Study on nude mice inoculated with Mycobacterium leprae by multiple routes

Immune-deficient nude mice were inoculated with nude mouse derived Mycobacterium leprae by multiple routes (intravenously, subcutaneously at the foot pads and ears). The results showed that these inoculated animals were capable of producing a great number of Mycobacterium leprae to a level 10 per gram of tissue and were detected histopathologically to have heavy lepromatous lesions. The dissemination of the infection was found particularly in sites with lower body temperature. The organisms have a partiality to striated muscles and peripheral nerves. The authors suggest that experimental leprosy in nude mice is a very useful tool for leprosy research, especially in countries without armadillos. Compared with the single-route inoculation reported previously, multiple-route inoculation is more available.

[Imaging diagnosis of carcinoma of the ampulla of Vater]

Ten patients with carcinoma of the ampulla of Vater were reviewed with both ultrasonography (US), CT scans (n = 10), and hypotonic double contrast duodenum examination (n = 5). Tumor was shown by US as abrupt obstruction of distal common bile duct (n = 6), a small mass well-delineated within the dilated distal common bile duct (CBD) (n = 4). The second part of duodenum was depicted clearly in CT scan without enhancement, and a small filling defect could be revealed at the inner surface in 5 cases, as well as an abrupt obstruction of distal CBD, local mass was shown in 4 cases. Enhancement of tumor manifested as local mass and/or ductal wall thickening after iv contrast administration was shown in 3 cases. One case with local lymph node enlargement (25 mm) was revealed by US as well as CT. Non-resectability is implicated by the ill-defined contour of tumor mass and/or portal vein, superior mesenteric artery and vein, but resectability cannot be excluded by displacement and distortion of these vessels with clear delineation. Detectability of lymph node smaller than 10 mm and evaluation of T, N staging are limited by imaging examination. Local filling defect and irregularity of mucous membrane of duodenum were revealed in 4 cases by hypotonic double contrast examination.

[A comparison analysis on methods of astigmatism examinations for children]

70 children 140 eyes with astigmatic refractive error were reported. The methods of examination included retinoscopy, autorefraction and keratometry. The data of eye astigmatism and keratic astigmatism measured by the methods were analyzed. It revealed that there existed a good identity among the three methods, and the relationship between eye astigmatism (EAs) and keratic astigmatism (KAs) shown by the formula EAs = 0.94 KAs - 0.13 was similar to that of previous reports. It is suggested that the keratometry be necessary as an assistant method of refraction to assure to get a reliable astigmatism result for children.

Diagnosis of astrovirus by reverse transcriptase PCR in stools from patients in the UK and Saudi Arabia

BACKGROUND

Astroviruses are becoming increasingly recognised as a cause of diarrhoea in children, and to a lesser extent, adults. Electron microscopy is the recognised standard for diagnosis but is not available in many centres.

OBJECTIVES

This study set out to evaluate a RT-PCR method for the diagnosis of astrovirus in faecal specimens.

STUDY DESIGN

130 diarrhoeal stools were collected prospectively both from Saudi Arabia and Leicester, UK. The patients from each centre were age-matched. Twenty control isolates from food service staff without clinical illness were also collected. Both electron microscopy (EM) and RT-PCR (for astrovirus serotype 1) were used to diagnose astrovirus infection.

RESULTS

Of 23 PCR-positive specimens, only 17 were detected by EM. The prevalence of astrovirus serotype 1 was determined by PCR as 1.5% in Saudi Arabia and 4.6% in the UK.

CONCLUSION

RT-PCR is a more sensitive alternative to EM for astrovirus serotype 1.

[Stimulating action of Carthamus tinctorius L., Angelica sinensis (Oliv.) Diels and Leonurus sibiricus L. on the uterus]

The experimental results indicate that the decoction of Chinese drugs Carthamus tinctorius, Angelica sinensis and Leonurus sibiricus has stimulating action on the uterus of mouse in vitro. The stimulating action of Carthamus tinctorius and Leomurus sibiricus has been found related to stimulating H1-receptor and alpha-adrenergic receptor of uterus, but the action of Angelica sinensis to stimulating H1-receptor of uterus only.

