Synergistic effects in the melting of DNA hydration shell: melting of the minor groove hydration spine in poly(dA).poly(dT) and its effect on base pair stability

We propose that water of hydration in contact with the double helix can exist in several states. One state, found in the narrow groove of poly(dA).poly(dT), should be considered as frozen to the helix, i.e., an integral part of the double helix. We find that this enhanced helix greatly effects the stability of that helix against base separation melting. Most water surrounding the helix is, however, melted or disassociated with respect to being an integral part of helix and plays a much less significant role in stabilizing the helix dynamically, although these water molecules play an important role in stabilizing the helix conformation statically. We study the temperature dependence of the melting of the hydration spine and find that narrow groove nonbonded interactions are necessary to stabilize the spine above room temperature and to show the broad transition observed experimentally. This calculation requires that synergistic effects of nonbonded interactions between DNA and its hydration shell affect the state of water-base atom hydrogen bonds. The attraction of waters into narrow groove tends to retain waters in the groove and compress or strain these hydrogen bonds.

[Glucocorticoid receptor-like antigen on neuronal plasma membrane of rat brain]

The existence of glucocorticoid receptor-like antigen on the synaptic plasma membrane (SPM) isolated from rat brain was demonstrated by ABC-gold technique. The SPM was first incubated with McAb 250 (a monoclonal antibody to the glucocorticoid receptor) and then biotinylated horse-anti-mouse IgG and streptavidin-gold (SAG) was added in proper order to the reacting system. The gold particles could be visualized on the external surface of neuronal processes under electron microscope. This is the first morphological demonstration of the existence of glucocorticoid receptor-like antigen on neuronal membranes.

Diterpenoid Alkaloids from Delphinium caeruleum

A new minor diterpenoid alkaloid, caeruline, was isolated from DELPHINIUM CAERULEUM Jacq. ex Camb. Its structure was elucidated as 1 on the basis of spectral evidence. Along with this new compound, three known diterpenoid alkaloids were also isolated from this plant and identified as tatsiensine, delcosine, and lycoctonine which had not been found in this herb previously.

Description of base motion and role of excitations in the melting of poly(dG).poly(dC)

We study the contribution of various vibrational modes to the melting of poly(dG).poly(dC). We find that the principal contribution comes from the H-bond breathing modes that have been observed in Raman scattering and that we have associated with helix melting. We show the softening of these modes on approach to melting in agreement with the observed behavior. We also describe the contribution to melting from base rotation modes that others have suggested are important in melting.

Energy flow considerations and thermal fluctuational opening of DNA base pairs at a replicating fork: unwinding consistent with observed replication rates

The effect of an open loop of various sizes on the thermal stability of the adjoining intact base pairs in a duplex DNA chain is studied in a lattice model of Poly(dG).Poly(dC). We find that for a Y-shaped fork configuration the thermal fluctuation at the fork is so enhanced that the life time of the adjoining base pair is much smaller than the 1 millisecond time scale associated with helicase separation of a base pair in some systems. Our analysis indicates that thermal fluctuational base pair opening may be of importance in facilitating the enzyme unwinding process during chain elongation of a replicating DNA. It is most likely that the thermal fluctuational opening of the base pair at the junction of a replicating fork is fast enough so that a DNA unwinding enzyme can encounter an unstacked base pair with reasonable probability. This conclusion can explain several experimental observations regarding the temporal relationship between ATP hydrolysis by accessory proteins and primer elongation by a holoenzyme complex in ssDNA. We also discuss a mechanism by which the energy associated with ATP hydrolysis may enhance the thermal driven base opening mechanism.

The formation and crystal structure of dihydronitidine and discussion of anticancer mechanism of nitidine cation

The paper reports the formation and crystal structure of dihydronitidine, expounds the reasons and conditions of easily formed oxynitidine, and discusses anticancer mechanism of nitidine (cation). The crystallographic parameters of dihydronitidine are: space group P(2)1/n, a = 12.54(1), b = 9.148(5), c = 14.748(8) A, beta = 92.12(6)degrees, Z = 4. 4108 independent reflections were collected within the range of 3 degrees < or = 2 theta < or = 54 degrees, of which 2137 intensity data with I > or = 3 sigma (I) were used in the structural determination. The crystal structure has been refined by full matrix least-square method to a final R of 0.050.

