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Biomedical subjects

K S Koh

Publications and source records attributed to K S Koh.

At least 37 records · Page 2Linked to original sources
PubMed1998

Superior gluteal vessel as recipient for free flap reconstruction of lumbosacral defect.

When the lumbosacral soft-tissue defect cannot be closed with a local flap, the option of a free flap should be considered. However, very few cases of free flaps have been reported, the reason being mainly difficulties in finding a suitable recipient vessel. Several vessels, such as inferior gluteal vessel, extension of thoracodorsal vessel with vein graft were reported as recipient vessels, but each one had its own drawbacks. The superior gluteal vessel has been used as a donor vessel in breast reconstruction after mastectomy but is thought to be undesirable as a recipient for microvascular anastomosis, mainly because of technical difficulty. From May of 1993 to March of 1997, five patients (one man and four women) received microvascular transfer of latissimus dorsi myocutaneous flaps using the superior gluteal vessel as a recipient. Their ages ranged from 11 to 64 years (mean 44 years of age). The causes of lumbosacral defects were tumor (1), trauma (1), radiation (2), and pressure sore (1). Before free flap transfer, the patients received an average of 2.8 operations for sacral lesions. Mean follow-up period was 12.4 months (2 to 40 months). A lateral approach was used to the superior gluteal vessel after elevation and retraction of gluteus maximus muscle. A thoracodorsal artery and vein were anastomosed to superior gluteal artery and vein in three cases, whereas in two cases, one artery and two veins could be anastomosed. All the flaps survived with complete recovery from sacral lesions. During the follow-up period, one case of partial skin graft necrosis and one case of a small superficial pressure sore developed, but there was neither dehiscence nor recurrence. The superior gluteal vessel is large in caliber, constant, with numerous branches, lying in proximity to the lesion, and relatively unaffected despite previous radiation. The technical difficulties with the deep location and short pedicle length can be overcome with some modifications in approach to the vascular pedicle. The superior gluteal artery and vein can be used as a recipient for the free tissue transfer when the lumbosacral defects cannot be covered with a conventional method.

Adolescent↗
PubMed1997

The use of P31 magnetic resonance spectroscopy to evaluate the effect of ATP-MgCl2 perfusion on the metabolism of rat skin island flaps.

Depleted levels of adenosine triphosphate (ATP) are described as one of the important causes of skin flap failure. This study evaluated the beneficial effects of intra-arterial perfusion of ATP-magnesium chloride (MgCl2) in ischemic neurovascular skin island flaps in the rat and observed the changes of the highenergy phosphate metabolite using phosphorus 31-(P31) magnetic resonance spectroscopy (MRS). The changes of ATP, phosphocreatine (PCr), and inorganic phosphate (Pi) were observed from P31 MRS and the ratios of each metabolite were compared. The extent of skin flap survival was assessed 7 days after operation using an image analyzer. The PCr/Pi ratio of the experimental group (ATP-MgCl2) was significantly different from the control group (balanced salt solution; p < 0.05). Furthermore, the infusion of ATP-MgCl2 (40.3%) significantly improved the area of flap survival compared to the control group (14.2%; p < 0.05). The ratios of PCr/Pi PCr/(PCr + Pi) correlated with the extent of flap survival, and correlation coefficients were 0.59 and 0.60, respectively. In conclusion, ATP-MgCl2 improved skin flap survival. We were able to assess the metabolic state of the ATP-MgCl2-perfused skin flap and found that PCr/Pi ratios correlated with flap survival.

Adenosine Triphosphate↗
PubMed1995

Study on the Korean adult cranial capacity.

Cranial capacity was measured in Korean adult skulls. The cavity was filled with rice seeds and the volume of the seeds were measured in a graduated cylinder. The results were 1470 +/- 107 (mean +/- standard deviation) in male and 1317 +/- 117 cc in female skulls. These values were in good accordance with those previously reported. In addition, regression formulae were obtained with the product of the length, breadth, and height of the skull as an independent parameter and the measured capacity as a dependent one. With known external measurements, the expected cranial capacity was as follows: when using baso-bregmatic height, male: capacity = 307.5 + 333 x 10(-6) x (length.breadth.baso-bregmatic height) female: capacity = -12.0 + 435 x 10(-6) x (length.breadth.baso-bregmatic height) and, when using auriculo-bregmatic height, male: capacity = 214.6 + 429 x 10(-6) x (length.breadth.auriculo-bregmatic height) female: capacity = 131.6 + 461 x 10(-6) x (length.breadth.auriculo-bregmatic height).

Adult↗
PubMed1981

Characterization of clones of tumorigenic feline cells transformed by a chemical carcinogen.

Tumorigenic clonal lines derived from soft agar colonies induced by DMBA-transformed feline embryo cells were isolated and characterized. The morphologically altered clonal cells formed large aggregates, growing in this aggregate form when suspended in liquid growth medium above an agar base and forming colonies in soft agar with high efficiency. When inoculated into athymic nude mice, chemically altered clonal cells produced progressively growing sarcomas. Cells established from the tumors morphologically resembled the DMBA-transformed feline embryo cells and were characterized as cat cells by karyological analysis. The tumorigenic lines were negative for feline oncornavirus-associated cell membrane antigen (FOCMA), and for "gag-X" the transformation-related polyprotein which is encoded by the replication defective feline sarcoma virus.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

Changes in the lecithin:sphingomyelin ratio during labor and the associated fetal heart rate patterns.