[Imaging diagnosis of localized pleural mesothelioma]

Nineteen cases of localized pleural mesothelioma (benign 9, malignant 8, unclassified 2) proved by surgery and pathology were analyzed. Imaging manifestations included large mass, elliptic or spindle in shape, often lobulated and well delineated, close to pleural surface. There were calcifications or cystic changes within the mass in some cases. Of the 9 benign cases, there were pedicles of 1-8 cm in length attached to the pleural surface in 5 cases. None of the benign mesotheliomas had chest wall invasion or rib destruction. Of the 8 malignant mesothelioma 2 were peduncalated, 5 had invaded chest wall with underlying rib destruction in 4 CT has obvious advantages for the evaluation of the location and extenst of mesothelioma. Apart from invasion of the underlying rib or soft tissue. Differentiation of benign from malignant localized mesothelioma can not be made by imaging diagnosis. As malignant localized mesothelioma often recurrs after surgery, closely following-up is recommended.

Use of a nested PCR method for the detection of astrovirus serotype 1 in human faecal material

In this paper we describe a reverse-transcription nested polymerase chain reaction method for detecting human astrovirus serotype 1. It has been evaluated on 56 UK diarrhoeal stool specimens and six non-UK specimens. The method has greater sensitivity than electron microscopy and may be a useful test in areas such as the UK where this serotype predominates.

[Studies on the early serodiagnosis of leptospirosis by dot-ELISA]

Thirty serum samples of patients with early leptospirosis from whom cultures of leptospira were positive were tested by dot-enzyme linked immunosorbent assay (dot-ELISA) and microscopical agglutination test (MAT). The results showed that the positive rate of dot-ELISA (40%) was higher than that of MAT (13.3%). One-hundred and ninety-eight serum samples from patients with clinical diagnosis of early leptospirosis were tested by dot-ELISA, MAT and blood culture. The results showed that the positive rate of dot-ELISA (64.6%) was higher than that of blood culture (15.2%) and MAT (14.1%). The longer the time of the illness, the lower the positive rate of the blood culture. However, the positive rate of dot-ELISA was stable in different stages of the illness.

Olfactory neurons in vitro show phenotypic orientation in epithelial spheres

Production and differentiation of olfactory neurons occur in spherical, multi-neuronal aggregates that form in cultures where dissociated newborn rat nasal cells are plated on to CNS glial cells. We show here that neuronal cell bodies were primarily located in the peripheral layers of the spheres, and almost every neuronal sphere contained one or several non-cellular central cavities. The dendrite-like processes of the olfactory neurons, immunostained for neuron-specific tubulin or the olfactory marker protein, were aligned and directed towards the central cavities. Olfactory neurons in the intact animal show a similar relationship with the nasal lumen. Non-neuronal cells formed multiple layers centrally, bordering the cavities. This degree of phenotypic re-creation is unusual in a dissociated monolayer culture system.

Growth of lactobacilli, Staphylococcus aureus and Escherichia coli in normal and mastitic milk and whey

The growth of three lactobacilli (Lactobacillus acidophilus, L. bulgaricus and L. casei), Staphylococcus aureus and Escherichia coli was followed in normal and mastitic milk and whey using the standard plate count method. L. acidophilus, L. bulgaricus 6032 and L. casei 6028 grew well in normal milk, but had decreased growth in mastitic milk if not pre-adapted in mastitic whey. S. aureus 26003 and E. coli 44102 showed enhanced growth in mastitic milk as compared with their growth in normal milk. These mastitis pathogens grew faster than the lactobacilli in both the normal milk and the mastitic milk. Among the lactobacilli, L. acidophilus and L. bulgaricus grew faster than L. casei in both types of milk samples. All the bacteria tested grew well in the normal and mastitic whey samples. However, they seemed to have enhanced growth in mastitic whey with the exception of L. casei. Pre-adaptation of the bacteria in mastitic whey in subculture markedly improved the growth of both pathogenic and non-pathogenic bacteria in mastitic milk. All the bacteria showed decreased replication in mastitic milk as compared with mastitic whey.