[Estimation of glucocorticoid membrane binding sites in synaptic plasma membrane isolated from porcine brain]

Using radioligand binding assay, we measured the Bmax and Kd of glucocorticoid membrane binding sites (GCMBS) in the synaptic plasma membranes isolated from different regions of porcine brain. The Kds of GCMBS in cerebrum, cerebellum, midbrain, thalamus, nuclei caudatus and hypothalamus are all around 200 nmol/L. The Bmax of GCMBS in the mentioned brain regions ranges from 218.98 fmol/mg to 486.95 fmol/mg protein.

The role of a minor groove spine of hydration in stabilizing poly(dA).poly(dT) against fluctuational interbase H-bond disruption in the premelting temperature regime

Experimental estimates of the premelting Adenine-Thymine base pair opening probability for some B-DNA sequences are two orders of magnitude smaller than those of other B-DNA sequences. The AT pairs in the sequence with smaller open probability seem to be those that have a well defined spine of hydration in the minor groove. We show that this spine of hydration can significantly enhance the thermal stability of the base pairs to which they are attached. The effect of this spine of hydration coupled with the possible stabilization effect contributed from neighboring GC pairs can explain the differences in the observed AT pair opening probability for different AT containing B-DNA sequences.

LPS-induced decrease of specific binding of 3H-dexamethasone to peritoneal macrophages of C57BL/6 mice

The effect of LPS on the specific binding of 3H-dexamethasone to peritoneal macrophages of C57BL/6 mice was studied. Scatchard plot of the specific binding of 3H-dexamethasone to the macrophages indicated that the Kd and Ro of glucocorticoid receptor was approximately 3.0 nM and 5,500 binding sites per cell, respectively. LPS, at the concentration of 10 ug/ml, caused a decrease in the specific binding of 3H-dexamethasone to macrophages after it interacted with the macrophages for different times. Con A, a mitogen for lymphocytes, did not significantly cause a decrease of glucocorticoid receptor in the macrophages at the concentration of 10 ug/ml. Our results indicated that the effect of LPS on the specific binding of 3H-dexamethasone to macrophages was different from the effect of Con A, which might be significant in the interaction of immune system and neuroendocrine system.

[Biphenotypic acute leukemia. Clinical, morphological, cytochemical and immunophenotypic studies]

The blast cells from 2 cases of acute leukemic patients classified as M1 type by FAB criterion simultaneously expressed lymphoid markers such as SmIgG, CD19, CD20, DR, PAS in case 1 and CD9, CD10, DR, PAS in case 2. The blast cells of these two cases also expressed CD38 antigen. The data on phenotype and cytochemistry in these two cases fulfil the criteria of biphenotypic acute leukemia proposed by Dr. Gale. The problems in diagnosis, treatment and prognosis of this kind of mixed acute leukemia were discussed.

Premelting thermal fluctuational interbase hydrogen-bond disrupted states of a B-DNA guanine-cytosine base pair: significance for amino and imino proton exchange

Modified self-consistent phonon theory when applied to the DNA double helix indicates the existence of fairly long-lived states in which single interbase H bonds are disrupted. One can then postulate a number of situations in which particular disrupted H bonds can enhance particular proton exchange. In this paper we postulate a number of such partially open states for a B-conformation GC base pair and calculate the probability of each of these states for a B-conformation poly(dG).poly(dC). We compare these probabilities to those probabilities needed to explain various observed proton exchange rates. We propose that, for a GC base pair in B conformation, there are two amino proton exchangeable states--a cytosine amino proton exchangeable state and a guanine amino proton exchangeable state; both require the disruption of only the corresponding interbase H bond. The imino proton exchange, however, requires the disruption of all three interbase H bonds and this defines a third open state. Our calculated probabilities for a GC base pair in these three states are in fair agreement with available experimental estimates from measurements of amino and imino proton exchange.

