Efficacy of a 3-substituted versus 17-substituted chemical delivery system for estradiol brain targeting

Brain-targeted delivery of estrogens has been achieved by a chemical delivery system (CDS) in which a molecular targetor (1-methyl-1,4-dihydronicotinate) was attached to the 17-alcohol of estradiol. Optimization of this effect was attempted with the isomeric 3-phenol ester. Estradiol 3-nicotinate was prepared with nicotinic anhydride, which selectively acylated the phenol position. Methylation and reduction gave estradiol 3-(1-methyl-1,4-dihydronicotinate) of the 3-E2-CDS. Theoretical and electrochemical investigation indicated that the 3-E2-CDS was more stable to oxidation than was the prototype 17-ester (17-E2-CDS). Systemic administration of the 17-E2-CDS produced high levels of the corresponding quaternary salt in the brain of rats, which disappeared with an estimated half-life of > 2 days, but 3-E2-CDS dosing resulted in no significant quaternary salt trapping. Pharmacological activity was potent and sustained after 17-E2-CDS dosing but transient after 3-E2-CDS administration. Thus, the 3-E2-CDS reduced the rate of weight gain in male rats but to a lesser extent and for a shorter duration than did the 17-E2-CDS. Similar effects were seen on pituitary hypertrophy, reduction in serum androgen concentrations, and involution of prostate and seminal vesicles. The results of these studies suggest that placement of the targeting ester at the phenol position increases dihydropyridine stability but, at the same time, reduces brain sequestration.

Thyroid cancer treated in Chang Gung Memorial Hospital (northern Taiwan) during the period 1979-1992: clinical presentation, pathological finding, analysis of prognostic variables, and results of treatment

This study is a retrospective analysis of 248 thyroid cancer patients who received their primary treatment in the Chang Gung Memorial Hospital during the period January 1979 to December 1992. Among these cases, there were 173 papillary thyroid cancers (69.8%), 52 cases of follicular thyroid cancer (21%), 7 cases of medullary thyroid cancer (2.8%), and 16 cases of anaplastic thyroid cancer (6.5%). The subjects included 184 female patients with a mean age of 40.7 +/- 14.3 years and 64 males patients with a mean age of 49.2 +/- 14.3 years. Most of the cases had a nearly total thyroidectomy after the diagnosis was confirmed by frozen section during the operation. During the follow-up period, 19 (8.2%) patients diagnosed with well-differentiated thyroid cancer died of thyroid cancer in contrast to 12 patients (75%) with anaplastic thyroid cancer. The 1-year Greenwood survival probabilities after the disease is diagnosed in papillary, follicular, and anaplastic thyroid cancer are 0.98, 0.86, and 0.25, respectively. For the analysis of prognostic variables in well-differentiated thyroid cancer patients, 16 factors were entered for univariate and multivariate analysis. Using a log-rank univariate analysis, survival was significantly associated with the cell type of the primary tumor, age, clinical staging, postoperative 131I pattern, tumor size, postoperative thyroglobulin (Tg) level and postoperative x-ray results. In the Cox multivariate regression analysis the combination factors that gave the best prognostic value were the association of x-ray finding (P = .004), age (P = .017), and Tg level (P = 0.19). In conclusion, thyroid cancer is not an unusual disease in Taiwan. As previously reported anaplastic thyroid cancer has a poor prognosis. In this limited period of follow-up study, the patients' age with postoperative first positive x-ray finding and Tg level may provide the prognostic factors for patients with well-differentiated thyroid cancer.

Sequential liver and bone biochemical changes in hyperthyroidism: prospective controlled follow-up study

OBJECTIVE

To reexamine the prevalence and sequential changes of liver and bone biochemical abnormalities in patients with hyperthyroidism.

