An ultrastructural analysis of neurites in the basal lamina of capillaries in the chinchilla cochlear nucleus.

In an ultrastructural study of the chinchilla anteroventral cochlear nucleus (AVCN), we found innervated capillaries in the layer of granule cells that comprises the dorsolateral portion of the AVCN and forms a cap over the principal portion of the nucleus. In 66% of 215 capillaries we examined in the granule cell layer of various levels of the AVCN, we found structures having ultrastructural features of axons that (1) were within the brain parenchyma and were in direct contact with the pericapillary basal lamina, or (2) were separate fro, the adjacent neuropil and, often in the company of astrocytic processes, were completely enveloped by the pericapillary basal lamina. An analysis of serial sections confirmed that neurites within the pericapillary basal lamina were in continuity with neurites in the brain parenchyma. Most neurites within the basal lamina of capillaries were next to pericytes, but some neurites were next to endothelial cells. None of the neurites adjoining capillaries had the abundance of synaptic vesicles typical of autonomic vasomotor nerve endings and synaptic terminals. Consequently, they may be sensory, responding perhaps to changes in hydrostatic pressure or chemical composition of the blood or cerebrospinal fluid. However, we cannot exclude the possibility that neurites which accompany capillaries in the AVCN terminate elsewhere. In the AVCN the innervation of capillaries is restricted to the superficial layer of granule cells. In none of 177 capillaries of the principal portion of the AVCN did we find an example of a neurite in contact with the pericapillary basal lamina, a pericyte, or an endothelial cell, although it was sometimes necessary to examine specimens at various angles of tilt to confirm that the pericapillary glial sleeve was continuous. Furthermore, we found no innervated blood vessels among 266 capillaries examined in the granular and molecular layers of the cerebellar cortex.

The function of the anterior cruciate ligament during anterior drawer and Lachman's testing. An in vivo analysis in normal knees.

In order to clarify the function of the anterior cruciate ligament (ACL) during clinical testing an in vivo arthroscopic method of assessing the tension of ACL was developed. Twenty young adult patients with normal knee ligaments and menisci were selected. A spring mechanism in the handle of the specially designed probe allowed the surgeon to apply a known perpendicularly directed force to the ligament while the amount of displacement was observed and recorded. Tension was determined in the anteromedial central and posterolateral portions of ACL before and during an anterior drawer test (knee flexed 90 degrees) and before and during a Lachman's test (knee flexed 15 degrees). The results were consistent in all 20 knees. Baseline tension was greater at 15 degrees of flexion than at 90 degrees. A Lachman's test produced maximal tension in the majority of the ligaments. The anterior drawer did not produce maximal tension in any portion of the ligament. Tension within the anteromedial and central portion of the ligament predominated during both uses. This analysis confirms the specificity of Lachman's test as an indicator of ACL integrity. The concept of two reciprocally functioning ACL "bands" by either anterior drawer or Lachman's test is not supported by our data.

[Bilateral epidural hematomas]. / Bilaterale epidurale haematomer.

Bilateral epidural haematomata are rare and comprise only approximately 2% of all the intracranial haematomata. The symptomatology frequently differs from that of unilateral haematomata in that lateralisation is frequently absent. Most commonly, protracted or secondary development of clouding of consciousness is encountered. In cases of head injury, the above mentioned symptoms are indications for emergency computed tomographic (CT) scanning. When operation is performed early, the prognosis is good.

A system for modelling forces on the hip joint in one-legged stance.

We describe a method of testing hip prostheses. The prosthesis is implanted in a proximal section of femur, which is loaded to model the forces applied through the acetabulum via the greater trochanter.

Ketorolac versus meperidine for pain relief after orthopaedic surgery.

In this double-blind, randomized, multicenter study, 244 patients with at least moderate pain after major orthopaedic surgery received intramuscular Ketorolac (60 mg followed by 30 mg) or intramuscular meperidine (100 mg or placebo) every 2 to 6 hours as needed for as many as 5 days. Analgesic response was evaluated for 6 hours after initial study drug administration and thereafter each night at bedtime. Both active treatment groups had similar 3-hour summed pain intensity difference and 3-hour total pain relief scores after the first dose that were superior to placebo. The 6-hour summed pain intensity difference and total pain relief scores were significantly higher with Ketorolac than with meperidine or placebo. The mean daily categorical pain intensity scores were comparable with Ketorolac and meperidine, and both were significantly superior to placebo. Patient ratings of overall medication efficacy were significantly better with Ketorolac than with meperidine. In both patient and observer evaluations, Ketorolac was significantly better tolerated than meperidine, and the number of patients reporting adverse events was lower with Ketorolac than with meperidine. Following major orthopaedic surgery, Ketorolac provided effective analgesia that was superior to placebo and at least comparable with meperidine. Ketorolac was better tolerated than meperidine.