Assessment of high-energy phosphorus compounds in the rat kidney by in situ31P nuclear magnetic resonance spectroscopy: effect of ischemia and furosemide

Summary ³¹P nuclear magnetic resonance (NMR) spectroscopy of the in situ rat kidney was performed by a surface coil method, and the effects of ischemia and furosemide infusion were assessed.³¹P NMR spectra of the kidney subjected to 30 min of ischemia returned completely to the pre-ischemic level after 60 min of reperfusion. But the³¹P NMR spectra after 60 min of ischemia did not recover, even after 120 min of reperfusion. Levels of -ATP and inorganic phosphate (Pi) decreased and the chemical shift of Pi increased after intravenous infusion of furosemide. This increase in chemical shift might signal an alkalotic change in intracellular pH. Furosemide infusion prior to ischemia is thought to protect the kidney from injury induced by 60 min of warm ischemia. The chemical shift of Pi returned to the pre-ischemic level earlier than -ATP and Pi. In conclusion, according to the findings of³¹P NMR spectroscopy, furosemide infusion prior to ischemia may be effective in protecting the kidney against ischemic injury. But the change in Pi peak and the causes of the dissociation of Pi and -ATP should be examined further.     

Multiprogrammable pacemakers. Complications. Nursing care

This paper deals with the study of 927 patients of both sexes, with multiprogramable pacemakers implanted during 1987-1988 period, at the "Comandante Manuel Fajardo" Teaching Hospital and the Institute of Cardiology and Cardiovascular Surgery. Complications accounted for 14.9% and the most frequent were, in decreasing order, as follows: sepsis of the pocket (46.7%), hematoma of the pocket, increased threshold and, in a lower percentage, aseptic necrosis (5.7%). Emphasis is made in the role of the nurse in front of a patient with pacemaker and of the different complications presented.     

Quinolone prophylaxis in neutropenic patients - efficacy versus resistance

To assess the efficacy of quinolones in the prophylaxis of infections in neutropenic patients with acute non-lymphocytic leukemia, and to evaluate the emergence of quinolone resistance in two University Hospitals in Brazil, we retrospectively compared 101 consecutive episodes of neutropenia managed with quinolone prophylaxis between 1989 and November 1993, and 26 previous episodes without prophylaxis, and reviewed the results of in vitro sensitivity of Gram-negative strains to quinolones in the same period. Prophylaxis with quinolones resulted in less episodes of bacteremias (21% vs. 69%, p=10(-7)), including Gram-negative bacteremias (6% vs. 38%, p=10(-5)), with no statistically significant difference in the death rate (18% vs. 31%, p=0.14, 95% confidence interval -6-32). The resistance of Gramnegative strains to quinolones rose from 7% to 18% between 1990 and 1993 (p=10(-5)). The resistance against ceftazidime and amikacin, the agents used in the empirical antibiotic therapy, increased in the same proportion as the quinolones. Given the limited benefit of quinolones as prophylaxis and the increasing number of quinolone-resistant Gram-negative strains observed in our hospitals, the use of quinolones as prophylaxis must be seriously questioned. A stricter control of the use of quinolones in these hospitals might decrease resistance.     

Pharmacological effects of concomitant administration of β-adrenoceptor blocker and agonist in normal subjects: characterization by heart rate response to exercise

The effects of a combination regimen of metoprolol and ₁-adrenoceptor agonist denopamine on resting and exercise heart rate have been studied in 10 normal volunteers. Maximal ramp upright bicycle exercise was performed three times at 1-week intervals. Two hours before each exercise test, 5 mg metoprolol plus 20 mg denopamine, 5 mg metoprolol plus a denopamine placebo, or two placebos were orally administered in a double-blind fashion.During exercise after placebo administration, heart rate increased in parallel with the exercise intensity. Compared to the placebo values, resting heart rate was significantly decreased by an average of 10 beats · min^–1 by 5 mg metoprolol, whereas it was not altered by the combination regimen. During exercise, however, both the combination regimen and metoprolol alone showed a significant negative chronotropic effect, decreasing peak exercise heart rate by an average of 14 and 21 beats · min^–1, respectively. Peak oxygen uptake was also significantly decreased by both regimens.We conclude that concomitant administration of 5 mg metoprolol and 20 mg denopamine exerts an effective -adrenoceptor blocking action during exercise but a minimal effect at rest in normal subjects. The combination regimen appears to have a favourable pharmacological profile for -adrenoceptor blocker therapy in patients with chronic heart failure.     

