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Biomedical subjects

K Koh

Publications and source records attributed to K Koh.

At least 19 recordsLinked to original sources
PubMed1992

Clinical trials of intrasplenic arterial infusion of interleukin-2 (IS-IL-2) to patients with advanced cancer.

We tried a infusion of interleukin-2 (IL-2) of a relatively low dose via an intrasplenic arterial catheter connected to a chronometric infusion (IS-IL-2). Eighteen patients of colorectal cancer with metastases to the liver or lung or of unresectable hepatoma received a 24 hour continuous infusion with low dose recombinant of IL-2 (mainly 8 x 10(5) JRU/day) for 25-40 days. All patients tolerated this protocol of the therapy and the main toxic effects were fever and general fatigue. Such serious toxicity as previously reported by high dose IL-2 therapy was not observed. Data of hepatic and renal functions were normal. IS-IL-2 therapy induced a high incidence of eosinophilia (12/18) and thrombocythemia (12/18). Peripheral natural killer (NK) and LAK activities were augmented in all patients and total white blood cell counts were increased during IS-IL-2 therapy. An increase in IL-2 receptor expression of peripheral blood mononuclear cells and significant rises in numbers of Leu11 (CD16)+, OKM1(CD11)+ and OKIa1(HLA-DR)+ were observed. Of 18 patients 12 were evaluable for their response to therapy. Partial response (PR) was observed in one unresectable hepatoma and 11 demonstrated no change (NC) or progressive disease (PD). Six patients were not evaluable because of additional therapy (3 cases) or decreasing tumor cell markers having no measurable lesions (3 cases). Three patients of colorectal cancer from an unresectable group were presumed to have micrometastases to the liver as suggested by an elevated serum CEA level. After receiving IS-IL-2 therapy they demonstrated a decrease in the serum CEA level for more than 3 years after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[An experimental study of gastrointestinal motility during chronic large bowel obstruction].

Gastrointestinal motility and plasma PYY levels were investigated under chronic progressive large bowel obstruction in dogs. The obstruction device was applied around the descending colon at a laparotomy and gastrointestinal motility was recorded with strain gauge force transducers in the conscious state. Complete obstruction occurred at 26 days (21-33 days). The duration of postprandial interruption of motor complex (DIMC) in the antrum and duodenum were prolonged progressively, at partial obstruction (17.7 +/- 2.7 hr; p less than 0.05) and complete obstruction (23.0 +/- 4.0 hr; p less than 0.01) vs in control (13.7 +/- 1.9 hr), while DIMC in the small bowel showed no significant changes. Progressive obstruction caused hypermotility in the proximal colon to the obstruction and hypomotility in the distal colon. These dysmotility were improved after resection of the obstructed segment and anastomosis. Plasma PYY levels in the fasting state showed no significant increase at complete obstruction (42.6 +/- 14.5 pmol/l) vs in control (32.9 +/- 10.2 pmol/l).

Animals↗
PubMed1992

Sudden unexplained death syndrome. A review and update.

Sudden unexplained death syndrome (SUDS) among young healthy Thai construction workers in Singapore has been given much publicity recently. From May 1982 to July 1990, 226 SUDS were reported among them. In this article we review and compare studies on SUDS in the United States and South-east Asia. So far, studies to identify the causal factors have been inconclusive and they cannot explain the male preponderance and occurrence of death during sleep. Current hypotheses about the cause of SUDS have included stress, genetic factors, dietary deficiency (particularly thiamine), potassium deficiency, melioidosis and sleep disorders. The following areas are suggested for further research: epidemiological investigations on SUDS at its source; in-depth case studies of families with and without SUDS; role of dietary factors, biochemical studies with respect to thiamine, pyruvate and potassium metabolism in the victims and susceptibles; and histopathological studies of cases and controls.

Adolescent↗
PubMed1991

Ultrastructural changes of the midgut epithelial cells in feeding and moulting nymphs of the tick Haemaphysalis longicornis.

The midgut epithelial cells in nymphs fed on laboratory rabbits were examined during feeding and after detachment. The midgut epithelium at the unfed stage consisted of digestive cells of lower activity, containing such nutritive substances as protein, lipid and glycogen. As feeding proceeded, the cells became active in intracellular digestion. At the middle of the feeding stage, the spent digestive cells derived from the active digestive cells began to be replaced by the new digestive cells of lower activity. After detachment, the pinocytotic activity of the above cells increased greatly, and the digestive activity increased to some extent. As a result, many large endosomes were formed by fusion of numerous pinosomes. Thereafter, endosomes decreased in size as digestion proceeded and there was an increase of haematin granules. On day 7 after detachment, the new digestive cells of lower activity, belonging to the 'nutritional reserve' type, appeared adjacent to the spent digestive cells which had almost exhausted all endosomes, and these new cells had completely replaced the spent cells by day 3 after moulting.

