Resection of lung metastases: long-term results and prognostic analysis based on 5206 cases--the International Registry of Lung Metastases

The International Registry of Lung Metastases was established in 1991 to asses the long-term results of pulmonary metastasectomy. The Registry has accrued 5206 cases of lung metastasectomy, from 18 departments of thoracic surgery in Europe (n = 13), USA (n = 4) and Canada (n = 1). Of these patients 4572 (88%) underwent complete surgical resection. The primary tumor was epithelial in 2260 (43%), sarcoma in 2173 (42%), germ cell in 363 (7%), and melanoma in 328 (6%) patients. The disease-free interval was 0 to 11 months in 1729 (33%) cases, 12 to 35 months in 1857 (36%) and more than 36 months in 1620 (31%). Single metastases accounted for 2383 (46%) cases and multiple lesions for 2726 (52%). Mean follow up was 46 months. Analysis was performed by Kaplan-Meier estimates of survival, relative risk of death and multivariate Cox model. The actuarial survival after complete metastasectomy was 36% at 5 years, 26% at 10 years and 22% at 15 years (median 35 months); the corresponding values for incomplete resection were 13% at 5 years and 7% at 10 years (median 15 months). Among complete resections, the 5-year survival was 33% for patients with a disease free-interval of 0 to 11 months and 45% for those with a disease-free interval of more than 36 months; 43% for single lesions and 27 for four or more lesions. Multivariate analysis showed a better prognosis for patients with germ cell tumors, disease-free interval of 36 months and more and single metastases. These results confirm that lung metastasectomy is a safe and potentially curative procedure.     

Comparison of prostate biopsy schemes by computer simulation

OBJECTIVES: To compare the ability of different biopsy schemes to detect cancer and predict tumor volume using our previously described prostate biopsy simulation system. In addition, we used the simulation system to evaluate the optimal location of transition zone biopsies. METHODS: Digital reconstructions of 180 radical prostatectomy specimens were used. Forty simulations were performed on each prostate for 10 biopsy schemes, including a previously reported five-region peripheral zone biopsy pattern and a new 11-core multisite-directed scheme consisting of sextant, two transition zone, one midline, and two anterior horn biopsies. For simulation of the transition zone biopsies, paired near-midline biopsies were simulated, with needle insertion points from the apex to the base of the prostate and with needle advances of 1 to 4 cm before firing. A total of 1,180,800 individual biopsy tracks were simulated. RESULTS: The 11-core multisite-directed biopsy scheme had the highest detection rate for cancers greater than 0.5 cc. This scheme reliably detected cancer in 94% (138 of 147) of the cases. These results were significantly better than those of the sextant biopsy scheme (P <0.001) and the five-region 18-core peripheral zone scheme (P = 0.03). Compared with other schemes, there were increases in small-volume (0.5 cc or less) cancer detection by both the 11-core multisite-directed and five-region schemes, but they were not statistically significant. The multisite and the sextant plus four transition zone biopsy schemes had the best correlation of mean total core cancer length with total cancer volume. In the simulation of the transition zone biopsies, the highest detection rate was observed when the biopsies were initiated at the most apical section and inserted for a depth of 3 cm before firing. CONCLUSIONS: Our simulation results suggest that the detection rate of prostate biopsies is not related solely to the number of cores taken. Core placement (the regions of the prostate from which samples are taken) is also important. The 11-core multisite-directed biopsy scheme performed the best, with improved cancer detection rates and tumor volume correlation over other schemes. On the basis of our simulations, this scheme has been chosen for clinical evaluation.     

Preventable hospitalization and avoidable maternity outcomes: implications for access to health services for Medicaid recipients

This study demonstrates how readily available hospital discharge data and small area methods can be used to identify potential problems of access to primary and prenatal outpatient health services for Medicaid populations. We examine whether rates of preventable hospitalization and avoidable maternity outcomes differ across geographic areas by their concentration of Medicaid recipients. Five county and twenty-four intra-county areas in Upstate New York are examined. Individuals living in Medicaid intra-county areas had significantly higher rates of these hospitalizations than persons living in non-Medicaid areas. Public health managers can use these methods to identify and compare areas in which access problems exist and to target and evaluate programs designed to improve access.     

Concurrent measurement of perceived speed and speed discrimination threshold using the method of single stimuli

Velocity matching using the method of Constant Stimuli shows that perceived velocity varies with contrast [Thompson, P. (1982). Perceived rate of movement depends upon contrast. Vision Research, 22, 377-380]. Random contrast jitter would therefore be expected to increase the slopes of psychometric functions, and thus the velocity discrimination threshold. However, McKee, S., Silverman, G., and Nakayama, K. [(1986) Precise velocity discrimination despite random variation in temporal frequency. Vision Research, 26, 609-620] found no effect of contrast jitter on thresholds, using the method of single stimuli. To determine whether this apparent discrepancy is due to the difference in methodology, or to the different ranges of temporal frequencies used in the two studies, we used the method of single stimuli to measure psychometric functions at three different velocities (0.5, 2.0 and 4.0 degrees/s). We found that contrast jitter increased thresholds at low but not at high velocities. Separate analysis of the psychometric functions at each contrast level showed that increases in contrast increased perceived velocity at low standard speeds (0.5 degree/s) but not at high. We conclude that the effect of contrast on perceived speed is real, and not a methodological artefact, but that it is found only at low temporal frequencies.     