Serial samples of amniotic fluid were taken from 38 patients in spontaneous labor and the lecithin:sphingomyelin (L:S) ratios were estimated. The fetal heart rate (FHR) pattern for each patient was analyzed, and the baseline rate, long-term variability, and periodic changes wee determined. It was found that changes in the L:S ratios were significantly correlated with the duration of labor and FHR long-term variability. Very low L:S ratios were observed in some patients whose infants did not subsequently develop respiratory distress syndrome. This raises the possibility that during labor the amniotic fluid is no longer representative of lung fluid, perhaps because of reduced tracheal fluid efflux, a process which may operate when the fetus is under stress.

Amniotic Fluid↗
PubMed1980

Impact of the national family planning program on fertility in rural Korea: a multivariate areal analysis.

The impact of the previous three years' input of the national family planning program on 1975 fertility levels in rural Korea was assessed using multivariate areal analysis techniques. Program input had a measurable negative effect on fertility, but the magnitude of the effect was lower than that of nonprogram factors. Holding availability of nonprogram methods of fertility limitation constant strengthened the impact of program input. It was suggested that the effect of the national program was statistically obscured by the selective concentration of program input in high-fertility, physician-poor areas.

Adult↗
PubMed1979

R--pulse wave timing: a technique for continuous cardiovascular monitoring in obstetrics--preliminary report.

A simple, noninvasive technique for continuous cardiovascular monitoring in obstetrics using R--pulse wave timing is described. This preliminary study suggests that different maternal heart rate/R pulse patterns are found in different clinical circumstances. A significant decrease in the R pulse interval occurred in the third trimester in both normal and diabetic women in the left lateral position when compared to the supine position. The R pulse intervals were all prolonged in the standing position in both gravid and nongravid women. During labor R pulse interval usually shortened during uterine contraction. Prolongation of R pulse interval was observed during thiopental injection, hypotension, and excessive bleeding at cesarean section. Exercise testing in healthy male subjects suggested that the change in R pulse interval becomes constant when the oxygen consumption rate reaches a plateau at 100% maximal work load. Further extensive clinical study appears worthwhile since it may add another dimension to cardiovascular monitoring and give an early indication of cardiovascular reserve.

Anesthesia, Obstetrical↗
PubMed1979

Obstetric factors influencing outcome in infants weighing from 1,001 to 1,500 grams.

The neonatal mortality rate has dramatically improved in recent years. Occurrence of these losses is concentrated in low-birth-weight infants. At Los Angeles County-University of Southern California Medical Center, the infants weighing less than 1,500 grams contribute two thirds of neonatal deaths, although they may represent only 1.5 per cent of total births. Such observations have led to the evaluation of obstetric factors as they relate to the outcome in the low-birth-weight infants weighing from 1,001 to 1,500 grams. Retrospective evaluation of 201 low-birth-weight-infants' charts demonstrated a tendency by the obstetrician to clinically underestimate fetal weight. In cases where fetal estimated weight and measured birth weight correlated, the mortality rate was 20 per cent; in cases of underestimation, the mortality rate rose to 50 per cent. Other obstetric factors evaluated were the use of FHR monitoring, the method of delivery, and the significance of the Apgar score.

Apgar Score↗
PubMed1979

The changing perinatal and maternal outcome in chorioamnionitis.

Chorioamnionitis is difficult to detect clinically, but its recognition in those at risk is essential. A retrospective study of 140 patients from among 26,129 deliveries was conducted over a 2-year period. The findings suggest that in modern obstetric practice, both perinatal and maternal complications associated with chorioamnionitis (particularly sepsis) are infrequent problems. Four neonatal deaths occurred but no infants died of sepsis. There were no maternal deaths, but 38 patients developed postpartum infections. Cesarean section did not appear to improve either perinatal or maternal outcome. With the use of appropriate modern antibiotics, extraperitoneal cesarean section and cesarean hysterectomy are probably no longer indicated. Not all neonates born out of a microbiologically contaminated intrauterine environment required antibiotic therapy, however, and individualization is recommended.

Amnion↗
PubMed1979

Electromechanical intervals of the fetal cardiac cycle.

The measurement of electromechanical intervals of the fetal cardiac cycle may be useful in the evaluation of cardiac status, since they are based upon sound physiological principles. Studies of EMIs in the human fetus are currently in their infancy and clinical evaluation of their usefulness awaits the development of adequate data acquisition, reduction and analysis techniques.

Animals↗
PubMed1978

Changes in fetal heart rate-uterine contraction patterns associated with eclampsia.

Eclamptic seizures have been associated with fetal bradycardia and rapid onset or progression of labor. The fetal heart rate (FHR)-uterine contraction patterns during 14 seizures in 10 eclamptic patients were studied. Some seizures occurred in patients in whom magnesium sulfate levels were in the therapeutic range. The FHR response during an eclamptic episode was generally prolonged bradycardia. Uterine activity was noted to increase during seizure activity and preceded the fall in FHR. As seizure activity subsided, uterine hyperactivity diminished and the FHR rose, frequently demonstrating compensatory tachycardia. The clinical implications and possible pathophysiologic mechanisms of the FHR-uterine contraction observations are discussed.

Adolescent↗