Optical and electrical interfacing technologies for living cell bio-chips.

Whole-cell bio-chips for functional sensing integrate living cells on miniaturized platforms made by micro-system-technologies (MST). The cells are integrated, deposited or immersed in a media which is in contact with the chip. The cells behavior is monitored via electrical, electrochemical or optical methods. In this paper we describe such whole-cell biochips where the signal is generated due to the genetic response of the cells. The solid-state platform hosts the biological component, i.e. the living cells, and integrates all the required micro-system technologies, i.e. the micro-electronics, micro-electro optics, micro-electro or magneto mechanics and micro-fluidics. The genetic response of the cells expresses proteins that generate: a. light by photo-luminescence or bioluminescence, b. electrochemical signal by interaction with a substrate, or c. change in the cell impedance. The cell response is detected by a front end unit that converts it to current or voltage amplifies and filters it. The resultant signal is analyzed and stored for further processing. In this paper we describe three examples of whole-cell bio chips, photo-luminescent, bioluminescent and electrochemical, which are based on the genetic response of genetically modified E. coli microbes integrated on a micro-fluidics MEMS platform. We describe the chip outline as well as the basic modeling scheme of such sensors. We discuss the highlights and problems of such system, from the point of view of micro-system-technology.

On-chip detection of cellular activity.

The use of on-chip cellular activity monitoring for biological/chemical sensing is promising for environmental, medical and pharmaceutical applications. The miniaturization revolution in microelectronics is harnessed to provide on-chip detection of cellular activity, opening new horizons for miniature, fast, low cost and portable screening and monitoring devices. In this chapter we survey different on-chip cellular activity detection technologies based on electrochemical, bio-impedance and optical detection. Both prokaryotic and eukaryotic cell-on-chip technologies are mentioned and reviewed.

Topical morphine in a canine model: a pilot study.

OBJECTIVE: To determine if topical morphine can enter the synovial cavity and the effect of ultrasound on this process. DESIGN: A randomized control trial to investigate which body fluids morphine enters after topical application. SETTING: A university animal laboratory. SUBJECTS: Ten mongrel dogs raised by the Comparative Medicine Department. All animals were certified to be free of disease, all had received standard scheduled immunizations, and none had been used for any other research. INTERVENTION: Topical morphine and ultrasound or topical morphine and sham ultrasound was applied to the knees of the dogs. Samples were obtained afterward from synovial fluid, serum, and urine, and were analyzed for the presence of morphine. MAIN OUTCOME MEASURES: Blood samples were collected every 60 minutes for 240 minutes, urine samples were collected at 120 minutes and 240 minutes, and synovial joint fluid was collected at 120 minutes and 240 minutes. The process of collection and analysis was the same for dogs treated with topical morphine and ultrasound and those treated with topical morphine and sham ultrasound. Fisher's exact test was used to test for an association between the use of ultrasound and the presence of morphine in the synovial fluid, serum, or urine. Two-sample t tests were used to test for group differences in mean body weight. RESULTS: All samples (synovial fluid, serum, and urine) were negative at time zero. All of the subsequent serum samples were negative for morphine. Two or three of the dogs in each group of five (ultrasound or sham ultrasound) had positive urine and synovial fluid samples at 120 and 240 minutes. Ultrasound did not affect the results. Body weight of the dogs influenced the results, with lighter animals having a significantly larger percentage (p=.03) of synovial fluid samples positive for morphine. CONCLUSION: Ultrasound did not affect the absorption of topical morphine in this canine model. Body weight may have influenced the results. Dogs that tested positive for morphine in synovial fluid had a lower mean body weight than dogs that did not test positive (p=.03).

Legging orthosis for venous and lymphatic insufficiency.

Presented are the description and advantages of a unique compression device in the form of a legging for the treatment of venous and lymphatic insufficiency. It consists of a number of pliable, unyielding, adjustable compression bands, from the knee to the instep. The bands are easily closed, tightened, and opened, which is particularly useful for the physically handicapped patient for whom the commonly prescribed elastic stocking is inappropriate because of the difficulty in putting it on and removing it. The effectiveness of the legging is enhanced by its nonelasticity, as has been long proven by the Unna boot, and its ability to maintain an unreduced compression level throughout its lifetime, regardless of edema changes.