Extracellular glutathione and gamma-glutamyl transpeptidase prevent H2O2-induced injury by 2,3-dimethoxy-1,4-naphthoquinone

Quinones are intracellular H2O2 generators that have been used extensively in models of oxidant injury; however, their toxicity is mediated partially through direct conjugation with glutathione (GSH). To focus upon the action of extracellular GSH in preventing H2O2-mediated toxicity, we used 2,3-dimethoxy-1,4-naphthoquinone (DMNQ), which cannot conjugate with GSH but does continuously generate H2O2 through redox cycling. A eukaryotic cell line (3T3-GGT) stably overexpressing gamma-glutamyl transpeptidase (GGT) activity was used to study the role of GGT in utilizing extracellular GSH against DMNQ-induced oxidative stress. DMNQ (0 to 150 microM) caused a dose-dependent decrease of intracellular GSH and adenosine 5'-triphosphate (ATP) in both control and 3T3-GGT cells. The rate of H2O2 escape into the medium during DMNQ exposure was also the same in both cell lines. Administration of GSH helped to maintain intracellular GSH and supported resistance to ATP depletion caused by DMNQ in 3T3-GGT cells but not in control cells. The protective effect of extracellular GSH was completely prevented by acivicin, an inhibitor of GGT. Our results suggest that GGT-dependent breakdown of extracellular GSH for subsequent intracellular resynthesis helped to maintain cellular GSH levels and increased cellular resistance against DMNQ-induced oxidative injury.

Studies on antibiotic 230 as a molluscicide

In the course of studying molluscicidal effects of microorganisms, a microorganism belonging to Streptomycetaceae, Streptomyces griseolus (Strain 230) was isolated from soil and a certain microbial ingredient proved to have a molluscicidal activity. The effective substance was named antibiotic 230. As a result of several investigations on the antibiotic, the following chemical features were made clear. The chemical substance was an indol-carbazole-heterocyclic compound, the molecular weight 446 and the molecular formula C28H26N4O3. The antibiotic demonstrated a molluscicidal effect against Oncomelania snails and their eggs both in the laboratory and in the field. The compound had a wide bacteriostasis spectrum and a slight toxicity to fish in addition to the above, but it was non-toxic to plants.

A fundus photographic method with narrow spectral band luminance

We perfected the narrow spectral band fundus photographic system using interference filters at the wavelengths of 417, 478, 500, 530, 547, 570, 589, 607, 628 and 648 nm. Tests about the light penetration of filters and exposure of various brand films were made on this system. Studies of the contrast of fundal tissues and structures under the different narrow spectral band light were made on 43 Chinese fellow eyes. The results indicates that the interference filters of 570 nm have the highest light penetration. Kodak and Gongyuan films (make in China) are the optimal ones. Narrow spectral band fundus photography can eliminate the chromatic aberration and therefore improve the documentation of fundal details, enhance the contrast of pictures as compared with routine white light fundus photography.

Genomic in situ hybridization to identify alien chromosomes and chromosome segments in wheat

Genomic in situ hybridization was used to identify alien chromatin in chromosome spreads of wheat, Triticum aestivum L., lines incorporating chromosomes from Leymus multicaulis (Kar. and Kir.) Tzvelev and Thinopyrum bessarabicum (Savul. and Rayss) Löve, and chromosome arms from Hordeum chilense Roem. and Schult, H. vulgare L. and Secale cereale L. Total genomic DNA from the introgressed alien species was used as a probe, together with excess amounts of unlabelled blocking DNA from wheat, for DNA:DNA in-situ hybridization. The method labelled the alien chromatin yellow-green, while the wheat chromosomes showed only the orange-red fluorescence of the DNA counterstain. Nuclei were screened from seedling root-tips (including those from half-grains) and anther wall tissue. The genomic probing method identified alien chromosomes and chromosome arms and allowed counting in nuclei at all stages of the cell cycle, so complete metaphases were not needed. At prophase or interphase, two labelled domains were visible in most nuclei from disomic lines, while only one labelled domain was visible in monosomic lines. At metaphase, direct visualization of the morphology of the alien chromosome or chromosome segment was possible and allowed identification of the relationship of the alien chromatin to the wheat chromosomes. The genomic in-situ hybridization method is fast, sensitive, accurate and informative. Hence it is likely to be of great value for both cytogenetic analysis and in plant breeding programmes.

