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Biomedical subjects

A Kwan

Publications and source records attributed to A Kwan.

At least 37 records · Page 2Linked to original sources
PubMed1997

Perioperative management of intra-partum seizure.

A young nulliparous woman previously diagnosed with pregnancy-induced hypertension suffered a seizure during active first stage labour. Pre-seizure blood pressure was borderline high but she did not fulfill other criteria for preeclampsia. She underwent emergency caesarean section for presumed eclampsia. Postoperatively, she deteriorated neurologically. CT scan showed an intracranial haemorrhage requiring neurosurgical intervention. The similarities of presentation of a primary cerebrovascular event and eclampsia following an intra-partum seizure made the differential diagnosis difficult.

Adult↗
PubMed1990

Palliative surgery for adenocarcinoma of the gastroesophageal junction.

Adenocarcinomas of the gastroesophageal junction are usually incurable at the time the patient is first seen. The charts of 21 consecutive patients with this condition were reviewed. All had histologically documented transmural extension of tumour and lymph-node or distant metastases. A variety of surgical techniques were used to restore the ability to swallow. From the charts of these 21 cases, the authors analysed the success in restoring swallowing, the length of hospital stay, the surgical death rate, complications, survival and the ability to swallow normally at the time of death. Restoration of normal or near-normal swallowing appears to be a realistic goal. Selection of an appropriate surgical option, with resection of the primary tumour when technically feasible, allows this to be done with negligible mortality and acceptable morbidity.

Adenocarcinoma↗
PubMed1986

Primary malignant tumours of the trigeminal nerve.

We report a case of primary malignant schwannoma of the trigeminal nerve, and review the 5 previously reported cases. Clinical presentation, along with radiological and pathological features are discussed.

Combined Modality Therapy↗
PubMed1986

Lack of association of HLA with thyroid cancer. An effect of iodine sufficiency and safe environment?

We examined HLA association with differentiated thyroid carcinoma in 45 patients from Newfoundland. No association was found. This finding contrasts with the description of an association of thyroid cancer with HLA-DR1 in Italy and Hungary (iodide deficient areas) and with DR7 in the American mid-west. We suggest that iodide deficiency predisposes DR1 + individuals to thyroid cancer and that this risk is negated by iodide sufficiency unless some other risk factor supervenes.

Adenocarcinoma↗
PubMed1984

Isolation and characterization of two forms of Met-tRNAf deacylase from rabbit reticulocyte ribosomes.

We have separated and purified two forms of Met-tRNAf deacylase (or two separate enzymes), an activity that mediates in part the suppression of polypeptide chain initiation that occurs in heme deficiency or with double-stranded RNA, 1000-fold from the 0.5 M KCl wash of rabbit reticulocyte ribosomes. Deacylase I is a minor activity with an S20,w of 5.9, D20,w of 4.9 and Mr of 110 000, while deacylase II is the major activity with an S20,w of 3.3, D20,w of 7.1 and Mr of 43 000. Both convert crude reticulocyte or pure yeast, wheat germ, and E. coli [35S]Met-tRNAf to [35S]methionine and tRNAfMet and have no effect on reticulocyte [35S]fMet-tRNAf, [3H]Ala-tRNA or [3H]Lys-tRNA. However, while deacylase I has similar activity throughout the pH range of 6.1-8.1, deacylase II has a sharp pH optimum at 7.9 and is almost completely inactive at 6.1. In addition, deacylase II shows a much greater affinity for pure Met-tRNAf than deacylase I (Km of 1.5-3 nM vs. 100 nM), and, while deacylase II is selectively inhibited by tRNAfMet, deacylase I is inhibited similarly by any added tRNA.

Acyltransferases↗
PubMed1984

Enterobronchial fistula.

Enterobronchial fistula is a rare condition. The authors describe a 47-year-old man who had a fistula between the small bowel and tracheobronchial tree, 8 years after resection of an adrenal carcinoma. The report illustrates the difficulties in diagnosis and the surgical treatment. In particular, the use of hyperosmolar, water-soluble contrast medium in radiologic investigations is to be avoided and the use of a double-lumen endotracheal tube is mandatory if a general anesthetic must be given. Despite its rarity, enterobronchial fistula can be diagnosed through a carefully taken history, confirmed safely by roentgenography and cured surgically.

Bronchial Fistula↗
PubMed1982

Effect of Met-tRNAf deacylase on polypeptide chain initiation in rabbit reticulocyte lysate.

