Wounding Nicotiana tabacum Leaves Causes a Decline in Endogenous Indole-3-Acetic Acid

We have previously observed that auxin can act as a repressor of the wound-inducible activation of a chimeric potato proteinase inhibitor II-CAT chimeric gene (pin2-CAT) in transgenic tobacco (Nicotiana tobacum) callus and in whole plants. Therefore, this study was designed to examine endogenous levels of indole-3-acetic acid (IAA) in plant tissues both before and after wounding. Endogenous IAA was measured in whole plant tissues by gas chromatography-mass spectrometry using an isotope dilution technique. (13)C-Labeled IAA was used as an internal standard. The endogenous levels of IAA declined two- to threefold within 6 hours after a wound. The kinetics of auxin decline are consistent with the kinetics of activation of the pin2-CAT construction in the foliage of transgenic tobacco.

[Effects of ginseng on hepatocellular carcinoma in rats induced by diethylnitrosamine--a further study]

The curative effects of Panax ginseng on hepatocellular carcinoma (HCC) in rats induced by diethylnitrosamine (DEN) were further studied. The size of cancerous nodes was quantitatively measured by image analysis instrument. The hepatocellular hyperplastic foci were quantitatively analysed with gamma-GT stain under microspectrophotometer. Pathological changes of hepatocytes were observed under light and electron microscope. The results of the investigation indicated that ginseng had significant inhibitory effect on HCC in rats induced by DEN and prolonged the survival time of the rats with HCC. The mechanism of inhibition of the development of HCC by ginseng was also preliminarily approached.

[Analysis of Trace elements in processed products of Pinellia ternata (Thunb.) Breit]

This article reports the detecting result of trace elements in processed products of Pinellia ternata and of the contents of As, Hg, Pb in the products processed with sulfur. The result shows that all the processing procedures are necessary and safe.

Three New Dibenzocyclooctadiene Lignans from Kadsura longipedunculata

Five dibenzocyclooctadiene lignans were isolated from the stems of KADSURA LONGIPEDUNCULATA collected in Guangxi province. Three of them are new compounds, named benzoyl-, isovaleroyl-, and isobutyroylbinankadsurin A. Binankadsurin A was isolated from nature for the first time. The absolute configuration of isovaleroyloxokadsurane, a spirobenzofuranoid lignan from K. COCCINEA, was confirmed by chemical correlation with isovaleroylbinankadsurin A.

Elastography: a quantitative method for imaging the elasticity of biological tissues

We describe a new method for quantitative imaging of strain and elastic modulus distributions in soft tissues. The method is based on external tissue compression, with subsequent computation of the strain profile along the transducer axis, which is derived from cross-correlation analysis of pre- and post-compression A-line pairs. The strain profile can then be converted to an elastic modulus profile by measuring the stresses applied by the compressing device and applying certain corrections for the nonuniform stress field. We report initial results of several phantom and excised animal tissue experiments which demonstrate the ability of this technique to quantitatively image strain and elastic modulus distributions with good resolution, sensitivity and with diminished speckle. We discuss several potential clinical uses of this technique.

Elastography: a quantitative method for imaging the elasticity of biological tissues

We describe a new method for quantitative imaging of strain and elastic modulus distributions in soft tissues. The method is based on external tissue compression, with subsequent computation of the strain profile along the transducer axis, which is derived from cross-correlation analysis of pre- and post-compression A-line pairs. The strain profile can then be converted to an elastic modulus profile by measuring the stresses applied by the compressing device and applying certain corrections for the nonuniform stress field. We report initial results of several phantom and excised animal tissue experiments which demonstrate the ability of this technique to quantitatively image strain and elastic modulus distributions with good resolution, sensitivity and with diminished speckle. We discuss several potential clinical uses of this technique.

[Anti-tumor effect of Cetraria laevigata Rassad. polysaccharides]

The anti-tumor effect of Cetraria laevigata polysaccharides has been investigated in mice using sarcoma 180; Ehrlich ascitic tumor, cervical carcinoma u-14 and leukemia L7217. The results show that Cetraria laevigata polysaccharides may inhibit the growth of sarcoma 180, Ehrlich ascitic tumor and cervical carcinoma u-14 in mice at a dose of 200mg/kg ip (1/5 LD50). However, the survival time of leukemia L7217 wasn't prolonged. The reticuloendothelial system phagocytic function in mice was increased at ip doses of 50 mg/kg and 100 mg/kg (1/10 and 1/20 LD50).