Determination of diclofop-methyl and diclofop residues in soil and crops by gas chromatography

A method is described for the determination of residues of the herbicide diclofop-methyl and its metabolite, diclofop, in soil and crops. The residues were extracted with acetone-light petroleum and extracts were concentrated (diclofop was derivatized to its pentafluorobenzyl derivative), and then the products were purified on a chromatographic column containing alumina, silver-alumina and Florisil. Finally, they were determined by gas chromatography using an electron-capture detector. The detection limits of diclofop-methyl and diclofop were between 0.01 and 0.05 mg/kg. The average recoveries were 76.4-97.2% and 72.8-105.2%, respectively, making the method suitable for statutory residue testing purposes.

Diterpenoid Alkaloids from Aconitum vilmorrianum

A new diterpenoid alkaloid, vilmorrianone ( 1), has been isolated from ACONITUM VILMORRIANUM Kom. The structure was elucidated by spectral methods and confirmed by X-ray diffraction analysis. Also four known diterpenoid alkaloids have been isolated and identified.

[The rapid effect of the iontophoretically applied cortisol on unit activity of neurons in three brain areas in rats]

The present study was undertaken to analyze whether the glucocorticoid (GC) effect was region specific in the brain. Na-cortisol-succinate (HC) was applied iontophoretically to cerebral cortex (CX), hippocampus (HPC) and PVN respectively and the effect on unit discharge rate in these three brain areas were compared. In cerebral cortex, the percentage of responsive neurons was only 8% (4/50), which was significantly lower than those in HPC (10/36, 27.8%) and PVN (9/35, 25.7%). The difference in the occurrence is paralleled with the known distribution of traditional GC cytosolic receptors in the brain. In all the three brain areas studied the main response to GC was inhibitory and the latencies of the responses were 9.6 +/- 6.5, 22.7 +/- 24.0, and 14.5 +/- 11.5 s and the durations of the after-effect were 74.8 +/- 66.5 (n = 4), 24.2 +/- 14.5 (n = 6) and 21.0 +/- 10.5 s (n = 9) respectively. The shortness of the latencies once again suggests that the mechanism involved is non-genomic. It is interest to note that in some HPC neurons the after-effect lasted for 1758 +/- 2148 s (n = 4). The results show that the rapid effect of GC on neurons is different in the three brain areas studied in regarding to the occurrence of responsive neurons and the duration of the after-effects.

[Role of the nucleus vestibularis medialis in vestibulo-sympathetic response in rats]

Experiments were performed on rats anesthetized with alpha-chloralose and urethane. The sympathetic response evoked by stimulation of the vestibular nerve root at its entrance to brain-stem was recorded from the ipsi-splanchnic nerve. Electrical stimulation of the vestibular nerve elecited a distinct averaged response in the ipsilateral splanchnic nerve. The mean latency of response was 45.8 +/- 6.98 ms with a duration of 55.21 +/- 5.35 ms. With increasing the strength of stimulation, the amplitude of response was increased, but the latency was unchanged. By monitoring the lamellar field potentials in NVM and choosing the locus of phase-reversal of field potential as the stimulating site, an averaged response in ipsi-splanchnic nerve with a latency of 32 ms was obtained, while the recorded splanchnic nerve response had a latency of 43 ms, when the vestibular nerve was stimulated. After electrolytic lesion of the rostral part of ipsi-NVM, the vestibulo-sympathetic response was significantly reduced. When a second lesion was placed in the caudal NVM, the response disappeared. Lesion in Deiters' nucleus had no effect on the vestibulo-sympathetic response. The results suggest that NVM is a critical relay station in vestibulo-sympathetic response recorded in the splanchnic nerve.

