Early holocene openlands in southern New England.

The pre-historical vegetation structure in temperate forest regions is much debated among European and North American ecologists and conservationists. Frans Vera's recent hypothesis that large mammals created mosaics of forest and openland vegetation in both regions throughout the Holocene has been particularly controversial and has provoked new approaches to conservation management. Thirty years earlier, American paleoecologists Herb Wright and Margaret Davis debated whether abundant ragweed pollen at Rogers Lake, Connecticut at 9500 yr BP signified local forest openings or long-distance transport of pollen from Midwestern prairies. Using new pollen records from Harvard Forest and the North American Pollen Database, we address this question and offer insights to the openland discussion. Ragweed and other forbs exceed 3.5% at five sites in a restricted area of southern New England between 10,100 and 7700 yr BP. Strong evidence suggests this pollen originated from the landscapes surrounding these sites (supporting Davis), as ragweed pollen percentages do not increase with longitude from New England to the Midwest. Ragweed pollen percentages are also unrelated to basin size and therefore unrelated to the proportion of extraregional pollen in New England. High forbs values were associated with increases in oak, decreases in white pine, and relatively high charcoal values. Modern pollen records with similar forb and tree percentages occur along the Prairie Peninsula region of the Upper Midwest. However, the closest analogue to the southern New England early Holocene assemblages comes from Massachusetts' Walden Pond in the early 18th century. These results and the affiliation of ragweed for open, disturbed habitats suggest that oak-pine forests with large openings persisted for over 2000 years due to dry conditions and perhaps increased fire frequency. This conclusion is corroborated by independent lake level and climate reconstructions. Because these early Holocene openlands have no detectable analogue in New England for the past 7000 years before European settlement, we suggest that all important openlands today are almost exclusively a legacy of Colonial agriculture and should be managed accordingly. Nonetheless, our results may have implications for forest dynamics accompanying projected climate change to more arid conditions in New England over the next century.

Pharmacologic and bacteriologic properties of SCH-27899 (Ziracin), an investigational antibiotic from the everninomicin family.

SCH-27899 is an investigational antibiotic from the everninomicin family, a group of oligosaccharide antibiotics produced by Micromonospora carbonacea. Information regarding the pharmacology, pharmacodynamics, pharmacokinetics, efficacy, and toxicity of this agent was obtained from a MEDLINE search and a review of abstracts presented at recent scientific meetings. SCH-27899 has in vitro bacteriostatic activity against a wide variety of gram-positive organisms, including highly resistant organisms such as methicillin-resistant Staphylococcus aureus, vancomycin-intermediate-sensitivity S. aureus, Streptococcus pneumoniae (both penicillin-susceptible and -nonsusceptible), and vancomycin-resistant enterococci. In vitro data, animal studies, and preliminary human studies indicate that it is effective and fairly well tolerated. Its place in therapy remains to be determined, and clinical trials continue.

Potential interaction between azithromycin and warfarin.

Azithromycin is considered unlikely to interact with warfarin. Unlike other macrolide antibiotics, it is not hepatically metabolized and did not produce an interaction with warfarin in a single-dose study. A 71-year-old woman with a prosthetic heart valve, stabilized with warfarin, had international normalized ratios (INRs) maintained between 2.5 and 3.5. Six days after she received a prescription for a 5-day course of azithromycin, her INR was 15.16. Phytonadione 10 mg was administered subcutaneously, and warfarin was held for 3 days until her INR fell to 2.10. She then was restabilized with warfarin. Until more information is known about the safety of warfarin and azithromycin, caution is advised when the agents are given together. Close monitoring of INR is recommended, and warfarin dosage adjustment may be necessary.

Artifactual echoes in B-mode images due to multiple scattering.