Single frequency operation of an injection-seeded Nd:YAG laser in high noise and vibration environments

We report on an experimental demonstration of single frequency operation of an injection-seeded Nd:YAG laser in a high noise and vibration environment.

[An experimental study on hepatic arterial embolization with 131I-MMC-GM]

We designed a new gelatin microsphere (GM, 65 micron in diameter), which could combine with mitomycin C and 131I. The test in vitro showed that the GM had excellent drug release effect. Hepatic arterial embolization was carried out in 6 dogs with 131I-MMC-GM. The dogs survived from 4 to 28 days before being killed. Scintigraphy indicated that high radioactivity was concentrated in the liver, but was very low in the blood and thyroid. Pathologic study found that the GM was trapped in hepatic arterioles. The GM was eliminated by foreign body giant cells and the lumen of arterioles was occupied by granulations 14-28 days after operation. 131I-MMC-GM is a multiple anticancer agent which can exert triple action of targeting chemotherapy, internal radiotherapy and arterial embolization.

[Germination temperature of seeds of medicinal plants]

According to our experiments in the last ten years, the germination behaviour of the seeds of medicinal plants may be classified into five types by different temperature requirements for germination: (1) low temperature type; (2) middle temperature type; (3) high temperature type; (4) alternating temperature type; (5) wide ranging temperature type. This classification is helpful for cultivators to determine the time of sowing.

[Toxic principles of Oxytropis glabra DC]

Eight alkaloids were isolated from Oxytropis glabra and identified as anagirine, thermopsine, N-methylcytisine, sparteine, baptifoline, adenine, dictamnine and ethyl allophanate respectively by spectral analysis and physicochemical methods. All these alkaloids were isolated from this genus for the first time and ethyl allophanate was found in nature for the first time.

[Relationship between the bacterial resistance induced by rifamdin and the RNA polymerase]

The results of our experiment in vitro showed that the activity of standard RNA polymerase decreased while the concentration of RFD and RFP increased, indicating that the target site of action of RFD was similar to that of RFP on RNA polymerase. Incorporation of [3H] UR into the RNA of sensitive cells of S. sureus and E. coli was strongly inhibited by RFD, but RFD did not affect the resistant strains. In purified DNA-dependent RNA polymerase of sensitive and resistant strains, the enzyme activity of sensitive E. coli a S. aureus strains was inhibited by RFD, but RFD did not inhibit that of the resistant strains (except the P. vulgaris). It can be concluded that a decreased susceptibility of RNA polymerase to RFD as well as a decreased permeability of bacterial envelope may induce bacterial resistance to the drug.

[Studies on monoclonal antibody against recombinant human granulocyte colony-stimulating factor]

Three hybridomas producing monoclonal antibodies (McAb) against recombinant human granulocyte colony-stimulating factor (rhG-CSF) have been established by fusing mouse myeloma SP 2/0 cells with spleen cells from a BALB/c mouse immunized with rhG-CSF. Ascites was produced from BALB/c mice by injecting substrain 2D4-B4 hybridoma cells intraperitoneally. The antibody was purified either by the caprylic acid-ammonium sulfate method or by euglobulin precipitation. The caprylic acid-ammonium sulfate method was superior to euglobulin precipitation in terms of purification and recovery of IgG. The 2D4-B4 McAb was determined to belong to the IgG3 subclass with a molecular weight of about 172,400 It was proved by Western Blot to react specifically with rhG-CSF. The stability and affinity of the McAb were analyzed as well. The potential clinical and experimental applications of this McAb are discussed.

[Pharmacological variations of Panax ginseng C.A. Meyer during processing]

Based on a comparative study on the documentation concerning the pharmacological actions of the red ginseng and the white ginseng, it has been found out that in promoting blood circulation, anti-thrombosis, fibrin dissolving activity, phagocytosis of reticular endothelium and anti-decrepit function on the red ginseng is stronger than the white one.

A Chinese female postnuptial leaving home model--a procedure for analyzing main parameters alpha and beta in the setting up, testing and estimation of the model

"The first section of this article...sets up a model for leaving home after marriage that is suited to China's situation. The second section performs a statistical test and verification of the formulated model for leaving home after marriage. The third section...proposes a method for analyzing the main parameters...in the model...." The model is set up along the lines of the Brass-Gompertz relational fertility model.