Transfection with γ-glutamyl transpeptidase enhances recovery from glutathione depletion using extracellular glutathione

Glutathione (L-gamma-glutamyl-L-cysteinylglycine) is an important constituent of the antioxidant and detoxifying mechanisms of cells. The plasma membrane bound enzyme, gamma-glutamyl transpeptidase (GGT), catalyzes the first step in the degradation of extracellular glutathione, the components of which are then used for de novo glutathione synthesis. We tested the hypothesis that an increase in GGT activity would enhance the utilization of extracellular glutathione by cells challenged with a glutathione-depleting agent. A eukaryotic system stably overexpressing GGT (nearly 200-fold) was developed by transfection of NIH-3T3 fibroblasts with a human placental GGT cDNA. These cells and controls were incubated for 30 min with 1 mM diethyl maleate, which caused approximately 80% intracellular glutathione depletion. Glutathione was added to the medium and cells were allowed to resynthesize intracellular glutathione. The transfected cells used extracellular glutathione much more efficiently than controls in terms of both the concentration dependence and the rate of glutathione resynthesis. Serine-borate, a competitive inhibitor of GGT, blocked the restoration of intracellular glutathione. The results support the hypothesis that the increase in GGT activity that occurs in some toxicologic or pathologic conditions could provide protection against glutathione depletion.

Exogenous glutathione protects endothelial cells from menadione toxicity

Administration of menadione (vitamin K3; 2-methyl-1,4-naphthoquinone) to cultured bovine pulmonary artery endothelial cells caused a dose- and time-dependent depletion of cellular ATP and depletion of intracellular glutathione (GSH). The toxicity of menadione was correlated with an increase of menadione-glutathione conjugate in the medium and with an increase in H2O2 generation. Recent studies have suggested that GSH may be useful as a pharmacological agent to prevent oxidant injury. In the present study, treatment with exogenous GSH prevented the loss of cellular GSH and ATP caused by menadione. Protection by extracellular GSH involved two mechanisms. In one mechanism, extracellular GSH was degraded by gamma-glutamyl transpeptidase, producing substrates for subsequent intracellular de novo GSH synthesis. We found that the protective effect of extracellular GSH was decreased by inhibiting gamma-glutamyl transpeptidase. In the other mechanism, GSH reacted in the medium with menadione to form a conjugate. Although formation of the menadione-glutathione conjugate within cells may contribute to menadione toxicity, addition of menadione-glutathione conjugate to the medium was found to be nontoxic to endothelial cells. Thus exogenous GSH protected endothelial cells by two mechanisms: maintenance of intracellular GSH and prevention of menadione entrance into cells.

Different patterns of rDNA organization at interphase in nuclei of wheat and rye

The physical location of the rDNA repeating units (25 S, 18 S and 5.8 S rRNA genes and the intergenic spacer sequences) was investigated in rye (Secale cereale L.) and wheat (Triticum aestivum L.) root tip meristematic cells by in situ hybridization using light and electron microscopy. The rDNA sequences are organized differently in the two related and intercrossable species. In rye (2n = 14, one pair of chromosomes with nucleolar organizing regions, NORs), two condensed blocks of rDNA-containing chromatin occurred in each interphase nucleus. The blocks were associated with the periphery of nucleoli and a single-labelled, decondensed rDNA fibre extended into the nucleolus from the block. We term this expression pattern terminal decondensation. In wheat (2n = 6x = 42, five pairs of chromosomes with NORs), inactive condensed labelled chromatin was found unassociated with nucleoli. Active NORs had some condensed rDNA associated with the nucleolar periphery, but, in contrast to rye, condensed rDNA was also found within the nucleolus. The condensed labelled rDNA in wheat nucleoli was visible as fluorescent foci in the light microscope and labelled condensed chromatin in the electron microscope. Its absence in rye shows that condensed rDNA need not be present in active plant nucleoli. Diffuse labelled sites of rDNA, likely to represent actively transcribed rDNA, were found in both rye and wheat. Active rDNA loci in wheat have many expressed segments separated by unexpressed, condensed, rDNA-fragmented decondensation-while each locus in rye has a single, unexpressed perinucleolar condensed block of rRNA genes. Thus the positions of actively transcribed genes within the tandem arrays of rDNA at each locus are fundamentally different in the two cereals. The NOR chromosome appeared to extend through the nucleolus, and active rDNA sequences did not loop out from chromatin into the nucleolus as is frequently described in nucleolar models.

[A quick method for the diagnosis of leptospirosis]

Seventy-nine sero-samples from patients with leptospirosis were tested by dot-ELISA and microscopical agglutination test (MAT). Results showed that the accordance rate was 96.19%. 20 sero-samples obtained from healthy people, 4 from hepatitis B(HBV) and 4 from epidemic hemorrhage fever (EHF) were negative by dot-ELISA. We believe dot-ELISA is a simple, rapid method which can be used to diagnose those patients with leptospirosis.