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Biomedical subjects

C C Yang

Publications and source records attributed to C C Yang.

At least 235 records · Page 13Linked to original sources
PubMed1992

Intravenous dipyridamole technetium-99m MMI myocardial perfusion scintigraphy for detection of coronary artery disease.

To evaluate the efficacy of stress technetium-99m MMI (N-2-methoxy-2-methyl propyl isonitrile) myocardial perfusion scintigraphy (Tc-99m MMI) using intravenous dipyridamole for detection of coronary artery disease (CAD), we collected 66 cases (53 men, 13 women, aged 40-79 years old) between Sept. 1990 and Oct. 1991. The cases were divided into two groups: group I involving 44 patients received coronary arteriography (CAG) examination without previous percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass graft (CABG); group II embracing 22 patients received no CAG examination but all were suffering from old myocardial infarction (MI) evidenced by history and electrocardiography (ECG). All cases underwent Tc-99m MMI planar and single photon emission computed tomography (SPECT) both on intravenous dipyridamole stress and separate day rest tests. Of the 44 group I patients receiving both Tc-99m MMI and CAG, 35 (79.5%) were positive and 7 (16%) were negative by both tests and another 2 (4.5%) were positive by CAG only. Of those positive by both tests, 21 (60%) suffered from identical coronary arterial involvement, including 13 one-vessel disease, 5 double-vessel disease and 3 triple-vessel disease. Of group II patients, 14 suffered from old inferior wall (IW) MI, 6 from old anterior or anteroseptal wall (AW) MI, 1 from old lateral wall (LW) MI and another 1 from combined old anterior and lateral wall (ALW) MI by ECG. Of the 14 patients with IWMI by ECG, all suffered from right coronary artery (RCA) disease but 7 (50%) of them from multivessel disease (MVD) by Tc-99m MMI. 5 of the 6 patients with AWMI by ECG suffered from left anterior descending coronary artery (LAD) disease, but 3 of them from MVD by Tc-99m MMI. Both patients with LWMI and ALWMI by ECG suffered from triple-vessel disease by Tc-99m MMI. The sensitivity of Tc-99m MMI in detecting CAD in group I was 95%, the specificity was 100%. The sensitivity for detection of individual coronary artery disease in LAD, left circumflex coronary artery (LCX) and RCA was 96%, 45% and 89% in this order and the respective specificity was 94%, 100% and 88%. In group II the sensitivity was 95%. The overall sensitivity of intravenous dipyridamole Tc-99m MMI for detection of CAD in groups I and II was 95%; specificity was 100% and accuracy was 95%. In conclusion, stress Tc-99m MMI using intravenous dipyridamole is a valuable method for evaluation and detection of CAD.

Adult↗
PubMed1992

[The detection of an early glomerular filtration rate change of spinal cord injury patients by renal scan].

A Technetium-99m DTPA computer-assisted renal scan and CCR studies were performed on 35 spinal cord injured patients who had been hospitalized in the rehabilitation ward of Kaohsiung Medical College Hospital for less than 6 months during the period of August 1988 to March 1990. For each patient, the glomerular filtration rate (GFR), the effective renal plasma flow (ERPF), and the filtration fraction (FF) were obtained by a renal scan. CCR was measured by conventional procedure and was corrected with body length, body weight and body surface. Least square fit linear regression analysis revealed the best correlation between GFR and CCR. Based on GFR values the renal function was classified into four grades from normal to severe damage and the change of renal function was analyzed using four corresponding factors. The results showed that the ratio of GFR impairment in early spinal injury is 48.6% (mostly mild impairment). There are not significant differences between levels of lesion, severity of injury or successfulness of bladder training by Fisher's exact test. Renal function deteriorated proportionally with age and most of those patients having the worst renal function belonged to an old age group. Thus age is also one of the major factors in renal function impairment. Single kidney function impairment was noted in two patients whose total GFR or CCR were in the normal range, which implied the characteristic of early detection of renal dysfunction by renal scan.

Adult↗
PubMed1992

[Detection of open processus vaginalis by radionuclide scintigraphy].

