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Biomedical subjects

J Kang

Publications and source records attributed to J Kang.

At least 271 records · Page 15Linked to original sources
PubMed1990

Length-tension relationship of urinary bladder strips from streptozotocin-diabetic rats.

Streptozotocin-induced diabetes mellitus or the consumption of 5% sucrose in place of drinking water cause an increase in rat urinary bladder capacity and mass. Length-tension curves were generated using bladder body strips isolated from control, diabetic, or sucrose-drinking rats to determine whether the length-tension relationship was altered by the bladder hypertrophy associated with diabetic and nondiabetic diuresis. In addition, we compared the data using three different methods of expression: (1) absolute grams tension developed; (2) grams tension/100 mg tissue, and (3) grams tension/mm2. The cross-sectional area of strips from diabetic rats was increased compared to the other two groups. The length-passive tension curves for all three groups increased with increasing tissue length to a plateau. No optimal resting length for generation of active tension was found. Strips from diabetic and sucrose-drinking rats reached the plateau at a slightly larger passive tension than did strips from control rats. In addition, strips from diabetic and sucrose-drinking rats generally developed a greater active tension than did strips from control rats depending on the method of data presentation used. The data suggest that the complex nonlinear arrangement of smooth muscle fibers in the bladder wall results in the unusual length-tension curves generated by urinary bladder strips (as compared to skeletal or vascular smooth muscle). This relationship would be of benefit in the urinary bladders of early-stage diabetic patients before neuropathy development, where the stretching of the bladder wall would allow accommodation without any compromise of bladder function. The data indicate that comparisons of bladder strip function from control and diabetic rats should be done at passive tensions of greater than or equal to 2 g to ensure that maximal active tension is generated.

Animals↗
PubMed1990

One-stage repair of colovaginal fistula complicating acute diverticulitis.

Fourteen patients with colovaginal fistula secondary to sigmoid diverticulitis were seen between 1964 and 1988. Thirteen had undergone prior hysterectomy. Three different operative approaches were used. Three patients were treated with colostomy alone; one died and the fistula persisted in one. Five patients underwent staged procedures. One patient died of complications after the second stage of a planned three-stage procedure. Four patients underwent a two-stage procedure (fistula takedown, colectomy with colostomy and colostomy closure), all with good results. Six patients were treated with one-stage fistula takedown, colectomy and primary anastomosis, without major complication. We advocate this as the procedure of choice and emphasize the following principles of epidemiology and management: 1) colovaginal fistula complicates diverticulitis in elderly women usually following hysterectomy; this association may be a factor in etiology; 2) vaginography is useful in diagnosis; and 3) planned one-stage repair is the best surgical approach.

Aged↗
PubMed1989

The PreA4(695) precursor protein of Alzheimer's disease A4 amyloid is encoded by 16 exons.

Alzheimer's disease (AD) is characterized by the cerebral deposition of fibrillar aggregates of the amyloid A4 protein. Complementary DNA's coding for the precursor of the amyloid A4 protein have been described. In order to identify the structure of the precursor gene relevant clones from several human genomic libraries were isolated. Sequence analysis of the various clones revealed 16 exons to encode the 695 residue precursor protein (PreA4(695] of Alzheimer's disease amyloid A4 protein. The DNA sequence coding for the amyloid A4 protein is interrupted by an intron. This finding supports the idea that amyloid A4 protein arises by incomplete proteolysis of a larger precursor, and not by aberrant splicing.

Alzheimer Disease↗
PubMed1989

Postoperative changes in hemostasis analyzed by the serial determination of fibrinopeptides and D-dimer.

In order to elucidate the postoperative changes in hemostasis, three molecular markers; fibrinopeptide A (FPA), fibrinopeptide B beta 15-42 (B beta 15-42) and D-dimer, were serially determined in 27 gastric resections (group A), 27 hepatic resections (group B) and 4 probe laparotomies (group C). Unexpectedly, a postoperative hypercoagulable state was transient and of a low magnitude, as determined by the obtained value of FPA. On the other hand, a significant fibrinolysis (an elevation of B beta 15-42) was observed immediately after surgery which continued for over 10 days. The early phase of fibrinolysis, up until the 3rd postoperative day, is likely to be primary fibrinolysis, as it was not accompanied by the formation of D-dimer, which results from the digestion of fibrin by plasmin. The late phase, however, is considered to be secondary fibrinolysis, as D-dimer was elevated during this phase. Despite the different surgical procedures, these changes were basically similar between the patients who underwent gastric resections and those who underwent liver resections. The postoperative changes in hemostasis as presented herein may therefore be the general physiological response, at least against abdominal surgery.

