Suppurative corneal ulceration in Bangladesh

Suppurative keratitis is an important preventable cause of blindness, particularly in the developing world. This study analyses 142 cases of suppurative keratitis referred to Chittagong Eye Infirmary, Bangladesh. Some 53.5% of cases were bacterial and 35.9% were fungal. The five most common pathogens were: Pseudomonas sp. 24%, Streptococcus pneumoniae 17%, Aspergillus sp. 13%, Fusarium sp. 7% and Curvularia sp. 6%. Gram stain and culture results were consistent in 62.6% of cases. Previous antibiotic treatment was a significant factor for failure of culture isolation and less so for Gram stain failure. On Gram stain, 55.9% of pseudomonal cases were missed, but only 2% of fungal cases were missed. Over all, Gram stain had a sensitivity of 62% and positive predictive value of 84% for bacterial cases, and 98% and 94% for fungal cases, respectively. Fungal ulcers were typically filamentous, but an antecedent history of trauma was not common. The most frequent injury was due to rice grains, but the inoculum appeared to be introduced during eye washing with contaminated water. Pseudomonal ulcers occurred most frequently in the monsoon season, and Fusarium cases were seen only in the hot, dry season.     

Nonheme iron in sickle erythrocyte membranes: association with phospholipids and potential role in lipid peroxidation

Previous studies documented the abnormal association of heme and heme proteins with the sickle RBC membrane. We have now examined RBC ghosts and inside-out membranes (IOM) for the presence of nonheme iron as detected by its formation of a colored complex with ferrozine. Sickle ghosts have 33.8 +/- 18.2 nmol nonheme iron/mg membrane protein, and sickle IOM have 4.3 +/- 3.0 nmol/mg. In contrast, normal RBC ghosts and IOM have no detectable nonheme iron. The combination of heme and nonheme iron in sickle IOM averages nine times the amount of membrane- associated iron in normal IOM. Kinetics of the ferrozine reaction show that some of this nonheme iron on IOM reacts slowly and is probably in the form of ferritin, but most (72% +/- 18%) reacts rapidly and is in the form of some other biologic chelate. The latter iron compartment is removed by deferoxamine and by treatment of IOM with phospholipase D, which suggests that it represents an abnormal association of iron with polar head groups of aminophospholipids. The biologic feasibility of such a chelate was demonstrated by using an admixture of iron with model liposomes. Even in the presence of tenfold excess adenosine diphosphate, iron partitions readily into phosphatidylserine liposomes; there is no detectable association with phosphatidylcholine liposomes. To examine the bioavailability of membrane iron, we admixed membranes and t-butylhydroperoxide and found that sickle membranes show a tenfold greater peroxidation response than do normal membranes. This is not due simply to a deficiency of vitamin E, and this is profoundly inhibited by deferoxamine. Thus, while thiol oxidation in sickle membranes previously was shown to correlate with heme iron, the present data suggest that lipid peroxidation is related to nonheme iron. In control studies, we did not find this pathologic association of nonferritin, nonheme iron with IOM prepared from sickle trait, high-reticulocyte, postsplenectomy, or iron-overloaded individuals. These data provide additional support for the concept that iron decompartmentalization is a characteristic of sickle RBCs.     

Toxic shock syndrome in scalded children

Five patients showing clinical signs resembling the 'toxic shock syndrome' presented over a 4-month period at the Wessex Regional Burns Centre. Toxin-producing isolates of Staphylococcus aureus were made from wound swabs in four of the five patients. Four different phage types producing four different toxins were observed. Seven other patients yielded staphylococci from wound swabs but did not develop the toxic shock syndrome. In three of these latter patients the staphylococcus isolated was toxin producing. Since the syndrome carries a significant mortality risk it is desirable that it is recognized and treated without delay. To this end a simplified set of criteria for the identification of probable toxic shock syndrome cases is proposed. The observations suggest that toxic shock syndrome is more common than previously supposed. The syndrome may show a broad spectrum in its clinical presentation, and involve a wide range of staphylococcal phage types with possible involvement of several different enterotoxins.     

