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Biomedical subjects

K N Ching

Publications and source records attributed to K N Ching.

At least 19 recordsLinked to original sources
PubMed1993

Effect of protein kinase-C depletion on inositol trisphosphate-mediated and cyclic adenosine 3',5'-monophosphate-dependent protein kinase-mediated adrenocorticotropin secretion.

We studied the effect of Ca2+/phospholipid-dependent protein kinase-C (protein kinase-C) down-regulation by chronic exposure to phorbol 12-myristate 13-acetate (PMA) on ACTH secretion by dispersed male rat anterior pituitary cells in a microperifusion system. Preincubation for 24 h and preperifusion for 3 h with 0.1 and 1 microM PMA significantly inhibited (by 85% and 91%, respectively) the specific cell binding of [3H]phorbol 12,13-dibutyrate, an index of protein kinase-C concentration, and significantly reduced (by 101% and 20%, respectively) the sustained plateau (final 15-min) phase of the ACTH response to arginine vasopressin (AVP) and (by 56% and 54%, respectively) the sustained (full 20-min) response to dioctanoylglycerol (DOG), both of which are mediated by protein kinase-C activation. In contrast, the spike (initial 5-min) phase of the response to AVP, which is mediated by intracellular Ca2+ release from inositol 1,4,5-trisphosphate (InsP3)-sensitive stores, was significantly increased (by 112% and 99%, respectively), but the spike-type response to ionomycin, which releases intracellular Ca2+ by an InsP3-independent mechanism, was unaffected. AVP significantly stimulated inositol bisphosphate and InsP3, but not inositol monophosphate, accumulation, and PMA pretreatment significantly enhanced their AVP-stimulated accumulation (by 86%, 34%, and 78%, respectively), an effect that was abolished by simultaneous preperifusion with PMA and cycloheximide to inhibit new protein synthesis. Enhancement of the spike phase response to AVP and AVP-stimulated InsP3 accumulation were lost within 1 h of PMA removal, but [3H]phorbol 12,13-dibutyrate binding and the sustained responses to AVP and DOG remained suppressed after 3 h. Pretreatment with 0.1 and 1 microM PMA slightly reduced the sustained responses to CRF (by 29% and 16%, respectively) and 8-bromo-cAMP (by 8% and 12%, respectively), which are mediated by protein kinase-A activation and extracellular Ca2+ influx via L-type voltage-sensitive Ca2+ channels, but not the response to KCl, which is mediated by extracellular Ca2+ influx via all types of voltage-sensitive Ca2+ channels. The sustained response to CRF was still suppressed 1 h after PMA removal, but returned to the control level by 3 h. When new protein synthesis was inhibited by preperifusion with cycloheximide alone for 3 h after 24-h PMA pretreatment, recovery from the effects of PMA was abolished. Three-hour exposure to cycloheximide without PMA pretreatment inhibited the sustained responses to CRF, AVP, and DOG, but not the spite response to AVP.(ABSTRACT TRUNCATED AT 400 WORDS)

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1991

Amount of urinary iodine excretion in residents of Taipei City--a hospital-based study.

The amount of urinary iodine excretion was measured by neutron activation analysis in 87 residents of Taipei City. The mean +/- SE of urinary iodine excretion expressed as ug iodine/g creatinine was 337.2 +/- 33.3 (335.3 +/- 59.5 for males and 338.4 +/- 40.6 for females). For each 10-year age group, from 20-29 to greater than or equal to 70, they were 396.6 +/- 106.1, 396.5 +/- 127.6, 306.5 +/- 116.7, 326.4 +/- 40.4, 338.1 +/- 64.3 and 222.9 +/- 100.6, respectively. Although there were no significant differences in sex and age, the amount of urinary iodine excretion was distributed in a very wide range from 38.6 to 1,526 ug iodine/g creatinine. Only 3% of the subjects excreted less than 50 ug iodine/g creatinine but 42.7% of our subjects excreted more than 300 ug iodine/g creatine. Iodine deficiency is not a real problem in Taipei City. However, about half of the Taipei City residents may take more than the suggested optimum amount of iodine.

Adult↗
PubMed1991

Aldosterone-producing adenoma--variable serum aldosterone response to postural change: a case report.

A 25-year-old female was admitted for evaluation of hypertension and hypokalemia. Plasma renin activity was suppressed and plasma aldosterone level was higher than normal. The CT scan of adrenal gland revealed a 2.5cm in size low density tumor mass over right adrenal area, and NP-59 adrenal scan showed early and persistent uptake of radioactivity in the right adrenal gland. Interestingly, the plasma aldosterone level was elevated, decreased and unchanged to postural change on three different occasions. After right adrenalectomy, the plasma aldosterone level decreased to 4.77ng/dl, blood pressure, serum potassium, and plasma aldosterone returned to normal response to postural change. Histologically, it was compatible with the picture of cortical adenoma. However, the tumor cell may not have reached autonomous function yet, since different responses of plasma aldosterone to postural change were observed clinically.

