Darstellung und polymerisation von O-vinylacetalen. Untersuchung von O-, S- und N-vinylverbindungen. VI

Formaldehyde- and acetaldehyde-O-vinylacetals were synthesized by dehydrohalogenation of the analogous β-hydroxyethyl-compounds. If initiated radically the monomers do not homopolymerize well but they form regular alternating copolymers with maleic anhydride. In case of the kationic polymerization the O? CH₂? O-groups act as chain transfer agents. On heating the poly-O-vinyl-acetals especially with LEWIS acids a hydride shift takes place, and polymers with ester-side-chains are formed.     

Multiple Separations in Microfabricated Channels: From Biological Microenvironments to DNA

A continuous sample introduction and separation scheme is presented as an alternative to the current slab gel and microfabricated chip technologies for biological separations. This new technique involves continuous sample introduction via a conventional small bore capillary coupled to a small dimension rectangular channel. Both free zone and size based separations have been carried out in the rectangular channel. Laser induced fluorescence and electrochemical detection schemes have been employed with this technique. Some of the areas this technology has been used to investigate include monitoring dynamic events from microenvironments, monitoring analytes over long periods of time, and performing DNA separations.     

Mechanism of slowing of mucociliary transport induced by SO2 exposure

Responses of nasal mucociliary transport mechanisms to exposure to 6 ppm SO₂ were studied in chickens in vivo. This model takes advantage of the natural cleft palate which exposes the mucociliated base of the nasal septum. Exposure to 6 ppm SO₂ decreased the mucociliary transport rate along the base of the nasal septum. The minimum force required to move an iron particle along this area of mucous membrane by use of a magnetic field in vivo increased significantly after SO₂ exposure, while the minimum force required to move an iron particle on a pool of mucus collected from the same chicken and tested in vitro showed no change after SO₂ exposure. The elastic recoil distance of mucus was measured both in vivo and in vitro. The in vivo recoil distance decreased significantly after SO₂ exposure, while SO₂ exposure did not change recoil distance in vitro. It is proposed that exposure of chickens to SO₂ results in the formation of multiple points of adhesion of strands of mucus between the acinar gland cells and the emergent extracellular mucus or adhesion of a mucous blanket to the cilia, causing mucociliary transport to be retarded or static.     

Evaluation of the clonidine-suppression test in the diagnosis of pheochromocytoma

Summary In this study we examined the preoperative value of the clonidine-suppression test in 15 patients with surgically proved pheochromocytomas. The result of the clonidine-suppression test was pathological (epinephrine plus norepinephrine above 500 ng/l 3 h after clonidine) in 10 of 15 patients (66%). These patients had relatively large tumors and higher basal norepinephrine plasma levels. Out of the 5 cases without a pathological clonidine test 4 had normal basal plasma catecholamine levels with the result that the clonidine test could not be properly applied and 1 case produced a false negative result. These 5 cases generally had smaller tumors and lower plasma catecholamine levels. Two of these cases had basally raised epinephrine values. The other three cases had either a paradoxical increase or a suspiciously low fall (less than 25%) in norepinephrine within the normal range. We conclude that the clonidine-suppression test is only reliable for the diagnosis of relatively large pheochromocytomas.Abbreviations MIBG metaiodobenzylguanidine - HPLC High-performance liquid chromatography     

Lymphocyte Depression Induced in Chickens on Diets Deficient in Vitamin A and Other Components

Chloroma (chloroleukemia) was induced in a splenectomized rat by repeatedly administering dimethylbenz(a)anthracene (DMBA) and was serially transplanted thereafter. Composed of immature myeloid cells, the tumor imparted a green discoloration to the tissues that it infiltrated extensively. Chloroma cells fluoresced red in ultraviolet light, produced a characteristic curve in spectrophotometry, and contained large amounts of myeloperoxidase. They included numerous intracytoplasmic granules of both types A and B, which contained occasional crystalline bars. Permanent lines of chloroma cells were established in tissue culture. These cells, while maintaining their initial morphology, ceased producing myeloperoxidase and subsequently induced white tumors when they were isotransplanted.     

