Sorption/Desorption of lincomycin from three arid-region soils.

The antibiotic lincomycin is commonly found in treated municipal waste water and in waste from swine and poultry production. Environmental disposal of these wastes has the potential to introduce a significant mass of lincomycin into the ecosystem. In the present study, a series of sorption and desorption experiments were conducted to determine the potential mobility of lincomycin in soils from arid environments. Sorption and desorption isotherms were obtained for lincomycin using three different soils. Isotherms were fit to the Freundlich equation. Adsorption of lincomycin was found to have a of 11.98 for a biosolid-treated soil (1.58% OC) and a of 210.15 for a similar unamended soil (1.42% OC). It was also found that for a low-organic-content soil the was 5.09. The differences in adsorption can be related to the soil pH and the pKa of lincomycin (7.5-7.8). When the soil solution pH is below the pKa, the cationic species of lincomycin dominates, resulting in increased water solubility. Interaction with the cation exchange complex is minimal due to a high solution cation concentration (Ca and Na). Desorption isotherms also indicate that when the solution pH is lower than the pKa, retention of lincomycin is reduced. Our results indicate that the mobility of lincomycin in these arid region soils is dependent on soil pH.

Duration of preclinical rheumatoid arthritis-related autoantibody positivity increases in subjects with older age at time of disease diagnosis.

OBJECTIVES: To investigate factors that may influence the prevalence and timing of appearance of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies during the preclinical phase of rheumatoid arthritis (RA) development. METHODS: 243 serial prediagnosis serum samples from 83 subjects with RA were examined for the presence of RF and anti-CCP antibodies. RESULTS: Of the 83 cases, 47 (57%) and 51 (61%) subjects had at least one prediagnosis sample positive for RF or anti-CCP, respectively. Gender and race were not significantly associated with the prevalence or timing of preclinical antibody appearance. Preclinical anti-CCP positivity was strongly associated with the development of erosive RA (odds ratio = 4.64; 95% confidence interval 1.71 to 12.63; p<0.01), but RF was not (p = 0.60). Additionally, as age at the time of diagnosis of RA increased the duration of prediagnosis antibody positivity for RF and anti-CCP increased, with the longest duration of preclinical antibody positivity seen in patients diagnosed with RA over the age of 40. In no subjects did symptom onset precede the appearance of RF or anti-CCP antibodies. CONCLUSIONS: The period of time that RF and anti-CCP are present before diagnosis lengthens as the age at the time of diagnosis of RA increases. This finding suggests that factors such as genetic risk or environmental exposure influencing the temporal relationship between the development of RA-related autoantibodies and clinically apparent disease onset may differ with age.

First non-vertebrate member of the myc gene family is seasonally expressed in an invertebrate testis.

We have cloned and characterized the first non-vertebrate member of the myc gene family, pAv-myc, from testes of the Northern sea star, Asterias vulgaris (Echinodermata). We have used an oligonucleotide that is complementary to the virtually 100% conserved vertebrate c-myc box A in the second exon and a cDNA library constructed from spermatogenically active testes. Relatives of this echinoderm existed approximately 100 million years prior to the origin of the earliest known organism for which c-myc sequence is currently available (the trout). Nonetheless, our cDNA encodes a protein with approximately 30% amino acid identity and 46% overall conservation to human c-myc. Regions of substantially higher conservation (63-95%) correspond in order to the transcriptional activation (boxes A, B and C), casein kinase II phosphorylation, nuclear-targeting, basic DNA-binding and oligomerization domains in the second and third exons of human c-myc. Sea star c-myc cDNA detects a 2.7-kb transcript on Northern blots of monthly samples of testicular tissue from field-collected individuals (n = 6-8), indicating peak expression during active spermatogenesis. This is also the first example of seasonal variation in expression of c-myc during spermatogenesis in laboratory or natural populations of any animal. It is intriguing to speculate about the potential oncogenic character of c-myc in this invertebrate, in which tumors have not yet been observed, and about the possibility that c-myc is more widely present in eucaryotes than has been anticipated.

Expression of homologues for p53 and p73 in the softshell clam (Mya arenaria), a naturally-occurring model for human cancer.

