Reading disabilities: the case of Chinese, Japanese, and English

A common hypothesis has considered apparent differences in the incidence of reading disability in Asian and Western languages to be related to orthographic factors. A reading test was constructed in English, Japanese, and Chinese to assess the validity of this proposal. Large samples of fifth-grade children in Japan, Taiwan, and the United States were given the test and a battery of 10 cognitive tasks. Strong evidence was found that reading disabilities exist among Chinese and Japanese as well as among American children. In discriminating between groups of poor and average readers by means of the cognitive tasks, the combined effects of general information and verbal memory proved to be the most powerful predictors in Japan and Taiwan. General information and coding emerged as the most effective predictors for American children. The results cast doubt upon the crucial significance of orthography as the major factor determining the incidence of reading disabilities across cultures.

RNA polymerase: linear competitive inhibition by bis-(3' to 5')-cyclic dinucleotides,NpNp

We have investigated the possible role of the bis-(3' to 5')-cyclic dinucleotides UpUp and ApUp as kinetic inhibitors of the DNA dependent RNA polymerase enzyme of E. coli, using T7 delta D111 deletion mutant DNA and several synthetic DNA polymers as templates. We have established that UpUp is a linear competitive inhibitor of the initiation phase of the polymerization (Ki = 28 microM using T7 delta D111 DNA as a template), but that it has no effect when added during the elongation phase. The compound ApUp is an inhibitor of the reaction only when poly(dA-T).poly(dA-T) is used as a template, and UpUp is an inhibitor of the reaction when poly(dA).poly(dT) was employed as the DNA template.

Fine-needle aspiration versus drill-needle biopsy of thyroid nodules: a controlled clinical trial

Percutaneous needle biopsy by two different methods was evaluated in a prospective controlled study of 167 consecutive patients with dominant thyroid nodules. Fine-needle aspiration was superior to high-speed drill-needle biopsy because of its higher diagnostic yield (93.9%). When a sample sufficient for diagnosis was obtained, the accuracy rate for both methods was comparable. Diagnostic errors were due to inadequate samples, difficulties in interpreting hypercellular adenomas, and geographic sampling problems. In the detection of thyroid cancer, neither technique alone appears completely adequate because of occasional false negative errors. The selection of patients for operation should depend on clinical parameters as well as the findings on fine-needle aspiration of thyroid nodules.

RNA polymerase: correlation between transcript length, abortive product synthesis, and formation of a stable ternary complex

In order to investigate the relationship between the stability of the ternary complex RNA polymerase-T7 D111 DNA-RNA product and the length of the bound RNA product, we have developed a protocol for the production of stable ternary complexes of known length and composition. The assembly of the ternary complex is achieved by utilizing a dinucleotide tetraphosphate (pppApU) as a selective primer, which is augmented by one or more appropriate nucleotides. The labeled products were characterized by autoradiography of gel electrophoresis patterns, which were then quantified. The criterion for stability is the protection from perturbations (a salt-jump or a rifampicin challenge), which effectively inhibit initiation. The formation of a bound ribotetranucleotide ternary complex confers stability and terminates abortive product synthesis.

The free forearm flap--a report of 25 cases

In 25 cases using microvascular techniques, free forearm flaps were used for reconstruction of various tissue defects. 15 flaps were used for repair of hand injuries, 5 for facial defects, 1 for lower extremity deformity and 4 for total rhinoplasty. All flaps survived. The arterial blood supply of the forearm flap comes from the cutaneous branches of the radial artery while its venous drainage is via cephalic vein and the radial comitantes veins. The forearm flap has a thin layer of subcutaneous fatty tissue, can provide quite large area of soft tissue and the vascular pedicle is long with moderately large calibre vessels. The donor area, however, has to be skin grafted, leaving an unsightly scar over the forearm which is one of the shortcomings of this flap. Secondly it means sacrificing a major arterial supply to the hand on the donor side.

Effects of ureteral obstruction on the toxicity of cephalosporins in the rabbit kidney

The nephrotoxicity of the cephalosporin antibiotics is closely related to their secretory transport into the proximal tubular cell at the antiluminal (blood) site. The present report describes the effects of transient ureteral obstruction, which increases intracellular concentrations of secreted organic anions, on the cortical uptake and the proximal tubular toxicity of several cephalosporins given in mildly toxic doses. Unilateral obstruction for 1-2 hr increased the cytotoxicity of cephaloglycin and cefaclor, both of which are rapidly secreted across the tubular cell, but not of cephaloridine, which undergoes minimal secretion. Bilateral obstruction significantly increased the toxicity of cefaclor, which is rapidly secreted, but not of cefazolin, which is slowly secreted. Finally, there was a further augmentation of the effects of obstruction on the toxicity of cefaclor by a minimally toxic pretreatment regimen of neomycin. Studies of cortical antibiotic concentrations support the conclusion that the effects on toxicity are largely the result of the increased intracellular accumulation that results from obstruction.

