Backscattering of light from a dielectric layer on a reflecting substrate.

Scattering of light from rough dielectric films is studied experimentally. It is shown that the interference pattern of the scattered field depends critically on the power spectrum of the roughness, especially on its long-scale component. When the height of roughness is small compared with the wavelength, the backscattering peak (if it exists) is due to the interference of the singly scattered fields; hence the properties of the backscattered peak are rather unusual. In particular, the width of the peak is determined by the thickness of the film and is independent of the parameters of disorder. The intensity of the peak increases with an increase of the rms height of the surface roughness and becomes independent of the rms when the roughness is of the order of the wavelength.

Raised serum prolactin in rheumatoid arthritis: genuine or laboratory artefact?

OBJECTIVES: Serum prolactin concentrations have been reported as higher, similar or lower in patients with rheumatoid arthritis (RA) compared with control subjects. We investigated whether low biological activity macroprolactin (a prolactin antibody complex), which is detected variably in different prolactin immunoassays, could account for the discrepant total prolactin results reported in RA. METHODS: We compared serum total prolactin and free prolactin in 60 women with RA and 31 female controls. RESULTS: No subject had hyperprolactinaemia or macroprolactinaemia. Serum concentrations of total and free (monomeric) prolactin were higher (P<0.05) in women with RA [mean (s.d.), 225.6 (104.6) and 201.6 (95.4) mU/l respectively] compared with controls [175.0 (68.5) and 154.0 (60.9) mU/l respectively]. CONCLUSIONS: We report higher serum free prolactin concentrations in women with RA compared with control subjects. This result indicates that the higher serum total prolactin levels in patients with RA are the consequence of increased free prolactin concentrations and are not due to macroprolactin.

Municipal hotlines and automated weather stations as a tool for monitoring bad odour dispersion: the northern Negev case.

Bad odours are often dispersed from chemical industries, waste dumps, sewer plants, and other facilities. They are indicative of pollution emissions from these sites and cause discomfort, apprehension, and sometimes signal the presence of health hazards. Monitoring the pollution by direct means, such as chemical analysis of ambient air, is obviously the most reliable mechanism to acquire data regarding pollution. However, this is not always possible. In this paper we report on the value of local government hotlines that record information provided by the public regarding bad odours. These data can alert the authorities to the existence of pollution and should be regarded as potentially useful when collected in conjunction with information from automated weather stations. An analysis of data from the Be'er Sheva municipality and the Ramat Negev regional council hotlines is provided. Complaints recorded by these systems were correlated with weather data from local automatic weather stations to indicate the sources of the bad odours. Wind direction was found to be highly correlated with bad odour and pollution sources, revealing consistent patterns in terms of the time of day and weather conditions.

Restorative proctocolectomy: Ochsner Clinic experience.

BACKGROUND: Restorative proctocolectomy, a standard operation for ulcerative colitis and familial adenomatous polyposis has significant complications, even in experienced hands. METHODS: We studied surgical outcome by retrospectively reviewing cases of restorative proctocolectomy done at Ochsner Foundation Hospital from 1982 to 1995. Demographic and clinical data from two periods (1982 to 1989 and 1989 to 1995) were compared to determine factors associated with improved outcome. RESULTS: We performed 145 ileal pouch-anal procedures. In 56 patients, 104 complications occurred. The more recent group had a greater incidence of inflammatory bowel disease, steroid use, and staged operations; reduced operative times and hospital stays; more general but fewer pouch-related complications. Pouch failures were similar for both groups. CONCLUSIONS: Perioperative outcome appeared to be associated with technical experience, improved perioperative care, exclusion of patients with Crohn's disease,judicious surgical reoperation for pouch complications, and use of a 3-stage procedure in malnourished patients or those with acute or toxic colitis.

Significance of a normal surveillance colonoscopy in patients with a history of adenomatous polyps.

