Case-referent study on occupational risk factors for bladder cancer in southern Israel

OBJECTIVE

To evaluate the possible association between occupational exposures (risk factors) and male bladder cancer in the Negev region (southern Israel) to enable preventive strategies to be applied.

METHODS

A total of 92 male bladder cancer patients, diagnosed at a regional medical center between 1989 and 1993, were studied by interview and compared with 92 males without oncological disease after matching by age and country of origin. A special questionnaire was developed to gather information on demography, life-time occupational history, smoking habits, coffee consumption, and health status. Statistical analysis of the case-referent data was done using the SPSS-5 package for performance of the chi-square test, conditional logistic regression, and multiple classification analysis.

RESULTS

Significant associations were found between bladder cancer occurrence and (1) three different groups of occupational exposures [a - solvents (P = 0.002, OR not computed due to the lack of exposed persons among referents), b - dusts (P = 0. 02; OR = 4.67), and c - exposure to multiple chemicals (P < 0.001, OR = 6.25); (2) nephrolithiasis (P = 0.02, OR = 11.00); and (3) cigarette smoking (P = 0.01, OR = 1.87).

CONCLUSIONS

Certain types of occupational exposure, different from that to aromatic amines and dyes, may be considered as contributing factors in the epidemiology of bladder cancer. Better identification of these chemicals and the work processes where they are used may help in abating such exposures, thus leading to a reduction in the risk for this relatively common cancer.

The effect of postsurgical naproxen and a bioabsorbable membrane on osseous healing in intrabony defects

BACKGROUND

Previous reports in the literature have shown that non-steroidal anti-inflammatory drugs (NSAID) may affect osseous tissues by either stimulating or inhibiting bone formation. This effect can be drug specific and different NSAIDs may produce opposite results. There are also reports showing that NSAIDs inhibit bone loss due to inflammatory disease process. The purpose of this randomized, controlled, blinded, clinical investigation was to determine the effect of a one week course of postsurgical naproxen on the osseous healing in intrabony defects.

METHODS

Twenty-four vertical osseous defects in 24 patients were treated with either a bioabsorbable membrane plus twice daily postsurgical naproxen 500 mg for one week (test or GPN group) or with a polylactide bioabsorbable membrane alone (control or GA group). Twelve patients were included in each group. Treatment was performed on either 2- or 3-wall or combination defects. All measurements were taken from a stent by a calibrated, blinded examiner and open measurements were repeated at the 9-month second stage surgery. Power analysis to determine superiority of naproxen treatment showed that a 12 per group sample size would yield 87% power to detect a 2.0 mm difference and 64% power to detect a 1.5 mm difference.

RESULTS

Open defect measurements from baseline to 9 months showed a statistically significant (P < 0.05) mean defect fill of 1.96 +/- 1.27 mm and 2.04 +/- 1.71 for the GPN and GA groups, respectively. This corresponded to a mean defect fill of 42% and a mean defect resolution of approximately 75% for both groups. The differences between GPN and GA groups were not statistically significant (P > 0.05). Defect fill of > or = 50% was seen in 6 defects (50%) in the GPN group and in 5 defects (42%) in the GA group.

CONCLUSIONS

The administration of postsurgical naproxen failed to produce osseous healing that was statistically superior to that obtained with polylactide bioabsorbable membranes alone.

The effect of postsurgical antibiotics and a bioabsorbable membrane on regenerative healing in Class II furcation defects

BACKGROUND

The purpose of this randomized, controlled, blinded, clinical investigation was to determine the effect of postsurgical antibiotics on osseous healing in Class II furcation defects.

