Retained pacemaker leads

Increasingly, functionless pacemaker leads are being abandoned in place because they cannot be safely removed. One hundred eighty-nine intact or partially removed pacemaker leads were abandoned in situ in 152 patients between Jan. 1, 1965, and Dec. 31, 1985. The leads, sometimes several leads in a single patient, were deemed uninfected at the time of abandonment in 137 patients and contaminated with Staphylococcus epidermidis in 15 patients. All of the contaminated leads have remained clinically uninfected during follow-up. One clean lead became infected early after implantation and the patient died after an open cardiac operation to remove that lead and an adjacent abandoned lead that was adherent to the subclavian vein. No other patient has had a late complication during follow-up to 256 months (mean 47.6). Properly managed abandonment of an uninfected lead can carry a very low complication rate.     

Cytophotometric investigations on atypical epithelial cells of the human seminal vesicle

Normal seminal vesicles were studied histologically in 80, and by Feulgen’s cytophotometric method in 10 autopsied cases (males, 44–82 years of age). In every case large, hyperchromatic nuclei were found. By cytophotometry euploid polyploid atypia was also shown in every case, which is characteristic of benign hormonal dysplasia.     

Chemical-shift imaging: a hybrid approach

The hybrid technique of projection-reconstruction echo-planar (PREP) imaging for obtaining chemical-shift images is demonstrated experimentally using a fluorine sample. The technique which is a variation on echo-planar imaging (EPI) relies on a multipass procedure. It is nevertheless quite efficient and consequently chemical-shift images may be produced in a few minutes. The method produces images in 64 chemical-shift regions, each region mapped spatially by 64 X 64 pixels. The imaging time was just over 4 min. These 64 chemical-shifted images can be straightforwardly added together to form an undistorted image of the complete object. In addition the chemical-shift spectrum can be extracted and the various chemical-shift images can be unambiguously assigned to the spectral peaks.     

Imipenem (N-F-thienamycin) versus netilmicin plus clindamycin. A controlled and randomized comparison in intra-abdominal infections

In a randomized study the clinical and bacteriologic effectiveness of imipenem was compared with the classical combination of netilmicin with clindamycin in patients who had surgery for an intraperitoneal infection, localized or generalized, with positive bacteriologic findings of the specimen taken at surgery. Excluded were all patients who received other antibiotics before surgery, or who died within 3 days after antibiotic therapy was started. Imipenem was given at a dose of 500 mg t.i.d., clindamycin 600 mg t.i.d., and netilmicin according to serum levels. The diagnoses ranged from postoperative peritonitis, gallbladder empyema, perforated gastroduodenal ulcer, small bowel perforation with and without obstruction, and perforated appendicitis to perforation of the colon. The bacteriologic work-up included examination of the primary specimen (aerobic and anaerobic), the urine, feces, and serologic testing for Candida albicans once or twice a week and after the course of antibiotic therapy. In addition, pH measurements of abscesses and drainage fluids were performed. Ninety-three patients entered the study. Forty-seven patients were treated with imipenem (test group), and 46 patients were treated with the combination therapy (control group). The two groups did not show significant differences in age, sex, diagnostic groups, risk factors, primary bacteriology, and duration of therapy (mean: 6.7 days). Thirty-eight patients (80.9%) treated with imipenem were cured, six patients (12.8%) were improved, and there were three (6.4%) failures. The respective numbers for the control group were 31 (67.4%), 10 (21.7%), and 5 (10.9%). The mean duration of hospitalization was 19 days for the test group and 24.5 days for the control group. There were four wound infections in the test group and 11 wound infections in the control group. Imipenem is at least as effective in the adjuvant therapy of intra-abdominal infections as the combination of netilmicin with clindamycin.     

Pathogenesis of adenocarcinoma complicating ureterosigmoidostomy. Experimental observations

Columnar metaplasia, dysplasia, and adenocarcinoma occurred in patches of bladder epithelium exposed to the fecal stream in rats. This suggests that such tumors complicating ureterosigmoidostomy may arise from ureteric epithelium, and that urine is not essential for their development.     

Acute obstruction by enterolith complicating jejunal diverticulosis. Case report

Two cases are presented in which the cause of small-bowel obstruction was enterolith originating in jejunal diverticula.     

Increased axonal transport in the rat optic system after systemic exposure to methylmercury: differential effects in local vs systemic exposure conditions

Axonal transport was studied by several techniques in the optic system of adult female Long-Evans rats following systemic exposure to methylmercury in 5 mM Na2CO3. Control rats were treated with the buffer alone. Four mg Hg/kg body weight for 4-6 days, or for 12 days, induced significant changes in the rate of protein synthesis in the retinal cells and in the rate of propagation of protein-bound radioactivity along the ganglion cell axons. Axonal transport of particulate material in both groups treated with methylmercury increased to a rate of 147 mm/day compared to 93 mm/day in controls. Methylmercury was distributed evenly throughout the retinogeniculate system. No clinical neuropathy was evident in either mercury-treated group. It is proposed that the increased rates of transport may represent an adaptive compensatory response to distal axonopathy caused by methylmercury. To investigate why systemic dosing produced effects opposite to those observed with local application of MeHg, various doses of MeHg were tested in the local and systemic paradigms, including doses which yielded equal concentrations of Hg in the retina. The results indicate that the differential response between the two treatment conditions is not a function of local dose, per se. Local and systemic application produce different dose-effect curves, which do not coincide at any dose.     

Comparison of PET, MRI, and CT with pathology in a proven case of Alzheimer's disease

Positron emission tomography (PET) with fluorodeoxyglucose (FDG), magnetic resonance imaging (MRI), and CT were carried out in a patient with Alzheimer's disease 16 months before he died. At autopsy, the gross appearance of the brain correlated with MRI and CT, which showed some regional atrophy. These were much less revealing than PET, which correlated with microscopic findings of neuronal loss and proliferation of glia. In areas of moderately impaired local cerebral metabolic rate of glucose, as revealed by reduced FDG uptake, there was some gliosis, primarily around the numerous senile plaques. In areas of severe metabolic impairment, there was a profound loss of neurons, extensive gliosis, and a diminished appearance of plaques. PET-FDG is a better measure of the severity of Alzheimer's disease than MRI or CT, because it reflects the degree of neuronal pathology.     

Self-administration of morphine into the lateral hypothalamus in the mouse

BALB/c mice were chronically and unilaterally implanted with a guide cannula, the tip of which was positioned 1 mm above the lateral hypothalamus (LH). On each experimental day, a stainless-steel injection cannula was inserted into the LH, and self-administration of morphine or vehicle in this brain area was studied by using a spatial discrimination test in a Y-maze. In a first experiment, we observed that when mice had access to morphine (0.1 microgram by injection) they rapidly discriminated the reinforced arm from the neutral arm of the maze in order to self administer, with increasing frequency, the drug into the LH. In contrast when only vehicle was present, the two arms were no longer discriminated. In a second experiment we compared the effects of 3 doses of morphine (0.1 microgram, 0.05 microgram and 0.025 microgram by injection); optimal discrimination was obtained with the lowest dose used. In a third experiment we observed that subcutaneous injections of naloxone (4 mg/kg) progressively reduced the number of self-administrations of morphine into the LH, a result which suggests that this response is dependent on an opiate receptor mechanism.