Analysis of DNA restriction fragments greater than 5.7 Mb in size from the centromeric region of human chromosomes

Pulsed electrophoresis was used to study the organization of the human centromeric region. Genomic DNA was digested with rare-cutting enzymes. DNA fragments from 0.2 to greater than 5.7 Mb were separated by electrophoresis and hybridized with alphoid and simple DNA repeats. Rare-cutting enzymes (Mlu I, Nar I, Not I, Nru I, Sal I, Sfi I, Sst II) demonstrated fewer restriction sites at centromeric regions than elsewhere in the genome. The enzyme Not I had the fewest restriction sites at centromeric regions. As much as 70% of these sequences from the centromeric region are present in Not I DNA fragments greater than 5.7 and estimated to be as large as 10 Mb in size. Other repetitive sequences such as short interspersed repeated segments (SINEs), long interspersed repeated segments (LINEs), ribosomal DNA, and mini-satellite DNA that are not enriched at the centromeric region, are not enriched in Not I fragments of greater than 5.7 Mb in size.

[Survey of Bacillus thuringiensis and Bacillus sphaericus from soils of four provinces of China and their principal biological properties]

A number of isolates of Bacillus thuringiensis and Bacillus sphaericus were obtained from soils of Southwestern Area and Shaanxi Province of China. Among isolates of B. thuringiensis were under 13 sorts of serotype in total of 23 sorts of B. thuringiensis and about 20% of auto-agglutinate strains. Rules of ecologic distribution of two sorts of bacteria were analysed. Toxicities on six species of insects, morphology and crystal proteins of B. thuringiensis, as well as toxicities, morphology and crystal proteins of B. sphaericus, were investigated. 22 strains of more efficient of B. thuringiensis and 2 strains of more efficient of B. sphaericus were obtained. It was shown that B. thuringiensis is actually soil microorganism, and resource of B. thuringiensis is much fruitful in Southwestern Area of China.

[Long-term follow-up study on surgical treatment of cryptorchism in children]

This article reports 1010 cases of cryptorchism managed by surgical treatment during the recent 30 years. The age range of the patients was from 4 months to 14 years. This series includes 342 left side, 456 right side and 212 bilateral lesions. Orchiopexy was performed on 1145 testes with three different forms of fixation excluding 33 cases of absent testis and 44 cases of testicular agenesis. Four hundred and fifty-five cases (527 testes) were available for follow-up study. Four hundred and seventeen testes (79.1%) descended into the scrotum, while 237 testes (45%) manifested atrophy. The results showed that orchiopexy into sub-dartos pouch and surgical treatment during 1 to 2 years of age can give the best results. In this article is discussed the age for surgical treatment, procedure of testicular fixation, surgical treatment of cryptorchism with impalpable testes, prevention of testicular atrophy etc.

Mutation of lysine 405 to serine in the parvovirus H-1 NS1 abolishes its functions for viral DNA replication, late promoter trans activation, and cytotoxicity

A consensus sequence in parvovirus nonstructural protein NS1 has been predicted to be an ATP-binding domain associated with an ATPase and a DNA helicase activity. To investigate the function of NS1 in viral gene expression, a site-directed mutagenesis converting NS1 lysine 405 to serine in parvovirus H-1 was carried out by the polymerase chain reaction. As shown previously, a parvovirus genome containing a deleted NS1 gene was excised from a bacterial plasmid and replicated when a wild-type NS1 gene was provided in trans but failed to be excised and replicate when the mutant NS1 gene was supplied. Interestingly, the serine 405 mutation totally lost the activity of trans activation on the virus late promoter (P38) in a chloramphenicol acetyltransferase (CAT) assay and it lost evidence for cytotoxicity in two tumor cell lines (HeLa Gey and NB324K). The serine 405 NS1 protein was translocated normally to the nucleus. These results suggest that the NS1 lysine 405 of H-1 in its putative purine nucleotide-binding site is essential for viral DNA replication and that this domain may be involved in the regulation of the P38 promoter by an unknown mechanism. The loss of NS1 cytotoxicity on tumor cells suggests that NS1 expression is the major cause of cell killing by parvoviruses, which may facilitate further study of the mechanism of oncosuppression by parvoviruses.

