Biomedical subjects
Publications and source records attributed to A Hadidi.
The presence of a choledochal cyst can be determined ultrasonographically. In two cases, the specific diagnosis of a choledochal cyst was made by identifying a bile duct that entered directly into a large cystic mass that was separate from the gallbladder.
In a prospective ultrasonic study of the pancreatic duct, 233 sonograms were obtained from 49 normal subjects. The duct in the regions of the head-neck and body was measured in the transverse/oblique planes. The mean diameter of the duct in the area of the head-neck was 3 mm; in the body proximal and distal to the neck, duct diameters were 2.1 and 1.6 mm, respectively.
This report presents 19 patients with obstructive jaundice with dilatation of the biliary tree. The obstruction was due to common hepatic duct stones in 14 and intraductal biliary neoplasm in 5. The diagnostic ultrasonographic features consisted of strong echoes with acoustic shadows in a dilated extrahepatic biliary duct for stone and echogenic protrusion into the dilated lumen casting no shadows for neoplasm. The correct diagnoses were made or suggested in 18 patients (94.7%).
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A modified ultrasound technique for demonstration of the extrahepatic bile duct was used in 75 patients and 135 normal subjects. The right and left hepatic ducts, common hepatic duct, and on occasion a part of a dilated cystic duct could be demonstrated with a rate of success of 100 per cent in patients and 98.5 per cent in normal subjects. Usually, the biliary tract can be demonstrated only in part in the conventional supine position, while the modified technique often improved the demonstration of the entire duct and in some cases of a main bile duct that cannot be evaluated in the conventional supine position.
High molecular weight tomato nuclear DNA was isolated from uninfected and potato spindle tuber viroid (PSTV)-infected tomato leaves. Restriction digests were fractionated on agarose gels, denatured and transferred to diazobenzyloxymethylpaper, and hybridized to 32P-labeled cloned double-stranded PSTV cDNA. No hybridization to DNA from either uninfected or infected tissue could be detected under conditions that permitted detection of cloned double-stranded PSTV cDNA at a concentration equivalent to one-fifth copy of PSTV-related DNA per haploid tomato genome. Hybridization of tomato DNA to 32P-labeled cloned soybean 18S and 28S ribosomal DNA sequences showed that the restricted nuclear DNA was suitable for hybridization to probes containing homologous sequences. Our results indicate that neither PSTV nor its complementary strand is transcribed from nuclear DNA but do not rule out the possibility of sequence homology between host DNA and a small portion of PSTV or its complement.
The grey-scale ultrasound, as a non-invasive imaging device, has been applied in differentiating obstructive and non-obstructive causes in a group consisting of 115 random patients suffering from jaundice. The present communication illustrates the echographic evaluation and the final diagnoses and also reports the rate of accuracy, which is 96.6% in this study. It can be concluded that echography is an accurate method with no contra-indications for the evaluation of jaundice and should allow earlier surgery when indicated.
Eighty-one liver hydatid cysts evaluated by gray-scale ultrasound were accumulated in our experience over a period of 2 years. The echographic evidence in accordance with our experience can be categorized as follows: (a) nonsuppurative hydatid cysts in which echo-free area within the fine homogeneous structure of the organ provide the basic clue to the diagnosis; then the echographic appearance of the wall offers further hints to the identity of solitary, multiloculated, and multiple cysts; (b) suppurative hydatid cysts in which, depending on the intensity of secondary microbial infection, the echo-free area turns to a low, medium, or high level of echoes while holding its constitutional pattern. This report is designed to present the various ultrasound patterns of hydatid disease of the liver and show how ultrasound may be most effective in achieving the correct diagnosis.
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Potato spindle tuber viroid can be separated into two fractions by polyacrylamide gelelectrophoresis in the presence of formamide and urea. One fraction contains predominantly circular molecules; the second fraction contains almost exclusively linear molecules. The purity of the fractions was estimated by electron microscopy of formaldehyde-denatured molecules. The length distributions of denatured circular and linear molecules were determined. Both circular and linear molecules were found to be infectious.
Poly (A) polymerase activity from cytoplasm and nuclei of 12-16-day-old mouse embryos has been partially purified by (NH4)2SO4 fractionation, DEAE-cellulose, phosphocellulose and tRNA-Sepharose affinity chromatography, and their properties have been compared. The nuclear and cytoplasmic enzymes exhibit similar chromatographic elution profiles, and similar biochemical and physical properties. Poly(A) polymerase has an absolute requirement for a divalent cation, ATP and an oligo- or polyribonucleotide primer. With tRNA, the divalent salt concentrations for optimum enzyme activity are 1 mM MnCl2 or 10 mM MgCl2. The enzyme activity with MnCl2 is 10-15-fold higher than that with MgCl2. The molecular weight of the native enzyme is about 65 000 and its sedimentation coefficient is around 4.5 S. The average chain length synthesized by the enzyme is between 10 and 13 nucleotides. The inhibitors of RNA polymerase do not affect poly (A) polymerase activity; however, some synthetic rifamycin SV derivatives are potent inhibitors of this enzyme.
Molecular hybridization experiments of (125)I-labeled potato spindle tuber viroid (PSTV) with DNA from uninfected or PSTV-infected tomato plants showed that infrequent DNA sequences complementary to PSTV exist in both uninfected and infected cells. DNA titration experiments revealed that at least 60% of PSTV is represented by sequences in DNA of several normal solanaceous host species. Phylogenetically diverse plants contain sequences related to less of the PSTV. PSTV-infected tomato or Gynura aurantiaca plants did not possess new PSTV sequences at detectable levels. These results support the hypothesis that PSTV may have originated from genes in normal solanaceous plants.
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