Premelting thermal fluctuational base pair opening probability of poly(dA).poly(dT) as predicted by the modified self-consistent phonon theory

We employ a mean field, modified, self-consistent phonon theory to evaluate the single base-pair opening rate and the probability of a base pair in the amino proton exchangeable state for the homopolymer poly(dA).poly(dT) at temperatures below the helix-coil transition region. Our calculated premelting single base-pair opening probabilities are in general agreement with several available experimental estimates from imino proton exchange and formaldehyde-induced DNA melting measurements. These calculated opening probabilities, however, are in disagreement with the prediction of the helix-coil transition theory. Possible reasons for the differences are discussed, especially the possible different definition of a meaningful open state in the premelting region. The premelting open state of the modified self-consistent phonon approximation theory seems to be appropriate to describe a solvent-accessible open configuration that is sufficient to facilitate important chemical reactions such as imino proton exchange and formaldehyde reaction with the bases. This can be compared with the completely unstacked open state of the helix-coil transition theory originally defined in the helix-coil transition region. We propose that the amino proton exchangeable state is different from the open state associated with melting and only involves the breaking of the amino interbase H bond. The agreement between the calculated and experimentally estimated probability of a base pair in the amino proton exchangeable state seems to support this hypothesis.

The biological function of rabbit blastocyst peptides (RBPs)

The inhibitory effect of rabbit blastocystic peptides (RBPs) on lymphocyte transformation was studied by the method of measuring the incorporation of 3H-thymidine into DNA. The results indicated that RBPs inhibited PHA-stimulated rat and human lymphocyte transformation in vitro. In the concentration ranging from 40 to 200 micrograms/2.5 ml, the inhibition was dose-dependent. No obvious inhibitory action was found with hCG (16-128) IU/2.5 ml), progesterone (250 ng-1 microgram/2.5 ml) and pregnant rabbit serum. It was further demonstrated that RBPs at a higher dosage (200 micrograms/ml) was inhibitory to PGF2 alpha secretion. On the other hand, the 3H-leucine incorporation of rabbit endometrium was enhanced by these peptides, and this action could be blocked by the addition of actidine.

An electrophysiological study on the membrane receptor-mediated action of glucocorticoids in mammalian neurons

The action of glucocorticoids (GC) on neuronal cell membrane was studied in isolated and superfused guinea pig coeliac ganglia by the intracellular recording technique. Cortisol succinate (F) hyperpolarized the membrane potential of 47 of 179 cells and changed the cell's input resistance with a latency of less than 2 min in vitro. The effect persisted under low Ca2+/high Mg2+ superfusing condition and could be blocked by RU 38486, a competitive antagonist of GC cytosolic receptor. Cortisol-21-bovine albumin conjugant exhibited the same effect. Corticosterone (B) elicited hyperpolarization in another 15 of 83 cells, but dexamethasone (Dex) did not. Dex, however, depolarized 2 of 18 cells. Aldosterone, cholesterol and vehicle (ethyl alcohol) caused no detectable change in membrane potential. In vivo studies by iontophoretic application of steroids to hypothalamic paraventricular (PVN) neurons showed that F inhibited the unit discharges in 68 of 97 PVN neurons, and the effect could be antagonized by RU 38486. Dex excited 30 of 100 neurons. Estradiol (E) also inhibited the discharges, but this inhibition was not antagonized by RU 38486. The effect of GC on PVN neurons was also examined in hypothalamic slices including the paraventricular nucleus. B inhibited 28 of 104 units and excited 7 of 104 cells, and both effects could be antagonized by RU 38486. The threshold of inhibitory response was about 10(-7) M, which is close to the physiological level of the hormone in plasma. The results suggest that GC can act non-genomically and specifically through its membrane receptor on the neuronal surface, and that there might be a chemical similarity between the membrane receptor and the traditional cytosolic GC receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

[Antitumor activity of 4-(4''-(2'',2'',6'',6''-tetramethyl-1''-piperidinyoxy)amino)-4'- demethyl epipodophyllotoxin in vitro]