Adenoma↗
PubMed1991

Etiology of adult goiter in Taiwan--a hospital-based study.

We studied the etiology of goiter on outpatient clinic basis with thyroid function test, measuring circulating thyroid autoantibodies and urinary iodine excretion. One hundred patients from endocrine and metabolic clinic with grade I or over goiter according to the WHO classification were included by random sampling after carefully excluding the pure thyroid cyst and thyroid cancer by sonographic examination and fine needle aspiration cytology. Among these 100 studied cases, 23 were classified as Graves' hyperthyroidism (group 1), 19 autoimmune thyroiditis (group 2), 14 simple goiter (group 3), 42 nodular goiter (group 4) and 2 subacute thyroiditis. All four groups of goiter showed female predominance. The mean +/- SD age and 24-hour % RAIU for these four groups were 33.9 +/- 14.5 and 64.3 +/- 24.4; 44.6 +/- 19.5 and 27.3 +/- 11.3; 37.5 +/- 15.9 and 27.5 +/- 9.0; and 47.5 +/- 16.4 and 36.1 +/- 16.7, respectively. Patients with Graves' hyperthyroidism were significantly younger in age than the nodular goiter group and had higher RAIU than the other three groups (p less than 0.05, Kruskal-Wallis ANOVA, multiple comparisons). There was no age or RAIU difference among groups 2-4. The amount of urinary iodine excretion distributed in a very wide range and exhibited no significant difference among four groups. Only 2 subjects had urinary iodine excretion below 50 micrograms iodine/g creatinine but 50% (49.3% of group 2-4) had urinary iodine excretion higher than 300 micrograms iodine/g creatinine. Iodine deficiency is not a real problem at present.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Silent corticotropic adenoma of pituitary gland--a case report.

A 79-year-old man complained progressive visual impairment and Diplopia for 2 weeks. A big pituitary tumor was found and partially removed by the surgeon eventually. The tumor cells were chromophobic with H&E stain and exhibited focal positive staining with PAS. Immunoperoxidase method demonstrated moderate positivity for adrenocorticotrophic hormone (ACTH), while staining for growth hormone (G.H) and prolactin were negative. The patient was eucorticoid clinically and biochemically. Since silent corticotropic adenoma of the human pituitary gland is rarely encountered clinically, a review of the literature is included in this article.

Adenoma, Chromophobe↗
PubMed1990

Comparison of insulin secretion and insulin sensitivity between normal and impaired glucose tolerance subjects with normal fasting plasma glucose.

To examine glucose-stimulated insulin secretion and insulin sensitivity in the normal subjects and patients with impaired glucose tolerance, we performed the oral glucose tolerance test (OGTT) and modified insulin suppression test in 34 non-obese subjects. The plasma glucose and insulin concentrations were measured during fasting and every 30 min up to 120 min following 75 g of oral glucose loading. Ten subjects were classified as impaired glucose tolerance (IGT), and 24 subjects were as having normal glucose tolerance. In addition, the insulin-stimulated glucose uptake was estimated in all subjects by measuring the final 30 min steady-state plasma glucose (SSPG) of a continuous infusion of somatostatin, insulin and glucose for 4 hours (modified insulin suppression test). The mean plasma glucose concentrations of fasting and 60, 90, 120 min during OGTT study were significantly higher in the IGT subjects than in the normals. In addition, the mean incremental glucose areas under the curve during OGTT study were also greater in the IGT subjects than in the normals. The mean serum insulin concentrations were significantly higher at 90 and 120 minutes in the IGT patients than in the normals. During the modified insulin suppression test, the mean SSPG concentrations were significantly higher in the IGT patients than in the normals under the similar steady-state plasma insulin in both groups. There was a good correlation between the incremental insulin areas under the curve (OGTT) and the SSPG in the normal subjects (p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Arrangements of alpha-globin gene cluster in Taiwan.

In a gene mapping study on 217 newborn babies in Taiwan with alpha- and zeta-globin probes, we have observed 4 cases (1.84%) of alpha-thalassemia-2 heterozygotes (zeta zeta-alpha/zeta zeta alpha alpha) without increased levels of hemoglobin (Hb) Bart's in the cord blood. Eleven subjects (5.07%) were found to have the South East Asian alpha-thalassemia-1 haplotype (zeta zeta--SEA/zeta zeta alpha alpha) with increased Hb Bart's levels ranging from 2.2 to 9%. One case, with Hb Bart's level of 14% in the cord blood, was found to have the genotype of zeta zeta--SEA/zeta zeta alpha alpha T (0.46%). Four heterozygotes (1.84%) were found with the triple alpha gene anti-rightward arrangement (zeta zeta alpha alpha alpha 3.7/zeta zeta alpha alpha). Twenty-one heterozygotes (9.68%) were found to have the triple zeta-globin gene arrangement (zeta zeta zeta alpha alpha/zeta zeta alpha alpha). A new triple zeta-globin gene variant with a BamHI polymorphism was also observed in this study.