PURPOSE: The aim of this study was to determine the appropriate surveillance for patients with a history of adenomatous polyps whose last colonoscopic examination was normal. METHODS: This was a retrospective review of a database of 7,677 colonoscopies (1990 to 1996). In patients under colonoscopic surveillance, we reviewed cases of patients who had received three colonoscopies (an index (initial) colonoscopy positive for adenomas and 2 follow-up colonoscopies (interim and final)). The risk of adenomas and cancers at final follow-up colonoscopy was compared between patients having a normal interim colonoscopy and those with a positive interim colonoscopy. The risk at final colonoscopy was also stratified by time interval and the size and number of adenomas at the initial index colonoscopy. RESULTS: Two hundred four patients undergoing surveillance for adenomas met inclusion criteria. At index colonoscopy the median polyp size was 1 cm and median frequency was three polyps. At all follow-up colonoscopies, we detected 493 adenomas and one cancer (median follow-up, 55 months). At 36 months patients with a normal interim colonoscopy (n = 91) had significantly fewer polyps than patients with a positive interim colonoscopy (n = 113; 15 vs. 40 percent; P = 0.0001). By 40 months, adenomas were detected in more than 40 percent of patients in both groups. The risk after a normal interim colonoscopy was not affected by time interval or number or size of polyps. Adenomas found subsequent to a normal interim colonoscopy were dispersed throughout the colon in 28 patients and isolated to the rectosigmoid in 6 patients. CONCLUSIONS: In patients with a history of adenomas, a normal follow-up colonoscopy is associated with a statistically but not clinically significant reduction in the risk of subsequent colonic neoplasms. These patients require follow-up surveillance colonoscopy at a four-year to five-year interval.

The natural history of isolated rectosigmoid adenomatous polyps: is flexible sigmoidoscopy a safe alternative for surveillance?

PURPOSE: Colonoscopic surveillance is recommended for patients with adenomatous polyps. Significant cost savings would result from identification of subgroups of patients in whom less costly surveillance would suffice. This study was performed to determine the natural history of patients undergoing removal of isolated rectosigmoid adenomas and to establish whether flexible sigmoidoscopy might be adequate for follow-up. METHODS: A retrospective review of a database of 7,677 colonoscopies, from 1990 to 1996, identified patients who had a minimal follow-up of two years after removal of adenomatous polyps isolated to the rectosigmoid. Polyps detected on surveillance colonoscopy were categorized as distal (< or =60 cm from anal verge), proximal (>60 cm from anal verge), and diffuse (proximal plus distal). The risk of polyp formation was determined by actuarial analysis using the Kaplan-Meier method. RESULTS: Sixty-two patients undergoing surveillance for adenomas met inclusion criteria. At the index colonoscopy, 124 isolated rectosigmoid polyps were identified. The median polyp size was 1 cm and median frequency was one polyp. The median follow-up time for the entire cohort (N = 62) was 53 months. At follow-up surveillance colonoscopy, 105 additional adenomas were discovered and removed in 40 patients. No malignant polyps were detected. The pattern of polyps detected were proximal (n = 19), rectosigmoid (n = 16), and diffuse (n = 5). CONCLUSIONS: The majority (65 percent) of patients with isolated rectosigmoid polyps have additional polyps on long-term surveillance, and 60 percent of patients will have these polyps located proximal to the reach of a sigmoidoscope. Therefore, flexible sigmoidoscopy is not a safe alternative for surveillance of patients with isolated rectosigmoid polyps.

Synovial sarcoma: a multivariate analysis of prognostic factors in 112 patients with primary localized tumors of the extremity.

PURPOSE: Synovial sarcoma is a high-grade tumor that is associated with poor prognosis. Previous studies analyzing prognostic factors are limited because of inclusion of heterogeneous cohorts of patients with nonextremity and recurrent tumors. The objective of this study was to determine independent prognostic factors of primary synovial sarcoma localized to the extremity. PATIENTS AND METHODS: Between July 1, 1982, and June 30, 1996, 112 patients underwent surgical resection for cure at our institution and then were followed-up prospectively. Clinical and pathologic factors examined for prognostic value included age, sex, tumor site and location, depth, size, microscopic status of surgical margins, invasion of bone or neurovascular structures, and monophasic or biphasic histology. The end points analyzed were the time to first local recurrence that was not preceded by a distant recurrence, time to any distant recurrence, and time to disease-related mortality. These end points were modeled using the method of Kaplan and Meier and analyzed by the log-rank test and Cox regression. RESULTS: The median duration of follow-up among survivors in this cohort of 112 patients was 72 months. The 5-year local-recurrence, distant-recurrence, and mortality rates were 12%, 39%, and 25%, respectively. Tumor size > or = 5 cm (P =.001; relative risk [RR] = 2. 7; 95% confidence interval [CI], 1.5 to 5.2) and the presence of bone or neurovascular invasion (P =.04; RR = 2.3; 95% CI, 1.0 to 5. 3) were independent adverse predictors of distant recurrence. Tumor size > or= 5 cm (P =.003; RR = 2.3; 95% CI, 1.4 to 6.3) and the presence of bone or neurovascular invasion (P =.03; RR = 2.7; 95% CI, 1.0 to 6.5) were also independent adverse predictors of mortality. CONCLUSION: The natural history of primary synovial sarcoma of the extremity is related to tumor size and invasion of bone and neurovascular structures.