Homologues for human p53 (Hsp53) and p73 (Hsp73) genes were cloned and expression patterns for their corresponding proteins analysed in tissues from normal and leukemic softshell clams (Mya arenaria). These are the first structural and functional data for p53 and p73 cDNAs and gene products in a naturally occurring, non-mammalian disease model. Core sequence of the predicted clam p53 (Map53) and p73 (Map73) proteins is virtually identical and includes the following highly conserved regions: the transcriptional activation domain (TAD), MDM2 binding site, ATM phosphorylation site, proline rich domain, DNA binding domains (DBDs) II-V, nuclear import and export signals and the tetramerization domain. The core sequence is a structural mosaic of the corresponding human proteins, with the TAD and DBDs resembling Hsp53 and Hsp73, respectively. This suggests that Map53 and Map73 proteins may function similarly to human proteins. Clam proteins have either a short (Map53) or long (Map73) C-terminal extension. These features suggest that Map53 and Map73 may be alternate splice variants of a p63/p73-like ancestral gene. Map73 is significantly upregulated in hemocytes and adductor muscle from leukemic clams. In leukemic hemocytes, both proteins are absent from the nucleus and sequestered in the cytoplasm. This observation suggests that a non-mutational p53/p73-dependent mechanism may be involved in the clam disease. Further studies of these gene products in clams may reveal p53/p73-related molecular mechanisms that are held in common with Burkitt's lymphoma or other human cancers.

Curriculum for musculoskeletal radiology.

Although general suggestions have been made regarding a radiology residency curriculum, no specific list of entities has been offered. Over the past ten years, we have developed a resident-run morning conference in musculoskeletal radiology that is supervised by faculty and covers a specific curriculum. We offer our curriculum as an example that may assist other departments in developing their own curricula.

A pseudo-outbreak of respiratory infection with Acinetobacter species.

We describe an apparent outbreak of respiratory infection with Acinetobacter species involving 14 patients over 8 days. Epidemiological investigation revealed two consecutive pseudo-outbreaks of infection caused by two consecutive, unrelated laboratory errors in the processing of sputum, nasopharyngeal, and endotracheal aspirates.

Haemorrhagic colitis: detection of verotoxin producing Escherichia coli O157 in a clinical microbiology laboratory.

Faeces (n = 1319) were examined over three months for the presence of non-sorbitol fermenting, verotoxin producing Escherichia coli (serotype O157). Seven isolates were found, four from patients with bloodstained diarrhoea and three from patients with no evidence of blood in the faeces. Screening of all faecal samples with specific O157 antiserum for non-sorbitol fermenting organisms and agglutination was an important adjunct to clinical and microscopic findings and helped detect cases of verotoxin producing E coli which might otherwise have been missed.

A rapid technique for detection of resistance to chloramphenicol in Streptococcus pneumoniae and comparison with minimum inhibitory concentration and disk-diffusion methods.

Fifty-two strains of Streptococcus pneumoniae were examined for production of chloramphenicol acetyltransferase (CAT) by a rapid technique based upon induction of enzyme activity and chemical assay. This method was compared with one measuring the minimum inhibitory concentration (MIC) by agar dilution and a diffusion test with disks containing 10 micrograms, 30 micrograms and 50 micrograms of chloramphenicol. The MIC for 13 chloramphenicol-resistant strains was 16 mg/L and for 39 sensitive strains less than or equal to 4 mg/L. The chemical assay clearly distinguished resistant from sensitive strains; it was technically simple and provided results within 90 min. The distinction between sensitive and resistant bacteria in the disk diffusion assay was clearer with 10-micrograms than with 30-microgram and 50-micrograms disks. However, the chemical CAT assay, with enzyme induction, is recommended when a rapid result is required.

Correct placement of epidural steroid injections: fluoroscopic guidance and contrast administration.

We prospectively evaluated 316 caudal-approach epidural steroid injections given by staff radiologists and residents in our department over a 1-year period. Needle placement was checked with fluoroscopy and corrected if necessary. When the needle tip was within the sacral canal, nonionic contrast material was injected. If epidural contrast was not observed, the needle tip was repositioned. Of 111 procedures performed by physicians who had given fewer than 10 epidural steroid injections, 53 (47.7%) resulted in correct nonfluoroscopically directed placement of the needle. For physicians who had performed between 10 and 50 such procedures, 62 (53.4%) of 116 had correct nonfluoroscopically directed placement. For staff physicians, 55 (61.7%) of 89 placements were correct. Even when the sacral hiatus was easily palpated and a staff physician was confident that he or she was within the epidural space, fluoroscopy revealed incorrect placement 14.2% of the time (seven of 49 procedures). In addition, when the needle was positioned within the sacral canal and no blood was evident on Valsalva maneuver or aspiration, the injection was venous in 29 of 316 procedures (9.2%). The presence of blood on the needle stylus was not a reliable indicator of venous placement of the needle. Our findings indicate that fluoroscopy is essential for correct placement of epidural steroid injection. Contrast administration is necessary to avoid venous injection of steroids.