Molecular recognition in the minor groove of the DNA helix. Studies on the synthesis of oligonucleotides and polynucleotides containing 3-deaza-2'-deoxyadenosine. Interaction of the oligonucleotides with the restriction endonuclease EcoRV

An improved procedure for the preparation of 3-deaza-2'-deoxyadenosine (d3CA) is described which is suitable for the synthesis of gram quantities of this analogue. Using phosphoramidite chemistry d3CA has been incorporated into the Eco RV restiction endonuclease recognition sequence (underlined) present in the self-complementary dodecamer d(GACGATATCGTC). The modified oligonucleotides have been thoroughly characterised by nucleoside composition analysis, circular dichroism and thermal melting studies. Studies with Eco RV show that incorporation of d3CA into either the central or outer dA-dT base-pair results in a substantial reduction in the rate of cleavage. The two-step conversion of d3CA to 3-deaza-2'-deoxyadenosine-5'-O-triphosphate (d3CATP) via the 5'-O-tosylate is also described. d3CATP is not a substrate in the poly[d(AT)].poly[d(AT)] primed polymerisation for either E. coli DNA polymerase I or Micrococcus luteus DNA polymerase. In a more detailed kinetic analysis d3CATP was shown to be a competitive inhibitor of E. coli DNA polymerase I with respect to dATP.

Plant regeneration from cotyledon protoplasts of Xinjiang muskmelon

Cotyledon protoplasts were isolated from seedlings of Xinjiang muskelon (Cucumis melo var.saccharinus) grown under sterile conditions and cultured in modified Miller medium. High frequency division of the protoplast-derived cells was observed. Agarose bead culture with B6S3 tobacco crown gall nurse cells was found most suitable for the cotyledon protoplasts when compared with other culture methods. Intact plants were regenerated from the protocalli by a two-step culture procedure with liquid and then solid media.

Dibenzocycloalkenimine (MK-801) stimulates phosphoinositide hydrolysis in rat cerebral cortical slices)

Dibenzocycloalkenimine (MK-801), a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist, induced a concentration-dependent accumulation of inositol monophosphate in rat cerebral cortical slices. This effect appears unrelated to antagonism of NMDA receptors as AP-7 and PCP did not cause comparable effects. In addition, the MK-801-induced response was unaffected by NMDA or glycine, alone or in combination, Zn2+, or the removal of Mg2+ from the buffer. These results indicate a novel site of action for MK-801 associated with activation of phosphoinositide hydrolysis.

[Adult diarrhea rotavirus in Jilin, China]

In May 1986, an outbreak of epidemic acute diarrhea occurred in one city and three counties in Yanbian area. The diarrheal cases were seen in all age groups, the majority of the cases were seen in adult age group. No bacterial pathogens were isolated in 22 fecal samples examined, however rotavirus like particles of 52-68 nm in diameter were found in 50% (11/22) of fecal samples by the immunoelectron microscopy using convalescent sera. Examination by the adult diarrhea rotavirus (ADRV) ELISA kit showed positive reaction in 86% (6/7) of fecal extracts, however in all 22 fecal extracts examination using ELISA kit for detection of group A rotavirus showed negative reaction. The PAGE patterns of viral RNAs similar to those of ADRV were seen in 13 out of 22 fecal extracts. The detection rate by PAGE analysis was 59%. Based on the above data, the etiological agent of the epidemic acute diarrhea, which occurred in Yanbian area, was identified to be ADRV.

[Active oxygen radicals produced by the leukocytes in patients with malignant lymphoma]

The electron spin resonance (ESR) spectra of the active oxygen radicals produced during the respiratory burst of PMA-stimulated leukocytes and the oxygen consumption were studied with ESR spin trapping technique and spin probe oximetry for 31 times in 17 cases of malignant lymphoma. The results showed that the spectra produced from the PMA-stimulated patients' leukocytes were dominantly spin adducts of DMPO-hydroxyl radicals, DMPO-OH; and the decrease of oxygen consumption during respiratory burst suggested that the function on respiratory burst, was inhibited. From the results of kinetic observations of the patients conditions, it was shown that the respiratory burst and oxygen consumption were improved, even close to normal, when the patient's condition was in remission or amelioration. This paper is the first to report the active oxygen radicals produced from malignant lymphoma patient's leukocytes with ESR. This is helpful for a better understanding of the mechanism of cancerous proliferation and metastasis.

[The measurement of radial bone mineral content in children]

The bone mineral contents of radius of 255 boys and 243 girls (7 to 16 year old of the Han nationality, living in Chengdu) were measured with Bone Mineral Analyzer (Type:SPA-I). The standard values of g/cm was made. There was a positive correlation between the value in boys or girls and chronological age, height or weight. The coefficients were respectively 0.83, 0.77, 0.64 in boys and 0.82, 0.82, 0.82 in girls (P less than 0.005). At the age of 13 (in boys or in girls) the value of the g/cm was the highest.