METHODS

Twenty-four Class II furcation defects in 24 patients were treated with either a polylactide bioabsorbable membrane, demineralized freeze-dried bone allograft (DFDBA) plus antibiotics (GBA or test group) or with a polylactide membrane and DFDBA alone (GB or control group). Twelve patients were included in each group. The antibiotic regimen consisted of ciprofloxacin 250 mg twice daily and metronidazole 250 mg tid for 1 week followed by a 7-week regimen of doxycycline hyclate 50 mg daily. Treatment was performed on either mandibular buccal or lingual, or maxillary buccal Class II furcation defects. Defects were randomly selected by a coin toss for treatment and all open and closed measurements were performed by a blinded examiner. Final open and closed measures from a stent were repeated at the 9-month second stage surgery. Power analysis to determine superiority of antibiotic treatment showed that a 12 per group sample size would yield 93% power to detect a 1.5 mm difference and 64% power to detect a 1 mm difference.

RESULTS

Mean open horizontal probing depth reductions at 9 months were greater for the GBA group than for the GB group (2.92+/-1.78 versus 2.50+/-1.62 mm); however, these differences were not statistically significant. Seven of 12 furcations (58%) in the GBA group demonstrated >50% vertical defect fill at 9 months compared to 8 of 12 furcations (67%) in the GB group. There were no significant differences in mean open horizontal probing depth reduction between smokers and non-smokers in either the GBA or GB groups. Membrane exposure did not appear to affect regenerative healing in either the GBA or GB groups.

CONCLUSIONS

The administration of postsurgical antibiotics did not produce statistically superior osseous healing of Class II furcation defects. This result may be attributable to membrane design which facilitates connective tissue ingrowth, thereby preventing bacterial downgrowth and contamination of the newly regenerated tissues.

Cancer incidence and risks in selected agricultural settlements in the Negev of Israel

Medical staff of two Negev kibbutzim invited epidemiologists to help them investigate cancer rates among their members. Our objectives were (a) to determine whether the cancer rate in the kibbutzim was elevated or abnormal and (b) to determine the role of agricultural and other relevant exposures if cancer incidence was elevated. We validated cases of cancer by kibbutz records and by surveying other information; we computed expected values on the basis of the age-sex-calendar period and site-specific cancer incidence rates reported by the Israel Cancer Registry for the entire population; and we compared the data for the 2 kibbutzim with data derived for similar age and sex groups in 2 other kibbutzim, which were assumed not to have increased cancer rates. In addition, we planned and conducted a case-referent study, including the design, pretest, and use of questionnaires, including data about lifetime exposures (i.e., type of work and its duration, agricultural and industrial chemicals, smoking and alcohol use, demographic variables, health experiences, and family history). In only one of the kibbutzim, for which high cancer rates were suspected, was there significant excess for all sites in persons who were less than 40 y of age. In one of the "comparison" kibbutzim, we found increased cancer rates overall. Much of the excess in the high cancer kibbutzim was in hematological cancer (i.e., leukemia and lymphoma). Multiple years of work in fields, orchards, and landscape, as well as orchard work that commenced before 1960, were associated with increased risk of cancer (p < .08). We also found an association between cancer rate and numbers of industrial chemicals used (p < .08). Pipe and cigarette smoking were also associated with increased cancer incidence. In the multivariate analysis, the association with calendar year in which orchard work was started and multiple exposures to industrial chemicals was stronger than associations noted in the univariate analyses. Although duration of agricultural work or multiple industrial exposures were clearly associated with increase in cancer risk, we were unable to identify the causal role of specific agent(s). Nonetheless, educational programs for cancer prevention can be based, in part, on the results of such a study.

The Computational Complexity of Probabilistic Planning

We examine the computational complexity of testing and finding small plans in probabilistic planning domains with both flat and propositional representations. The complexity of plan evaluation and existence varies with the plan type sought; we examine totally ordered plans, acyclic plans, and looping plans, and partially ordered plans under three natural definitions of plan value. We show that problems of interest are complete for a variety of complexity classes: PL, P, NP, co-NP, PP, NP^PP, co-NP^PP, and PSPACE. In the process of proving that certain planning problems are complete for NP^PP, we introduce a new basic NP^PP-complete problem, E-MAJSAT, which generalizes the standard Boolean satisfiability problem to computations involving probabilistic quantities; our results suggest that the development of good heuristics for E-MAJSAT could be important for the creation of efficient algorithms for a wide variety of problems.