The processus vaginalis usually obliterates spontaneously from the inguinal ring to the scrotum after the descent of testis has been completed. Under certain conditions, it can be reopened. In present reports, 3 cases with open processus vaginalis were described. The first one is a case of uremia due to chronic glomerulonephritis, suddenly suffering from right scrotal and penile swelling, following continuous ambulatory peritoneal dialysis (CAPD) for 4 months. The second one is a case of uremia, due to unknown etiology, suddenly developing right scrotal and penile swelling after 5 months of CAPD. The third one is a case with uremia of uncertain etiology, suffering from bilateral scrotal and penile swelling in the first month of CAPD, following a wrong procedure, by adding some 200cc more dialysate. Three mCi of Tc-99m phytate or pertechnetate, added into the bag of peritoneal dialysate for each patient, allowed us to visualize a peritoneo-vaginal communication. After surgery one of the patients who had been given followup treatment by radionuclide scintigraphy showed no passage of the labeled infusion in the swollen side of the scrotum. A previous postmortem study of adults dying without clinically apparent inguinal hernia demonstrated an open processus vaginalis in 20% of groins examined. Thus, this study suggests that in placement of catheters for CAPD or ventriculo-peritoneal shunt, Tc-99m pertechnetate/phytate may be given through intraperitoneal injection to detect a subclinical open processus vaginalis.

Adult↗
PubMed1992

[Treatment of large skin defect with 6:1 meshed skin autograft and 1.5:1 meshed fresh porcine skin overlay].

The use of expanded mesh skin graft from limited donor sites has greatly increased wound coverage. However, grafts with an expansion size of 6:1 or greater often heal slowly or are lost because of local infection. Three patients with large skin defects in lower extremity have been treated with 6:1 mesh autograft overlayed by 1.5:1 fresh porcine skin mesh graft. Epithelium grown from both grafts could be found. The autografts continuously expanded under the xenografts. The outer xenografts gradually separated and desquamated, on an average, in 14 days. This technique enables resurfacing of a large area of skin defect from smaller donor sites.

Aged↗
PubMed1992

Microsurgical replantation of avulsed scalp--two cases report.

Two female patients with scalp avulsion were treated successfully by microsurgical replantation. The first patient suffered an avulsion of the right half of scalp and which survived fully after replantation. The second patient suffered avulsion of the entire scalp as well as the forehead skin and nape of the neck. Almost all of the avulsed part survived except partial skin loss in the posterior neck and left occipital area. Only one temporal artery and one vein was anastomosed in each case. Near normal hair growth recurred in both cases.

Adult↗
PubMed1992

Reconstruction of children's scalp defects with the Orticochea flap.

From January 1985 to February 1990, 4 children with scalp defects were selected for use of the Orticochea flap technique for reconstruction. The ages ranged from 15 months (the youngest in the literature) to 7 years. The defects ranged from 6 x 7 to 11 x 13 cm. Three defects were traumatic and 1 was acute lymphocytic leukemia septic emboli in cause. All these children got satisfactory results with follow-up periods ranging from 5 months to more than 5 years. With these preliminary experiences, we have verified that the Orticochea flap scalp reconstruction surgery described 20 years ago can be performed safely even in children, especially when tissue expansion is not suitable or readily available.

Child↗
PubMed1991

Dissociation of lethal toxicity and enzymic activity of notexin from Notechis scutatus scutatus (Australian-tiger-snake) venom by modification of tyrosine residues.

Notexin from Notechis scutatus scutatus snake venom was subjected to tyrosine modification with p-nitrobenzenesulphonyl fluoride (NBSF), and four modified derivatives were separated by h.p.l.c. The results of amino acid analysis and sequence determination revealed that only Tyr-7, Tyr-70 and Tyr-77 were modified in notexin. Modification of Tyr-7 resulted in decreases in lethal toxicity and enzymic activity by 70.2% and 22.7% respectively. Conversely, modification of Tyr-77 caused a 1.8-fold increase in enzymic activity, in contrast with the loss of 52.5% of lethality. A drastic decrease in lethal toxicity was observed when both Tyr-7 and Tyr-70 were modified, whereas the enzymic activity decreased by only 35.8%. Likewise, the derivative in which Tyr-7 and Tyr-77 were modified retained 44.4% of enzymic activity, but showed a marked decrease in lethal toxicity. It is obvious that modification of tyrosine residues causes a decrease in lethal toxicity of notexin, which does not directly correlate with the change in enzymic activity. On the other hand, the antigenicity of NBS derivatives remained unchanged. The modified derivatives retained their affinity for Ca2+, indicating that the modified tyrosine residues did not participate in Ca2+ binding. These results indicate that modification of tyrosine residues can differentially influence the enzymic activity and lethal toxicity of notexin, and suggest that notexin might possess two functional sites, one being responsible for the catalytic activity and the other associated with its lethal effect.