Imaging of skeletal and soft tissue injuries in and around the knee.

This article addresses the place of MR imaging in the diagnosis of knee injuries. MR imaging of subtle fractures and bone contusions is described with emphasis placed on those types of fractures frequently associated with specific patterns of soft tissue injury. Soft tissue injuries are divided into ligamentous, meniscal, and muscular; each is discussed separately. The MR imaging appearance of these lesions is explained.

Seasonal patterns of ornithine decarboxylase activity and levels of polyamines in relation to the cytology of germinal cells during spermatogenesis in the sea star, Asterias vulgaris.

The activity of ornithine decarboxylase (ODC) and levels of polyamines were measured in the testes of Asterias vulgaris collected throughout an annual spermatogenic cycle. Samples of the testes were prepared for light and electron microscopy to observe the associated changes in the cytology of germinal cells. The specific activity of ODC increased at the onset of testicular growth, decreased during the coldest period of the winter when testicular growth was minimal, and increased again early in the spring when testes grew maximally. Increased activity of ODC resulted in increased levels of polyamines and was correlated with either mitotic or meiotic germinal cell divisions, or both. Spermine levels were always greater than putrescine, followed by spermidine. Highest levels of polyamine synthesis coincided with the onset of spermatogonial proliferation during the fall and with the period of meiotic differentiation and spermiogenesis in the spring. Mid-summer (July) testes were small (0.3-0.5 gonad index (GI)) and contained amitotic spermatogonia arrested in G(1) of the cell cycle. Mitotic and pre-meiotic testes (October/November) increased slightly in size (0.3-1.4 GI) and contained actively dividing spermatogonia, most of which differentiated into primary spermatocytes. Testes from February and March were large (1-6.75 GI), but the proliferative status of their spermatogonia and primary spermatocytes varied. Spermatogonia and primary spermatocytes from early February testes were not dividing. In testes obtained in March, both spermatogonial mitosis and meiosis of spermatocytes resumed, coincident with increased field water temperatures.

Radiologic manifestations of adult tuberculosis.

Adult pulmonary tuberculosis commonly presents with radiographic findings of upper lobe cavitary opacities, in which case the correct diagnosis is usually suspected. However, other radiographic presentations of this disease in the adult include intrathoracic adenopathy, pleural effusion, lower lobe consolidation, a miliary pattern, and a solitary nodule. In these latter cases, tuberculosis may not be considered in the differential diagnosis. This article discusses the protean manifestations of adult pulmonary tuberculosis.

Pulmonary embolism: chest radiographic abnormalities.

The value of chest radiography in the diagnosis of pulmonary embolism has been investigated extensively. Although the chest radiograph seldom permits one to say whether embolism is or is not present, it is still an essential component in the evaluation of the patient with suspected pulmonary embolism. This article stresses the radiographic abnormalities that occur with pulmonary embolism and defines the role of the chest radiograph for evaluation of this disorder.

Exposure to ultraviolet radiation (290-400 nm) causes oxidative stress, DNA damage, and expression of p53/p73 in laboratory experiments on embryos of the spotted salamander, Ambystoma maculatum.

Developing embryos of the spotted salamander, Ambystoma maculatum, exposed to ultraviolet radiation (UVR; 290-400 nm) in the laboratory show a significant sensitivity to UVB (290-320 nm) radiation. Embryos in laboratory experiments exhibited significant DNA damage during exposures to UVR despite a significant increase in the production of the protective pigment melanin in response to UVR exposure. DNA damage occurs as a result of both the direct effects of exposure to UVR, and the indirect effects are mediated by the production of reduced oxygen intermediates. The production of reactive oxygen species initiates the expression of p53/p73 that leads to either DNA repair or apoptosis. When similar experiments are conducted on salamander embryos exposed to solar UVR in vernal pools, the embryos show significantly less sensitivity and higher survivorship. The differences between laboratory and field experiments are a result of the attenuation of UVR caused by the accumulation of dissolved organic carbon within the pools of these wooded areas. These findings suggest that northeastern populations of spotted salamanders are sensitive to UVR but are not significantly affected by present-day irradiances of UVR in the field. These results do suggest that continued decreases in stratospheric ozone over temperate latitudes have the potential to affect spotted salamanders in their natural habitats.