METHODS

A consecutive series of 95 patients with hyperthyroidism and 66 controls with euthyroid goiter seen during same period were studied. The patients were treated with propylthiouracil (PTU) 300 mg/day for 2 months, followed by 100-150 mg/day for 3 months and a subsequent maintenance dose of 100 mg/day. Serum aspartate amino-transferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), bilirubin, ALP isoenzymes, and hepatitis markers were studied before therapy and at 2 and 5 months after PTU therapy was begun.

RESULTS

Seventy-two [75.8%, confidence interval (CI) 67.2-84.4%] of the 95 patients had at least one biochemical abnormality. AST, ALT, ALP, GGT, and bilirubin were elevated in 27.4%, 36.8%, 64.2%, 16.8%, and 5.3%, respectively. Of the 34 patients with ALT elevation, 62% showed gradual normalization of ALT, whereas 38% (CI 21.9-54.5%) showed transient, asymptomatic, but significant (p < 0.025) further elevation of ALT during PTU therapy. Overt hepatitis developed in one patient. None of these changes was due to hepatitis A, B, C, or delta virus infection or autoimmune hepatitis. Changes of serum GGT parallel those of ALT. In contrast, serum ALP (primarily bone isoenzyme) rose significantly (p < 0.01) as T4 and T3 levels declined at 2 months after therapy.

CONCLUSIONS

The results suggest that hyperthyroidism is often associated with abnormal biochemical tests, particularly ALP elevation, and thus may pose diagnostic confusion. The increase of bone isoenzyme accounts for the elevations in total ALP level before and during therapy. Serum ALT and GGT abnormalities usually subside during PTU therapy, but transient asymptomatic PTU hepatotoxicity occurs in one-third of the patients. Discontinuation of PTU is not required unless overt hepatitis develops.

Expression and biochemical characterization of human glucose-6-phosphate dehydrogenase in Escherichia coli: a system to analyze normal and mutant enzymes

We have developed a system to characterize normal and mutated glucose-6-phosphate dehydrogenase (G6PD) enzymes in vitro. Normal or mutant G6PD cDNA was subcloned into a pGEX-3X vector, which allowed production of a functional fusion protein in Escherichia coli. When we compared the recombinant normal enzyme with authentic human G6PD, indistinguishable Km values for glucose-6-phosphate (G6P) and NADP were obtained, and the utilization rates for two substrate analogues (2-deoxy G6P and deamino NADP) also showed no difference between the enzymes. This system was used to assay a biochemically uncharacterized variant, G6PD Taipei (493 A-->G; 165 Asn-->Asp), plus two other known mutations (487 G-->A; 163 Gly-->Ser and 592 C-->T; 198 Arg-->Cys) that are located close to or within the putative G6P binding domain. Our results show that the G6PD activities of these three mutants were greatly reduced. No significant alteration in G6PD kinetics was observed for both 487 and 493 mutations. However, a drastic reduction in the Km for G6P (4-fold decrease) and tremendous increases in utilization rates of 2-deoxy G6P (32-fold increase) and deamino NADP (6-fold increase) were associated with the 592 mutation. This results suggests that arginine 198 in human G6PD, possibly located within the putative G6P binding domain, may play an important role in binding the substrate G6P. In addition, we and others have recently identified that at least nine different types of mutations are responsible for G6PD deficiency in Chinese. In this report, we also present the occurrence rate of each mutation present in the population of Taiwan.