Animals↗
PubMed1991

Function learning: induction of continuous stimulus-response relations.

This research investigates how people learn to select particular response magnitudes along one physical dimension (duration) when given stimulus magnitudes from another dimension (spatial extent). Stimuli and correct responses were related by either a power function, a logarithmic function, or a linear function with a positive intercept. The power function was learned quickly and accurately. In contrast, systematic response biases occurred during the early phases of learning the logarithmic and linear functions. As practice progressed, however, the biases gradually disappeared. These results support an adaptive regression model. According to it, people learn functions through a subjective process analogous to statistical regression. There is assumed to be an initial constraint that treats stimulus-response pairs as if a power function characterizes them.

Female↗
PubMed1991

[Clinical and experimental studies on gastrointestinal motility following total colectomy: direct measurement (strain gauge force transducer method, barium method) and indirect measurement (hydrogen breath test, acetaminophen method)].

In a clinical study, we examined the clinical assessment of bowel function and lactulose hydrogen breath test in 14 patients after total colectomy. All patients within one year after ileostomy closure had 'poor' function and showed no increase of hydrogen breath gas concentration. 10 of 12 patients more than one year showed increase of hydrogen breath gas concentration, and 8 of them had 'fair' function. The oro-neorectal transit time (ONTT) in 'poor' group was shorter than in 'fair' group and control (p less than 0.05). The increase of hydrogen breath gas suggests changes of bacterial flora and colonization of the remained ileum. In an experimental study, we performed subtotal colectomy with the J-pouch reservoir in 11 dogs. We examined ONTT with barium method, gastric emptying with acetaminophen method, and gastrointestinal motility with strain gauge force transducers. Although ONTT at one month after operation had been shorter than control, ONTT at 3 and 6 months became longer than at one month. The gastric emptying after subtotal colectomy was significantly slower than control. Although the propagation velocity of interdigestive migrating complex (IMC) in the jejunum and ileum at 2 weeks had been faster than control, the velocity at 4 weeks and 3 months became slower than at 2 weeks. The frequency of IMC and prolonged propagated contraction in the J-pouch reservoir decreased. The specimen of J-pouch reservoir resected at 6 months showed villous atrophy, crypt elongation, decrease of muscle layers thickness and disappearance of solitary follicles. Therefore, the suppressed motility in each sites of the gastrointestinal tract, increase of anaerobic and colonization of the ileum implied 'adaptation' after total colectomy.

Acetaminophen↗
PubMed1991

Clinical aspects of health screening for senior citizens.

Out of a total of 1,224 subjects aged 55 years and above who attended the Senior Citizens' Health Care Centres for health screening, new medical conditions were picked up for the first time in 472 subjects, giving an overall pick-up rate of 38.6%. This rate increased with age rising from 29.4% among those aged 55-64, to 45.8% among those aged 65-74 and to 51.4% in the 75 years and above. This trend was found to be of statistical significance (p greater than 0.001). The objective of the health screening programme in the Senior Citizens' Health Care Centres is to detect geriatric problems early in order to take adequate steps to prevent disability and dependency states, so that the elderly may continue to live at home. In this paper, we studied the 472 subjects with abnormal medical conditions. The pick-up rates (per 100) of medical conditions were as follows: cataract 13.8, other eye conditions 6.5, deafness 4.5, other ear conditions 2.7, diabetes mellitus 2.5, hypertension 2.2 and osteoarthritis 1.6. The socio demographic profile and the medical conditions of the 472 subjects were also studied, with implications on their quality of life in future. We recommend that physicians specifically screen for diabetes mellitus, hypertension, eye and ear abnormalities in all asymptomatic elderly, during periodic health check ups.

Aged↗
PubMed1991

Health screening for the elderly--the Singapore Senior Citizens' Health Care Centres' experience 1986-1989: an overview.

A systematic health screening programme for the elderly aged 55 years and above was implemented in the first Senior Citizens' Health Care Centre (SCHCC) in 1986. This programme was expanded to two more SCHCCs by 1989. The first 1,224 clients aged 55 years and above, who attended this programme in the first three SCHCCs were studied in this paper. The characteristics of the elderly who voluntarily attended the SCHCCs for health screening were studied with respect to their referrals, socio demographic status, whether they had regular physician care, the existing medical problems and the new medical problems picked up at health screening. Of those screened, 49.6% were referred for the programme by relatives and self, and 28.2% by community centres, thus, showing that community and family supported the programme. Only 7.2% of referrals to the screening programme came from general practitioners and 4% from polyclinic doctors. It is interesting to note that 40% of clients had no regular physician care. About two thirds (57.2%) had one or more existing chronic medical conditions or disability at the time of screening. The majority with existing conditions had hypertension (24.8%) and diabetes (15.5%). Other existing conditions were ischaemic heart disease (6.2%), cataract (3.9%) and asthma (3.6%). The pick-up rate of medical conditions among the clients at the time of health screening was 38.6% for the whole group. This showed a rising trend from the younger to the older age groups being 29.4% in the age group 55 to 64, to 45.8% in the age group 65 to 74, and 51.4% in the age group 75 years and above (p less than 0.001). Some of the topical issues related to a health screening programme for the elderly have been discussed.