Synthesis and antimalarial activity of (+)-deoxoartemisinin

(+)-Deoxoartemisinin (2), a new and more active antimalarial agent, was successfully prepared from artemisinin in one step using NaBH4 and BF3.Et2O in THF. (-)-Deoxodeoxyartemisinin (5), a potential metabolite of deoxoartemisinin, was also prepared either from 2 or from artemisinic acid. 2 shows 8-fold increased antimalarial activity in vitro against chloroquine-resistant malaria as compared to artemisinin (1). Compound 2 possesses superior in vivo antimalarial activity to 1.

Ultrastructural morphogenesis of 4-ipomeanol-induced bronchiolitis and interstitial pneumonia in calves

The two objectives of this research were 1) to describe the ultrastructural morphogenesis of pulmonary damage and repair induced in calves after treatment with 4-ipomeanol and 2) to characterize infiltrating pulmonary inflammatory cells by bronchoalveolar lavage. Interstitial edema was observed as early as 4 hours after intravenous injection of 4-ipomeanol (5 mg/kg body weight) and progressed to severe alveolar edema by 72 hours. Damage to type I alveolar epithelial cells and terminal bronchiolar nonciliated cells included dilation of endoplasmic reticulum and perinuclear envelopes and was present at 4 hours after treatment. Necrosis and sloughing of these cells from basement membranes occurred at times from 12 to 96 hours after treatment. Alveolar capillary endothelial cells had mild dilation of endoplasmic reticulum at times from 12 to 72 hours after treatment. Necrosis of endothelial cells was not observed. Inflammatory cell infiltrates in bronchioles and alveoli were dominated by macrophages and neutrophils. Significant elevations (P less than 0.05) in numbers of neutrophils and macrophages were recovered by bronchoalveolar lavage at times from 24 to 96 hours after 4-ipomeanol-treatment. Hyperplasia of nonciliated bronchiolar epithelial cells and of type II alveolar epithelial cells were observed at 72 and 96 hours after treatment. The results indicate that type I alveolar epithelial cells and nonciliated bronchiolar epithelial cells are most susceptible to 4-ipomeanol-induced damage and necrosis in calves. 4-ipomeanol-induced pulmonary edema in calves occurs prior to ultrastructurally-demonstrable, mild, alveolar capillary endothelial cell damage.

[Determination of eucalyptole in eucalyptus oil by gas chromatography]

This paper reports the determination of eucalyptole in eucalyptus oil by gas chromatography. The results were similar to the specifications in the Chinese Pharmacopoeia. The method is simple, rapid, accurate and sensitive and requires only small amount of samples. The coefficient of variation is less than or equal to 0.52%.

Rare cavernous haemangioma of the hypopharynx with numerous phleboliths

Cavernous haemangiomata occur quite commonly, but one situated in the hypopharynx which contains as many as 240 phleboliths, as reported here, is a rare curiosity. The clinical manifestations, angiographic findings and the operative procedure of this case are described with a brief review of the formation of phleboliths in cavernous haemangiomas.

[Protective effects of Panax notoginseng saponins on experimental myocardial injury induced by ischemia and reperfusion in rat]

Effects of total saponins of Panax notoginseng (PNS) and purified ginsenosides Rb1 and Rg1 from PNS on myocardial injury induced by cardiac ischemia and reperfusion were studied with rat hearts in situ and in vitro. In pentobarbital-anesthetized rats, PNS pretreatment (100 and 200 mg/kg) provided significant reduction in myocardial infarct size after left descending coronary artery ligation (40 min) and reperfusion (120 min) in comparison with the control. PNS 12.5 and 25 mg/L, Rb1 10 mg/L, and Rg1 10 mg/L significantly decreased cardiac CPK release, attenuated myocardial Ca2+ accumulation, reduced malondialdehyde (MDA) production and prevented reduction of superoxide dismutase (SOD) activity in comparison with the control in perfused isolated rat hearts with global ischemia (40 min) and reperfusion (15 min). The results show that PNS, Rb1, and Rg1 prevent cardiac ischemia and the action is considered to be related to the inhibition of lipid peroxidation.