In B-mode images, echoes, which appear to arise from inherently anechoic regions due to scattering from neighbouring echogenic regions, can be considered artifactual. We have observed multiple scatter contributions to such artifactual echoes in images of plane boundaries between random scattering phantoms and anechoic regions. For the strongest scattering phantom studied, multiple scatter echoes were 3-9% of the average phantom signal using two sharply focused transducers, an annular array in pulse echo mode, and an annular array/cone hybrid. Multiple scatter was less than 5% for a conventional transducer. Echo amplitudes were also measured in normal excised human liver and breast tissue. It was estimated that artifactual echoes due to multiple scatter would be negligible in B-mode images of liver. However, for breast imaging, the level of artifactual echoes was estimated to be similar to that found for our strongest scattering phantom.

Quantitative contrast measurements in B-mode images comparison between experiment and theory.

Quantitative measurements of image contrast were carried out for B-mode images of anechoic spheres (cysts) embedded in a random scattering medium. Four transducer geometries were used: (a) f/5.7 spherical transducer in pulse echo mode, (b) f/2.4 spherical transducer in pulse echo mode, (c) f/2.4, 30 degrees cone (hybrid transducer), (d) f/5.7, 30 degrees cone (hybrid transducer). The image contrast was also calculated via two methods; (i) a three-dimensional computer simulation and (ii) a relatively simple numerical convolution which relates the image of a small point-like scatterer [point spread function (PSF)] to image contrast. Generally, good agreement was found between the experimental measurements and the values calculated via both theoretical methods. The results indicate that image contrast is not determined solely by the full width at half maximum (FWHM) of the PSF. In particular, the results demonstrate the importance of far off-axis contributions of the ultrasound beam to the significant degradation of contrast in images obtained with high resolution (low f-number) axicons.

Case report: pulmonary calcification in smallpox handler's lung.

Smallpox handler's lung was first described by Morris Evans and Foreman in 1963. During the South Wales smallpox outbreak of 1962 several nurses were noted to develop a "flu-like" illness following an exposure to smallpox patients. The late development of pulmonary calcification in one of these nurses, who is now 74 years old, is described.

Interpretation of lymphoscintigrams in suspected lymphoedema: contribution of delayed images.

Interpretation of lymphoscintigrams in patients with extremity oedema may be adversely affected by any variation in the acquisition protocol. The purpose of this study was to determine whether delayed (2-24 h post-injection) views provide information incremental to the first 60 min of acquisition. In a 5-year period, 31 patients (10 males, 21 females, mean age 46 years) with extremity oedema or recurrent cellulitis underwent lymphoscintigraphy using 99Tcm-antimony trisulphide colloid (99Tcm-Sb2S3). All subjects underwent an initial dynamic acquisition of the pelvis and legs for 60 min, with further images obtained after 2-24 h. Films and reports were retrospectively reviewed by an experienced observer to determine whether delayed views provided information incremental to early images. Using standard qualitative criteria, lymphoscintigrams were classified as normal (n = 12) or consistent with lymphoedema (n = 19). However, 6 of 19 (32%) patients with lymphoedema displayed normal transit of radiopharmaceutical and a normal appearance of regional lymph nodes on views acquired up to 1 h after injection; localized dermal backflow (n = 5) or lymphocoele (n = 1) were seen only on delayed images (P < 0.02). These data indicate that delayed lymphoscintigraphy images are important for the diagnosis of lymphoedema and should be obtained even when lymphatic transit of 99Tcm-Sb2S3 and lymph node appearance at 1 h are normal.

The aquatic fate of triclopyr in whole-pond treatments.