Pneumocystis carinii isolated from lung lavage fluid in an infant with cystic fibrosis.

Pneumocystis carinii (P. carinii) cysts were identified in bronchoalveolar lavage fluid from a 15-week-old child newly diagnosed with cystic fibrosis who presented with bronchitis, pneumonia, and weight loss. The child was not infected with human immunodeficiency virus (HIV), and there was no evidence of impaired immunity or exposure to individuals with known or suspected P. carinii disease. Culture of the lavage fluid also revealed pathogens typical of lung disease associated with cystic fibrosis. It is suspected that the presence of P. carinii in this patient represented a new acquisition, as has been described in immunocompetent infants and children. Whether P. carinii infection complicated cystic fibrosis-associated lung disease in this patient is unknown.

Ribosomal protein gene expression is cell type specific during development in Dictyostelium discoideum.

Starvation for amino acids initiates the developmental cycle in the cellular slime mold, Dictyostelium discoideum. Upon starvation one of the earliest developmental events is the selective loss of the ribosomal protein mRNAs from polysomes. This loss depends upon sequences in the 5' non-translated leader of the ribosomal protein (r-protein) mRNAs. Here evidence is presented which indicates that those cells which will become prestalk cells express the ribosomal protein genes during development under starvation conditions. Cells which enter the prespore pathway shut off r-protein synthesis. The promoter and 5' non-translated leader sequences from two ribosomal protein genes, the rp-L11 and the rp-S9 genes, are fused to the Escherichia coli beta-galactosidase reporter gene. While beta-galactosidase enzyme activity is detected in situ in most growing cells, by 15 h of development beta-galactosidase enzyme activity is largely lost from the prespore cells although strong beta-galactosidase enzyme activity is present in the prestalk cells. These observations suggest the possibility that the ribosomal protein mRNAs are excluded from polysomes in a cell-type-specific manner.

All patients with small intramural rectal cancers are at risk for lymph node metastasis.

PURPOSE: Although local excision can be curative in patients with early-stage rectal cancer, approximately 20 percent of patients will develop local recurrence, many as a result of unrecognized and unresected regional lymph node metastases. Our objective was to determine if standard pathologic factors can predict lymph node metastases in small intramural rectal cancers and provide a basis for patient selection for nonradical surgery. METHODS: Between June 1986 and September 1996, 318 patients with T1 or T2 rectal cancers underwent radical resection at our institution. Of these, 159 patients (48 T1 and 111 T2) were potentially eligible for curative local excision (< or =4 cm in size, < or =10 cm from the anal verge, no synchronous metastases), and the prevalence of lymph node metastases based on T stage and other pathologic factors was analyzed in this group. RESULTS: The overall frequency of lymph node metastasis was 15 percent (24/159 patients). T stage (T1, 10 percent; T2, 17 percent), differentiation (well-differentiated or moderately differentiated, 14 percent and poorly differentiated, 30 percent), and lymphatic vessel invasion (lymphatic vessel invasion-negative, 14 percent and lymphatic vessel invasion-positive, 33 percent) influenced the risk of lymph node metastasis. However, only blood vessel invasion (blood vessel invasion-negative, 13 percent and blood vessel invasion-positive, 33 percent) reached statistical significance as a single predictive factor (P=0.04). Tumors with no adverse pathologic features (low-risk group) had a lower overall frequency of lymph node metastasis (11 percent) compared with the remaining tumors (high-risk group, 31 percent; P=0.008). However, even in the most favorable group (T1 cancers with no adverse pathologic features) lymph node metastases were present in 7 percent of patients. CONCLUSION: In rectal cancer patients potentially eligible for local excision, the overall risk of undetected and untreated lymph node metastases is considerable (15 percent). The use of pathologic factors alone after local excision does not reliably assure the absence of lymph node metastases.

A randomized clinical trial of acellular pertussis vaccines in healthy adults: dose-response comparisons of 5 vaccines and implications for booster immunization.

