Outpatient lumbar myelography. Initial results in 79 examinations using a low-dose metrizamide technique

Seventy-nine patients underwent lumbar myelography on an outpatient basis, with a low (3.75 g) dose of metrizamide as the radiocontrast agent and a 25-gauge spinal needle used for lumbar puncture. No patient experienced significant neurotoxicity following the examination; 70.8% (56 of 79) experienced minimal (23%) or no (48%) side effects. Three patients (3.8%) were admitted to the hospital for management of common side effects (headache, nausea/vomiting, back pain). We obtained postmyelographic computed tomographic scans on 96% (76 of 79) of the patients. Our initial results suggest that outpatient lumbar myelography is safe and can be performed with a very acceptable incidence of side effects.     

Cocaine-induced behavioral sensitization and D1 dopamine receptor function in rat nucleus accumbens and striatum.

Based on electrophysiological data showing that repeated cocaine administration produces persistent enhancement of D1 dopamine (DA) receptor-mediated responses in nucleus accumbens (NAc), we investigated whether changes in neurochemical properties of these receptors resulted when rats were injected with cocaine (15 mg/kg) for 6 days followed by a 7-day abstinence period. D1 DA receptor density and affinities for either [3H]SCH 23390 or DA were similar between NAc and striatum and between saline and cocaine treatment groups. DA-stimulated adenylyl cyclase activity was 1.5-fold higher in striatum than in NAc; however, repeated cocaine treatment produced no persistent changes in enzyme activity in either brain area.     

[S]TBPS binding sites are decreased in the colliculi of mice with a genetic predisposition to bicuculline-induced seizures

Several differences have been found in GABAergic function between the long sleep (LS) and short sleep (SS) mice which were genetically selected for different ethanol-induced sleeptimes, and it has been suggested that these differences may explain their differential ethanol sensitivity. However, these lines also differ in seizure susceptibility, a behavior which may also be mediated by GABAergic pathways. Thus, it is difficult to associate differences in GABA neurochemistry with either of these behaviors, particularly when only two selected lines are used. We measured differences in the density and affinity of the [³⁵S]TBPS binding site on the GABA_A receptor/Cl⁻ ionophore complex in discrete brain areas; and in order to determine the relationship between receptor binding and behavioral differences, we included mice from 5 of the LS and SS recombinant inbred strains (LS × SS RI) in addition to mice from the LS and SS lines. [³⁵S]TBPS binding in sagittal brain sections was analyzed by quantitative autoradiography, and the amount of binding differed depending on whether bicuculline was added to inhibit endogenous GABA binding. In the presence of bicuculline, the number of [³⁵S]TBPS sites in SS mice was highest in the colliculi (4.5 ± 0.5 pmol/mg protein), cerebellum (4.8 ± 0.6 pmol/mg), hippocampus (3.2 ± 0.7 pmol/mg) and cortex (2.9 ± 0.3 pmol/mg). The B_max was two-fold lower in both superior and inferior colliculi (IC) of LS mice. There were no differences between lines in B_max in any other area and in K_d values in any area (58 ± 4.0 nM). When we compared [³⁵S]TBPS binding in the LS × SS RI strains, B_max values in IC were negatively correlated with latency to bicuculline-induced seizures but were not correlated with the duration of ethanol-induced sleeptime. These data support the hypothesis that differences in GABAergic neurochemistry in these mouse lines may not always be related to differences in ethanol sensitivity and point to GABAergic receptors in IC as possibly being involved in determining seizure sensitivity to bicuculline.     

Outflow and overflow of picogram levels of endogenous dopamine and DOPAC from rat striatal slices: improved methodology for studies of stimulus-evoked release and metabolism

An improved method for the rapid and sensitive determination of endogenous dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) in superfusates of single rat striatal slices, using high-performance liquid chromatography (HPLC) coupled with 'coulometric' electrochemical detection (EC), is described. Superfusates are directly injected into an HPLC-EC system following addition of a small aliquot of solubilized ascorbate-oxidase. DA and DOPAC are both separated and quantitated in 3-5 min. Twelve to 15 samples can be analyzed each hour with a nominal detection limit of 1.0 pg per injection for each compound or 10-20 pg/ml of superfusate. The present method was used to study changes in DA and DOPAC outflow and overflow in superfusates of single striatal slices following electrical field stimulation, both in the absence and presence of the catecholamine uptake inhibitor nomifensine. Studies of 1 min superfusate collections clearly showed that electrical field stimulation produced a latent increase in DOPAC as compared to DA. The routine sensitivity and sample throughout of the method allows for studies of both outflow and overflow of DA and DOPAC, as well as studies involving time-dependent overflow of these compounds.     

Ultrasound of the whole breast utilizing a dedicated automated breast scanner

Innovations in design of a dedicated breast scanner resulted in automation of the scanning process, the production of high resolution images of the whole breast and an efficient mode of image review. The results of clinical evaluation of the prototype of this breast scanner investigating normal breasts as well as benign and malignant breast lesions are presented.     

Complications of percutaneous nephrostolithotomy

In 224 patients, renal stones were removed from the urinary tract using either direct extraction with a basket or forceps (59 patients), ultrasonic lithotripsy (164 patients), or infusion chemotherapy (one patient). Residual stone fragments were present more frequently in patients treated with ultrasonic lithotripsy (27%) than with direct extraction (5%). Other complications included hemorrhage (eight patients), catheter dislodgement (four patients), large amounts of urine extravasation (three patients), glycine ascites (three patients), infection (two patients), pneumothorax (one patient), and a prolonged ileus (one patient). More complications occurred among the first 50 patients than the last 50 patients, even though more difficult cases, including patients with staghorn calculi, were accepted during the latter period. Although a learning curve exists, complications can be minimized by attempting to treat more favorable cases during the initial experience.     

Clinical study of multiple breath biomarkers of asthma and COPD (NO, CO(2), CO and N(2)O) by infrared laser spectroscopy

Breath analysis is a powerful non-invasive technique for the diagnosis and monitoring of respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD). Exhaled nitric oxide (NO) and carbon monoxide (CO) are markers of airway inflammation and can indicate the extent of respiratory diseases. We have developed a compact fast response quantum cascade laser system for analysis of multiple gases by tunable infrared absorption spectroscopy. The ARI breath analysis instrument has been deployed in a study of exhaled breath from patients with asthma or COPD. A total of 173 subjects participated, including both adult and pediatric patients. Patients in asthma or COPD exacerbations were evaluated twice-during the exacerbation and at a follow-up visit-to compare variations in breath biomarkers during these events. The change in exhaled NO levels between exacerbation and 'well' visits is consistent with spirometry data collected. Respiratory models are important for understanding the exchange dynamics of nitric oxide and other species in the lungs and airways. At each patient's visit, tests were conducted at four expiratory flow rates. We have applied a trumpet model with axial diffusion to the multi-flow exhaled nitric oxide data, obtaining NO alveolar concentrations and airway fluxes. We found higher airway fluxes for those with more severe asthma and during exacerbation events. The alveolar concentrations from the model were higher in adults with asthma and COPD, but this trend was less clear among the pediatric subjects.