The aquatic fate of the triethylamine salt formulation of triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) was determined in whole-pond applications in closed (no water exchange) systems in California, Missouri and Texas in two studies conducted in 1995 and 1996. These studies determined dissipation rates of triclopyr and its principal metabolites, 3,5,6-trichloropyridinol (TCP) and 3,5,6-trichloro-2-methoxypridine (TMP) in water, sediment and finfish. Ponds at each site containing a healthy biological community were treated at 2.5 mg AE litre-1 triclopyr. Water and sediment samples were collected through 12 weeks post-treatment, and non-target animals were collected through 4 weeks post-treatment. Dissipation rates for triclopyr, TCP and TMP were similar at each of the study sites, despite differences in weather, water quality, biotic community, light transmission and geographic location. Half-lives of triclopyr in water ranged from 5.9 to 7.5 days, while those of TCP and TMP ranged from 4 to 8.8 and 4 to 10 days, respectively. Levels of triclopyr and TCP declined in sediments at half-lives ranging from 2.8 to 4.6 days and 3.8 to 13.3 days, respectively. No TMP was detected in sediment. Triclopyr and TCP cleared from fish in relation to concentrations found in the water column. TMP levels in fish were generally an order of magnitude higher than levels of triclopyr and TCP, particularly in the visceral portion of the animals. No adverse effects on water quality or on the non-target biotic community were found following triclopyr applications. Results of these studies were comparable to those of triclopyr dissipation studies conducted in reservoirs, lakes and riverine systems in Georgia, Florida, Minnesota and Washington, indicating that the degradation and dissipation of triclopyr and its metabolites are similar in representative systems throughout the USA.

Operative cholangiography--techniques and inadequacies.

The effectiveness of three methods of operative cholangiography in outlining biliary anatomy was assessed in 60 patients undergoing routine cholecystectomy for gallbladder calculi. X-rays were scored according to bile duct visualization and an overall score calculated. There were no statistically significant differences between the three groups. However, ductal opacification was inadequate in a majority of patients. It is suggested that closer cooperation with the radiologist and more emphasis on technique are required if cholangiography is used to identify unsuspected calculi.

Elastic constants of Ultrasonic Additive Manufactured Al 3003-H18.

Ultrasonic Additive Manufacturing (UAM), also known as Ultrasonic Consolidation (UC), is a layered manufacturing process in which thin metal foils are ultrasonically bonded to a previously bonded foil substrate to create a net part. Optimization of process variables (amplitude, normal load and velocity) is done to minimize voids along the bonded interfaces. This work pertains to the evaluation of bonds in UAM builds through ultrasonic testing of a build's elastic constants. Results from ultrasonic testing on UAM parts indicate orthotropic material symmetry and a reduction of up to 48% in elastic constant values compared to a control sample. The reduction in elastic constant values is attributed to interfacial voids. In addition, the elastic constants in the plane of the Al foils have nearly the same value, while the constants normal to the foil direction have much different values. In contrast, measurements from builds made with Very High Power Ultrasonic Additive Manufacturing (VHP UAM) show a drastic improvement in elastic properties, approaching values similar to that of bulk aluminum.

Use of a Strecker oesophageal stent in the treatment of benign oesophageal stricture.

The use of self-expanding prostheses in the management of malignant oesophageal strictures has become well established. The majority of benign peptic oesophageal strictures can be successfully managed using endoscopic or fluoroscopically guided balloon oesophageal dilatation combined with long-term drug therapy, particularly using proton pumper inhibitors. Although endoscopic oesophageal dilatation can be performed on an outpatient basis, it requires repeated hospital visits. There is a small risk of oesophageal perforation whilst cardio-respiratory complications may be encountered during the use of intravenous sedation in an elderly population. The use of a self-expanding Strecker stent in a 98 year old woman with a benign oesophageal stricture is described.

Colonic gallstone ileus.

Colonic obstruction is a very rare complication of gallstone disease. A case is described in a 63-year-old female patient. Radiological investigation, including plain abdominal X-ray and contrast studies, aided in the diagnosis.

Routine chest radiography following endoscopic oesophageal dilatation for benign peptic oesophageal strictures.

Endoscopic oesophageal dilatation is a well-established procedure for management of patients with benign oesophageal strictures. The most important complication of the procedure is perforation with a recorded incidence of approximately 1%. Patients undergoing the procedure require close observation after dilatation. Routine chest radiographs are advisable following the procedure.

Localized giant pseudo-polyposis in ulcerative colitis.

Localized giant pseudo-polyposis is a rare complication of ulcerative or granulomatous colitis. A case illustrating the typical radiological findings is described. Recognition of this condition is important since it may simulate malignancy.