Insulinoma--clinical experience in ten cases

During the period between January 1981 and December 1992, a total of ten patients with pathologically confirmed insulinoma were studied. All patients presented with variable degrees of neuroglycopenic symptoms and Whipple's triad. The ratio of insulin to glucose after an overnight fast was greater than 0.3 in 90% (9/10) of patients. Eight patients who received supervised fasting developed neuroglycopenia with relative hyperinsulinemia within 48 hours of fasting. Four of 8 patients developed hypoglycemia during a 5-hour oral glucose tolerance test (OGTT). Calcium infusion test was more sensitive in patients with an initially higher plasma glucose. The detection rates of various localization studies were 12.5% (1/8) by abdominal ultrasonography, 37.5% (3/8) by abdominal CT scan, 50% (5/10) by selective superior mesenteric and celiac arteriography. Transhepatic portal venous sampling (THPVS) detected insulinomas in 4 of 4 cases. Endoscopic ultrasonography and intraoperative ultrasonography were performed on 1 and 2 cases respectively, and were able to localize the lesions successfully. All patients received surgical treatment including enucleation (n = 2), subtotal pancreatectomy (n = 3) and distal pancreatectomy (n = 5). All patients had single tumors which were all benign islet cell adenomas. The mean size of the tumors was 15.5 +/- 2.0 mm in diameter (range: 8 to 30 mm) and mainly located in the body (50%) and tail (40%), only 1 in the pancreatic head. All symptoms of hypoglycemia subsided after operation. Hyperglycemia was observed in all patients immediately after operation, and most of them resumed normoglycemia within 8 days. However, the 2 patients who had impaired OGTT preoperatively had persistent hyperglycemia after operation and therefore were diagnosed as having diabetes (NIDDM).

Value of serum alkaline phosphatase in evaluating hyperplasia of parathyroid glands in chronic hemodialysis patients

To investigate the value of serum alkaline phosphatase in evaluating hyperplasia of parathyroid glands in hemodialysis patients, 28 hemodialysis patients who had parathyroid sonography examinations for secondary hyperparathyroidism were studied retrospectively. There were significant elevations of serum alkaline phosphatase, parathyroid hormone (PTH), serum total calcium, and dialysis duration in patients with sonography-detectable parathyroid (N = 17) as compared with those of sonography-undetectable (N = 11) parathyroid. Hemodialysis patients who have both higher serum alkaline phosphatase (> 94 IU/L) and considerably elevated serum PTH (9 x or higher) are likely to have sonography-detectable parathyroids (positive predictive value of 93%). Patients with mildly or moderately elevated serum PTH but normal serum alkaline phosphatase are less likely to have sonography-detectable parathyroids (negative predictive value is 100%). These findings suggest that the elevation of serum alkaline phosphatase could be a valuable parameter in addition to the high serum PTH level in predicting hyperplasia of parathyroid glands in chronic hemodialysis patients.

Effect of gliclazide on plasma lipids and pancreatic beta cell function in non-insulin-dependent diabetes mellitus

Eighteen patients with non-insulin-dependent diabetes mellitus (NIDDM), who were newly diagnosed or had their oral hypoglycemic agents discontinued for more than 3 months, were studied to evaluate the effect of gliclazide on glycemic control, plasma lipids and beta cell function. The mean fasting plasma glucose (249 +/- 11 vs 170 +/- 10 mg/dl, p < 0.001), postprandial plasma glucose (353 +/- 16 vs 237 +/- 16 mg/dl, p < 0.001) and HbA1C (9.6 +/- 0.4 vs 6.5 +/- 0.3% p < 0.001) decreased significantly after 3-months of gliclazide treatment. The beta cell function showed a significant increase in fasting serum C-peptide (1.8 +/- 0.2 vs 2.1 +/- 0.3 ng/ml, p < 0.05) and an insignificant increment in serum C-peptide after glucagon stimulation (2.2 +/- 0.3 vs 2.2 +/- 0.4 ng/ml, p < 0.1). In 8 cases with an initial serum cholesterol above 200 mg/dl, the serum cholesterol decreased significantly (236 +/- 8 vs 200 +/- 12 mg/dl, p < 0.05). However, LDL-cholesterol (164 +/- 8 vs 145 +/- 13 mg, p > 0.05) and HDL-cholesterol (66 +/- 5 vs 54 +/- 9 mg, p > 0.05) showed insignificant decrease after gliclazide therapy. In 4 patients with hypertriglyceridemia, the serum triglyceride decreased (441 +/- 161 vs 239 +/- 73 mg/dl, p > 0.1), but this was not statistically significant. These findings suggest that hyperglycemia, fasting serum C-peptide levels and hypercholesteremia are significantly improved after a 3-month period of gliclazide therapy in NIDDM patients.