Antihypertensive effects of lofexidine in patients with essential hypertension

1 Single oral doses of lofexidine, 0.1, 0.3, and 0.6 mg produced dose related decreases in supine and standing arterial pressure and heart rate in nineteen patients with essential hypertension. 2 A mean oral antihypertensive threshold dose of less than 0.1 mg was estimated. 3 Lofexidine decreased mean urinary noradrenaline excretion 28% and caused significant retention of sodium and water. 4 The most prominent side effects were sedation and orthostatic dizziness. 5 Lofexidine is pharmacologically similar to, but apparently less potent than clonidine as an antihypertensive agent.

Prevention of cephalosporin nephrotoxicity by other cephalosporins and by penicillins without significant inhibition of renal cortical uptake

Prevention of cephalosporin nephrotoxicity in animal models by probenecid or p-aminohippurate requires treatment regimen that produce sustained inhibition of cortical accumulation of the toxic antibiotic. In contrast, cephaloridine nephrotoxicity in the rabbit can be prevented by a limited single dose of cephalothin. In the present report further studies were done in which it was demonstrated that cephaloridine nephrotoxicity can be prevented by doses of other cephalosporins or penicillins that produce little or no reduction of the cortical concentrations of toxic cephalosporin. More limited studies revealed similar protection by benzylpenicillin against cephaloglycin, also without reduction of cortical concentration. Finally, similar limited-dose administration of penicillin eliminated tha additive toxicity of cefazolin and neomycin. This selective protection against the toxic cephalosporins by the less toxic or nontoxic cephalosporins and by the penicillins, without inhibition of overall cortical accumulation of the toxic antibiotic, may provide a subcellular probe for the study of the molecular basis of cephalosporin nephrotoxicity.

Non-endocrine carcinoid tumour of the uterine cervix: aspects of diagnosis and treatment. Case report

A case of primary well-differentiated carcinoid tumour of the uterine cervix in a Chinese woman of 62 years without endocrine symptoms is reported and its clinico-pathological features, ultrastructure and response to radiotherapy discussed. To our knowledge, it is the first of such cases seen in Hong Kong. Clinically, it presented as a polypoid lesion. The initial diagnosis was squamous carcinoma of cervix stage Ib and the patient was treated with radiotherapy. The tumour disappeared after application of first intracavitary irradiation of 4500 mg h. After completion of 9000 mg h, Wertheim hysterectomy followed and no residual tumour was found. Retrospective staining of the pre-irradiation cervical tumour by Grimelius method was positive for argyrophil granules and electron microscopic study demonstrated neurosecretory granules in the cytoplasm and established the diagnosis.

Inhibitory effects of selenium on the growth of L1210 leukemic cells

Selenium has been shown to inhibit L1210 cells both in vitro and in vivo. The death of L1210 cells in vitro as indicated by trypan blue exclusion was dependent upon the form and concentration of selenium tested. Incubation of L1210 cells in buffer containing selenium at 1 microgram/ml for 1 hr prior to inoculation into mice significantly retarded the ability of the cells to propagate in vivo. Sodium selenite injected i.p. increased the longevity of mice inoculated with L1210 cells. Administration of 40 microgram selenium as sodium selenite daily for 7 days resulted in a 65% increase in longevity of mice inoculated with 10(5) L1210 cells. Injections of sodium selenite at doses of 40 microgram/day or less for 7 days did not significantly alter growth, liver weight, or red and white blood cell counts. The efficacy of selenium therapy was dependent upon the total number of tumor cells given in the initial inoculum. Selenium administration as sodium selenite was shown to be more effective in increasing the longevity of L1210-inoculated mice than was treatment with sodium selenate, selenocystine, or selenomethionine. Sodium selenite treatment at 20, 30, or 40 microgram/day in mice inoculated with 10(2) cells resulted in 50, 80, and 90% cures, respectively. Supplementation of the drinking water with 3 ppm selenium as sodium selenite increased the longevity of L1210-inoculated mice by approximately 30%. Combined therapy with selenium (30 microgram/day) and methotrexate resulted in a significantly longer life span of L1210-treated mice than resulted from either compound administered separately.

Residual trophoblastic disease in association with partial hydatidiform mole

A 10-year retrospective study was carried out of cases diagnosed as hydatidiform mole at the University of Hong Kong. Strict morphologic criteria established in a previous report were used to study the association of the partial mole syndrome with residual trophoblastic disease. Of the total of 138 cases available, 13 were found to be partial moles, 1 of which was followed by trophoblastic disease that required chemotherapy. This subsequently proved to be an invasive (partial) mole, the first example of its kind to be verified by pathology. The extent of the association between partial mole and subsequent trophoblastic disease and the spectrum of the pathologic lesions actually underlying the latter remain to be determined by further retrospective and prospective studies.

