Biomedical subjects

S G Tsao

Publications and source records attributed to S G Tsao.

5 recordsLinked to original sources

PubMed2001

The umbilicus in laparoscopic surgery.

BACKGROUND: This study examines the factors related to infection and incisional herniation after laparoscopy at the umbilicus, as compared with those at remote sites. METHODS: From a prospective database of 561 cholecystectomies, 190 inguinal hernia repairs, 71 Nissen fundoplications, and 51 ventral hernia repairs, 873 consecutive Hasson cannula sites, 748 umbilicus sites, and 125 remote sites were analyzed. RESULTS: The wound infection rate was found to be 6%: 7% at the umbilicus (9% after cholecystectomy and 2% after other operations [p < 0.05]) and 0% at remote sites (p < 0.05). Excluding cholecystectomy, the umbilical infection rate was 2%, similar to that at remote sites. The postoperative ventral hernia rate was at 0.8%, the same at the umbilicus as elsewhere. The rate was similar for gallbladder and nongallbladder operations and correlated with the postoperative wound infection rate, but not with the preexisting fascial defect rate. CONCLUSIONS: Wound infection at the umbilicus is similar to that at other sites, except after cholecystectomy. Postoperative ventral hernia at the umbilicus is similar to that at other sites and not related to preexisting fascial defects.

Adult↗

PubMed2001

The tail of the learning curve for laparoscopic cholecystectomy.

BACKGROUND: This study estimates the number of laparoscopic cholecystectomies required until improvement ceases, assesses the magnitude of such improvement, and provides some insight into the mechanism by which it takes place. METHODS: Data from 500 consecutive laparoscopic cholecystectomies were analyzed from a prospective data base for number of short and long operations and operative time. RESULTS: There was a 40% decrease (P <0.05) in average operative time over the first 200 operations. Significant decrease in the number of longer operations, increase of shorter cases, and decrease in the range of operative time were noted. The major contributor was a marked shortening of longer cases, without much increased speed of shorter operations. CONCLUSIONS: For laparoscopic cholecystectomy, improvement persists for about 200 operations, resulting in a 40% reduction in operative time. The primary mechanism of improvement seems to be an ability to deal more effectively with difficult cases.

Cholecystectomy, Laparoscopic↗

PubMed1992

A micronucleus-limited sequence family in Tetrahymena thermophila: organization and sequence conservation.

During macronuclear development in the ciliated protozoan Tetrahymena thermophila, sequence reorganization including sequence loss occurs. Addressing questions about the organization and nucleotide sequence of micronucleus limited regions can lead to insights about mechanisms of DNA rearrangements during macronuclear development as well as mechanisms for the maintenance of the stability of micronucleus-limited sequence families. We have previously identified a moderately repetitive micronucleus-limited sequence family called X-H (family members hybridize to an approximately 450 bp Xbal-HindIII restriction fragment), completely absent from macronuclear DNA. The first member of this family which we isolated is associated with terminal sequences characteristic of a Tel-1 element, a putative micronuclear transposable element. Two additional family members have been isolated which are not closely associated with Tel-1 terminal sequences. We have nucleotide sequence data for three cloned members of the X-H family. This analysis has demonstrated that the longest cloned members of the X-H family share a region of homology of approximately 2,400 bp and are highly conserved, differing only by small insertions or deletions of 100 bp or less. The sequences from one of the sequenced family members flanking the region of homology are themselves mostly micronucleus-limited.

Animals↗

PubMed1983

Hybridization of nucleic acids directly in agarose gels.

Nucleic acids, both DNA and RNA, separated on agarose gels can be visualized by direct hybridization of the dried gel with appropriate radioactive probes. This method does not involve the transfer of the nucleic acid from the gel. The method requires less manipulation than other procedures; it is extremely rapid, sensitive, and inexpensive. These attributes make this procedure a valuable alternative or supplement to the commonly used methods for visualization by hybridization of nucleic acids separated on agarose gels.

Bacteriophages↗

PubMed1982

Reorganization of unique and repetitive sequences during nuclear development in Tetrahymena thermophila.

Genomic libraries of macro- and micro-nuclear DNA of the ciliate protozoan Tetrahymena thermophila were constructed in the bacteriophage vector lambda gt WES lambda B. Screening of these libraries with a probe for the repeated hexamucleotide sequence C4A2 showed many phage from the micronuclear library but few if any macronuclear sequences having homology to this probe. This is consistent with C4A2-repeating elements being present predominantly if not exclusively at or near the termini of macronuclear DNA. Sequences flanking C4A2-repeating elements were isolated from a number of purified phage and were used as hybridization probes to restriction endonuclease digested macro- and micro-nuclear DNA. These experiments revealed a repeated sequence family as well as unique sequences present only in micronuclear DNA. The repeated sequence element appears to be dispersed throughout the genome. Phage-containing individual members of this micronucleus limited sequence family were purified from the micronuclear library. Some of these phage contained sequences which hybidized to macronuclear DNA. These fragments therefore contain a "transition" region between micronucleus-limited sequences and sequences present in both nuclei.

Animals↗