The possible role of Met-tRNAf deacylase in the regulation of protein synthesis in rabbit reticulocyte lysate by the hemin-controlled translational repressor (HCR) or the double-stranded RNA-activated inhibitor (dsI) has been examined. Inhibition of protein synthesis by either HCR or dsI is associated with a marked increase in the steady state level of 48 S initiation complexes, containing a 40 S ribosomal subunit, globin mRNA, and a reduced level of Met-tRNAf, suggesting that the rate of 60 S subunit addition may be inhibited and that subunit-bound Met-tRNAf may become deacylated by Met-tRNAf deacylase. The addition of highly purified Met-tRNAf deacylase to lysate samples incubated with HCR or dsI reduces the [35S]Met-tRNAf labeling of 48 S complexes to even a lower level but has no effect on the high level of [35S]Met-tRNAf associated with 43 S complexes in the plus hemin control. The effect of added deacylase on the labeling of 48 S complexes with [35S]Met-tRNAf can be overcome by adding eIF-5 or a soluble reticulocyte protein that has been termed the reversing factor, but not by the addition of eIF-2. Added deacylase has no effect on the level of mRNA in 48 S complexes or the labeling of these complexes with [35S]fMet-tRNAf. When lysate samples were labeled with Met-tRNAf, purified from wheat germ or yeast, and doubly labeled with 32P at the 5' end and [35S]methionine aminoacylation, HCR reduced the level of 32P and 35S-labeled tRNAMetf in 48 S complexes to a similar degree, suggesting that once it has become deacylated, tRNAMetf dissociates from the 40 S subunit.

Acyltransferases↗
PubMed1980

Remyelination following viral-induced demyelination: ferric ion-ferrocyanide staining of nodes of Ranvier within the CNS.

Ferric ion-ferrocyanide (Fe-FeCN) staining was used to stain nodes of Ranvier in remyelinating central nervous system (CNS) axons following viral-induced demyelination. As at normal nodes, Fe-FeCN staining was observed on the cytoplasmic surface of the nodal axolemma of remyelinated fibers. These fibers were identified on the basis of inappropriately short internode lengths and thin myelin sheaths. Thus, newly formed nodes along remyelinated CNS axons recapitulate at least one normal nodal membrane property.

Animals↗
PubMed1979

A chylous mesenteric cyst and a study of its contents.

A case of a patient with a large chylous cyst in the mesentery of the small intestine is presented. After excision of the cyst, the chyle was analyzed with special reference to its protein and lipid content. The composition of the chyle compared with that of intestinal lymph of experimental animals suggests that the fluid in the cyst has undergone concentration in terms of protein.

Adult↗
PubMed1974

The roles of intraluminal chyme and vasomotor response in the pathogenesis of non-occlusive intestinal infarcts.

The purpose of this study is to clarify the role of intraluminal chyme and the splanchnic vasomotor reaction on the pathogenesis of non-occlusive intestinal infarcts. In 5 mongrel dogs, 3 types of intestinal loops were created. A cervical loop, which is a heterotopic autotransplant of a segment of intestine, contains no chyme and is disconnected from the splanchnic innervation. A Thiry-Vella loop simultaneously constructed in the abdomen is also devoid of intraluminal chyme, but is still innervated. The intestine-in-continuity possesses both splanchnic innervation and intraluminal chyme. Hemorrhagic shock was then induced and the morphological response of the three types of intestine examined. The results indicate that the cervical loop is least damaged, whereas both the Thiry-Vella loop and the intestine-incontinuity are both severely damaged. It is concluded that in the non-occlusive hemorrhagic infarction of the intestinal mucosa, the peculiar splanchnic vasomotor response plays the dominant role. The pathogenesis of non-occlusive intestinal infarcts and its clinical implications are discussed.

Animals↗
PubMedDate not supplied

Characterization of hilar lymph node by 18F-fluoro-2-deoxyglucose positron emission tomography in healthy subjects.

One hundred and seventy-nine images were collected from healthy subjects who underwent whole-body 18F-fluoro-2-d-deosyglucose positron emission tomography (FDG-PET) for health examination. Images showing visually increased FDG uptake based on a five-point visual scale in the hilar regions were included for analyses. We evaluated the sizes, standard uptake values (SUV), and lesion-to-background (L/B) ratios of the hilar lymph nodes (HLN). Fifty of 179 (28%) subjects had visually increased FDG uptake in the hilar regions with a total of 84 HLN. By a five-point visual scale, 67 out of 84 (79.8%) HLN were grade 2, 16 out of 87 (19%) were grade 3, and 1 out of 84 (1.2%) was grade 4. The average size of the HLN was 1.55 x 1.46 cm. SUV of the HLN ranged from 1.132-2.975 with an average of 1.8 +/- 0.44. L/B ratio of the HLN ranged from 1.05-2.63 with an average of 1.52 +/- 0.39. Twenty-eight % of healthy subjects who underwent whole-body FDG-PET demonstrated visually increased FDG uptake in the HLN. However, all of the 84 HLN had a size < 2 x 2 cm, SUV < 3.0 and L/B ratios < 3.

Adult↗