameless skull-mounted guide.     

Convergence of occipital nerve and superior sagittal sinus input in the cervical spinal cord of the cat

Co-existence of facial and occipital pain may occur in occipital neuralgia, migraine and cluster headache; suggesting convergence of trigeminal and cervical afferents. Such convergence has been shown in humans and other animals, but the site and extent of this are uncertain. In anaesthetized adult cats, the superior sagittal sinus and occipital nerve were stimulated electrically, and extracellular recordings made in the dorsolateral area of the upper cervical cord using glass-coated tungsten electrodes. Of 49 units in 10 cats, 33 (67%) had input from the superior sagittal sinus and the occipital nerve. Thirteen (27%) had superior sagittal sinus input and 3 (6%) had occipital nerve input. Convergent receptive fields were identified mechanically in 7 units. These experiments in cats show convergent input from occipital nerve and superior sagittal sinus on dorsolateral area units in two-thirds of cases studied. This experimental site of trigeminocervical convergence may relate to referral of pain in occipital neuralgia and other headaches.     

Nonsteroidal anti-inflammatory drugs (NSAIDs) and the kidney

In patients with PG-dependent renal function, NSAID administration constantly reduces GFR and RBF in a dose-dependent fashion. In this situation, the risk of overt acute renal failure is high and should be taken into proper account. In contrast, the incidence of NSAID-related renal structural alterations appears to be very low, yet the absolute number of patients may be significant considering the wide use of such drugs. Concerning the antiproteinuric effect of NSAIDs, the unfavourable ratio risk/benefit does not seem to support their indication in proteinuric nephropathies. The development of PGHS-2 selective inhibitors is promising, and may open new therapeutical strategies in the treatment of the progression of renal disease.