The future of health care, Part 2. The PPMC debate. Panel discussion

In Part 2 of this second annual panel discussion, Jeff Goldsmith, Barbara LeTourneau, Uwe Reinhardt, and physician executives from three physician practice management companies (PPMCs) examine this burgeoning new industry. They grapple with questions (and occasionally with each other), such as: Are PPMCs delivering what they promise? What will separate successful PPMCs from the rest? When PPMCs win, who loses? What value do PPMCs add to health care? What lies ahead for this industry? Could Wall Street pressure cause PPMCs to put profit ahead of physicians and patients? And, what roles will physician executives play in PPMCs?

Reducing costs and improving processes for the interventional cardiology patient

The cardiology unit at the University of Chicago Hospitals developed a cost-saving mechanism in the care of postinterventional cardiology patients, reducing time spent in the coronary care unit. Increased nursing education and training and better identification of patient outcomes made this collaborative effort a cost-saving and effective pilot.

Teledentistry: protocols for the transmission of digitized radiographs of the temporomandibular joint

Tomograms of the temporomandibular joint were digitized in three different formats using a PC-based system. The image resolution for various projections was determined at different camera-film distances. Three series of images were transmitted by telephone, and transmission times were measured. The original radiographs, the digitized images, the transmitted images and the transmitted-and-printed images were presented to 10 observers, who were asked to rate image quality. No difference in image quality was found between the initial digitized and the transmitted images. However, transmitted and transmitted-and-printed images were of significantly lower quality than the original radiographs or the digitized images viewed on a computer monitor. Transmission time was reduced significantly (50%) by cropping the images before transmission. The image quality of individual radiographs was better than radiographs formatted as a series.

Persistence of penicillin G benzathine in pregnant group B streptococcus carriers

OBJECTIVE

To determine if streptococcicidal levels of penicillin G benzathine can be detected in maternal serum 4 weeks after treatment with 4.8 million units.

METHODS

Thirty-seven pregnant women with positive group B streptococcus vaginal or urine cultures were each given 4.8 million units of penicillin G benzathine. Maternal blood samples were collected after injection and at delivery. Serum penicillin levels were measured by high-pressure liquid chromatography. Follow-up cultures were done when possible.

RESULTS

None of the patients had serum penicillin levels below 0.20 microgram/mL 30 days after treatment. Cord blood levels were approximately 50% lower than maternal levels. In all but three subjects, cord blood levels exceeded 0.06 microgram/mL, the minimal inhibitory concentration for group B streptococcus. The three exceptions were patients who delivered more than 100 days after treatment. Group B streptococcus cultures were negative at the time of delivery in 72% of cases. None of the patients with positive cultures were moderately or heavily colonized.

CONCLUSION

In pregnant women, penicillin G benzathine levels are high enough to inhibit the growth of group B streptococcus for more than 4 weeks after injection with 4.8 million units. Further studies are needed to evaluate whether this regimen can prevent neonatal colonization and invasive group B streptococcus disease.

Clastogenic factors in the plasma of children exposed at Chernobyl

Clastogenic factors (CFs), as they were described previously in accidentally or therapeutically irradiated persons, in A-bomb survivors and in liquidators of the Chernobyl nuclear power plant, were also detected in the plasma of Chernobyl-exposed children. A high percentage of plasma ultrafiltrates from 170 children, immigrated to Israel in 1990, exerted clastogenic effects in test cultures set up with blood from healthy donors. The differences were highly significant in comparison to children immigrated from 'clean' cities of the former Soviet Union or children born in Israel. The percentage of CF-positive children and the mean values of the adjusted clastogenic scores (ACS) were higher for those coming from Gomel and Mozyr, which are high exposure sites (IAEA measurements), compared to those coming from Kiev. There was no correlation between residual 137-Caesium body burden and presence of CFs. However, both measurements were not done at the same time (in 1990 and 1992-1994, respectively). Also no relationship could be revealed between enlargement of the thyroid gland and CF-positivity. CFs are not only observed after irradiation, but in a variety of chronic inflammatory diseases with autoimmune reactions. They were also described in the congenital breakage syndromes, which are hereditary diseases with the highest cancer incidence in humans. Whether the clastogenic effects continuously produced by circulating CFs represent a risk factor for malignant late effects deserves further study and follow-up. Since CF formation and CF action are mediated by superoxide radicals, prophylactic treatment with antioxidants may be suggested for Chernobyl-exposed children, whose plasma induces a strongly positive CF-test.