Technetium-99m pertechnetate scan for ectopic gastric mucosa in children with gastrointestinal bleeding

The detectability of ectopic gastric mucosa by Technetium (Tc)-99m pertechnetate abdominal scanning was investigated by reviewing 62 such scans in 52 pediatric patients with gastrointestinal hemorrhage. The histologic diagnoses and clinical conditions were correlated to the findings of the scans. There were 21 true-positives, 35 true-negatives, one false-positive and five false-negative studies. The overall sensitivity of this scan for the detection of ectopic gastric mucosa was 81%, the specificity was 97% and the accuracy was 90%.

Abnormalities of sodium transport in non-insulin-dependent diabetes: association with renal disease

We investigated both sodium-lithium countertransport (Na-Li CT) and ouabain-sensitive sodium transport (Na pump) of erythrocytes in healthy subjects (group A), patients with non-insulin-dependent diabetes (NIDDM) without nephropathy (group B), patients in the proteinuric stage (group C), and those in the renal insufficiency stage (group D). Erythrocytes from all four groups had a similar initial water and ionic content and were loaded with similar degrees of Li and Na for efflux studies. There were no significant differences in erythrocyte Na-Li CT or Na pump among the four groups. However, the maximal rate of Na-Li CT was significantly higher in a group of subjects with essential hypertension when compared with groups A, B and C, consistent with the view that there is a genetic marker for essential hypertension. Ouabain-insensitive Na efflux (Na leak) of erythrocytes was found to be significantly higher in group D than in groups A or B. Also, a significant positive correlation existed between Na leak and urine protein levels of the subjects studied. Our results thus indicate that in contrast with insulin-dependent diabetic patients (IDDM) where an elevated Na-Li CT is observed, with diabetic nephropathy, Na-Li CT in NIDDM is apparently not associated with nephropathy; rather the ouabain-insensitive Na efflux appears to be correlated with the stages of nephropathy in NIDDM. The association suggests that the rate of ouabain-insensitive Na efflux may provide an index for assessing the degree of nephropathy in NIDDM patients.

An AM1 molecular orbital study of alpha-D-glucopyranose and beta-maltose: evaluation and implications

Chemical reactivity and other characteristics of alpha-D-glucopyranose and beta-maltose were evaluated within a semiempirical molecular orbital (AM1) framework. Theoretically generated structures compared well to those determined by X-ray crystallographic techniques. Calculations suggested that the secondary hydroxy functions (OH-2 and OH-3) of the mono- and di-saccharides were more acidic than the primary alcohol (OH-6), which is consistent with experimental findings. In addition, the enhanced reactivity of the OH-3 locus, which is observed upon OH-2 alkylation of the object sugars, was rationalized in terms of increased OH-3 acidity. The chemical behavior of the monomers examined may be insightful in explaining the reactivity of glucopyranose polymers.

Diabetes mellitus and hypertension based on the family history and 2-h postprandial blood sugar in the Ann-Lo district (northern Taiwan)

From July 1988 to June 1990, we performed an epidemiological study on the prevalence of hypertension and diabetes mellitus (DM) in the Ann-Lo district, a suburban area of Northern Taiwan. One third of the population in the district was randomly sampled. A total of 9087 persons were screened with 67.4% participating. Following completion of the questionnaire blood pressure, 2 h postprandial blood sugar were determined. DM was defined when the blood sugar was over 200 mg/dl or the subject had a diabetic history. Hypertension was defined if the systolic blood pressure was over 160 mmHg or the diastolic blood pressure over 95 mmHg. Statistical comparisons were performed with a chi-square test, analysis of covariance, stepwise multiple regression and Pearson correlation matrix. In this study, the prevalence rate of DM was 2.6% and of hypertension was 6.4%. For those patients 40 years or older, the prevalence rate for DM was 8.0% and for hypertension was 19.7%. The prevalence of hypertension was 24.8% in overt diabetes and 5.2% in the normal subjects. Analysis of the data between risk factors of DM revealed that DM correlated with age, body mass index, hypertension, smoking, family history of DM and correlated negatively with education. Hypertension correlated with gender, alcohol intake and smoking, sugar level, age and body mass index. The prevalence rate of diabetes and hypertension were quite high in the district and this study pointed out the important risk factors for hypertension and DM in Taiwan.