Aged↗
PubMed1989

Physiological phases of nymphal molting defined by mobility, body weight decrease, and excretion in Haemaphysalis longicornis (Acari: Ixodidae).

Based on the rate of body weight decrease, the nymphal premolting period in Haemaphysalis longicornis Neumann was divided into three phases: a period of rapid weight decrease following detachment, a period of slight decrease, and another period of relatively rapid decrease before molting. Phase 1 was characterized by increased guanine excretion and mobility. The rate of weight decrease during phase 1 was greater in males than in females. During the premolting period, excreta consisted only of guanine and were devoid of hematin. In phases 2 and 3, neither excretion nor mobility was observed. Twenty-eight percent of the females and 40% of the males did not undergo phase 3. Adult body weight decreased rapidly until about day 5 after molting, after which weight was maintained until the end of the experiment. Guanine was excreted in large quantities just after molting and in small amounts for 4 d thereafter. Hematin excretion followed guanine excretion and was concentrated in a 3-d period starting 4 d after molting. The beginning of hematin excretion coincided approximately with the point at which body weight was maintained at a constant state. There were no quantitative differences per unit of body weight between the sexes with the exception of the rate of body weight loss during nymphal phase 1.

Animals↗
PubMed1989

[An experimental study of the gastrointestinal motility in conscious dogs with strain gauge force transducers].

Interdigestive motor complex (IMC) from the stomach to the ileum and colonic migrating motor complex (CMMC), and the effects of motilin and PYY to them were studied in conscious dogs with strain gauge force transducers (SG). In fasted dogs, IMC cycle times were 100.5 +/- 7.5 min in from the antrum to the ileum and propagation velocity of the small intestine was fastest in the proximal jejunum (4.85 +/- 0.81 cm/min), slowest in the distal ileum (0.81 +/- 0.08 cm/min). The duration of postprandial interruption of motor complex (DIMC) was longer in the antrum and duodenum in 8 dogs of the twelves than the middle and lower intestines. Ileo-colonic propagation rates of IMC that reached to the terminal ileum were 95/116 (81.9%), but the frequency of CMMCs was about 4 times higher than that of IMCs. Each colonic motor complex were classified into four patterns, such as aboral migrating complex (A), oral migrating complex (O), discrete complex (D) and giant migrating contractions (G), and the starting point of migrating complex was marked with -, like A, O or G. Thus, independency index (I I) in each site was defined as: I I = (sum of number of A, O, G and D)/(total number of colonic motor complex). I I was highest in colon 1 (70-80%) and next in colon 4. Motilin (0.5 microgram/kg.hr) elicited IMC like activities in the antrum, duodenum and proximal jejunum, but no effects in the middle and lower small intestine, and the colon. PYY infusion caused dose dependent inhibitions of IMC in the antrum and duodenum, but no effects in the below intestines as same as motilin. These findings suggest that IMCs are basal rhythms of gastrointestinal motility and IMCs occurring from the antrum to the proximal jejunum are more sensitive to the factors as eating or gut peptides.

Animals↗
PubMed1988

Retinal folds in the shaken baby syndrome.

We examined two children with presumed shaken baby syndrome. Both children suffered severe, indirect closed head trauma with intracranial hemorrhage, sharply increased intracranial pressure, and extensive neurologic damage. In addition to extensive retinal and preretinal hemorrhages, bilateral symmetric white ring-shaped retinal folds were seen encircling the macula outside the vascular arcades. These retinal folds may be a hallmark of shaking injuries in child abuse victims.

Child Abuse↗
PubMed1988

Expression of the gene for main intrinsic polypeptide (MIP): separate spatial distributions of MIP and beta-crystallin gene transcripts in rat lens development.

