A technique for improved blood sampling during sleep studies

Research protocols often require that blood samples be drawn during sleep. This study compares the efficacy of obtaining nocturnal blood samples using a standard heparinized intravenous setup versus the same intravenous setup used in conjunction with a small chemical heating pad. The chemical heating pad significantly improved the number of blood samples obtained and the maintenance of intravenous patency. The use of a chemical heating pad is an economical way to resolve the frustration of lost blood samples while maintaining a reasonable environment to monitor sleep.     

A thin gel layer technique for improved resolution in two-dimensional immunoelectrophoresis

A modification of the two-dimensional (crossed) immunoelectrophoresis (2D-IE) method characterized by the employment of a thin gel layer (0.3 mm) was developed. A rectangular Millipore filter dehydrates an area of the gel, thereby forming a basin which is charged with antiserum by means of a special applicator. This 2D-IE technique was compared with the techniques by Weeke [Scand. J. Immunol. 2: suppl. 1, pp. 47-56, 1973] and by Lebecq et al. [J. immunol. Methods 66: 219-226, 1984] using a model system comprising an antigen preparation from Mycobacterium intracellulare and a corresponding antiserum. Analyses by the technique described resulted in a distinct, multilinear precipitation pattern with dense and sharp precipitates contrasting well against the background.     

An improved technique for mitosis counting

Mitosis counting remains one of the most valuable prognostic indicators in tumor pathology; however, as currently carried out it is time consuming and not reproducible. In this study, 6 different pathologists, using different microscopes, arrived at widely different mitotic counts on the same slide, ranging from 4 to 16. These differences were mainly due to the different field areas of the various microscopes used and the method used for counting and recording. In evaluating the most active 10 HPF, the count ranged from 10 to 19. Instead, when an average of 40 fields was recorded, the range was 4-11. Using the mitosis/volume index, which expresses the number of mitotic figures per mm2 of viable tumor, the counts ranged from 8 to 10, a marked improvement. However, this method is complicated and not "user-friendly.' We suggest a variation of the technique by which a 2 mm2 rectangle is drawn on a cover slip and mounted under the microscope, centered on the most mitotically active area of the tumor. The mitoses in that area are counted (=n) and the percent of viable tumor (=x%) is estimated under low magnification. The number of mitoses per mm2 of viable tumor (cs-MAI) is then calculated according to the formula Cs-MAI=100n/2x. Using this modified method, the range of mitoses counted by the different observers was very narrow (9 to 11), and the time required for the counting was only 5-10 minutes.     

A filtering method for signal equalization in region-of-interest fluoroscopy

A method to significantly reduce the exposure area product in fluoroscopy using a pre-patient region-of-interest (ROI) attenuator is presented. The attenuator has a thin central region and a gradually increasing thickness away from the center. It is shown that the unwanted brightening artifact caused by the attenuator can be eliminated by attenuating the low spatial frequencies in the detected image using digital image processing techniques. An investigation of the best image processing method to correct for the presence of the attenuator is undertaken. The correction procedure selected is suitable for use with real-time image processors and the ROI attenuator can be permitted to move during image acquisition. Images of an anthropomorphic chest phantom acquired in the presence of the ROI attenuator using an x-ray image intensifier/video chain are corrected to illustrate the clinical feasibility of our approach.     

An improved technique for Ia-determination in guinea pigs

The serological typing of determinants within the guinea pig histocompatibility complex (GPLA-complex) has, until now, largely been carried out by the 51Cr-release technique. As target cells, a mixture of B and T cells from peripheral blood and lymph nodes were used. However, for the detection of Ia-determinants, which predominantly are expressed on the surface of B cells, the use of lymphocyte suspensions with a relatively low content of B cells can cause some evaluation problems. We have developed a simple method for obtaining a relatively pure suspension of B cells, making use of the ability of guinea pig T cells to form rosettes with rabbit red blood cells and the possibility of removing these by sedimentation on lymphoflot. By employing these purified B cells, an improved serological detection of Ia-determinants of the guinea pig histocompatibility complex is made possible.     

A video analysis technique for organ dose assessment in pediatric fluoroscopy: applications to voiding cystourethrograms (VCUG)

The time-sequence videotape-analysis methodology, originally developed by Sulieman et al. [Radiol. 178, 653-658 (1991)] for use in tissue dose estimation in adult fluoroscopy exams, has been adapted to the study of the newborn voiding cystourethrogram (VCUG). Individual frames of fluoroscopic and radiographic video were analyzed with respect to unique combinations of field size, field center, projection, tube potential, and mA or mAs, respectively. A modified version of the stylized ORNL newborn model was coupled to the MCNP4C radiation transport code to report organ doses per unit entrance air kerma (free-in-air) for each identified x-ray field. A series of urinary bladder models was additionally developed representing the organ at differing stages of contrast filling. The technique was subsequently applied to two patients, a 3-month male and a 1-month female, examined via a conventional fluoroscopy system used just prior to departmental conversion to digital systems. The effective dose to these patients was estimated as 0.47 mSv and 1.36 mSv, respectively (ratio of 2.9). Corresponding ratios of cumulative fluoroscopy time and entrance air kerma were 2.2 and 1.6, respectively. For the male patient, the mean percent dose contribution from fluoroscopy for all irradiated organs was 71 +/- 12%, while that value for the female patient was 88 +/- 4%.     