Amino Acid Sequence↗
PubMed1991

Adipofascial turn-over flap for reconstruction of the dorsum of the foot.

Local adipofascial turn-over flaps with skin grafts were successfully used to reconstruct complicated skin defects over the dorsum of the foot in 7 patients. The blood supply of the flap comes from perforators in the base and from the surrounding subcutaneous and fascial plexuses. A new concept of base-to-flap area ratio is proposed to predict the survival of the turn-over flaps in addition to the conventional base-to-length ratio. This appears to be a valuable technique for difficult wounds of the dorsum of the foot.

Adult↗
PubMed1991

Venom constituents of Notechis scutatus scutatus (Australian tiger snake) from differing geographic regions.

Column chromatography and polyacrylamide gel electrophoresis of Notechis scutatus scutatus venom showed that the venoms from different geographical locations had variations in their constituents. The venom collected from South Australia region contained both notexin and notechis II-5. The relative quantity of notechis II-5 was about three times that of notexin. On the other hand, the venom from Victoria region contained large amounts of notexin, but lacked notechis II-5. Instead, an unknown nontoxic protein, designated as notechis II-5b, exhibiting weak phospholipase A2 activity appeared in the position of notechis II-5 elution. This protein had an N-terminal sequence of N-L-I-Q-L-S-N-M-I-K-C-A-I-P-G-S-Q-P-L-F, sharing 45% homology with notexin and notechis II-5 and 60% homology with notechis II-1. The antibodies raised against Trp-modified notexin inhibited the enzymatic activities of notexin and notechis II-5 by 88 and 68%, respectively. However, the affinity of notexin for the antibodies was nine-fold greater than that of notechis II-5. This result is contrary to the previous finding (Mollier et al., FEBS Lett. 250, 479-482, 1989) in which notexin and notechis II-5 had similar binding affinities for antibodies raised against native notexin. This observation suggests that the antibodies prepared in this study could differentiate between isoforms of notexin.

Amino Acid Sequence↗
PubMed1991

Microskin grafting of rabbits with pigskin xenograft overlay.

Pigskin xenografts were used to replace allografts in microskin grafting (10:1 expansion ratio) on 15 rabbits. Rabbits were selected randomly for the removal of the overlaid pigskin at days 7, 10 or 14 for the evaluation of the degree of epithelialization. Histological examination of the removed pigskin 7 days after application showed obvious eosinophilic changes in the epidermal cells and pyknotic changes of the nuclei, however in some areas newly formed epidermis could be found. The pigskin became an eschar or slough on day 14. The microskin autografts proliferated and expanded actively under the protection of this overlaid pigskin. The epidermis increased in thickness and with increasing differentiation. The dermal layer was well vascularized with a large number of capillaries and fibroblasts. The wound was covered by the neoepithelium with almost normal skin texture on day 14, by which time the overlaid pigskin became a dry eschar. In areas where the overlaid pigskin was sloughing, the epithelialization of the underlying microskin grafts was not complete at the same time. In these animal studies of microskin grafting, these overlaid pigskin xenografts showed the same effects as those of allografts.

Animals↗
PubMed1991

Management of hypertrophic scars on the pubic area with an iliac flap.

Postburn hypertrophic scars on the pubic area are rare. A local iliac flap has been used in four female patients for covering the raw areas after total excision of these scars. The largest flap in this series was 7 x 13 cm. Although bilateral flaps could be used simultaneously, only a unilateral flap was used in each patient. All the donor sites were closed primarily. The postoperative course was uneventful in each patient. Itching subsided completely in all patients and distortions of the genitalia were corrected. There was no recurrence of the scar formation in the follow-up period from 2 to 7 years. The only drawback of this flap for coverage of the symphysis pubis is that it is hairless. The experience with the present patients proved that this is an easy, quick and reliable method for removing hypertrophic scars on the pubic area.

Burns↗
PubMed1991

Limb salvage of infected diabetic foot ulcers with microsurgical free-muscle transfer.

