A population study of the natural history of Wolff-Parkinson-White syndrome in Olmsted County, Minnesota, 1953-1989

BACKGROUND: Virtually all natural history studies of Wolff-Parkinson-White (WPW) syndrome have been case series and, as such, have been constrained by referral biases, skewed age and sex distributions, or brief follow-up periods. The purpose of our study was to examine the natural history, the development of arrhythmias, and the incidence of sudden death in an entire cohort of pediatric and adult WPW patients from a community-based local population. METHODS AND RESULTS: We identified 113 residents of Olmsted County, Minnesota, during the period 1953-1989 using the centralized records-linkage system provided by the Mayo Clinic and the Rochester Epidemiology Program Project. Medical records and ECGs were reviewed to confirm the diagnosis and to establish pathway location by ECG criteria. Follow-up, via record review and telephone interview, was complete in 95% of subjects through 1990. The incidence of newly diagnosed cases was approximately four per 100,000 per year. Preexcitation was not present on the initial ECG of 22% of the cohort. Approximately 50% of the population was asymptomatic at diagnosis, with 30% subsequently having symptoms related to arrhythmia at follow-up. Two sudden cardiac deaths (SCD) occurred over 1,338 patient-years of follow-up, yielding an overall SCD rate of 0.0015 (95% confidence interval, 0.0002-0.0054) per patient-year. No SCD occurred in patients asymptomatic at diagnosis. CONCLUSIONS: The incidence of sudden death in a local community-based population is low and suggests that electrophysiological testing should not be performed routinely in asymptomatic patients with WPW syndrome. Nevertheless, young, asymptomatic patients, particularly those < 40 years old, should return for medical follow-up should symptoms develop.     

Murine cytomegalovirus-inhibitory effects of ImuVert

ImuVert, a sterile preparation composed primarily of Serratia marcescens membrane vesicles and ribosomes, was significantly inhibitory to murine cytomegalovirus (MCMV) infections in BALB/c mice. Antiviral activity was manifested as increased survivor number and decreased recoverable virus titers in spleens, lungs and salivary glands. Treatments were intraperitoneal (i.p.) beginning 24 h pre, 4 h post- or 24 h post-virus inoculation and then repeated 4 days later. Doses of 5, 16 or 50 micrograms/mouse were effective; 160 micrograms/mouse, which caused host weight loss in toxicity controls, was not inhibitory to the infection. A single i.p. treatment of mice substantially augmented natural killer (NK) cell activity and increased total B-cells, while reducing total T- and T-helper cells. A late (48 h) decline in T-cell function and transient increases in B-cell function were observed in the treated animals. Serum interferon was not induced. Mice pretreated with anti-asialo GM1 antibody to reduce their NK cell populations, then infected with MCMV and treated with ImuVert were protected to the same degree as normal animals. Severe combined immunodeficient mice infected with MCMV and treated with ImuVert were not protected from the infection. These data suggest ImuVert to act by a mechanism other than NK cell activation in preventing MCMV infections.     

Role of glutathione, glutathione S-transferases and multidrug resistance-related proteins in cisplatin sensitivity of head and neck cancer cell lines

Spontaneous proliferative liver lesions were found in 15 (13 males and 2 females) of 244 (122 of each sex) transgenic (Tg) mice carrying the human prototype c-H-ras gene (rasH2). The liver lesions included 3 foci of cellular alteration, 1 hepatocellular adenoma, 5 hepatocellular carcinomas, and 4 hepatic hemangiosarcomas in the males and 1 focus of cellular alteration and 1 hepatocellular carcinoma in the females. The mutation patterns of the human and endogenous mouse c-H-ras codon 61 in these proliferative liver lesions were analyzed by DNA amplification using polymerase chain reaction, single-strand conformation polymorphism (PCR-SSCP), and oligonucleotide dot blot hybridization. The hepatocellular carcinomas in 4 males and 1 female contained a point mutation in the mouse c-H-ras gene: 3, 1, and 1 carcinomas had a CAA to AAA transversion at the first base of codon 61, a CAA to CTA transversions, and a CAA to CGA transition at the second base of codon 61, respectively. No point mutations in the human c-H-ras transgene were detected in any hepatocellular carcinoma. All 4 hepatic hemangiosarcomas had a CAG to CTG transversion at codon 61 of the human c-H-ras gene, but no point mutations were detected in codon 61 of the mouse c-H-ras gene. No mutations in human or mouse c-H-ras codon 61 were detected in altered cell foci or hepatocellular adenoma. These results indicate that spontaneous liver tumors in rasH2 Tg mice contain different mutation patterns depending on the histologic type or cell origin of the tumors (i.e., hepatocellular carcinomas or hepatic hemangiosacomas). The absence of similar mutations in foci of cellular alteration and the hepatocellular adenoma suggests that the occurrence of codon 61 point mutations is a late event in the progression of hepatocellular neoplasia in rasH2 Tg mice.     