Hepatic injury during propylthiouracil therapy in patients with hyperthyroidism. A cohort study

OBJECTIVE

To evaluate the incidence, severity, and course of propylthiouracil-induced hepatic injury in patients with hyperthyroidism.

DESIGN

Cohort study.

SETTING

Outpatient clinic of a university-based hospital.

PATIENTS

Fifty-four patients with normal aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values and a definite diagnosis of hyperthyroidism.

INTERVENTION

Treatment with propylthiouracil, 300 mg/d for 2 months followed by 100 to 150 mg/d for 3 months and a subsequent maintenance dose of 100 mg/d.

MEASUREMENTS

Liver biochemical tests were studied before therapy and 2 months and 5 months after starting propylthiouracil therapy. The patients were monitored with clinical evaluation and weekly liver biochemical tests after AST or ALT levels became abnormal. Serologic markers of hepatitis A, B, C, and delta virus infection were also studied when appropriate.

RESULTS

Fifteen (28%; 95% CI, 16% to 42%) of the 54 patients showed ALT elevations 2 months after propylthiouracil therapy. The mean peak ALT level for these patients was 1.35 mu kat/L (range, 0.65 3.85 mu kat/L). None of these patients had symptoms or hyperbilirubinemia. Liver biopsy in three patients showed mild perivenular focal necrosis or ill-defined granuloma composed of foamy histiocytes with ceroid pigment and mild fatty metamorphosis. Despite continued propylthiouracil therapy at a reduced dose, ALT levels returned to normal in 13 of 15 patients in the following 3 months. None of these ALT elevations resulted from hepatitis A, B, C, or delta virus infection. No statistical difference was seen in the pretreatment characteristics between patients with and those without ALT elevation, except that the former had a higher pretreatment T4 level (270 +/- 12.9 compared with 237 +/- 7.72 nmol/L, P = 0.027) and T3 level (7.22 +/- 0.72 compared with 5.85 +/- 0.39 nmol/L, P = 0.048).

CONCLUSIONS

Propylthiouracil-induced subclinical liver injury is common and is usually transient and asymptomatic. Therapy with propylthiouracil may be continued with caution in the absence of symptoms and hyperbilirubinemia.

[Cushing's syndrome with pregnancy. Report of three cases]

Cushing's syndrome with pregnancy is rare, and only about 60 cases have been reported. In the recent 4 years, 3 cases were diagnosed in Chang Gang Memorial Hospital. They presented with serious maternal complications early in the second month of pregnancy, including hypertension, proteinuria and lower leg edema. Unfortunately it was not diagnosed until the 20th week of pregnancy. They had the same hormone profile as other Cushing's syndrome patients who were not pregnant. Under the supportive treatment they had outcomes of two premature deliveries and one still birth. Just after delivery all patients received left adrenalectomy and pathology showed adenoma. All of them had good recovery courses. According to the literature, early treatment (surgical operation, medical treatment, or irradiation) could decrease maternal morbidity and fetal loss rate.

[Using 131I-MIBG and 99mTc-MDP bone scan for localization of rare extra-adrenal pheochromocytomas: report of 2 cases]

It is difficult, but important, to diagnose extra-adrenal pheochromocytomas before surgery. Failure to recognize the existence and nature of an extra-adrenal pheochromocytoma can cause life-threatening problems even in a minor surgical operation. We present two rare cases of extra-adrenal pheochromocytomas which were detected by 131I-MIBG scintigraphy. One of them was intrapericardial, and the other was a vesical pheochromocytoma. We used a combined 99mTc-MDP bone scan and 131I-MIBG scintigraphy to locate the pheochromocytomas. Both cases of extra-adrenal pheochromocytoma were correctly diagnosed preoperatively and successfully resected in the subsequent operations.