An improved mechanical technique for assisted hatching

BACKGROUND: Varied clinical outcomes of assisted hatching (AH) have been reported. We attempt to investigate whether the size of the zona opening created by AH is adequate for blastocyst hatching, and, if not, set up a new method to improve it. METHODS: A new AH technique, long zona dissection (LZD), was established, and experiments were performed to compare the effects of different sizes of zona opening on complete hatching of blastocysts in mouse and human embryos in vitro. RESULTS: The LZD technique can create a long zona slit on early embryos, even blastocysts, with the slit size beyond two-thirds of zona diameter. Compared with three-dimensional partial zona dissection, LZD can significantly enhance the hatching speed and the rate of complete hatching of mouse blastocysts (93.9%). All (100%) human blastocysts completely hatched following LZD; however, when the slit size after AH was about two-fifths of zona diameter, more of the larger inner cell masses (ICM) became trapped by the zona opening during hatching than the smaller ICM (53.3 versus 12.5%, P = 0.01). CONCLUSIONS: Zona opening of moderate size following AH is inadequate for the completion of blastocyst hatching in vitro; in some cases, however, it can be significantly improved by LZD.     

透视下行子宫输卵管造影中近端输卵管梗阻假阳性因素分析

目的提高子宫输卵管造影中诊断输卵管近端梗阻的准确性。方法选择600例生殖医学中心的不孕受检者,年龄21～45岁,平均年龄34岁。随机分成A、B、C、D 4组,A组222例444条输卵管,B组121例242条输卵管,C组135例270条输卵管,D组122例244条输卵管。在实时透视下行子宫输卵管优维显造影,分析输卵管造影中近端输卵管梗阻的假阳性因素。结果导管顶端位于输卵管开口处121例,其中98例（80.99%）导致同侧宫角及输卵管不显影;经适当外拉或旋转导管后112例（92.56%）同侧宫角显影,其中84例（69.42%）同侧输卵管近端显影,仅有37例为近端输卵管梗阻。因球囊过大或过小导致造影剂未能充盈宫角者135例,其中78例（57.78%）单侧近端输卵管不能显影,经调整后59例（43.70%）单侧输卵管近端显影,仅19例为单侧近端输卵管梗阻。122例受检者仅以盆腔正位观察,有48例（39.34%）单侧输卵管近端不能显影,改变体位后35例（28.69%）近端输卵管得以显影。4组子宫输卵管造影中,B、C、D 3组输卵管近端梗阻率均低于A组常规输卵管造影,D组输卵管梗阻率明显低于前3组。结论在透视下行子宫输卵管造影,能及时判断造成近端输卵管不显影的假阳性因素并及时纠正,可直接提高输卵管显影率及诊断准确性。     

A technique for improved fixation of the pigeon central nervous system for electron microscopy

The central nervous system (CNS) of the pigeon has been difficult to fix with consistency, and consequently this problem has impeded ultrastructural studies of various parts of the pigeon brain. Here we describe a method for effective fixation of the pigeon CNS and discuss the three principal problems associated with good fixation of this animal's brain. The animal was deeply anesthetized and the thoracic cavity was opened without collapsing the pectoral girdle upon the brachiocephalic trunks and the common carotids. The perfusion pressure was raised to 140–150 mm Hg to overcome the high resistance of the small diameter, long common carotids. Heparin was added to the wash buffer to retard coagulation of blood in the vascular bed of the brain. The method is not foolproof, but with care excellent fixation can be achieved.     

In search for predictive factors for atopy in human cord blood

Since early prevention is regarded as an important corner stone in the management of atopic diseases, the identification of reliable markers detecting individuals at risk are of major interest. Therefore, many efforts have been made to unravel reliable predictors for atopy which might identify children at risk and allow the initiation of preventive strategies at an early stage. In the past, much scientific energy has been forced in particular on the development of as noninvasive methods as possible to reach this goal. It is obvious that the identification of markers for atopy at the earliest time of life – namely immediately after birth – represents one of the most attractive attempts. In consequence various studies have been initiated to address this issue investigating markers for atopy in cord blood. Most of them have been geared to our current knowledge about cellular and soluble factors which are dysregulated in adolescent atopic individuals. Although the findings of these studies will improve our knowledge about the initial evolution of atopy, several parameters evaluated did not show any association or have led to almost conflicting results. In order to provide an up-date about the current developments in this field, recent research findings on predictive factors for atopy in cord blood are summarized in the following synopsis.     