Acute experimental neuronal injury in the newborn lamb: US characterization and demonstration of hemodynamic effects

Background and purpose: Microinjection into the brain with N-methyl-D-aspartate (NMDA), a synthetic analogue of glutamate, has been used as a chemical model of perinatal hypoxic-ischemic injury. Little is known about the sonographic characteristics and hemodynamic consequences of these cytotoxic lesions. An understanding of these features may be useful in the early sonographic identification of stroke in newborns.Methods: Twenty newborn lambs were anesthetized, paralyzed, and mechanically ventilated. Between 0.5 and 5 mole NMDA in 0.2 ml phosphate buffered salinen=18), or buffered saline only (n=2) was injected into the right putamen under sonographic guidance. Serial grey-scale and color Doppler images of the brain, Doppler spectra of the middle cerebral and thalamostriate arteries, cerebral blood flow (CBF) determinations using radiolabeled microspheres (n=9), and cerebral oxygen extraction (n=4) were obtained before, and at 15, 60, and 120 min after NMDA injection. Pathologic examination was obtained in 11 animals.Results: Homogeneous, well defined, moderately echogenic lesions surrounded by marked focal hyperemia on color Doppler were identified in every animal injected with 5 mole NMDA within minutes of injection. Lesions were characterized by focal areas of chromatolysis and cytoplasmic shrinkage, with scattered petechial hemorrhage. No lesions or hyperemia were observed in the animals injected with normal saline. Mean supratentorial CBF increased from 64±9 ml/min/100 g (control) to 152±30, 115±19, and 102±8 ml/min/100 g at 15, 60, and 120 min after injection respectively. The most marked increases occurred in right midbrain (467% of control), diencephalon (388%), and temporal lobe (282%), but were also observed in homotopic regions of the left hemisphere, and in pons, medulla, and cerebellum. Mean blood flow velocity in the middle cerebral artery, and thalmoperforator artery correlated well with changes in hemispheric and midbrain CBF respectively. (r=0.57–0.74,p=0.0001, andr=0.65–0.67,p=0.0001 respectively).Conclusions: Focal brain lesions may be identified by sonography within minutes after experimentally induced neuronal injury. Alterations in echotexture are primarily due to intracellular cytoplasmic changes and microscopic hemorrhage. Local intracerebral injection of NMDA in newborn lambs increases both local and global CBF.Supported in part by USPHS NIH grant NS 20020     

Risk stratification after myocardial infarction

The optimal approach to risk stratification after myocardial infarction remains controversial. Early risk stratification is designed to identify those patients who may benefit from mechanical myocardial revascularization procedures or more intensive medical therapy to prevent early adverse outcomes. Use of exercise testing and noninvasive cardiac imaging to identify residual myocardial ischemia and left ventricular dysfunction in order to divide patients into high- and low-risk groups has gained increasing acceptance. Patients at high risk then undergo cardiac catheterization. There is also support for early cardiac catheterization to permit the rapid identification of patients who may benefit from mechanical revascularization. The challenge to physicians is to select the most accurate, safe, and cost-effective approach at their particular institution.     

Treatment of severe side effects after vagotomy and gastroenterostomy by closure of gastroenterostomy without pyloroplasty

We describe nine patients who had severe, persistent abdominal pain, vomiting, dumping, or diarrhoea several years after truncal vagotomy and gastroenterostomy had been performed for duodenal ulceration. Each patient was judged to have a bad clinical result (Visick grade 4). There was no evidence of recurrent ulceration in any of the patients, and in each the patency of the pyloric canal was confirmed radiologically or endoscopically. Each patient was treated by simply dismantling the gastroenterostomy without addition for a pyloroplasty. In one patient the surgeon suspected that a vagal trunk might have been left intact, and a revagotomy was performed by the "highly selective" technique. Postoperatively, none of the patients developed gastric retention. Symptomatic improvement occurred in eight patients, and four of them achieved perfect results (Visick grade 1). Side effects are common after vagotomy and gastroenterostomy, and are largely attributable to the presence of the gastroenterostomy stoma. Our results show that the symptoms may be alleviated by closing the gastroenterostomy, without precipitating gastric retention.     

The Pharmacokinetics and Metabolism of Human Relaxins in Rhesus Monkeys

Two forms of chemically synthesized human relaxin (hRlx and hRlx-2) were administered as 88 µg/kg intravenous bolus doses to pregnant and nonpregnant rhesus monkeys. No significant differences in pharmacokinetics were observed between pregnant and nonpregnant animals for either form of relaxin; however, clearance of hRlx (3.1–3.4 ml/min/kg) was significantly slower than clearance of hRlx-2 (6.2–6.5 ml/min/kg) in both pregnant and nonpregnant animals. Although the terminal half-lives for hRlx and hRlx-2 were similar (148–157 min), the initial and steady-state volumes of distribution were somewhat larger for hRlx-2 (71–85 and 398–418 ml/kg, respectively) than for hRlx (61–65 and 294–319 ml/kg, respectively). The metabolism of hRlx-2 was also investigated in pregnant and non-pregnant rhesus monkeys after iv bolus (0.44 mg/kg) or 60-min infusion (1.1 mg/kg) administration. Fast atom bombardment mass spectral analysis of the relaxin immunoreactivity isolated from the plasma indicated that hRlx-2 was partially degraded by removal of amino acids from the C terminus of the B chain. The percentage of intact material declined over a 60-min time course. At 60 min post-dose, intact hRlx-2 was 46–64% of the detected material. Degraded forms representing loss of one and four amino acids (hRlx) from the C terminus of the B chain were 11–13 and 19–34% of the detectable material, respectively.