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Biomedical subjects

L T Ho

Publications and source records attributed to L T Ho.

At least 145 records · Page 8Linked to original sources
PubMed1989

The effect of sexual activity on androgen metabolism, androgen-receptor translocation, and glandular weight of ventral prostates of rats.

The present study was conducted to determine whether sexual activity exerts an effect on the action of androgen in the rat prostate. Eight-week-old Sprague-Dawley male rats were divided into two groups. Rats were grouped with female rats (sexualactive), or male (sexual-inactive) rats, and sacrificed 6 months later, The ventral prostates were dissected, homogenized and processed into cytosol and nuclei fractions. Testosterone and dihydrotestosterone were quantified by radioimmunoassay, and androgen receptor was determined by 'exchange assay' with radioactive methyltrienolone incubated for 18 h at 15 degrees C. The main result were: 1) The steroid levels of testosterone and dihydrotestosterone in plasma and in the cytosolic fraction of prostate showed no significant difference between the two group of rats. 2) The prostatic nuclear dihydrotestosterone concentration of the sexual-active group (4.3 +/- 0.83 pmol/mg DNA, N = 6) was significantly higher (P less than 0.01) than that of the sexual-inactive group (1.68 +/- 0.43, N = 6). 3) The androgen receptor was significantly higher (P less than 0.05) in nuclear extract (0.64 +/- 0.11 pmol/mg DNA, N = 6) and significantly lower (P less than 0.01) in cytosol (53.4 +/- 5.7 fmol/mg protein, N = 6) of the sexual-active group than those of the sexual inactive group (0.42 +/- 0.13, N = 6 and 74.6 +/- 11.8, N = 6, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
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

Forskolin stimulation of pepsinogen secretion from frog esophageal mucosa is partly mediated by intrinsic cholinergic neurons.

Forskolin was found to stimulate pepsinogen secretion from frog esophageal mucosa. The stimulation was dose-dependent and was accompanied with a great increase in tissue cAMP content. The response to forskolin mimicked the action of bethanechol and was not additive with bethanechol. The stimulatory effect of forskolin was inhibited by 50% in the presence of either atropine or tetrodotoxin. On the other hand, incubation in a calcium-free medium not only reduced the response to forskolin by 45% but also eliminated the influence of atropine and tetrodotoxin. These results indicate that forskolin may stimulate pepsinogen secretion from the frog esophageal mucosa via activating adenylate cyclase, and part of its effect may arise from eliciting acetylcholine release from the intrinsic neurons.

Animals↗
PubMed1989

The content and composition of immunoreactive somatostatin in monkey pancreas.

A highly sensitive and specific radioimmunoassay (RIA) was developed for analyzing somatostatin (SRIF-LI). The monkey pancreas was lyophilized and extracted with 2N acetic acid. The content and composition of immunoreactive somatostatin in monkey pancreas were then evaluated by chromatography process and RIA. The concentration of SRIF-LI in monkey pancreas was around 513.8 ng/g dry weight. At least 3 components of SRIF-LI were detected in pancreatic extracts. The major component of SRIF-LI (about 92%) was SS-14, and other two were SS-28 and a form bigger than SS-28.

Animals↗
PubMed1989

Cushing's syndrome: analysis of 188 cases.

From January 1962 through April 1988, 188 patients with Cushing's syndrome were hospitalized at the Veterans General Hospital. Iatrogenic Cushing's syndrome was found in 123 (65.4%) of the patients. The other 43 patients (22.9%) had excess secretion of adrenocorticotropin (ACTH) and 22 patients (11.7%) had benign or malignant adrenocortical tumors. The clinical features and the functional reserve of the adrenal glands in those patients with iatrogenic Cushing's syndrome were evaluated. A retrospective analysis of the diagnostic rate of the various endocrine evaluations and the radiological examinations was also carried out. Four approaches were used in the management of Cushing's syndrome: (1) pituitary surgery, (2) pituitary irradiation, (3) adrenal surgery, and (4) drug therapy. Both the clinical and hormonal responses to these four management types were evaluated. The endocrinological, radiological, surgical and pathological experiences of 25 patients with Cushing's disease treated with pituitary surgery are presented. Five patients (20%) had an atypical endocrine pattern (20% false-negative). Twenty-four patients received a pituitary CT scan and 16 patients (66.7%) had positive CT findings. Of these 25 patients, 19 had pathology-proven microadenomas (less than 1cm), one had macroadenoma (greater than 1cm) and 5 had no evidence of adenomatous tissue. Among the 22 patients with adrenal Cushing's syndrome, 4 (18%) were suffering from adrenocortical carcinoma and 18 (82%) with benign adrenal tumors. The incidence of left adrenal adenoma was approximately twice that of right adrenal adenoma. The cure rate of adrenocortical adenoma by surgical treatment with unilateral adrenalectomy was excellent, but for adrenocortical carcinoma was poor.

