A case of lumbosacral polyradiculitis in an HIV-1-positive man (CDC IIB) leading to a flaccid paraplegia below the level of L4 is reported. A detailed analysis of several cerebrospinal fluid samples led to the suspicion of a bacterial infection. After treatment with antibiotics and tuberculostatic agents the neuropathy improved and the patient has survived for 2 years. In contrast to similar cases that were probably caused by cytomegalovirus in terminal stages of AIDS, it is argued that an unidentified bacterial infection was the cause of the polyradiculitis in the present case.

Series IAfter anaesthesia with diethyl-ether one common carotid artery was ligated and transsected. Twenty-four hours later the animals were exposed to carbon monoxide (3000 ppm in room air) for 90 minutes while held in a plastic box with a volume of 3001, allowing the exposure of eight animals at a time. The gas mixture was stirred by a fan. The concentration of carbon monoxide was continuously monitored inside the plastic container and in its immediate vicinity by an infrared spectrometer (URAS I, Hartmann & Braun, FRG) to assure a continuous exposure of the animals and to protect laboratory personnel against accidental leaks. At the 48th hour after exposure the rats were anaesthetised with diethyl-ether and perfused via the ascending aorta with formalin after briefly washing out the vasculature with saline.

Transoesophageal ultrasound imaging of the spinal canal through an intervertebral disc was successfully achieved in 44 of 50 adults (18 women and 32 men; mean age 56 years, range 22-79) who, for cardiological indications had transoesophageal echocardiography. On average, five (range 1-11), usually sequential, segments were visualized. In 37 patients pulse-synchronous sagittal displacement of the spinal cord was noted, presumably caused by cerebrospinal fluid pulsation. In one woman, with known syringomyelia, the spinal cord cavity was well shown. Real-time demonstration of dynamic events in the spinal canal opens up new possibilities for the diagnosis and follow-up monitoring of spinal diseases.

SUMMARY Unilateral cerebral infarcts were produced in the rat by ligation of one common carotid artery and a subsequent exposure to carbon monoxide. In animals which had undergone an additional ligation of the external jugular veins leading to a moderate increase of the cephalic venous pressure the outcome of the procedure was ameliorated significantly. Venous pressure elevation was thought to reduce the venous vascular resistance effectively by preventing the leptomeningeal veins from collapsing. Collapse of the leptomeningeal veins probably occurred during the severe carbon monoxide-induced hypotension causing a steep increase of cerebral vascular resistance.There is evidence that the threshold value of cerebral perfusion pressure below which cerebral infarcts occur is conspicuously clear-cut.' 2 We presume that this in part can be attributed to the collapse of leptomeningeal veins, which is known to increase flow resistance. Since a collapsed vessel can be distended by adding a flow resistance to its outlet we tested the hypothesis that the incidence of hypotension-induced brain lesions could be reduced by elevating the cephalic venous flow resistance. We used a modified Levine procedure which has been described in detail.3 Material and methodsThe experiments were perfonned with unstarved male albino rats of the Chbb:THOM strain. Series IIn 88 of 175 animals (body weight: 300-400 g) both external jugular veins were ligated at the time of unilateral common carotid artery ligation. Twenty-four hours later the carbon monoxide exposure (3000 ppm in room air, 90 minutes duration) was performed.

SUMMARY Unilateral cerebral infarcts were produced in the rat by ligation of one common carotid artery and subsequent exposure to carbon monoxide. The incidence and extension of brain infarcts was increased in animals with additional ipsilateral cervical preganglionic sympathectomy. Sympathectomy did not affect markedly the respiration and systemic circulation. The effect of sympathectomy was attributed to a cutaneous vasodilation, leading to an extracranial steal phenomenon.The role of the cervical sympathetic innervation of the cerebral vessels is controversal. It is generally accepted that the influence of the sympathetic innervation on the extracranial vasculature is much more effective than on the intracranial bed. Since the extra-and intracranial vascular beds are connected in parallel, and since flow through the carotid bifurcation is not hampered by ligation of the common carotid artery, our model permits the study of the effects of ipsilateral cervical sympathectomy on the cephalic vasculature. Materials and methodsThe experiments were performed with male rats (Chbb:THOM strain). Series III In animals with enophthalmos and ptosis the presence of miosis, the most important sign of sympathetic deficit, was demonstrated as follows: in four animals without dissection of the common carotid artery a preganglionic cervical sympathectomy was performed. After 9 to 50 days the animals were sedated (haloperidol 0-2 mg/kg body weight) and 30 minutes later both eyes were photographed after 60 s of complete darkness. We used an operating microscope and a light flash for photographic purposes. A series of six photographs was taken and the entire sequence was repeated twice. The greatest diameter of the pupil was measured on the prints. Series IVIn 18 unanaesthetised and unrestrained animals the following parameters were monitored before, during and for 80 minutes after carbon monoxide exposure (3000 ppm in room air, 70 minutes duration): systemic arterial blood pressure, heart rate, respiration rate, and EEG. For the recordings a slip ring assembly was used (for details cf ref 1). In seven of these animals the ipsilateral sympathetic chain had been divided.