The safety and immunogenicity of 5 acellular pertussis vaccines (ACVs) were compared in a multicenter, randomized, double-blind trial. A total of 481 healthy adults were given a single intramuscular booster dose of ACV or placebo. Three different dose levels were tested for 4 ACVs: full strength (the dose level proposed for infant immunization), one-third strength, and one-tenth strength. For 1 multicomponent vaccine, only the pertussis toxoid dose level varied. Minor injection site reactions were common and similar in frequency among vaccinated groups. Late-onset injection site reactions were seen in all ACV groups. Dose-related increases in mean antibody titers against vaccine antigens were seen after immunization with all ACVs. Antibody responses against antigens not known to be present in the vaccines were detected after immunization with 4/5 ACVs. Antibody levels fell significantly during the year after immunization. These data support evaluation of ACVs for broader use among adolescents and adults.

Dictyostelium ribosomal protein genes and the elongation factor 1B gene show coordinate developmental regulation which is under post-transcriptional control.

Starvation for amino acids initiates the developmental program in the cellular slime mold, Dictyostelium discoideum [19, 20]. One of the earliest developmental events is the decline in ribosomal protein synthesis [2, 17, 29, 30]. The ribosomal protein mRNAs are excluded from polysomes with 20 min to 1 h following the removal of nutrients, and their mRNA levels decline sharply at about 9 h into the 24-h developmental cycle [28, 31, 35, 36]. It has been generally assumed that the decline in r-protein mRNA levels during late development reflected a decline in the transcription rate [12, 32, 43]. Here we demonstrate that this is not the case. The transcription rates of three ribosomal protein genes, rpL11, rpL23 and rpS9 as well as an elongation factor 1B gene have been determined during growth and development in Dictyostelium. Throughout growth and development the transcription rate of the ribosomal protein genes remains relatively constant at 0.2%-0.5% of the rate of rRNA transcription while the elongation factor 1B gene is transcribed at 0.4%-0.6% of the rRNA rate. This low but constant transcription rate is in contrast to a spore coat protein gene Psp D, which is transcribed at 6% of the rRNA rate in late developing cells. The elongation factor 1B gene appears to be co-regulated with the ribosomal protein genes both in terms of its transcription rate and mRNA accumulation. Dictyostelium has been a popular model for understanding signal transduction and the growth to differentiation transition, thus it is of significance that the regulation of ribosome biosynthesis in Dictyostelium resembles that of higher eukaryotes in being regulated largely at the post-transcriptional level in response to starvation as opposed to yeasts where the regulation is largely transcriptional [27].

Nutritional rickets in suburbia.

OBJECTIVE: Vitamin D deficiency continues to be a problem in pediatrics. This report presents four children, one Caucasian male and three African-American females aged 4 to 24 months who were treated for vitamin D deficiency rickets. METHODS: One female was diagnosed in the Emergency Department during evaluation of a viral syndrome, another presented with hypocalcemic seizures and the third was a self-referral for evaluation of widened wrists. The male had biochemical rickets discovered incidentally during a hospitalization for pneumonia. All were breastfed without formula supplements. The 24-month female had severe cow and soy protein allergies and received multivitamin supplements intermittently. Birth order was from third to sixth child. Two families practiced Islam and the mothers wore veils. The females had a weight deficit for height. The females demonstrated a rachitic rosary, widening of the wrists and leg bowing. At diagnosis the serum calcium was 5.0-8.6 mg/dl, the inorganic phosphorus was 1.5-3.9 mg/dl and the alkaline phosphatase was 408-3324 U/L. The serum intact parathormone levels and the vitamin D levels were measured at Nichols Laboratories. The 25-OH vitamin D levels were 2-22 ng/ml and the 1,25(OH)2 vitamin D levels were 14-122 pg/ml. All had elevated parathormone levels. The three females had roentgenographic evidence of rickets. Two of the children also demonstrated iron deficiency. RESULTS: All patients responded to Vitamin D supplements, beginning at 2000 IU for the male and 8,000-10,000 IU daily for the females. Two children were also given calcium supplements. The three females all showed complete healing of the rickets radiologically within six months. The serum intact parathormone demonstrated an inverse correlation with the serum calcium during recovery (r=-0.669; p<0.05). CONCLUSION: Vitamin D deficiency does still occur. Breastfed children of multiparous mothers, with increased skin pigmentation, living in the higher latitudes are at increased risk and would benefit from vitamin D supplementation while breastfeeding.

Report of a US public health service workshop on hypotonic-hyporesponsive episode (HHE) after pertussis immunization.