[Low dose radioiodine treatment of papillary thyroid carcinoma in a child--a case report]

The thyroid carcinoma is rare in children and the optimal management is rather controversial. We report a case of a 7-year-old boy who had right neck masses and proved to be papillary thyroid carcinoma after near-total thyroidectomy. Post-operative 20 mCi radioiodine-131 (I-131) ablation scan, lung metastasis was suspected but the chest X ray was normal. After being lost to follow up for 4 years, the patient returned with the complaints of cough; the chest X ray was still normal. He then received 5 treatment with low dose (30 mCi) I-131 therapy and continued thyroxine replacement. Progressive decrease both of the thyroglobulin level and the intensity of radioactivity of lung were noted. After a total doses of 193 mCi I-131 therapy, neither pulmonary fibrosis nor bone marrow suppression was seen. Although the low dose (< or = 30 mCi) I-131 therapy was recommended, it was limited for the ablation therapy of the remnant thyroid tissue. Upon consideration of economics and the convenience of not being admitted to the isolation room, the low dose I-131 therapy seems feasible for children with thyroid carcinoma with systemic disease. However, the long term efficacy needs further evaluation.

A new method for the estimation of the aqueous solubility of organic compounds

Using a semiempirical quantum chemical method (AM1), various properties (dipole moment, charge distribution, geometrical parameters, etc.) of 331 compounds were calculated. Various linear functions of these properties and their combinations were fitted to reproduce experimental aqueous solubilities. An 18-parameter function was derived that is reasonably simple, yet appears to be able to describe the aqueous solubilities of a wide range of organic compounds. The parameter set is essentially the one used in a recent similar study of octanol-water partition coefficients. The derived equation has important predictive value.

Apolipoprotein levels in normolipidemic non-insulin-dependent diabetes mellitus

The purpose of this study was to examine the change in apolipoprotein and lipoprotein levels in patients with normolipidemic untreated non-insulin-dependent diabetes mellitus (NIDDM). Fifteen untreated, non-obese male NIDDM patients without hyperlipidemia were chosen, and 15 healthy subjects, matched for age, sex, body weight, alcohol consumption and cigarette smoking served as the control group. We observed that the concentrations of plasma total cholesterol (TC), triacylglycerol (TG) and very low density lipoprotein cholesterol (VLDL-C) were identical in both NIDDM and control groups. The levels of low-density lipoprotein cholesterol (LDL-C) were slightly increased in the diabetic group, but the difference did not reach statistical significance in our study. High-density lipoprotein cholesterol (HDL-C) was lower in the NIDDM group than in the controls. Significantly increased TC/HDL-C and LDL-C/HDL-C ratios were found in NIDDM patients compared with controls. The apolipoprotein A-I (apo A-I) and apolipoprotein A-II (apo A-II) levels were decreased in NIDDM patients, while the apolipoprotein B (apo B) level remained similar to that of the control subjects. The ratio of apo A-I/apo B was decreased significantly in the NIDDM group. Our results suggest that NIDDM patients are at higher risk of coronary heart disease, even if they remain normolipidemic.