Assessment of a prototype battery operated wax-knife for domiciliary and surgery use

The aims of this study were to examine a prototype battery operated wax-knife, assess the extent to which manufacturer's claims have been achieved and determine its potential for clinical use. The mean time required for the wax-knife to achieve an operating temperature of 150 degrees C was 20.2(+/-4.3) s. The mean operating temperature of the ceramic blade was 155.4(+/-3.9) degrees C, range 150 degrees C to 162 degrees C. The mean usage time following full battery recharge was 42 (+/-2) minutes. The wax-knife provided a direct heating tool which retained many of the characteristics of the traditional wax-knife and was suitable for use in the surgery and in domiciliary situations.     

A systematic transition to flexible manufacturing

The transition from basic automation to flexible manufacturing is an expensive and tedious procedure. It requires meticulous planning and almost clairvoyant forecasting to insure that the initial flexibility obtained is sufficient to allow growth and expansion in the future. This paper will suggest a systematic and methodological approach to achieve optimal flexibility and describe the present results of its application to an ongoing system transformation.

Conclusions based on existing levels of completion are presented along with identification of critical and non critical flexibility requirements. The considerations and steps taken are summarized in a procedural format which may then be applied to a wide variety of system transformations.     

Fabrication and selective surface modification of 3-dimensionally textured biomedical polymers from etched silicon substrates

A new method is described for producing biomedically relevant polymers with precisely defined micron scale surface texture in the x, y, and z planes. Patterned Si templates were fabricated using photolithography to create a relief pattern in photoresist with lateral dimensions as small as 1 micron. Electroless Ni was selectively deposited in the trenches of the patterned substrate. The Ni served as a resilient mask for transferring the patterns onto the Si substrate to depths of up to 8.5 microns by anisotropic reactive ion etching with a fluorine-based plasma. The 3-dimensional (3-D) textured silicon substrates were used as robust, reusable molds for pattern transfer onto poly (dimethyl siloxane), low density poly (ethylene), poly (L-lactide), and poly (glycolide) by either casting or injection molding. The fidelity of the pattern transfer from the silicon substrates to the polymers was 90 to 95% in all three planes for all polymers for more than 60 transfers from a single wafer, as determined by scanning electron microscopy and atomic force microscopy. Further, the 3-D textured polymers were selectively modified to coat proteins either in the trenches or on the mesas by capillary modification or selective coating techniques. These selectively patterned 3-D polymer substrates may be useful for a variety of biomaterial applications.     

Echinococcal disease and the provision of humanitarian surgical aid in Bosnia

The Canadian Armed Forced have been deployed to the republics of the former Yugoslavia since 1992 as part of the United Nations Protection Force and the NATO-led Implementation Force. Most of the combat arms units have been supported by small, self-contained surgical teams for essential surgery. Considerable benefit is gained by cooperating with civilian surgeons. The experience of treating five patients with complicated hydatid disease endemic to the area is examined. Treatment of these patients requires performing major surgical procedures under austere conditions and must be undertaken with care. Careful selection and communication with the surgical nursing team and civilian surgeons is essential. Well selected cases can also pay tremendous dividends in terms of maintaining the skills of personnel who must be prepared for any emergency in addition to providing vital surgical assistance to these patients.