Hypotonic-hyporesponsive episode (HHE) is a term used to describe a somewhat heterogenous group of clinical disorders that have been reported primarily in association with whole-cell pertussis vaccination. A 1991 review by the Institute of Medicine determined that the evidence available was indeed consistent with a causal relation between whole-cell pertussis-diphtheria-tetanus immunization and HHE, but that the evidence was insufficient to indicate a causal relationship between HHE and the subsequent development of permanent neurologic damage. More recent data from clinical trials conducted in Europe suggest that HHE also occurs after vaccination with acellular pertussis vaccines. The US Food and Drug Administration, in collaboration with the US Public Health Service, sponsored a workshop on HHE in Rockville, Maryland, on June 19, 1997. The primary goals of the workshop were to develop a case definition of HHE and to evaluate the general design and feasibility of possible studies of HHE using the federal Vaccine Adverse Event Reporting System (VAERS), a national passive surveillance system. The goals of such studies would be to understand better the acute HHE event and to evaluate the possibility of long-term sequelae. Case Definition. There has been no generally accepted definition of HHE, and a standard definition would be useful for vaccine safety work and would potentially facilitate interstudy comparisons of the growing number of licensed vaccines containing acellular pertussis components. The workshop defined HHE as an event of sudden onset occurring within 48 hours of immunization, with duration of the episode ranging from 1 minute to 48 hours, in children younger than 10 years of age. All of the following must be present: 1) limpness or hypotonia, 2) reduced responsiveness or hyporesponsiveness, and 3) pallor or cyanosis or failure to observe or to recall skin coloration. HHE is not considered to have occurred if there is a known cause for these signs (eg, postictal), if urticaria is present during the event, if normal skin coloration is observed throughout the episode, or if the child is simply sleeping. This inclusive (sensitive) case definition will allow investigators, through the technique of stratification according to certain characteristics (eg, time from vaccination to onset of HHE), to attempt to hone the definition and make it more specific. Refinement of the definition of HHE has been hindered by the lack of information on its pathophysiology and by the lack of pathognomonic signs, symptoms, and diagnostic tests. Another hindrance is that by the time the child presents for medical evaluation, the signs of HHE often have normalized. Moreover, different mechanisms may be involved in different individuals whose events meet this workshop's HHE definition. Further Study of HHE. Probably the most important question about HHE is whether it has any permanent sequelae. The workshop assessed the possible contribution VAERS-based studies could make to answering this question and found substantial methodologic problems; however, ongoing studies in Sweden and The Netherlands have the potential to provide useful information on this question. The most useful contribution of VAERS data would be in a descriptive study of HHE, with a possible case-control study of factors that may affect the risk of HHE after vaccination, rather than a study of possible permanent sequelae. The workshop participants felt that a detailed descriptive study of approximately 100 HHE events reported during a 1- to 2-year period could provide a more in-depth description of HHE cases in greater numbers than has been published previously, but the study would not address the issue of long-term sequelae of HHE. Better descriptive data may lead to new hypotheses concerning risk factors, etiology, and pathophysiology of HHE that might be evaluated further by studying subsequent cases and controls from VAERS or from other sources, depending on the hypoth

Service program diagnostics and decision support technology for improving health technology service efficiency and productivity.

Our in-depth survey of both the state of the art and the results of application, implementation, and rollout of problem resolution diagnostics in control help desks and field service clearly shows the potential of online remote diagnostics technology (Figure 9) to improve service force productivity and efficiency and to make more effective use of service resources (people and parts). Our survey of the current and planned future expenditures for diagnostics used in field service clearly indicates that the overall service diagnostics market is currently sizable, in the range of $2 billion as of 1997, and is projected to grow to approximately $2.6 billion by 2000. This current expenditure and growth will occur primarily in the electronics arena, but there are still substantial development and application investments occurring in both electromechanical and mechanical areas. We believe that the pace of investment will fall off as the service industry shifts from development and experimental research to the application and rollout of standard off-the-shelf technology. Thus, the overall pattern of the diagnostics market indicates a continuing increase in expenditures by the field service industry for electronics-oriented service diagnostics and some increase with respect to use of this technology in electromechanical and mechanical applications. The application and use of diagnostics technology will also be affected by the ability of the field service management community to recognize the need to search for an optimum as opposed to a feasible solution to dispatch, assignment, call screening, call avoidance, and logistics deployment. The further rollout of affordable wireless communications technology such as Ardis and Ram mobile and the new cellular-based CPDP technology, coupled with the increased availability of inexpensive wireless-based laptops, portables, and CD-ROM-based problem resolution and diagnostics technology clearly shows the value of this technology in improving service productivity, efficiency, and profitability. As we move from very expensive academically and research and development-oriented diagnostics applications to the purchase and use of off-the-shelf software and predeveloped knowledge bases, it is clear that this technology will be broadly applied.

