Investigation of a whole-body receiver coil operating at liquid nitrogen temperatures

This communication describes the design and application of a receiver coil operating at liquid nitrogen temperature and intended as a surface coil in a whole-body imager. Its particular application is seen as the external receiver for parasitic internal or implanted detectors.     

Peribursal fat plane of the shoulder: anatomic study and clinical experience

A comprehensive anatomic and radiographic analysis of the peribursal fat plane in 12 cadavers confirmed that the fat plane seen on radiographs represents extrasynovial fat lining the subacromial bursa and documented the anatomic relations of the bursa. A three-part retrospective clinical evaluation of rotator cuff tears, calcific tendinitis, and rheumatoid arthritis was performed. Two osteoradiologists blindly graded the appearance of the peribursal fat plane with the shoulder in external versus internal rotation in 21 patients with arthrographically intact rotator cuffs and 21 patients with disrupted rotator cuffs. The peribursal fat plane was seen better with disrupted rotator cuffs. The peribursal fat plane was seen better with the shoulder in internal rotation and was seen in 60% of control subjects but only 21% of patients with rotator cuff tears. Partial or complete obliteration of this fat plane is a sensitive (79%) but less specific (60%) indicator of rotator cuff tears. Obliteration of the peribursal fat plane by inflammatory processes in adjacent tissues, including calcific tendinitis and rheumatoid arthritis, occurred with a high frequency.     

Rupture of the posterior tibial tendon: CT and surgical findings

Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.     

Further consideration of the clonal nature of Salmonella typhi: evaluation of molecular and clinical characteristics of strains from Indonesia and Peru.

We examined envelope protein profiles, chromosomal restriction endonuclease digest patterns, and immune responses to envelope proteins for collections of Salmonella typhi strains isolated in Peru and Indonesia. Only minor differences in envelope protein patterns were apparent among strains. Strains from 7 of 20 Indonesian patients had a distinct chromosomal digest pattern compared with patterns of Peruvian and other Indonesian strains. Strains with this pattern carried the gene for the j flagellar antigen (H1-j); differences in response to envelope proteins of j and d strains were noted on immunoblot analysis. Our data suggest that there are genotypic and phenotypic differences among S. typhi strains. The clinical importance of these differences remains to be fully evaluated; however, in this study it was not possible to show a clear correlation between strain characteristics and disease severity.     

Presentation of abdominal tuberculosis to general surgeons.

Abdominal tuberculosis (TB) continues to give rise to diagnostic and therapeutic challenges. A total of 24 patients with abdominal TB who presented to general surgeons over a 9-year period have been reviewed. Most (92 per cent) of these patients were Asian; only one had a past history of pulmonary TB. The most common presenting complaint was abdominal pain in 21 patients (88 per cent) with the associated symptoms of weight loss in 18 (75 per cent), anorexia in 15 (62 per cent) and night sweats in 13 (54 per cent). A tissue diagnosis was obtained in 18 patients (75 per cent) and 17 patients (71 per cent) underwent laparotomy. These results show that the diagnosis of abdominal TB is still difficult to establish, and that many patients undergo laparotomy despite the existence of less invasive diagnostic procedures.     

Purification of the human blood platelet thromboxane A2/prostaglandin H2 receptor protein.

The human platelet thromboxane A2/prostaglandin H2 receptor has been purified 6100-fold to apparent homogeneity by a three-step chromatographic procedure with an overall yield of 6%. A 6-fold purification of the receptor was first achieved by chromatography of 3-[(3-cholamidopropyl)dimethyl-ammonio]-1-propanesulfonate (CHAPS)-solubilized membrane proteins from human platelets on a diethylaminoethyl (DEAE)-Sepharose column. The DEAE eluate fractions containing receptor activity were then applied to a newly developed affinity column using the cyclohexyl derivative of SQ30,741 (SQ31,491) as the immobilized ligand. Elution of the receptor from the affinity column with BM13.177 yielded a further purification of 1700-fold. An additional 4-fold receptor purification from the affinity column eluate was achieved by HPLC using GPC 500 and GPC 100 columns connected in tandem. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining of the HPLC eluate containing purified receptor revealed a single, distinct band with a molecular weight of 55,000. The receptor binding activity was detected with [3H]SQ29,548 using a newly developed binding assay which involved immobilization of the receptor on polyethyleneimine-treated glass fiber filters. The binding of [3H]SQ29,548 to the purified receptor was time dependent, saturable, reversible and highly specific. Unlabeled SQ29,548, BM13.505, and U46619 (but not thromboxane B2 or 6-keto prostaglandin F1 alpha) competed for [3H]SQ29,548 binding to the purified receptor in a concentration-dependent manner. Scatchard analysis of [3H]SQ29,548 binding to the purified receptor revealed the presence of a single class of high-affinity binding sites, with a Kd of 4 nM and a Bmax of 17 nmol/mg protein.     

Expression of neuronal intermediate filament proteins ON1 and ON2 during goldfish optic nerve regeneration: effect of tectal ablation

Goldfish retinal explants were used to study optic tectum participation in the regulation of intermediate filament protein synthesis in retinal ganglion cells during optic nerve regeneration. Retinas were explanted at various times after removal of the contralateral optic tectum. The synthesis of the intermediate filament proteins ON1 and ON2 in the cultures was quantitated by labeling with [35S]methionine, followed by two-dimensional gel electrophoresis, autoradiography, and densitometry. Neuritic growth from the explants was quantitated based on fiber length and density. In retinal explants placed in culture after 23 days of optic nerve regeneration, the synthesis of ON1 and ON2 was reduced when the tectum had been ablated. In contrast, synthesis of these proteins in explants placed in culture at an earlier stage of regeneration was not affected by tectal ablation. At all time points tested, neuritic outgrowth from retinal explants was stimulated by tectal ablation. These findings indicate that the synthesis of the ON1 and ON2 intermediate filament proteins during regeneration is not directly regulated by axonal volume. Further, our findings suggest that interaction between growing axons and tectum is important for sustained expression of these proteins during the later stages of optic nerve regeneration.     

cAMP production via the adenylyl cyclase pathway is reduced in RCS rat RPE.

cAMP production was investigated in retinal pigment epithelium (RPE) cells isolated from normal rats and from rats with an inherited retinal dystrophy (Rdy/p+). In normal RPE cells, 5'-[N-Ethylcarboxamido]-adenosine (A2 receptors) produced a fivefold increase in the level of cyclic adenosine monophosphate (cAMP) over basal levels. However, only a onefold increase in cAMP was observed in dystrophic cells. cAMP production by prostaglandins E1 and E2 (prostaglandin receptors) in dystrophic RPE cells was only 29-38% of the level observed in normal cells. Direct stimulation of adenylyl cyclase by 10 mumol/l forskolin increased cAMP levels in normal RPE cells by 90 fold over basal, but only by sixfold in the dystrophic cells. These data suggest there may be a defect in the adenylyl cyclase signaling pathway in dystrophic RPE cells.     

Monoclonal antibody for avian thymic hormone.

Avian thymic hormone (ATH), a parvalbumin with immunomodulating properties, was used as antigen for development of a hybridoma cell line. Hybridoma screening by enzyme-linked immunosorbent assay (ELISA) led to the culture, purification, and characterization of an hybridoma, designated 4A6, which secretes IgG1 that is specific for ATH. The monoclonal antibody (MAb) was characterized by techniques involving indirect competitive and non-competitive ELISA, Western Blot analysis, and immunohistological staining. The MAb was highly specific for ATH with no cross-reactivity to other chicken tissue extracts or commercially available parvalbumins.