Abdomen↗
PubMed1989

Sequences within the spacer region of yeast rRNA cistrons that stimulate 35S rRNA synthesis in vivo mediate RNA polymerase I-dependent promoter and terminator activities.

Sequences within the spacer region of yeast rRNA cistrons stimulate synthesis of the major 35S rRNA precursor in vivo 10- to 30-fold (E. A. Elion and J. R. Warner, Cell 39:663-673, 1984). Spacer sequences that mediate this stimulatory activity are located approximately 2.2 kilobases upstream from sequences that encode the 5' terminus of the 35S rRNA precursor. By utilizing a centromere-containing plasmid carrying a 35S rRNA minigene, a 160-base-pair region of spacer rDNA was identified by deletion mapping that is required for efficient stimulation of 35S rRNA synthesis in vivo. A 22-base-pair sequence, previously shown to support RNA polymerase I-dependent selective initiation of transcription in vitro, was located 15 base pairs upstream from the 3' boundary of the stimulatory region. A 77-base pair region of spacer DNA that mediates transcriptional terminator activity in vivo was identified immediately downstream from the 5' boundary of the stimulatory region. Deletion mutations extending downstream from the 5' boundary of the 160-base-pair stimulatory region simultaneously interfere with terminator activity and stimulation of 35S rRNA synthesis from the minigene. The terminator region supported termination of transcripts initiated by RNA polymerase I in vivo. The organization of sequences that support terminator and promoter activities within the 160-base-pair stimulatory region is similar to the organization of rDNA gene promoters in higher organisms. Possible mechanisms for spacer-sequence-dependent stimulation of yeast 35S rRNA synthesis in vivo are discussed.

Base Sequence↗
PubMed1988

Localization of the putative precursor of Alzheimer's disease-specific amyloid at nuclear envelopes of adult human muscle.

Cloning and sequence analysis revealed the putative amyloid A4 precursor (pre-A4) of Alzheimer's disease to have characteristics of a membrane-spanning glycoprotein. In addition to brain, pre-A4 mRNA was found in adult human muscle and other tissues. We demonstrate by in situ hybridization that pre-A4 mRNA is present in adult human muscle, in cultured human myoblasts and myotubes. Immunofluorescence with antipeptide antibodies shows the putative pre-A4 protein to be expressed in adult human muscle and associated with some but not all nuclear envelopes. Despite high levels of a single 3.5-kb pre-A4 mRNA species in cultured myoblasts and myotubes, the presence of putative pre-A4 protein could not be detected by immunofluorescence. This suggests that putative pre-A4 protein is stabilized and therefore functioning in the innervated muscle tissue but not in developing, i.e. non-innervated cultured muscle cells. The selective localization of the protein on distinct nuclear envelopes could reflect an interaction with motor endplates.

Adult↗
PubMed1988

Identification, transmembrane orientation and biogenesis of the amyloid A4 precursor of Alzheimer's disease.

The precursor of the Alzheimer's disease-specific amyloid A4 protein is an integral, glycosylated membrane protein which spans the bilayer once. The carboxy-terminal domain of 47 residues was located at the cytoplasmic site of the membrane. The three domains following the transient signal sequence of 17 residues face the opposite side of the membrane. The C-terminal 100 residues of the precursor comprising the amyloid A4 part and the cytoplasmic domain have a high tendency to aggregate, and proteinase K treatment results in peptides of the size of amyloid A4. This finding suggests that there is a precursor-product relationship between precursor and amyloid A4 and we conclude that besides proteolytic cleavage other events such as post-translational modification and membrane injury are primary events that precede the release of the small aggregating amyloid A4 subunit.

Alzheimer Disease↗
PubMed1988

Intraoperative management of a dysfibrinogenemic patients with gastric cancer.

The intraoperative management of a dysfibrinogenemic patient with gastric cancer is reported herein. In order to avoid abnormal bleeding, the fibrinogen level during a cancer-operation should be maintained above 60 mg/dl. Cryoprecipitate, however, is not suitable for fibrinogen supplementation because of its short life in vivo.

Adenocarcinoma↗