The use of bacteria as markers of leukemic lymphocytes and for the isolation of natural killer cells

Human lymphocyte subpopulations as well as leukemic lymphocytes can be identified and enumerated in blood smears by using bacteria that bind spontaneously to lymphocytes or by using bacteria to which antibodies are chemically coupled. The mechanism of natural binding of bacteria to lymphocytes was shown to involve a lectin on the lymphocyte surface and a carbohydrate on the bacteria. Also, we found that natural killer (NK) cells can be separated by negative selection using monolayers of bacteria. A subpopulation of T cells, identified by their binding of B. globigii, was shown to be suppressors for NK cells.

Calcium and microtubule dependence for increased ornithine decarboxylase activity stimulated by beta-adrenergic agonists, dibutyryl cyclic AMP, or serum in a rat astrocytoma cell line

Ornithine decarboxylase (ODCase; L-ornithine carboxy-lyase; EC 4.1.1.17) activity was increased 5-20 fold above basal activity by N(6),O(2')-dibutyryl cyclic AMP, isoproterenol, epinephrine, or fetal calf serum in confluent C6-2B rat astrocytoma cells. Serum increased ODCase activity by a mechanism apparently independent of cyclic AMP because it decreased intracellular cyclic AMP. Calcium ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) buffers (pCa = 6.4) reduced basal ODCase activity and blocked the increase in activity by beta-adrenergic agonists, dibutyryl cyclic AMP, or serum. Readdition of calcium to pCa = 4.0 restored the ability of the cells to respond to these agents. The rise in ODCase activity stimulated by isoproterenol, dibutyryl cyclic AMP, or serum was also blocked by the microtubule disrupting agents, vinblastine and colchicine, and by the microfilament disrupting agent, cytochalasin B. Lumicolchicine, an analog of colchicine that does not disrupt microtubules, was ineffective. The microtubule and microfilament disrupting agents and EGTA had no effect on the intracellular accumulation of cyclic AMP. Cycloheximide inhibited protein synthesis >95% within 30 min, and caused an immediate decline of stimulated ODCase activity with a half-time of 20-30 min. The inhibition of ODCase activity by colchicine or EGTA was distinct from that seen with cycloheximide and could not be correlated to their effects on general protein synthesis. Colchicine or EGTA each caused identical rates of decline in ODCase activity with a half-time of 20-30 min after an initial lag period of about 60 min.

The effects of alpha adrenergic agents on human platelet aggregation

The effects of alpha adrenergic agonists and antagonists on human in vitro platelet aggregation were studied to characterize further the platelet alpha adrenergic receptor. Aggregation induced by ADP and U46619; a stable prostaglandin endoperoxide analog, was potentiated by alpha adrenergic agonists, an effect which was completely blocked by the alpha adrenergic antagonist phentolamine (1 X 10(-6) M) but not by prazosin (1 X 10(-6) M). The order of potency for the alpha adrenergic agonists in potentiating ADP-induced aggregation was clonidine greater than or equal to epinephrine greater than alpha-methylnorepinephrine greater than norepinephrine greater than phenylephrine greater than methoxamine. Epinephrine-induced platelet aggregation was blocked by phentolamine, yohimbine, dihydroergotamine, clonidine and lofexidine but not by phenoxybenzamine (1 X 10(-5) M). These findings suggest that: 1)clonidine and lofexidine are partial agonists and 2) that the alpha adrenergic receptor of the platelet is different from the classical postsynaptic alpha adrenergic receptor and more closely resembles presynaptic alpha adrenergic receptors.

Enhancement of methacholine-stimulated guanosine 3':5'-cyclic monophosphate formation in supersensitive guinea pig vasa deferentia

Decentralization of the guinea pig vas deferens resulted in supersensitivity of the contractile response to methacholine. Methacholine also elevated cyclic GMP to a greater extent in the decentralized vas deferens than in sham-operated controls. Decentralization did not alter basal cyclic AMP or cyclic GMP content. These observations are analogous to the enhanced responsiveness of cyclic AMP formation in supersensitive beta adrenergic systems.

Serial liver biopsy observations in hepatitis B antigen carriers by light and electron microscopy

Liver morphology and function were restudied after an interval of 1 1/2-2 years in 21 Chinese men with hepatitis B antigen (HBsAg). Antigenemia and mild liver histopathology disappeared in one individual who developed antibody to HBsAg(Anti-HBsAg). 20 subjects who were chronic carriers of HBsAg had mild histological abnormalities which were usually persistent and were more commonly lobular than portal. Particularly striking were focal necrosis, eosinophilic bodies, ground-glass cytoplasmic change, and, by electron microscopy, microtubular structures within cytoplasmic membranous cysternae. Interval development of chronic aggressive hepatitis was observed in only one subject. This study suggests that the great majority of HBsAg carriers have a good prognosis at least over a 1 1/2-2-year period, and that liver biopsy is most indicated in those with persistent liver function abnormalities.