Flush solution 2, a new concept for one-to-three-day hypothermic renal storage preservation. Functional recovery after preservation in Euro-Collins, Collins' C2, hypertonic citrate, and F.2 solution

Experiments were performed on the quality of renal functional recovery after 24, 48, or 72-hr hypothermic storage preservation of canine kidneys in Euro-Collins solution (EC), Collins' solution C2, hypertonic citrate solutions (HC, HC-D2O), or our new flush solution 2 (F.2). Clearance tests (inulin, paraaminohippuric acid, and creatinine) and resorption rates for sodium, potassium, and glucose indicated a high superiority in the early functional recovery of F.2-preserved kidneys after all preservation periods tested. The excellent function after preservation in F.2 contrasted especially with the poor or even absent function after 72-hr preservation in HC and HC-D2O or EC. Thus F.2--a hyperosmolar solution containing sucrose with a balanced Na-K relation on the basis of "heavy water" (D2O)--is especially suitable for preservation up to 72 hr if cyclosporine is used for immunosuppression in the recipient. The recipient can be supplied with an organ with immediate good functional recovery because cyclosporine banishes the higher risk for rejection of these well-functioning organs; simultaneously, the possibility for continuous functional supervision allows avoidance of nephrotoxic side effects from the immunosuppressant.     

Computed tomography in the differential diagnosis of the enlarged retrorectal space

The value of computed tomography (CT) in the differentiation of an enlarged retrorectal space was analyzed in 132 cases. Classification of barium enema findings into those with simultaneous mucosal alterations and those without any visible lesions of the rectal mucosa seems to be useful. Computed tomography helps in those cases without mucosal changes to differentiate between retrorectal fibrosis, tumorous masses, and inflammatory diseases of the colon. It also demonstrates the lack of pathologic lesions in equivocal cases of pelvic lipomatosis and so-called "normal variants." If simultaneous mucosal involvement on barium enema--especially in rectal carcinoma or recurrent carcinoma of the rectum--is found, CT may show the perirectal extension of tumorous masses and thus help to clarify local operability.     

Novel 6-Month Treatment for Drug-Resistant Tuberculosis,United States

The US Food and Drug Administration approved a 6-month regimen of pretomanid, bedaquiline, and linezolid for extensively drug-resistant or multidrug-intolerant tuberculosis after a trial in South Africa demonstrated 90% effectiveness 6 months posttreatment. We report on a patient who completed the regimen using a lower linezolid dose.     

Symptomatic native arterial occlusions: early experience with "over-the-wire" thrombolysis

"Over-the-wire" thrombolysis was successfully accomplished in eight patients with symptomatic lower-extremity ischemia. The authors used a 5-F catheter with multiple side holes designed to pulse-spray urokinase directly over the guidance of a 0.035-inch guide wire. The mean occlusion length was 11.5 cm (range, 5-27 cm). Complete thrombolysis was achieved after delivery of a mean of 480,000 IU of urokinase in a mean infusion time of 48 minutes. One embolic complication was successfully treated with the catheter-wire system. No bleeding complications occurred. Over-the-wire thrombolysis is an alternative method of administering urokinase for the treatment of arterial occlusions.     

The World Bank's perspective on global health

Over the next 25 years, as populations age and tobacco consumption increases, most developing regions will likely see noncommunicable diseases become the leading causes of disability and premature mortality. The already existing problems of malnutrition and infectious diseases will remain. In this context, the World Bank is examining its role and contribution to global health. From a small start approximately 25 years ago, the Bank has greatly expanded its role in international health, population, and nutrition to become the largest single external financier of health activities in low- and middle-income countries. Many other Bank-supported activities affect health, including poverty reduction, housing, water and sanitation, and the education of girls. The Bank is also increasingly active in health policy debates, publishing numerous studies annually. Most of these studies focus upon specific countries, but some address key issues of concern to many developing countries. This article explains why the Bank continues to expand its resources devoted to health and the rationale for the changing emphasis of its activities in the field.