This study was comprised of 9 diabetic patients with 10 infected foot ulcers, including osteomyelitis in 4 limbs and gangrene in 3 limbs. Adequate debridement of these complicated wounds inevitably resulted in exposure of bones or tendons. All defects were successfully reconstructed with free gracilis muscle flaps covered with split-thickness skin grafts. No recurrence of ulcer or infection was noted in the muscle-transplanted area during the follow-up period. Laser Doppler perfusion monitor measurement showed that the perfusion unit of the denervated free muscle flap increased to a peak at the second week after transplantation; the neovascularization of the grafted skin, the progressive decrease of the muscle swelling, and the decreased interstitial pressure may be the main contributing factors. The perfusion unit of the muscle flap reached equilibrium with the surrounding tissue at about 8 weeks after microsurgical transfer. Lower extremity amputation is a major health problem in the diabetic population. The microvascular free-muscle transfer was proved to play an effective and important role in limb salvage in diabetic patients with infected foot ulcers. The gracilis muscle flap was recommended due to its lack of bulkiness and minimal donor site deformity.

Aged↗
PubMed1991

A convenient method to differentiate the monoclonal antibodies with differing immunochemical properties.

Three monoclonal antibodies (mAbs) against Naja naja atra phospholipase A2 (PLA2) were prepared by hybridoma technique. Of which two mAbs, 1E531 and 5F92 inhibited the enzymatic activity of PLA2, but 5F6F10 did not. 1E531 and 5F92 nearly exhibited the same binding patterns which was different from that observed with 5F6F10 toward the chemically modified derivatives and homologous variants of PLA2 as revealed by enzyme immunoassay. This suggests that, based on the results of comparative analysis on their relative reactivity with modified derivatives and PLA2 homologues, the mAbs with different immunochemical properties could be differentiated.

Animals↗
PubMed1990

Enzymatic coupling of cholesterol intermediates to a mating pheromone precursor and to the ras protein.

The post-translational processing of the yeast a-mating pheromone precursor, Ras proteins, nuclear lamins, and some subunits of trimeric G proteins requires a set of complex modifications at their carboxyl termini. This processing includes three steps: prenylation of a cysteine residue, proteolytic processing, and carboxymethylation. In the yeast Saccharomyces cerevisiae, the product of the DPR1-RAM1 gene participates in this type of processing. Through the use of an in vitro assay with peptide substrates modeled after a presumptive a-mating pheromone precursor, it was discovered that mutations in DPR1-RAM1 cause a defect in the prenylation reaction. It was further shown that DPR1-RAM1 encodes an essential and limiting component of a protein prenyltransferase. These studies also implied a fixed order of the three processing steps shared by prenylated proteins: prenylation, proteolysis, then carboxymethylation. Because the yeast protein prenyltransferase could also prenylate human H-ras p21 precursor, the human DPR1-RAM1 analogue may be a useful target for anticancer chemotherapy.

Amino Acid Sequence↗
PubMed1990

The N-terminal amino group essential for the biological activity of notexin from Notechis scutatus scutatus venom.

Notexin from Notechis scutatus scutatus snake venom was modified with trinitrobenzenesulfonic acid, and the major trinitrophenylated (TNP) derivative was separated by high-performance liquid chromatography. Modification resulted in the incorporation of only one TNP group on the N-terminal alpha-amino group. The TNP derivative showed a precipitous decrease in enzymatic activity and lethal toxicity, whereas the antigenicity remained unchanged. However, trinitrophenylation did not significantly affect the secondary structure of the toxin molecule as revealed by the CD spectra. The results, that the modification reaction was accelerated by the Ca2+ and that the TNP derivative retains its affinity for Ca2+, indicate that the N-terminal alpha-amino group did not participate in the Ca2(+)-binding. The TNP derivative could be regenerated with hydrazine hydrochloride. The biological activities of the regenerated notexin are almost the same as those of native notexin. These results suggest that the N-terminal alpha-amino group is essential for the phospholipase A2 activity and lethal toxicity of notexin, and that incorporation of the TNP group on the N-terminal alpha-amino group might give rise to a distortion of the active conformation of notexin.

Amino Acid Sequence↗
PubMed1990

Immediate reconstruction of the penis with an iliac flap.

Immediate reconstruction of the penis can save time and significantly reduce postoperative psychological morbidity. A patient suffered a cancerous lesion in his glans penis. After total amputation, an iliac flap based on the superficial circumflex iliac artery was used to reconstruct the penis. The subcutaneous tissue around the vascular pedicle was carefully preserved for enhancing the venous drainage of the new penis. A self-sculptured silicone implant was inserted later to increase the penile rigidity. The advantages of this technique include ready availability, easy mobilisation, hairlessness, elimination of multi-staged procedures, and saving time. The patient is pleased with the operative results.

Amputation, Surgical↗