The main intrinsic polypeptide (MIP) is the major protein present in the lens fiber cell membrane and is the product of a gene which, as far as is known, is expressed only in the lens. We have used in situ hybridization and immunofluorescence microscopy to characterize the expression of this gene during the course of development in the rat. At progressive stages of lens morphogenesis, we find that synthesis of the protein is closely tied to the accumulation of MIP mRNA in cells that are committed to terminal differentiation, first in the elongating presumptive primary lens fibers and later in the secondary fibers as they differentiate from the anterior epithelial cells. The transcripts accumulate in the basal cytoplasm of the primary fibers and in the cytoplasm which surrounds the cell nucleus in the secondary fibers. We have compared this pattern of expression with that of a gene for a cytoplasmic protein, beta-crystallin beta-A1/A3. In sharp contrast to the localized concentrations seen for the MIP mRNA, beta-A1/A3 transcripts are relatively uniformly distributed throughout the cytoplasm. Neither MIP nor crystallin gene appears to be transcriptionally active in the undifferentiated epithelial cell, but transcripts from the beta-A1/A3 gene appear earlier in fiber cell differentiation than do those from the gene for MIP.

Animals↗
PubMed1988

[A case of advanced gallbladder carcinoma of a 77-year-old female successfully resected with extended right hepatic lobectomy with caudate lobectomy and pancreatoduodenectomy].

A 77-year-old woman was admitted with obstructive jaundice. US and CT demonstrated a solid mass 2.5cm in diameter in the hepatic hilum. Cholangiography revealed not only severe stenosis of the hilar hepatic duct but also involvement of the right-posterior-inferior-ventral branch and right caudal branch. Angiography showed almost normal appearance except cystic artery. Duodenal invasion was also detected by per oral duodenography. These findings forced to plan extended right hepatic lobectomy with caudate lobectomy and pancreatoduodenectomy for radicality. In spite of the aged and her complications such as DM, hypertension, scoliosis and bradyacusia, liver function was good and she was mentally very active for life. Therefore, planned operation was performed and the suitability of this operation was proved by histological examination. She underwent resection of the abdominal wall for recurrence 8 months after and now alive without the disease 27 months after the first operation. It is stressed that the most suitable operation should be selected conceiving the mode and severity of cancer extension which is revealed by precise preoperative examinations and extended operation may be indicated in even the elderly if various conditions are good.

Adenocarcinoma↗
PubMed1987

Incorporation of intraportal ammonia-N into blood and tissue nitrogenous compounds in chickens fed low and high protein diets.

1. 15N-Percentage of the amide of glutamine in total blood non-protein-15N was 42 and 48% in chickens fed 5 and 20% protein diets, respectively, when 15N-ammonia was intraportally-infused for 6 hr. 2. The infused ammonia-15N also appeared in the amide of free glutamine in the liver and kidney in large amounts at both levels of protein intake. 3. The 15N incorporated into glutamine-amide in the blood, liver and kidney and non-protein-15N in plasma were greater in chickens fed the low protein diet than in those fed the high protein diet (P less than 0.05 except kidney of P less than 0.01). 4. About 60% of the amide-N of the glutamine which was increased during 6 hr infusion of ammonia was derived from infused ammonia-N and the remainder from endogenous nitrogen, irrespective of protein intake. 5. These results suggest that glutamine is the most important intermediate in detoxication of intraportal ammonia in chickens.

Ammonia↗
PubMed1987

Effect of insulin on excretion and retention of infused glutamine amide-N in chickens (Gallus domesticus).

1. The purpose of this study was to examine the effects of insulin on urinary excretion and retention of the intravenously infused glutamine amide-15N in chickens. 2. Insulin pretreatment reduced urinary total 15N excretion (P less than 0.05) and enhanced 15N retention in chicken body (P less than 0.05), but it did not affect non protein-15N retained in the liver and blood. 3. Insulin decreased the incorporation of the infused glutamine amide-15N into urinary uric acid as well as the excretion of other N-derived urinary uric acid (P less than 0.05), which resulted in a significant decrease in total urinary uric acid (P less than 0.05). 4. There was no effect of insulin on urinary appearance of the infused glutamine amide-15N in the form of ammonia.

Ammonia↗
PubMed1986

An update of the indications for penetrating keratoplasty. 1979 through 1983.

We performed a retrospective analysis of the clinical and pathologic diagnoses of 497 corneal buttons that had been submitted to the Estelle Doheny Eye Pathology Laboratory, Los Angeles, during the five-year period 1979 through 1983. The leading indications, in order of decreasing frequency, were pseudophakic bullous keratopathy (17.5%), regrafts (15.1%), aphakic bullous keratopathy (10.9%), corneal trauma (9.3%), and Fuchs' endothelial dystrophy (9.1%). The emergence of pseudophakic bullous keratopathy as the most common cause for penetrating keratoplasty correlates well with the dramatic increase in the number of cataract extractions with intraocular lens implantations performed since the mid-1970s. Less frequent indications for penetrating keratoplasty included the following: corneal scars (6%); active ulcerative keratitis (7%); keratoconus (6%); keratitis secondary to virus (5%); non-Fuchs' corneal dystrophies (3%); congenital corneal opacities (3%); interstitial keratitis (2%); and chemical burns (1%).

Adolescent↗