The antitumor activity of a new podophyllotoxin spin-labeled derivative, 4-(4''-(2'',2'',6'',6''-tetramethyl-1''-+piperidinyoxy)amino)-4'- demethylepipodophyllotoxin (GP-7) First synthesized by us, was studied in vitro. It was found that the proliferation of SGC-7901 cells was markedly inhibited by GP-7 depending the concentration and exposure time. At concentration of 0.04-100 mg/L, the inhibition rates were 15.5-92.6% ID50 was 0.42 mg/L. After exposure to GP-7 greater than 0.5 mg/L for 24, 48, 72 and 96 h, the inhibition rates of cells were 25.1, 49.0, 71.4 and 84.9% respectively. The dose-response curve of GP-7 on SGC-7901 cell was similar to that of etoposide (VP-16). The colony formation of SGC-7901 cell was also inhibited by GP-7 in a concentration dependent fashion with ID50 1.63 mg/L. At concentrations of 0.1-0.5 mg/L, the inhibitory effects were stronger than that of VP-16. GP-7 decreased the mitotic index (MI) of SGC-7901 cell and had no effect on microtubule assembly and disassembly in vitro, which suggested that GP-7 did not act on M phase.

[Effects of corticosterone on spontaneous discharges of rat hypothalamic paraventricular neurons in vitro]

Experiments were performed to investigate the effects of corticosterone on electrical activities of paraventricular neurons in rat hypothalamic slices. In unstimulated conditions, most of the neurons had either a slow irregular (48.1%) or fast continuous pattern (42.5%) of discharge. Only a small portion (9.4%) of the cells shows phasic activity. During perfusion of the slices with corticosterone (10(-7), 10(-6) mol/L), 25 out of 104 paraventricular neurons were profoundly inhibited with a short latency, 8 neurons were excited and the remaining cells showed no response. The response, the magnitude of the cells which depended upon the concentration of corticosterone, could be reversed by concomitant application of RU38486 (10(-7), 10(-6) mol/L), a competitive antagonist of glucocorticoid's cytosolic receptor. These results provide further evidence that corticosterone has rapid effects on rat hypothalamic paraventricular neurons, and suggests the existence of membrane receptors for glucocorticoid in paraventricular neurons.

[Effects of noradrenaline and acetylcholine on electric activity of paraventricular neurons of rat hypothalamic slices]

The effects of noradrenaline (NA) and acetylcholine (ACh) on 90 paraventricular neurons from 31 hypothalamic slices prepared from rat were observed. After perfusing the brain slices with NA (10(-6) mol/L, 3 min), discharge rate of 14/73 (17%) nonphasic and 7/12 (58.3%) phasic neurons was significantly increased, while that of 10/73 (12%) nonphasic and 2/12 (16.6%) phasic neurons was significantly decreased, even ceased. 50/73 (64%) of the nonphasic and 3/12 (25%) of the phasic neurons were non-responsive. The effects of NA on the nonphasic neurons were completely blocked by alpha receptor blocker phentolamine. The effects of NA on phasic neurons were partly blocked by phentolamine or propranolol (beta receptor blocker). After perfusing hypothalamic slices with ACh (10(-7) mol/L, 3 min), the firing rate of 15/73 (19%) nonphasic and 6/12 (50%) phasic neurons was increased, while that of 9/73 (11%) nonphasic and 2/12 (16.6%) phasic neurons was decreased. 54/73 (69%) nonphasic and 4/12 (33.3%) phasic neurons were non-responsive. The effect of ACh on the neurons could be reversed by atropine. The effect of scopolamine (M blocker) is similar to that of atropine. The experimental results suggest that the excitatory or inhibitory effect of NA or ACh on paraventricular neurons has mediated respectively by alpha, beta or M receptors.