Polyclonal B cell activation of IgG2a and IgG2b production by infection of mice with lactate dehydrogenase-elevating virus is partly dependent on CD4+ lymphocytes

Concentrations of IgM and IgG isotypes were determined by capture ELISA in plasma of Swiss, BALB/c and C58/M mice. Plasma IgG isotype concentrations, especially of IgM, IgG1 and IgG2a, varied considerably between mouse strains, batches of mice of the same strain and individual mice and as a function of age. Infection of the mice with LDV, which is known to replicate primarily in a subpopulation of macrophages, consistently resulted in a rapid elevation of plasma IgG2a (or of IgG2b in some Swiss nu/+ mice), but no plasma IgG increases were observed in mice immunized with inactivated LDV. Plasma IgG2a elevation after LDV infection was greatly delayed and reduced by depletion of the mice of CD4+, but not of CD8+, T cells by administration of protein-G-purified anti-CD4 or anti-CD8 mAbs, and completely inhibited by repeated treatment of the mice with cyclophosphamide. Treatment with anti-CD4 mAbs, or cyclophosphamide also greatly reduced the production of anti-LDV antibodies, while not significantly affecting the replication of LDV in these mice. Nude Swiss mice also failed to produce anti-LDV antibodies, though supporting normal LDV replication. Plasma IgM, IgG1, IgG2a and IgG2b levels increased in LDV-infected nu/nu mice, but similar changes were observed in uninfected mice. The results indicate that the LDV-induced polyclonal activation of B cells requires productive LDV infection of mice and is, at least partly, dependent on functioning CD4+ cells. They suggest that productive infection of the LDV-permissive subpopulation of macrophages leads to the activation of CD4+ T lymphocytes of subset 1 and their Spleen cells from 5-day LDV-infected BALB/c mice incorporated [3H]thymidine 2-3 times more rapidly in vitro than spleen cells from companion uninfected mice, whereas their responses to concanavalin A and lipopolysaccharide were reduced 60-70%.

[The relation of vasoactive intestinal peptide and acute hypoxia]

In order to observe the effect of acute hypoxia on release of vasoactive intestinal peptide (VIP), the plasma VIP content was determined in anesthetized dogs by a specific radioimmunoassay technique during acute hypoxia. Blood gases and hemodynamics were monitored simultaneously. After inhalation of 10% oxygen. the plasma VIP levels elevated along with decrease in PaO2 and increase in pulmonary artery pressure. The plasma concentration of VIP in the portal vein increased significantly from 106 +/- 21 pg/ml before hypoxia to 173 +/- 36 pg/ml 15 minutes after the onset of hypoxia (P less than 0.01). The difference of arterio-venous VIP content increased from -3 +/- 6 pg/ml before hypoxia to +9 +/- 7 pg/ml after inhalation of 10% oxygen for 30 minutes. The results suggested that VIP was released from the gastrointestinal tract as well as from the lung in case of hypoxia and pulmonary hypertension. It is considered that the release of VIP may be an adaptive and compensatory response, promoting vasodilation and perfusion in vital organs.

Rotation invariant pattern recognition with a programmable joint transform correlator

A circular harmonic expansion filter is real value implemented in a joint transform correlatora rchitecturet o perform rotation invariant pattern recognition.

The effects of pH on hyaluronate as observed by light scattering

Hyaluronate was investigated over a wide pH range, and at near zero and intermediate ionic strength, using dynamic and total intensity light scattering. Commercially obtained rooster comb hyaluronate was purified, and solutions were prepared in pure water by low-power bath ultrasonication and subsequent filtering. These solutions were of low polydispersity and appeared to contain single molecules of hyaluronate. Despite the absence of added electrolyte, these solutions yielded well-behaved Zimm plots. Increasing ionic strength and changing pH decreased radii of gyration and increased diffusion constants. Except for what appeared to be slow hydrolysis at either extreme of pH, molecular weights remained constant under all pH and ionic strength conditions. Under all solvent conditions investigated, diffusion coefficients increased with decreasing hyaluronate concentration. Unsonicated, lightly centrifuged solutions without added electrolyte were polydisperse, and their light scattering intensity was dominated by what appeared to be stable hyaluronate aggregates. The results are interpreted in terms of the polyelectrolyte properties of hyaluronate and its tendency to form stable entanglements, especially at low ionic strength. Previous light scattering studies in the literature on hyaluronate have shown widely varying results. The present article briefly reviews this literature and attempts to explain the variation among the previous results, emphasizing the Kuhn statistical segment length as an indicator of whether results are influenced by polydispersity or contaminants causing hyaluronate aggregation.