Asian People↗
PubMed1989

Changes in serum thyroid hormone and thyroglobulin levels after surgical treatments for toxic and non-toxic goiter.

We assessed changes in serum total tri-iodothyronine (TT3), total thyroxine (TT4), free thyroxine (FT4), reverse tri-iodothyronine (rT3), thyroid stimulating hormone (TSH), and serum thyroglobulin (hTg) levels in 20 patients with toxic diffuse goiter who received subtotal thyroidectomy after metabolic control with antithyroid drugs and 22 patients with non-toxic solitary nodular goiter who received lobectomy only. In the first 2 days postoperatively the toxic diffuse goiter group had approximately a 50% decrease in the mean serum TT3 concentration, and a 28% decrease in the mean serum TT4 concentration. In the same period, the non-toxic nodular goiter group had approximately a 30% decrease in mean serum TT3 concentration, and a 15% decrease in mean serum TT4 concentration. The toxic diffuse goiter group and the non-toxic nodular goiter group each had transient elevations of the mean serum rT3 concentration, amounting to 34% and 48% respectively. Neither group had any change in the mean serum FT4 level, while both showed a several-fold elevation of serum hTg. At the 6th week postoperatively in both groups, the mean serum TT3 level had returned to the preoperative value, the mean serum TT4, rT3 and hTg levels were significantly lower than preoperative values, and the mean serum FT4 level remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Diabetic ketoacidosis and hyperglycemic hyperosmolar nonketotic coma--a reappraisal after seven years].

In treating DKA and HHNK, low dose insulin therapy has been confirmed to be efficient and with less complications than traditional high dose insulin therapy. In 1981, we have reported 157 cases of DKA and HHNK at VGH. Between January 1986 and December 1987, 98 cases of DKA and HHNK were encountered at VGH. 40 patients had 48 episodes of DKA their mean age were 56 years. Comparing with the previous report, we found that the main precipitating factors were infection (41.6% vs 38.8%), omission of insulin (27.1% vs 34.7%) and there were cases without any precipitating factors (18.7% vs 24.8%). 3 cases died (6.2% vs 7.3%) in three days. During treatment, hypoglycemia were found in 4 cases (8.3% vs 5.2%) and hypokalemia were noted in 30 cases (62.5% vs 42.3%). 47 patients had 50 episodes of HHNK, their mean age were 68.7 years. Comparing with the previous experience, the main precipitating factors were infection (44% vs 45.7%), omission of insulin (16% vs 20%) and cardiovascular disorder (12% vs 31.4%), there were some episodes without any precipitating factors (20% vs 8.6%). 10 cases died (20% vs 20%) in three days, hypoglycemia were noted in 2 cases (4% vs 3%) and hypokalemia in 20 cases (42% vs 27.3%). It seems, even with better knowledge, facilities and increased experience in the management of diabetic emergencies, no dramatic change in morbidity and mortality was noted over the past 7 years.

Aged↗
PubMed1989

Primary hyperparathyroidism and coexisting hyperthyroidism--review of the literature.

Concomitance of hyperthyroidism and hyperparathyroidism is rare and only forty-nine well documented cases could be found in the literature. In the present study, only forty-three patients with adequate available clinical and laboratory data are reported. Hypercalcemia was found in all the patients and five of them (12%) had acute hyperparathyroidism. Two patients were also pregnant and had pancreatitis. Hypercalcuria was found in 73% and hypophosphatemia in 55% of the patients. Eleven patients (26%) had renal concretions. Skeletal roentgenograms showed abnormalities in 63% of the patients. Elevated serum level of alkaline phosphatase was present in 64% of the patients. However, there seemed to be no correlation with the severity of the skeletal lesions. Thyrotoxicosis commenced before that of Hyperparathyroidism in twenty-three patients (53%) whereas in the remaining twenty patients it was impossible to determine which disease began first. The etiologies of hyperparathyroidism as well as the differential diagnosis of parathyroid-related and nonparathyroid-related hypercalcemia are discussed. Microscopically, 74% of the patients had a single adenoma; 16% had hyperplasia of one to three parathyroid glands. One patient had an adenoma in combination with hyperplasia of one parathyroid gland, one had an adenoma and three hyperplastic glands, one had adenomas of two parathyroid glands in combination with hyperplasia of one parathyroid gland, and the other one had carcinoma of a parathyroid gland.2+ Finally, if a thyrotoxic patient still has hypercalcemia when becoming euthyroid after antithyroid therapy, coexisting hyperthyroidism should be considered and an operation should be performed as surgical treatment cured both diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1989

Subacute thyroiditis--61 cases review.