Effect of a 1.5 Tesla magnetic field on Greenfield filters in vitro and in dogs.

The authors have tested four Greenfield filters for deflection in a 1.5 Tesla magnetic field and found large variations in the amount of deflection among filters. They also placed two filters in dogs and checked the filter for migration by taking radiographs before and after magnetic resonance imaging (MRI) scans. They found no evidence of migration. They conclude that, while most Greenfield filters respond to a magnetic field, the chance of migration of a filter because of an MRI scan is small. Therefore, MRI scanning of patients with Greenfield filters has little risk.

The third head of gastrocnemius in CT images.

A 17 year old male patient was undergoing a CT scan for pain and swelling of the left knee. The CT images of both legs, taken simultaneously, revealed an asymmetry of the musculature in the popliteal fossa of the right leg. Serial images indicated the presence of a third head joining the medial head of gastrocnemius.

Acanthamoeba: ecology, pathogenicity and laboratory detection.

Acanthamoeba spp. are ubiquitous free-living protozoa found in a wide range of environmental niches. They are resistant to disinfectants, temperature variation and desiccation and are responsible for two recognised diseases in humans, granulomatous amoebic encephalitis and keratitis. Both infections are rare, although the latter is currently receiving more attention following the association between Acanthamoeba and the wearing of contact lenses. Laboratory diagnosis is unusual but not beyond the bounds of most routine clinical microbiology departments. In this review the various aspects surrounding the ecology, pathogenicity and laboratory detection of Acanthamoeba spp. are considered.

Indium-111 leukocyte localization in infected prosthetic graft.

Infective endocarditis can be difficult to prove, even in the face of strong clinical suspicion. A case in which standard methods of diagnosis failed to demonstrate endocarditis in a patient with recurrent Staphylococcus aureus bacteremia and porcine aortic valve is reported. An In-111 labelled leukocyte SPECT study demonstrated uptake in the aortic root and leaflets, and autopsy demonstrated vegetations on the leaflets. In-111 may prove useful in demonstrating endocarditis in patients with prosthetic valve infection.

Interventional musculoskeletal radiology.

Interventional procedures constitute a significant proportion of musculoskeletal radiology. Percutaneous needle biopsy is the ultimate diagnostic technique for the evaluation of musculoskeletal neoplasms and infections. The procedure is accurate, rapid, and safe. It is ideally suited for the diagnosis of metastatic disease and round cell neoplasms. Several needle procedures have been used for the diagnosis and treatment of low back pain. Diskography is primarily a diagnostic test used to determine the symptomatic disk level when multilevel disk disease is present and also to diagnose internal disk disruption. Nerve block with local anesthetic is also used to locate the symptomatic level in patients with multilevel abnormalities. Epidural steroid injection is a therapeutic procedure that commonly is used in patients with low back pain and has been shown to be most effective in patients with disk herniation. Facet joint injection with local anesthetic and steroid is performed to diagnose and treat the facet syndrome. Other needle procedures in the musculoskeletal system include sacroiliac joint aspiration and injection, prosthetic joint aspiration to evaluate potential infection, distention arthrography, and injections of the coccyx for coccydynia.

Radiographic and orthopedic evaluation of wrist trauma.

This paper was written to enable radiologists to contribute more usefully to the diagnosis and treatment of various wrist injuries. All imaging modalities are discussed to equip the radiologist for his difficult task. We present a systematic approach to the evaluation of wrist trauma patients beginning with initial plain films and proceeding through more invasive or sophisticated studies in order to achieve a definitive diagnosis. Toward this end a flow chart has been developed as a quick reference source. The authors have then described the anatomy and kinematics of the wrist to further the radiologist's understanding of the forces involved and the injuries produced by trauma. From this foundation individual injuries are then discussed together with the best methods of making the proper diagnosis of each. Criteria for adequate treatment of various injuries are also presented.