[Effects of serotonin on the electric activity of paraventricular neurons of in vitro rat hypothalamic slices]

Hypothalamic slices were prepared with a vibratome. The spontaneous discharge of 46 paraventricular neurons was recorded by glass microelectrode from 20 such slices, and effects of serotonin on spontaneous discharge were observed. After perfusing the brain slices with artificial cerebro-spinal fluid containing serotonin (10(-6) mol/L) for 3 min, discharge rate of 16 units is significantly increased with latency 1.21 +/- 1.21 (mean + SD) min, this response is blocked by serotonin antagonist, cyproheptadine. The discharges of 3 units were decreased, but 25 units non-responsive. The experimental results suggest that about 1/3 of paraventricular neurons can be activated by topical application of serotonin via the activation of 5-HT receptors.

[Responses of midbrain central gray neurons activated by hypothalamic paraventricular nucleus (PVH) stimulation to somatic afferent input in rats]

Extracellular single unit recordings were made from 318 neurons within the midbrain central gray in urethane-anesthetized rats. Following electrical stimulation of the hypothalamic paraventricular nucleus (PVH), 10% of the units in central gray (CG) were antidromically activated, while 7.5% were orthodromically excited, and 0.7% were orthodromically inhibited. Among these antidromically activated neurons, 28 units were further examined for their responsiveness to peripheral somatic sensory stimulation. Strong electrical stimulation of contralateral sciatic and tibial nerve, and tail pinching produced excitation in 12 and inhibition in 2 units. No significant responses to non-noxious stimulation were observed in these units. Of the 26 orthodromically activated units, 14 were excited and 4 inhibited by the sciatic nerve stimulation or tail pinching. These results support the hypothesis that CG is one of the relay stations in the afferent pathway of somatic sensory especially, noxious, information transmitting to the PVH, and that the PVH may play a role in central pain control or modulation via their descending influence on CG unit.

[Rubinstein-Taybi syndrome--a report of three cases]

The main features of Rubinstein-Taybi syndrome include special facial appearance, broad thumbs, great toes and mental retardation. This syndrome presents many organogenetic and systemic deformities and various congenital ocular abnormalities, such as epicanthus, antimogoloid palpebral fissures, highly arched eyebrows, long eyelashes, obstruction of nasolacrimal ducts, strabismus and iris coloboma. In this paper we report three children with Rubinstein-Taybi syndrome with the above systemic and ocular clinical findings, and think that the lacrimal abnormality should not be overlooked in this syndrome. We brief discuss the genetics of this syndrome and suggest that the search for minimal chromosomal defects by high resolution technique might be useful for etiologic and genetic research.

[Iris nodules, ocular findings and blood grouping in neurofibromatosis]

Through the analyses of 22 cases of neurofibromatosis (NF) patient ranging from 3 months to 63 yrs. old. We found that 4 cases had bilateral hearing loss and 2 of them were excluded from acoustic neuroma. The ocular appearance showed lid neurofibroma in 12 cases, orbital bone abnormalities in 4 cases, iris nodules in 20 cases (90%), congenital glaucoma (4 eyes) in 3 cases which showed abnormal gonioscopy in 3 eyes, lens opacity in 2 cases, mild and moderate myopia in 8 eyes, and high myopia in 7 eyes, occupying 16% of the total. 11 cases belong to 5 pedigrees showing autosomal dominant inheritance. The ABO and MN blood grouping of the NF cases and families in the pedigree showed that NF was more related to ABO than MN blood group. The ocular appearance, especially the shape and number of iris nodules in relation to age and diagnosis is discussed. The significance of 1 case of retinitis pigmentosa, 7 cases of high myopia in relation with NF should be further studied.

[Rapid membrane effects of adrenocorticoids on celiac ganglion cells of guinea pig]

Intracellular recording technique was used to determine the effects of corticosterone, dexamethasone, aldosterone and cholesterol on the resting membrane potentials and membrane resistance of cells in isolated celiac ganglion of guinea pigs. Hyperpolarization was elicited by corticosterone in 15 out of 83 cells, but was not caused by dexamethasone, which depolarized the membrane in 2 out of 18 cells. In addition, depolarization was also elicited by corticosterone in 2 out of 83 cells. Aldosterone and cholesterol caused no detectable changes of membrane potential and membrane resistance. It is suggested that the membrane effects of adrenocorticoids, which obviously could not be explained by traditional genomic mechanism for their short latency, may indicate the existence of membrane receptors for adrenocorticoids in celiac ganglion neurons of guinea pigs.