Reducing costs and improving processes for the interventional cardiology patient

The cardiology unit at the University of Chicago Hospitals developed a cost-saving mechanism in the care of postinterventional cardiology patients, reducing time spent in the coronary care unit. Increased nursing education and training and better identification of patient outcomes made this collaborative effort a cost-saving and effective pilot.

Identification of the temporomandibular joint and adjacent cephalometric landmarks using a dual sensitivity screen-cassette system

OBJECTIVES

Clinical evaluation of a cassette with dual speed screens for cephalometric radiography.

METHODS

Two lateral cephalometric radiographs were taken on 20 consenting subjects using the TMJ Orthoceph Slimline Cassette System (TOSCS), incorporating circular Trimax 12 screens in the area adjacent to the temporomandibular joint, and a control cassette (Trimax 8 screens). Ten pairs of radiographs with optimal image quality were randomly presented to 10 observers trained in cephalometric interpretation. Observers rated the overall diagnostic quality of each radiograph and of the TMJ region on an ordinal scale. They then located specific landmarks and traced the TMJ anatomy using acetate overlays. Overlays were digitized by a single operator who repeated tracing placements and digitizations to determine the error of recording method. Landmark variability was compared in the x- and y-axis by the Wilcoxon matched-pairs signed ranks test (p < 0.05). Six repeat tracings were performed and assessed by percentage of repeated observations above the maximum affordable error. Fossa space values were analyzed by the coefficient of variation (CV). The variability of the angular and linear values was also compared.

RESULTS

TOSCS image quality was perceived as significantly better than the control. Method error was 0.34 mm in the x-axis and 0.4 mm in the y-axis. Interobserver variability was 2 to 3 times greater than intraobserver. There was less variability with TOSCS for identification of basion (x-axis), center-of-rotation (x-axis) and condyle (posterior) (x-axis). However, this was clinically insignificant. Accurate determination of the fossa space was not possible as CV varied from 23 to 84%. No differences in the variability of angular or linear values variability were found.

CONCLUSIONS

While observers preferred TOSCS, no significant clinical differences could be demonstrated between the two systems.

Lamivudine in children with human immunodeficiency virus infection: a phase I/II study. The National Cancer Institute Pediatric Branch-Human Immunodeficiency Virus Working Group

The safety, tolerability, pharmacokinetic profile, and preliminary activity of lamivudine (2'-deoxy-3'-thiacytidine), a novel cytidine nucleoside analogue with antiretroviral activity, in human immunodeficiency virus (HIV)-infected children beyond the neonatal period were studied. Ninety children received dosages of 1-20 mg/kg/day. Pharmacokinetic evaluation demonstrated serum and cerebrospinal fluid concentrations that increased proportionally to dose. As of January 1994, 11 children had been withdrawn from study for disease progression and 10 because of possible lamivudine-related toxicity, and 6 had died. CD4 and CD8 cell counts remained stable over 24 weeks in therapy-naive children and decrease slightly in previously treated children. Quantitative immune complex-dissociated p24 antigen and HIV RNA were decreased significantly at 12 and 24 weeks. In vitro resistance to lamivudine was documented in sequential virus isolates from some patients by 12 weeks. Lamivudine was well-tolerated and exhibited virologic activity in children, although future use in children is likely to be in combination antiretroviral regimens.

Macrophages during fibrosis following scleral fistulising surgery in a rat model

PURPOSE

Glaucoma filtration surgery can fail in a minority of patients as a result of fibrosis in the subconjunctival bleb space and closure of the scleral fistula. In this study, the rat eye has been used as an experimental model for fistulising surgery in order to evaluate the clinical manifestation of bleb failure with the morphological events of the wound healing process.