Selection of neighborhood controls: logistics and fieldwork.

This paper describes the logistics and fieldwork involved in assembling 123 neighborhood controls for a case-control study investigating the relationship between cholecystectomy and right-side colon cancer. All neighborhood controls were matched pairwise to cases on sex, age at diagnosis (+/- years), and race. Eighty-six percent of the neighborhood controls were also matched on street of residence and the remaining 14% on census tract. Study subjects were contacted by mail and then interviewed by telephone with regard to their gastrointestinal surgical history. The mean number of necessary households contacted to obtain each control was nine. When data were stratified by age, the mean number of necessary households contacted increased with increasing age of the cases. Only 3.3% (35/1065) of the residents from these households refused complete participation in the telephone interview. The distribution of fieldwork activities by hours worked is also reported. Similar findings were observed for males and females. Neighborhood controls are a commonly used comparison series. Data from this report may be used to modify the general impression that assembling neighborhood controls can be a difficult task. We urge other investigators to report fieldwork activities used in identifying their control series. These data will be valuable in planning and budgeting case-control studies.

Carpal tunnel syndrome: median nerve stress test.

The purpose of this study was to determine the effect of wrist position on distal sensory and motor latencies of the median nerve. An orthosis was devised to maintain the wrist either in extension or in flexion while measuring these latencies. Fourteen patients with presumptive carpal tunnel syndrome (CTS) and 12 control subjects were evaluated following extension or flexion of the wrist for 5 and 10 minutes. Results showed an increase in distal latencies for both groups; the highest increment was found among CTS patients following 5 minutes of wrist flexion. Since it is not uncommon for patients to present with classical CTS symptoms but without electrodiagnostic findings in support of such diagnosis, it is suggested that such patients be reevaluated after 5 minutes of wrist flexion (median nerve stress) test.

Effect of blood microfilters on complement activity in human plasma.

While many devices that come into direct contact with patients' blood have been shown to be safe with respect to their effects on the cellular components and coagulation system of blood, many have not been examined with respect to their potential to activate the complement system. We present evidence that suggests that a combination of nylon plus polypropylene, and a combination of polyester plus polypropylene, found in blood microfilters used to protect patients from gaseous and particulate embolism during cardiopulmonary bypass, produce significant (p less than 0.01, p less than 0.05, respectively) C3a generation during incubation in heparinized plasma. Filter mesh composed of nylon plus polypropylene produced significantly more (p less than 0.01) C3a than the polyester plus polypropylene combination.

Ultrastructure of the foveal glands of the ticks, Dermacentor andersoni Stiles and D. variabilis (Say).

The foveal glands of Dermacentor variabilis appear to consist of 2 cell types. The outer cells (Type I) are active, with large areas of abundant finely granular material, apparently precursors of the mature secretory granules. The inner cells (Type II) are apparently storage cells. They are highly vacuolated and contain coarsely granular material as well as presumably mature secretory granules. The foveal glands of D. andersoni contain only Type II cells with extensive accumulations of presumably mature secretory granules.

Some ultrastructural and functional aspects of the golgi àpparatus of Thelohania sp. (Microsporida) in the shrimp Pandalus jordani Rathbun.

Electron microscope observations on Thelohania sp. in the shrimp Pandalus jordani support the view that the Golgi complex in Microsporida is a "classical" one, composed of vesicular, vacuolar, and cisternal components. During development of the sporoblast, a portion of the Golgi complex is seen as an electron-dense reticulum enmeshing the core of the polar filament. Associated with the reticulum are electron-dense bodies. The reticulum and "dense bodies," reported in several previous publications, have not been well understood and have been given a variety of names. The evidence favors the view that these structures have secretory activity in which the reticulum concentrates or synthesized material, some of which takes the form of membrane-bounded granules. It is suggested that the most appropriate name for the reticulum is "reticulum golgien," and the the correct name for the "dense bodies" is the standard cytologic term, "secretion granules." The secretion granules apparently remain in the posterior part of the spore, and may be stored there for some as yet undetermined use.