The ocular findings in glucose-6-phosphate dehydrogenase deficiency

57 cases with G6PD deficiency and 62 with normal G6PD activities as controls in Chonghua County, Guangdong Province were examined in the respects of visual acuity, color vision, corneal sensitivity, lens, vitreous and fundus. The results showed that the incidences of congenital lenticular opacities and congenital color blindness in G6PD deficiency group were higher than those in the controls. However, there were no findings such as pale conjunctiva, sallow sclera, pallor papillae and macular edema, which could be seen frequently in patients with favism. The hemoglobin values of all the cases were within normal range, which indicated that the subjects with G6PD deficiency usually didn't manifest hemolysis but only had a hereditary susceptibility, and the ocular findings in favism might result from hemolytic anemia, tissue anoxia and unknown toxic substances from vicia faba.

Visual field versus visual evoked potentials in maculopathies and optic neuropathies

Both kinetic and static visual fields and visual evoked potential (VEP) were tested in 52 patients with maculopathies and in 29 patients with axial optic neuropathies. The results of central static quantitative perimetry and pattern reversal VEP were compared. The amplitude and latency of P100 were correlated with the total loss of central visual threshold in maculopathies. While the P100 latency was not correlated with the total loss of the central visual threshold in neuropathies, their latency delay was more obvious than that in maculopathies. We arrived at the conclusion that both VEP and visual field are necessary for assessing function loss and reflecting different pathological mechanisms in macular and optic nerve diseases.

Points that merit consideration in the diagnosis of retinoblastoma

According to the clinical appearances and the characteristics of the onset of 86 Rb cases, some points in the diagnosis merit consideration: 1) Since the average symptomatic age was 21.75 months and the mean diagnostic age was 24.32 months, children under 3 years with leukocoria should be carefully examined, while adult Rb should not be neglected. 2) The primary symptom of Rb is mostly leukocoria, but Rb eyes without any symptoms or leukocoria (26 out of 105 eyes in our groups) might also be encountered. 3) 4 out of the 86 cases were retinocytoma which is supposed to be a type of Rb degeneration or benign Rb. 4) Attention should be paid to abnormalities and second primary tumors in Rb patients. 5) The pedigree investigations, twin method and laboratory studies in Rb such as chromosome analysis, EsD, LDH measurement and RFLP technique are useful in the prenatal diagnosis, early diagnosis and the diagnosis of the carriers.

The electroretinogram in Marfan's syndrome

Marfan's syndrome (MS) is an inherited disease of connective tissue. The most characteristic ocular change is dislocation of lens, but myopia and retinal detachment also can occur. We examined 11 MS patients using electroretinography (ERG). 6 cases showed normal ERG. 5 cases had abnormal ERG. One had retinal detachment. 3 had myopia and 1 case suffered from secondary glaucoma. The defects of visual function were shown by electrophysiological test in those MS patients.

Ocular survey of deaf-mute children

Through routine ocular examination of 279 Deaf-mute students in Lie De School in Guangzhou in 1988 by visual chart, Yu Zi Ping Pseudoisochromatic plate, portable slit lamp and direct ophthalmoscope, 100 persons (35.8%) were found to have ocular defects in one or both eyes. The incidence of ocular defects was higher than that of the normal populations. Among the ocular abnormalities, fundus defects occupied 28.6%, error of refraction, 17.9%. 17.9% of the eyes had the vision lower than 1.0 and the error of refraction was the main cause. Cases of hereditary syndromes were found: Usher syndrome, 2 cases; Goldenhar syndromes, 2 cases (brother and sister); Waardenburg syndrome, 1 case; von Recklinghausen's syndrome, 1 case. In comparing with the other articles, the ocular defect, visual disturbance, error of refraction, way of examination as well as types and characteristics of some syndromes were briefly discussed. The importance of special examinations for diagnosis, early correction of refractive error, avoidance of consanguineal marriage among deaf-mutes were emphasized.