Adolescent↗
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

Immunogenicity of highly purified porcine and human insulins in diabetic patients with high titers of insulin antibody.

Twenty-nine non-insulin-dependent diabetic Chinese subjects previously treated with conventional porcine isophane insulin (NPH) for a period of time, whose titer of serum insulin antibody was greater than 40% were changed to either highly purified pork insulin (Nordisk, Denmark) or human insulin of recombinant DNA origin (Eli Lilly, USA) for 1 year in a double-blind and randomized trial. The human (n = 16) and pork insulin (n = 13) groups were carefully matched for age, sex and measures of metabolic control. In highly purified pork-insulin-treated patients, the glycated hemoglobin and fasting blood sugar values began to fall significantly from a mean of 13.2% to 12.3% (p less than 0.05) and 228 mg/dl to 183 mg/dl (p less than 0.005), respectively, 2 months after the commencement of this study, whereas insulin antibody levels began to fall significantly from a mean of 61.8% to 49.5% (p less than 0.01) 6 months after the start of the study. Also, daily insulin doses increased significantly from a mean of 58 units to 70 units (p less than 0.005) 6 months after the start of the study. In human-insulin-treated patients, there were no significant changes in the glycated hemoglobin values. The fasting blood sugar levels fell significantly (p = 0.0515) at the end of the study period but the insulin antibody levels did not show any significant change during the same study period. Daily insulin dose increased significantly from a mean of 51 units to 57 units (p less than 0.01) 4 months after beginning the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Insulin resistance in obesity and noninsulin dependent diabetes mellitus.

Insulin clamp studies were carried out on 13 non-diabetics and 12 non-insulin-dependent diabetics (NIDDM). Based upon the body mass index (BMI), they were further divided into obese (BMI greater than or equal to 27 kg/m2) and nonbese groups (BMI less than 27 kg/m2). All received euglycemic insulin clamp study (Humulin-S 40mU/m2/min). Thermoregulated venous samplings were done every five minutes for measurements of plasma glucose (PG) and immunoreactive insulin (IRI). Steady state plasma glucose (SSPG) was obtained 20-80 minutes and kept for 100 more minutes. The data of final 40 minutes of clamp were used for analysis. Variations in SSPG and metabolic clearance rate of glucose (MCRG) instead of glucose infusion rate (M) value were used to assess the insulin sensitivity. The results showed that insulin resistance was noted in obese non-diabetic and diabetic subjects as well as in non-obese diabetic patients, as evidenced by higher basal IRI and lower MCRG than non-obese normal controls. Correlation analysis revealed that there was no correlation between the reduction of MCRG and the BMI in either non-diabetic or diabetic patients. There was a strong negative correlation between MCRG and the ambient fasting plasma glucose in the diabetic group, whereas this correlation was not found in the non-diabetic group. In conclusion, obesity with or without diabetes did have remarkable insulin resistance. In non-diabetic obese subjects the insulin resistance did not go up as the BMI increased further. In diabetic patients, both obesity and hyperglycemia contributed significantly insulin resistance.

Adult↗
PubMed1989

The establishment of a radioimmunoassay of calcitonin in human serum.

A sensitive sequential radioimmunoassay of calcitonin (CT) is described. Synthetic human CT was used for 125I-labelling and for preparation of anti-sera. The labelled hormone was purified by QUSO and P10 column. The specific activity of the purified 125I-CT was 39.8 Ci/g. The anti-sera was produced by immunization of guinea pigs with human synthetic CT which was conjugated with carbodiimide onto BSA (bovine serum albumin). Separation of free from antibody bound 125I-labelled CT was performed using DCC precipitation. Standard curves of extracted plasma, extracted plasma plus human CT were parallel to the standard curve. Recovery of 62.5 to 500 pg/ml CT were in the range of 80.72 to 113.4%. The Scatchart plot of the binding data showed a straight line with a kd of 56 pM and Bmax of 35 pM. The specificity of the antiserum was good. The lower limit of detection was 31.25 pg/ml. Our results indicate that this assay system may be useful in both clinical use and research.

Calcitonin↗
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↗
PubMed1988

A space-resolved fluorometer and its application to immunoassay.