METHODS

A conjunctival bleb was successfully formed in 25 rats and was examined daily using slit lamp microscopy to evaluate postoperative inflammation and the presence of a bleb. At defined post-operative time points, serial frozen sections of eyes were stained immunohistochemically using a panel of monoclonal antibodies directed against known surface markers on rat immune/inflammatory cells. Positively stained cells were counted (a) in the bleb site, (b) at the sclerostomy and (c) at the suture site.

RESULTS

Following an initial post-operative inflammation, a surgically formed sclerostomy and conjunctival bleb underwent a granulation and scarring response so that by 7-19 days the bleb had disappeared. Using the monoclonal antibodies applied in this study, it was possible to show that macrophages most likely play a major and pivotal role throughout the sequence of events that lead to repair of the fistula and closure of the bleb. It was also noted that the presence of an otherwise inert nylon suture used to close the incised conjunctiva can serve as a focus for macrophages.

CONCLUSION

The rat has been successfully used as an experimental model of fistulising surgery and its subsequent failure. The use of a panel of monoclonal antibodies directed against specific surface markers on immune-inflammatory cells, highlighted macrophages to be prominent in all stages of this wound healing process.

Resistance to (-)-2',3'-dideoxy-3'-thiacytidine (3TC) in HIV-1 isolated from paediatric patients

We conducted detailed virological evaluations of 16 HIV-1-infected paediatric patients treated with 3TC (lamivudine) monotherapy. High-level phenotypic resistance against this compound (up to 2,500-fold) was seen in virtually all cases, usually within 8-12 weeks of initiation of therapy. This was concomitant with the appearance of the M184V mutation in viral reverse transcriptase, previously shown to be responsiblefor such resistance. Viral burden fell in virtually all cases after commencement of therapy, and remained below baseline in each instance studied, despite a rebound effect and the appearance of drug resistance. Viral isolates from some patients underwent a switch from a non-syncytium-inducing (NSI) to a syncytium-inducing (SI) phenotype during the course of the study, although no relationship was apparent between dose of drug employed, time to development of drug resistance or time of appearance of SI phenotype.

Polytetrafluoroethylene bypasses to infrapopliteal arteries without cuffs or patches: a better option than amputation in patients without autologous vein

PURPOSE

This study was undertaken to evaluate our results of polytetrafluoroethylene (PTFE) tibial and peroneal artery bypasses done for limb salvage.

METHODS

Within a group of patients undergoing infrainguinal limb salvage bypasses at our institution between January 1986 and May 1995, 63 patients faced an immediate amputation, had no autologous vein on duplex examination and operative exploration, and had only a tibial or peroneal artery as an outflow vessel for bypass. Most of these patients (82%) had two or more prior ipsilateral infrainguinal bypasses. These 63 patients underwent 66 PTFE bypasses to a tibial or peroneal artery without a distal anastomotic vein cuff or an adjunctive arteriovenous fistula. Our results were then compared with those reported from infrapopliteal (crural) bypasses performed with alternate autologous vein sources or PTFE in conjunction with various recommended adjuncts.

RESULTS

The 3- and 5-year cumulative primary graft patency rates for our PTFE infrapopliteal bypasses were 39%+/-7% and 28%+/-9%, respectively. Secondary graft patency rates were 55%+/-8% and 43%+/-10% at 3 and 5 years, respectively. Limb salvage rates were 71%+/-7% at 3 years and 66%+/-8% at 5 years. Two-year actuarial patient survival rate was only 67%+/-7%.

CONCLUSIONS

These results indicate that a PTFE bypass to an infrapopliteal artery remains a worthwhile option in patients without usable autologous vein. The secondary patency and limb salvage rates were acceptable in this setting and were not significantly different from the best results reported with prosthetic tibial/peroneal bypasses with distal vein cuffs or patches (74% at 1 year; 58% at 3 years), arteriovenous fistulas (71% at 1 year) or composite arm vein grafts (39% and 29% at 3 and 5 years, respectively).