C-peptide response to glucagon in patients with non-insulin-dependent diabetes mellitus

To understand pancreatic beta cell function in patients with non-insulin-dependent diabetes, we analyzed C-peptide response to glucagon in 101 nonketotic patients with onset of diabetes at over 25 years of age and duration of diabetes of more than one year. The fasting serum C-peptide values (FCP), maximal incremental (delta CP) and 6-minute (6'CP) serum C-peptide values after 1 mg of intravenous glucagon administration were not related to age at diagnosis (r = 0.12, 0.06 and 0.10, respectively), duration of diabetes (r = 0.15, 0.05 and 0.10, respectively), fasting plasma glucose concentrations (r = 0.01, 0.18 and 0.12, respectively) or glycohemoglobin (HbA1c, r = 0.13, 0.22 and 0.16, respectively). In contrast, they showed a clear positive correlation with body mass index (BMI, r = 0.36, 0.52 and 0.41, p < 0.001). In order to evaluate the beta cell function in patients with different responses to treatment modalities, a subgroup of 45 patients was divided into three groups: diet successes (DS, n = 14), oral hypoglycemic agent (OHA) successes (OS, n = 19) and OHA failure (OF, n = 12). Among the three groups, patients in the OF group had the longest duration of diabetes (9.4 +/- 1.9 years) and the lowest BMI (19.3 +/- 1.0 kg/m2). Serum C-peptide responses to glucagon were different in the three study groups. Patients in the DS group had the highest response and patients in the OF group had the lowest response. However, the differences in mean FCP, delta CP and 6'CP among the three groups were not statistically significant, and there was a wide overlap of individual C-peptide values.(ABSTRACT TRUNCATED AT 250 WORDS)

Diverse point mutations result in glucose-6-phosphate dehydrogenase (G6PD) polymorphism in Taiwan

Glucose-6-PHOSPHATE dehydrogenase (G6PD; EC 1.1.1.49) deficiency is the most common human enzymopathy, affecting more than 200 million people worldwide. Although greater than 400 variants have been described based on clinical and biochemical criteria, little is known about the molecular basis of these G6PD deficiencies. Recently, the gene that encodes human G6PD has been cloned and sequenced, which enables us to examine directly the heterogeneity of G6PD at the DNA level. During the past 10 years, we examined the G6PD activity in 21,271 newborn Chinese infants (11,400 males and 9,871 females) and identified 314 (2.8%) males and 246 (2.5%) females having low G6PD activity. The G6PD gene from 10 randomly selected affected individuals and their relatives was polymerase chain reaction (PCR) amplified, subcloned, and sequenced. Our results indicate that at least four types of mutation are responsible for the G6PD polymorphism in Taiwan. The first type of mutation (487 G----A) was found in an affected Chinese with a G to A change at nucleotide 487, which results in a (163)Gly to Ser substitution. The second type of mutation (493 A----G) is a novel mutation that has not been reported in any other ethnic group and was identified in two affected Chinese. This mutation causes an A to G change at nucleotide position 493, producing an (165)Asn to Asp substitution. Interestingly, the 487 G----A and 493 A----G mutations create Alu I and Ava II recognition sites, respectively, which enabled us to rapidly detect these two mutations by PCR/restriction enzyme (RE) digestion method. The third mutation (1376 G----T) was found in four affected Chinese. This mutation causes a G to T change at nucleotide position 1376 that results in an (459)Arg to Leu substitution. The 1376 G----T mutation seems to be the dominant allele that causes G6PD deficiency in Taiwan. Finally, two affected Chinese were identified as having the fourth mutation (1388 G----A). This mutation causes a G to A change at nucleotide 1388 that produces an (463)Arg to His substitution. Our studies provide the direct proof of the genetic heterogeneity of G6PD deficiency in the Chinese populations of Taiwan and the PCR/RE digestion method is suitable for simultaneous detection of the 487 G----A and 493 A----G mutations.

An extended version of a novel method for the estimation of partition coefficients

Using the semi-empirical AM1 method, 302 compounds have been studied and equilibrium properties calculated. Functions based on linear combinations of subsets of calculated properties have been fit to the 1-octanol-water partition coefficients. The best such semi-empirical approach function has 18 parameters, has a standard deviation of 0.306, and seems to describe the partition coefficients of the 302 compounds. The predictive power of the function was tested and found to be good. Since this new version is based on a much larger number of, and structurally more varied, compounds and uses an improved, new function, we expect it to be a very useful method to predict partition properties of a wide variety of compounds.