To examine the hospitalized patients with available data suggesting subacute thyroiditis, we have reviewed 80 hospital charts over the last 11 years and the data demonstrated 61 patients (48 females, 13 males, Aged 22-75 years) had evidence of subacute thyroiditis clinically or pathologically. Fifty seven of those patients had the clinical manifestation of severe tenderness over the neck, and others were painless. The thyroid function test were abnormal in 53% (30/57) of cases. All had rapid sedimentation rate (46/46). The thyroid antibodies were positive in 26% (10/39) of cases. Sixteen patients received unnecessary thyroid operation and complicated with hypothyroidism with or without hypoparathyroidism in two cases. In conclusion, all patients with painful or painless goiter should be appreciated carefully with additional study such as aspiration cytology to avoid misdiagnosis and inappropriate management.

Adult↗
PubMed1989

Concurrent hyperthyroidism and hyperparathyroidism: influence of hyperthyroidism on serum magnesium, free calcium and parathyroid hormone.

A patient with concomitant primary hyperparathyroidism and Graves' disease with hyperthyroidism was observed during treatment with carbimazole. His serum free calcium levels was initially elevated (6.3mg/dl, normal 4.5-5.3 mg/dl) whereas his serum magnesium level was depressed (1.6 mg/dl, normal 1.7-2.8 mg/dl), but immunoreactive parathyroid hormone levels were only slightly increased (96 pg/ml, normal less than 86 pg/ml). During therapy with carbimazole, the patient became euthyroid and serum free calcium levels decreased to 6.0 mg/dl whereas serum magnesium levels increased to 2.3 mg/dl, and parathyroid hormone increased to values clearly indicative of hyperparathyroidism (185 pg/ml). A subtotal thyroidectomy and parathyroidectomy corrected both diseases in this case. These observations suggested that hyperthyroidism per se causes a decrease in serum magnesium levels and also potentiates the osteoclastic effects of parathyroid hormone resulting in an exacerbation of hypercalcemia which in turn produced a relative inhibition of hormone secretion by the abnormal parathyroid tissue.

Adult↗
PubMed1989

Treatment of recurrent thyroid cysts by injection of tetracycline or minocycline.

We analyzed the effects of tetracycline hydrochloride or minocycline hydrochloride sclerotherapy on 66 recurrent thyroid cysts. All were hemorrhagic lesions except one serous cyst; cytologic study showed all were benign. On average, three treatments were given until resolution or the patient became unavailable for follow-up. The cumulative frequency of cyst disappearance was 33%, 45%, 52%, and 59% after 1, 2, 3, and 4 treatments. Five additional patients had cyst resolution after six to 19 treatments, and the serous lesion did not resolve. Cysts requiring more than two treatments were larger at presentation than those resolving after one or two treatments. Side effects in 179 treatments were local pain lasting ten to 20 minutes in 4.5%, radiated pain lasting one to two hours in 4.5%, fatigue lasting one to two days in 3.9%, and a febrile sensation lasting one to two days in 2.8%. Hemorrhagic thyroid cysts can usually be cured by repeated tetracycline or minocycline sclerotherapy with tolerable side effects.

Cysts↗
PubMed1988

Assessment of HBV persistent infection in an adult population in Taiwan.

In order to study the prevalence of hepatitis B virus (HBV) in the adult population of Taiwan, we screened for the presence of HBV DNA in 205 blood samples from adult (20-59-year-old) volunteers. According to the serological markers of HBV, samples were divided into three groups: group I (173 subjects) was negative for both HBsAg and HBeAg; group II (14 subjects) was positive for both HBsAg and HBeAg; and group III consisted of 18 subjects who were HBsAg-positive but HBeAg-negative. Plasma HBV DNA was not detected in group I, but it was found in 85.7% and 11.8% of samples in group II and group III, respectively. A free-form HBV DNA was found in 14.3% of the leukocyte samples in group II. Furthermore, an integrated form of HBV DNA was detected in the leukocytes of two cases of group I who remained healthy based on clinical data. HBV DNA was also detected in the spermatozoa and liver cells of one of the cases.

Adult↗
PubMed1988

The molecular basis of HbH disease in Taiwan.

We have determined the molecular characteristics of alpha-thalassemia in 12 HbH subjects from Taiwan by restriction endonuclease mapping with alpha- and zeta-specific probes. We have found four types of defects in the alpha-thalassemia-2 genetic determinant: -alpha 3.7 type I; -alpha 4.2; alpha CS alpha; and alpha alpha T. All HbH subjects carried the --SEA genotype in the alpha-thalassemia-1 determinant. At least two different subtypes of --SEA genotype were observed in this study.

DNA Restriction Enzymes↗