Conversion factors for the estimation of effective dose in paediatric cardiac angiography

Conversion factors, which relate the kerma-area product to effective dose, have been estimated for paediatric cardiac x-ray angiography. Monte Carlo techniques have been used to calculate the conversion factors for a wide range of projection angles for children of five ages and for adults. Correction factors are provided so that the conversion factors can be adjusted for different tube potentials and filtrations.     

A 3D kinematic estimation of knee prosthesis using X-ray projection images: clinical assessment of the improved algorithm for fluoroscopy images

In this paper, we propose three ideas to improve a kinematic estimation algorithm for total knee arthroplasty. The first is a two-step estimation algorithm that improves estimation accuracy by excluding certain assumptions needed for the pattern matching algorithm reported by Banks and Hodge. The second is incorporating a 3D geometric articulation model into the algorithm to improve estimation accuracy substantially for the depth translation, and to introduce contact points’ trajectories between the articular surfaces. The third is an algorithm to process estimation even when the silhouettes of two components overlap. To assess our algorithm’s potential for clinical application, we carried out two experiments. First, we used a robot to position the prosthesis. Estimation accuracy was checked by comparing input data to the robot with the estimates from X-ray photographs. Incorporating our articulation model remarkably reduced the error in the depth translation. Next, we performed a clinical assessment by applying the algorithm and articulation model to fluoroscopy images of a patient who had recently had TKA.     

Optimisation in fluoroscopy

Optimisation of radiation protection in fluoroscopy is important since the procedure could lead to relatively high absorbed doses both in patients and personnel resulting in acute radiation injury. Optimisation procedures include adjustment of the fluoroscopy equipment such as exposure factors as well as proper use of automatic brightness control and pulsed fluoroscopy. It is also important to gain the benefits of image processing and the higher sensitivity of flat panel detectors as compared to image intensifier-TV systems.Proper positioning of the patient with respect to detector and X-ray tube is of fundamental importance to image quality and radiation dose to the patient. Both image quality and radiation dose are also affected by the methodology used with parameters such as magnification factor, increased filtration, use of last-image-hold and the use of a grid.There is a direct relation between patient dose and the absorbed dose to the personnel since this is mostly due to scattered radiation from the patient. If the correct methodology and the correct radiation protection devices are used, the absorbed dose to the personnel could be minimised to acceptable levels even for those working with complex procedures.In order to have an organised review of all aspects of optimisation, it is recommendable to have an active quality system at the department. This system should define responsibilities and tasks for persons involved.     

A study of motion in gastrointestinal x-ray fluoroscopy

Studying motion in the gastrointestinal (G.I.) tract is the first step towards our goal of designing a digital algorithm for real-time noise and motion blurring reduction by temporal and spatial averaging in x-ray fluoroscopy. The present work concerns the types of motion relevant to G.I. fluoroscopy (e.g., motion of the walls of the oesophagus, the stomach, the small intestine, and the colon), and measurement of the range of velocities in different parts of the G.I. tract from tape recorded fluoroscopic sequences. The relationship between image contrast and velocity, the effects of motion on system response, and in particular the influence of these parameters on the evaluation of velocities will also be discussed.     

An improved perfusion technique for fixation of sheep myocardium

Although sheep have been widely used as models in the study of cardiac physiology, corresponding morphologic and morphometric data are scanty. For meaningful correlation of morphometric data with physiological information, it is desirable that fixation of the heart occur under controlled conditions. This paper describes a technique for in situ, retrograde aortic perfusion fixation of sheep myocardium under conditions of controlled pressure and minimal wastage of fixative. This is achieved by the application of snares around the brachiocephalic trunk and aortic arch, which are tightened at the start of the perfusion. These isolate the ascending aorta and the coronary vasculature from the remainder of the circulation and allow fixation of the whole heart at a controlled pressure. The method produces good fixation and contrast for transmission electron microscopy and is applicable to late-gestation fetuses, lambs, and adult sheep.     

An improved technique for nasal inhalation challenge tests.

An improved technique for nasal inhalation challenge tests is described. It includes an improved delivery system utilizing a Maxi-Myst air compressor delivering a flow of room air controlled by an in-line, electroncially timed solenoid which precisely controls the duration of compressor activity. A No. 251 DeVilbiss atomizer will deliver 0.1 + 0.01 gm/spray when the flow rate is 11.5 L/min, the duration of atomizer activity is approximately 0.1 sec, and the amount of liquid in the atomizer insert is kept between 0.75 and 2.0 ml. Nasal aerosol challenge of 0.1 ml of isotonic phosphate-buffered saline per nostril produced less variability in nasal airway resistance (NAR) response than 0.2 ml, and the smaller volume proved satisfactory for 6 consecutive saline challenges at 15-min intervals. A new face mask, which did not impinge on the bridge of the nose or paranasal structures, yielded lower baseline values of nasal airway resistance and much less variability in these measurements. Techniques employed in objectively quantitating nasal responses to various exogenous substances are briefly but critically reviewed.