Case report of 14-year survival after radiotherapy for clinical T3 esophageal carcinoma, with local recurrence finally rescued by surgery

A 51-year-old man with increasing dysphasia was admitted to our hospital on March 18, 1985. Several examinations revealed thoracic esophageal squamous cell carcinoma 11 cm in length staged T3N0M0 (stage IIA) by UICC 1987. As he rejected our proposal of surgery, definitive radiotherapy (60 Gy) was delivered, and complete response was obtained. The patient had been doing well for 5 years after radiotherapy until superficial local recurrence was discovered at a periodic endoscopic examination. High-dose-rate intraluminal brachytherapy (10 Gy/2 Fr) was administered. After a 3-year disease-free interval, superficial recurrence developed in the same location, and early gastric cancer was detected as a secondary cancer. Radical salvage surgery was performed. The patient was alive and disease free 5 years and 5 months after surgery. We present this rare case of a patient who survived 14 years after the initial radiotherapy. The present case demonstrated the importance of long-term follow-up after radiotherapy, long-term local controllability of relatively low doses of intraluminal brachytherapy after superficial recurrence, and the feasibility of salvage surgery as long as local recurrence is limited to within the mucosal layer.     

Two-dimensional photon counting imaging and spatiotemporal characterization of ultraweak photon emission from a rat's brain in vivo

The process of metabolic reactions within living cells leads to spontaneous ultraweak light emission. The development of a system for highly sensitive imaging and spatiotemporal analysis of ultraweak photon emission from a rat's brain is reported in this paper. The equipment used in this experiment consists of a two-dimensional photon-counting tube with a photocathode measuring 40 mm in diameter, a highly efficient lens system, and an electronic device to record time series of a photoelectron train with spatial information. The sensitivity and ability to extract spatiotemporal information from sequential data of a single photoelectron train were examined. The minimum detectable radiant flux density of the system was experimentally estimated to be 9.9 x 10(-17) W/cm2 with a 1-s observation time. Spontaneous photon emission was demonstrated from an exposed rat's cortex in vivo without adding any chemical agent or employing external excitation. An image of ultraweak photon emission was compared with one obtained after cardiac arrest. The intensity after cardiac arrest was depressed to approximately 60% of before that. The regional properties of time courses of emission intensity were also demonstrated, indicating the potential usefulness for spatiotemporal characterization of photon emission with mapping of physiological information such as oxidative stress. This technology constitutes a novel method, with the potential to extract pathophysiological information from the central nervous system.     

Fractal dimensions in the occurrence of miniature end-plate potential in a vertebrate neuromuscular junction

1. Occurrence of miniature endplate potentials (MEPP) in the sartorius muscle of Rana catesbiana in high Mg2+ Ringer solution were observed in standard intracellular recording. Intervals and amplitudes of sequentially occurring MEPP were registered and analyzed. 2. Interval histograms of a time series of MEPP showed exponential-like pattern as reported in the classical study by Fatt and Katz (1952). The cumulative distribution of the intervals plotted in logarithmic axes showed two distinct phases. In shorter intervals (< 1s), curve along exponential decay was observed, and in longer intervals (> or = 1s) linear decay can be seen. The latter power-law relation gave dimensions of 4.111 +/- 0.812 (mean and S.D.). Self-similarity in longer range implies a time-scale invariant nature and may suggest fractal nature in restoration process of synaptic vesicles, while exponential decay in the short time interval range implies random release of transmitter packet from the readily releasable pool. 3. Fluctuation of amplitudes in sequentially occurred MEPP were analyzed according to Higuchi's cumulative route-length analysis. The estimates for sequential amplitude curve showed the power-law relation in a logarithmic plot whose inclination (= D) estimated with linear regression analysis was 1.996 +/- 0.007 (mean and S.D.). This results indicate that fluctuation in the amplitude of MEPP shows possible maximum complexity as a graphic curve in 2-D plane. Similar result was obtained for fluctuation of intervals of successively occurring MEPP.     

Adjuvant immunotherapy using fibroblasts genetically engineered to secrete interleukin 12 prevents recurrence after surgical resection of established tumors in a murine adenocarcinoma model

BACKGROUND: To explore effective therapeutic strategy against cancer of the gastrointestinal tract, tumor vaccination using fibroblasts secreting interleukin-12 (IL-12) was developed as an adjuvant therapy against murine tumor after surgical resection. METHODS: Initially, IL-12 was genetically engineered into fibroblasts (IL-12/3T3 cells), and then we evaluated in vivo and in vitro antitumor effects. In the vaccination model, irradiated C-26 tumor mass was reinoculated intradermally with IL-12/3T3 cells in mice as a tumor vaccine to examine how much it suppresses tumor recurrence. RESULTS: IL-12/3T3 cells producing 7.2 ng/10(6) cells/24 h murine IL-12 in vitro exerted dose-dependent potent tumor suppression when coinoculated with C-26 cells in vivo. Specific immunity was also acquired in 63% of mice in vivo. In the vaccination model, protective immunity was developed in 70% of mice that were inoculated with irradiated tumor mass and IL-12/3T3 cells. In addition, local recurrence was not observed in vaccinated mice, although 44% of control mice had recurrence. CONCLUSIONS: Coinoculation of genetically engineered fibroblasts secreting IL-12 with irradiated tumor mass was proved to be an effective tumor vaccine. This system of vaccination is easily applicable to clinical situations, particularly to human gastrointestinal tract cancers.