Continuous wave two-photon scanning near-field optical microscopy

We have implemented continuous-wave two-photon excitation of near-UV absorbing fluorophores in a scanning near-field optical microscope (SNOM). The 647-nm emission of an Ar-Kr mixed gas laser was used to excite the UV-absorbing DNA dyes DAPI, the bisbenzimidazole Hoechst 33342, and ethidium bromide in a shared aperture SNOM with uncoated fiber tips. Polytene chromosomes of Drosophila melanogaster and the nuclei of 3T3 Balb/c cells labeled with these dyes were readily imaged. The fluorescence intensity showed the expected nonlinear (second order) dependence on the excitation power in the range of 8-180 mW. We measured the fluorescence intensity as a function of the tip-sample displacement in the direction normal to the sample surface in the single- and two-photon excitation modes (SPE, TPE). The fluorescence intensity decayed faster in TPE than in SPE.     

Phosphorescent platinum/palladium coproporphyrins for time-resolved luminescence microscopy

The rostral ventromedial medulla (RVM) is an important mediator of the supraspinal component of opioid antinociception. Previous studies have suggested that activation of the cloned mu- and delta-opioid receptors (MOR1 and DOR1 respectively) in the RVM produces the antinociception mediated by spinally projecting neurons. In the present study, we investigated the expression of mRNA encoding either MOR1 or DOR1 in the RVM of rats. In addition, we examined quantitatively the expression of MOR1 and DOR1 mRNAs in spinally projecting RVM neurons including serotonergic (5HT) cells by using in situ hybridization, immunocytochemistry, retrograde tract-tracing, and the physical disector. Brainstem neurons were labeled in 14 male Sprague-Dawley rats by applying Fluoro-Gold (FG) topically to the dorsal surface of the lumbosacral spinal cord. Five-micrometer-thick cryostat sections were cut and in situ hybridization was performed by using full-length cRNA probes labeled with 35S-UTP. We found that 43% of RVM projection neurons expressed MOR1 mRNA and 83% of RVM projection neurons expressed DOR1 mRNA. Of 192 retrogradely labeled cells in the RVM, 51 cells (27%) were immunoreactive for 5HT. Of this population, half appeared to be labeled for the mRNA encoding MOR1 and over three-fourths appeared to be labeled for the mRNA encoding DOR1. Thus, we conclude that bulbospinal neurons express MOR1 and DOR1; moreover, MOR1 and DOR1 are expressed by significant proportions of 5HT neurons projecting to or through the dorsal spinal cord.     

New results using Laue diffraction and time-resolved crystallography

PURPOSE: To determine the antiproliferative effect of minoxidil on human corneal epithelium (hCE) proliferation in vitro and to assess whether topical minoxidil can significantly alter corneal topography after radial keratotomy (RK) by inhibiting myofibroblast activity in the keratotomy wound. SETTING: Corneal Research Laboratory, University of Chicago, Illinois, USA. METHODS: In the in vitro evaluation, proliferating hCE was exposed to minoxidil (0.1 to 2.0 mM) for 96 hours to determine the minimum inhibitory dose. Human corneal epithelium cell proliferation was assessed by the incorporation of bromodeoxyuridine (BRDU) into DNA. In the in vivo analysis, eight New Zealand albino rabbits had an eight-incision bidirectional RK on one eye and were divided into two groups. The control eyes (n = 3) received tobramycin and dexamethasone (TobraDex), ciprofloxacin hydrochloride (Ciloxan), and balanced salt solution (BSS) drops four times a day for 3 weeks, while the treatment eyes (n = 5) received TobraDex, Ciloxan, and minoxidil 1.0 mM drops four times daily for 3 weeks. The net change in corneal curvature at 3 weeks was analyzed with corneal topography. Myofibroblast activity in the keratotomy wound was assessed using alpha smooth muscle actin staining techniques. RESULTS: At concentrations of 1.0 mM and above, minoxidil caused a statistically significant, dose-dependent reduction in hCE cellular proliferation ranging from 29 to 44% (P < .05). Minoxidil (1.0 mM) caused a statistically significant central corneal flattening effect of 4.66 diopters (D) after RK in the treatment eyes compared with 1.11 D in the control eyes (P = .05). Histologically, minoxidil-treated keratotomy wounds lacked cells with contractile elements consistent with myofibroblast differentiation. Corneal epithelial wound healing was similar in both groups. CONCLUSION: At the appropriate dose, topical minoxidil may be a useful adjunctive treatment that can reduce the number of undercorrections after mini-RK without apparent toxicity to the corneal epithelium.     

New techniques in neurosurgery

Society demands for exactness and low complication rates of surgical treatment are high. Surgical training in the apprentice manner has been significantly reduced in Denmark since 1981 and e.g. the ability to visualize in three dimensions among younger neurosurgeons has diminished. Computer technology now makes it possible to create 3-D images that with incorporation of functionality leads to a faster and better understanding of neuroanatomy. In addition--for the sake of precision--true robotic instrumentation and navigational instruments have been introduced. The technological investments are compensated by reduced costs due to operative complications. A prerequisite for these developments are a close collaboration between medical doctors and engineers, keeping the respect for humanity intact. A survey of developmental areas in the neurosurgical techniques of today is given.     

New techniques in indirect reduction of long bone fractures

The most important and demanding part of operative fracture treatment concerns the reduction and correct alignment of the fracture fragments, which must be gentle to the bone and surrounding soft parts to preserve the essential blood supply to all tissues. The so called indirect reduction techniques apply the principles of nonoperative fracture care (ligamentotaxis) in combination with surgical tools and a number of techniques, where by the exposure of the most critical fracture focus can be minimized. New implant designs, low contact plates, cannulated screws, unreamed nails, pinless and hybrid external fixators, are helpful adjuncts: however, the surgical technique remains of paramount importance. The essence of careful handling of the soft and hard tissues has been stressed time and again. With the introduction of biological or minimally invasive surgery, the techniques of indirect reduction have had a renaissance. A few examples are described.     

深部开采的新技术新设备

２１世纪我国将有更多金属矿山进入深部开采。文中对国外深部开采所发明与使用的新技术，设备作一简要介绍。     

New imaging techniques for assessing cardiac function

In summary, newer imaging technologies yield three-dimensional pictures of the left ventricle. Detailed information is provided on regional wall motion, wall thickening, and ventricular volumes, which can be helpful in managing patients with cardiac disease. MR imaging gives the highest resolution images, and MR angiography can be invaluable in assessing the anatomy of an aortic dissection. Gated tomography with a technetium-based myocardial perfusion tracer can be thought of as a low-resolution cine MR imaging study. Combined function and perfusion nuclear studies performed at rest in an ICU can give information on myocardial perfusion and stunning, which is helpful in managing patients with acute ischemic syndromes. First pass RNA is probably the most accurate method for measuring RVEF and can be performed at the bedside using a portable multicrystal camera. Serial measurements of RVEF may be helpful in managing patients with pulmonary hypertension of various causes. For patients with documented acute myocardial infarction or chest pain and no acute myocardial necrosis or for patients undergoing preoperative risk assessment, combined perfusion and function using nuclear techniques yields both stress-induced ischemia and resting ventricular function in a single procedure and is timely and cost effective.     

Cardiopulmonary resuscitation. New and controversial techniques

Primary care physicians may need to perform cardiopulmonary resuscitation (CPR) from time to time. Knowledge regarding CPR has become extensive, and it is hoped that greater success will be achieved in the future with the advent of new methods. A number of techniques and devices have received attention in the lay and professional press. If appropriate care is to be delivered, practicing physicians must be aware of what is proven technology and what is investigational.