Free circulating magnesium and renal magnesium handling during acute metabolic acidosis in humans.

Ion-selective electrodes have been designed for determining the ionized concentration of magnesium in blood, the biologically active form of this ion. The effect of acute acidosis induced by ammonium loading on circulating and urinary magnesium was investigated in 11 volunteers. No changes in plasma total and ionized magnesium were noted following administration of ammonium chloride. On the contrary, administration of ammonium chloride increased the plasma free magnesium fraction and the urinary magnesium excretion. The study demonstrates that the hypermagnesiuria induced by acute acidosis is not caused by ionized hypermagnesemia and supports the theory that acidosis decreases the circulating magnesium fraction that is bound to proteins.

Stage I rectal cancer: identification of high-risk patients.

BACKGROUND: Stage I rectal cancer (T1, T2 N0) is currently treated by surgical resection alone. Despite adequate surgical resection, approximately 10-15% of patients will develop recurrence. Identification of patients at high risk for recurrence could potentially lead to an improvement in outcome by selection of these patients for adjuvant therapy. METHODS: Between June 1986 and September 1996, 211 patients with primary rectal cancer (stage I) were treated by radical surgical resection alone. The medical data of all patients were entered into a database and prospectively followed. The following 10 prognostic factors were correlated with recurrence and tumor-related mortality: patient factors: age, gender, and preoperative carcinoembryonic antigen level; tumor factors: location from the anal verge (< 6 cm vs. > or = 6 cm), T stage (T1 vs. T2), intratumoral blood vessel invasion (BVI), intratumoral lymphatic vessel invasion, presence of tumor ulceration, and histologic differentiation; and treatment-related factors: extent of surgical resection--abdominal perineal resection versus low anterior resection. Univariate analysis of the effect of the prognostic factors on recurrence and tumor-related mortality were performed by the method of Kaplan-Meier and log rank test. Independent prognostic factors were determined by a multivariate analysis performed using the Cox proportional hazards model. RESULTS: The overall 5-year actuarial recurrence was 12% and tumor-related mortality was 10%. Independent predictors of recurrence were male gender and BVI. Independent predictors of tumor-related mortality were male gender, BVI, and poorly differentiated tumors. CONCLUSIONS: Despite radical resection, patients with stage I rectal cancer with male gender, BVI, and poorly differentiated tumors should be considered high-risk patients.

Thymic carcinoma: current staging does not predict prognosis.

BACKGROUND: Thymic carcinomas are currently staged by Masaoka classification, a staging system for thymomas. We retrospectively evaluated surgical patients with thymic carcinoma to determine prognostic factors and to evaluate the usefulness of Masaoka staging in this disease. METHODS: Our computerized tumor registry yielded 118 patients with thymoma. Review of pathologic material revealed 43 cases of thymic carcinoma. Collection of data was by review of hospital and physician charts and telephone contact with patients. Analysis of prognostic factors was performed in patients undergoing complete resection by the method of Kaplan-Meier and Cox proportional hazards regression. RESULTS: Between 1949 and 1993, 43 patients underwent surgery for thymic carcinoma. Overall survival was 65% at 5 years and 35% at 10 years. Overall recurrence was 65% at 5 years and 75% at 10 years. On univariate analysis, survival was not dependent on age, sex, tumor size, or Masaoka stage but was dependent on innominate vessel invasion. By multivariate analysis, survival was dependent only on innominate vessel invasion. CONCLUSIONS: Patients with thymic carcinoma have a high rate of recurrence. Tumor invasion of the innominate vessels is associated with a particularly poor prognosis. Although Masaoka staging is useful in staging patients with thymoma, it does not appear to predict outcome for patients with thymic carcinoma.

New trends in high-technology health care support services.

To understand clearly the economic dynamics of high-technology service and support in hospitals, the author used results of recent studies carried out by D. F. Blumberg & Associates, utilizing a variety of sources, to identify existing cost components of the typical 300- to 400-bed general hospital located in a major metropolitan area in the United States. The largest single functional component of cost is direct labor and benefits. Other major cost items include direct overhead administration and infrastructure costs and outside material equipment and supply purchases. This evaluation, based on extensive benchmarking comparison and market estimates, suggests that the issues of make, buy, or outsource are neither trivial nor easy to resolve in the health care field.