Lymphocyte chromosome survey in 80 patients with retinoblastoma

Cytogenetic analysis of eight cases of retinoblastoma patients was carried out to determine the occurrence of chromosome aberrations and to identify consistently associated clinical abnormalities. Among the 80 cases, 55 cases were unilateral, 25 cases were bilateral, seventy patients had a positive family history of Rb in 10 families. Normal chromosomes were found in 70 patients. Ten patients showed abnormal karyotypes: two cases of 13q deletion, one case of mosaicism of 13q deletion, one case of translocation between chromosomes 13 and 15 with the interstitial deletion of 13q, one case of 47, xxy, three cases of pericentric inversion of heteromorphic region of chromosome 9, two cases of pericentric inversion of chromosome Y. The patient who had the translocation between 13 and 5 with 13q deletion was found to have the characteristic midfacial appearance associated with 13q-deletion syndrome.

Membrane receptor-mediated electrophysiological effects of glucocorticoid on mammalian neurons

The nongenomic membrane receptor-mediated mechanism is an important but not fully explored facet in the action of steroid hormones. In the present study the action of glucocorticoid on nerve cell membrane was studied using isolated and superfused coeliac ganglion preparations by an intracellular electrophysiological technique. Glucocorticoid hyperpolarized the membrane potential of guinea pig ganglion neurons in vitro with a latency of less than 2 min. The effect persisted under low Ca2+/high Mg2+ superfusion conditions and could be abolished by RU38486, a competitive antagonist of glucocorticoid cytosolic receptor. Bovine albumin glucocorticoid conjugant exhibited the same effect. In neurons with spontaneous discharges the glucocorticoid-caused hyperpolarization of membrane potential decreased or eliminated the discharges. The results strongly suggest that glucocorticoid can act nongenomically through its neuronal membrane receptor. The steroid-induced hyperpolarization was accompanied by a change in the input resistance of the cell, indicating an involvement of some kind(s) of ion channel(s) in the action of glucocorticoid.

Tea and premenstrual syndrome in the People's Republic of China

We evaluated the hypothesis that tea consumption causes premenstrual syndrome by studying 188 nursing students and tea factory workers in the People's Republic of China via questionnaires distributed in classes (nursing students) or during routine physical examinations (tea factory workers). Analysis of the data revealed that tea consumption is strongly related to the prevalence of premenstrual syndrome and that the effects are dose-dependent.

Anticancer drugs. II. Synthesis and biological evaluation of spin labeled derivatives of podophyllotoxin

The spin labeled derivatives of podophyllotoxin, 4-[4''-(2'',2'',6'',6''-tetramethyl-l''-piperidinyloxy)amino] -4'-demethylepipodophyllotoxin(GP-7,3) and N-podophyllic acid-N''-[4-(2,2,6,6-tetramethyl-l-piperidinyloxy)] thiosemicarbazide(GP-4,5) were synthesized and tested for their anticancer activity against the mouse solid tumors S180 and HepA in vivo, and the mouse lymphocytic leukemia L1210 and human stomach carcinoma SGC-7901 cells in vitro. At equitoxic concentrations, the anticancer activity of GP-7(3) was found to be similar to that of the clinically used VP-16(2). The toxicity of GP-7(3) (LD50231.2 mg/Kg) is 3.3 times lower than that of VP-16 (LD50 69.5 mg/Kg). GP-7(3) exhibits low subchronic toxicity. The total chemical yield of GP-7 (26%) is 4 times higher than that of VP-16 (6%) (based on podophyllotoxin). Therefore, GP-7(3) seems to be a promising new entry into the podophyllotoxin class of anticancer drugs.