A metal surface has been added into a fluorometer to reflect the excited light and to reduce the light scattering. Due to the total separation of the fluorescent signal and the noise by directing them into different spaces, the resolution could be improved by several orders of magnitude. The same metal surface could also be used for immunoassays. The detection of alpha-fetoprotein in normal rat serum and human standard serum are given as examples. The results indicate that the apparatus and the method have significant advantages.

Antibodies, Anti-Idiotypic↗
PubMed1988

Somatostatin modulation of neurally mediated pepsinogen secretion from frog esophageal mucosa.

Frog esophageal mucosa contains peptic glands which are innervated by cholinergic neurons. When incubated in a medium containing 1.5 mM CaCl2, pepsinogen release from esophageal mucosa was increased by a high potassium concentration (55 mM KCl), 1,1-dimethyl-4-phenylpiperazinium (DMPP) or bethanechol. Whereas the response to bethanechol remained little changed, the response to high KCl concentrations or DMPP was abolished in the absence of Ca2+. The stimulatory effects of high KCl concentrations and DMPP were also eliminated by the presence of atropine or somatostatin. Furthermore, pepsinogen release in response to bethanechol was dose-dependently inhibited by somatostatin. Frog esophagus was found to contain somatostatin-like immunoreactivity, with a higher density at the end adjacent to the stomach. Chromatography of mucosa extract on Sephadex G-50 revealed a single peak of somatostatin-like immunoreactivity that coeluted with somatostatin-14. Immunohistochemical staining of the mucosa with peroxidase antiperoxidase technique demonstrated the presence of two varieties of somatostatin-like immunoreactivity-containing cells, one individually dispersed within the intercalated septa and the other in groups within the interlobular septa of the peptic glands. These results seem to indicate that somatostatin or somatostatin-like immunoreactivity may play a modulatory role in neurally mediated pepsinogen secretion in the frog esophagus.

Animals↗
PubMed1988

Insulin induces activation and translocation of protein kinase FA (a multifunctional protein phosphatase activator) in human platelet.

Protein kinase FA (an activator of the ATP.Mg-dependent multifunctional protein phosphatase) has been identified in both cytosol and plasma membrane isolated from human platelets. The FA activity in the cytosol is active whereas the FA activity in the membrane is inactive. Quantitative analysis further indicates that approximately 90% of total FA is present in the membrane whereas only 10% of FA is localized in the cytosol, suggesting that the inactive membrane-associated FA might be regulated. This notion has subsequently been demonstrated that exposure of platelets to physiological concentrations of insulin for only 1 min resulted in an increase in cytosolic FA activity to about 300% of control values in the absence of insulin and in a corresponding decrease in FA activity in the membrane. It is concluded that the molecular basis for insulin action on cellular metabolism may partly be mediated through the activation and translocation of protein kinase FA in the membrane. It is suggested that redistribution of protein kinase FA may represent a transmembrane signal of insulin.

Animals↗
PubMed1988

Insulin controlled-release microcapsules to prolong the hypoglycemic effect in diabetic rats.

A solvent evaporation process was employed for preparing insulin microcapsules by using biodegradable polymers [polylactic acid (PLA), HP-55] and non-biodegradable polymers [ethylcellulose (EC), ethylenevinyl acetate (EVA)]. The release behavior of insulin microcapsules in pH 7.4 phosphate buffer solution was undertaken by a continuous flow column method. Seven types of insulin microcapsules were respectively injected into the flanks of fasting-diabetic SD rats induced by streptozotocin. The glucose levels and insulin concentrations in the blood were periodically sampled from the tail and assayed by a glucose analyzer and RIA method. Body weights were measured twice per week. The release rate was controllably dependent on the polymer used. The PLA microcapsules could maintain normoglycemia only for five days, whereas the (PLA + 1%EVA) microcapsules exhibited two times the hypoglycemic effect of PLA microcapsules, but (PLA + 1%EVA) microcapsules treated with 4% wax extended the duration of hypoglycemic effects for two weeks. There was no significant effect for insulin-HP-55 microcapsules. The EC microcapsules prolonged the hypoglycemic effect for 15 days, however, the (EC + 1%EVA) microcapsules could maintain the same effect for up to three weeks. The slower the release rate of insulin microcapsules in vitro the longer the hypoglycemic effect of insulin microcapsules in vivo. A close relationship between in vitro release behavior and in vivo hypoglycemic efficacy of insulin microcapsules was obtained.

Animals↗