Difficulties using the Franco-Italian Glossary in assessing toxicity of cervical cancer treatment

Shakespeare TP, Ferrier AJ, Holecek MJ, Jagavkar RS, Stevens MJ. Difficulties using the Franco-Italian Glossary in assessing toxicity of cervical cancer treatment. Int J Gynecol Cancer 1998; 8: 51–55
We assessed the toxicities of patients treated for cervical cancer using the revised Franco-Italian Glossary (FIG). A total of 69 separate complications were appraised in 47 patients; however, only 43.5% of these side-effects could be accurately graded. In all, 56.5% of toxicities could not be scored for a variety of reasons: (1) the FIG does not account for all possible complications of cervical cancer treatment; (2) some important toxicities are regarded as too minor to be graded; (3) subjective assessment of some side-effects did not allow consensus to be reached when assigning a grade; (4) we could not accurately score toxicities using the FIG in a retrospective manner. Previous studies utilizing the FIG retrospectively have noted few problems with its use, with no indication of the number of toxicities unable to be graded. In view of the inability to grade the majority of complications in the present study in an accurate manner, we conclude that the revised FIG requires detailed data that are best collected prospectively and that several minor modifications of the glossary should be considered. Results of studies using the glossary retrospectively should be viewed with caution.     

川芎嗪诱导大鼠骨髓间质干细胞分化为神经元样细胞的研究

目的用川芎嗪(ligustrazin hydrochloride)在体外定向诱导SD青年鼠骨髓间质干细胞(mesenchymal stem cells，rMSCs)分化为神经元样细胞。方法用低糖DMEM冲洗骨髓腔，收集骨髓细胞悬液，接种在塑料培养瓶中。经体外扩增、纯化，选用第5代后的骨髓间质干细胞进行诱导分化。用10μg／LbFcF预诱导24h，更换成含川芎嗪的无血清培养基DMEM诱导间质干细胞分化为神经元样细胞。用免疫组织化学SABC法鉴定神经丝蛋白(NF—M)、神经元特异性烯醇化酶(NSE)、巢蛋白(nestin)、微管联合蛋白-2(MAP-2)、生长相关蛋白-43(GAP-43)、胶质纤维酸性蛋白(GFAP)的表达。结果第5代间质干细胞形态达到均一，呈梭形。用川芎嗪诱导15min到3h，间质干细胞胞体逐渐增大，并伸出细长突起形似神经元样细胞。免疫组织化学显示NF-M、NSE、nestin、MAP-2和GAP-43表达阳性，而GFAP阴性。对照组上述染色均为阴性。结论川芎嗪可诱导骨髓间质干细胞分化为神经元样细胞。     

Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability

X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG repeat expansion in the first exon of the androgen receptor (AR) gene. Disease-associated alleles (37-66 CAGs) change in length when transmitted from parents to offspring, with a significantly greater tendency to shift size when inherited paternally. As transgenic mice carrying human AR cDNAs with 45 and 66 CAG repeats do not display repeat instability, we attempted to model trinucleotide repeat instability by generating transgenic mice with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions in their genomic context. Studies of independent lines of AR YAC transgenic mice with CAG 45 alleles reveal intergenerational instability at an overall rate of approximately 10%. We also find that the 45 CAG repeat tracts are significantly more unstable with maternal transmission and as the transmitting mother ages. Of all the CAG/CTG repeat transgenic mice produced to date the AR YAC CAG 45 mice are unstable with the smallest trinucleotide repeat mutations, suggesting that the length threshold for repeat instability in the mouse may be lowered by including the appropriate flanking human DNA sequences. By sequence-tagged site content analysis and long range mapping we determined that one unstable transgenic line has integrated an approximately 70 kb segment of the AR locus due to fragmentation of the AR YAC. Identification of the cis - acting elements that permit CAG tract instability and the trans -acting factors that modulate repeat instability in the AR YAC CAG 45 mice may provide insights into the molecular basis of trinucleotide repeat instability in humans.      

Reflex inhibition of the quadriceps after meniscectomy: lack of association with pain

We have examined the severity and duration of reflex inhibition of quadriceps activation after arthrotomy and meniscectomy, its relationship with pain, and the effect of local anaesthesia on this relationship. Fourteen men, on completion of medial meniscectomy by arthrotomy, received either 10 ml (B10 group) or 15 ml (B15 group) of 0.5% bupivacaine hydrochloride ('Marcaine Plain') into the knee, or no injection (control group). Reflex inhibition of quadriceps was measured as the percentage reduction, from the ipsilateral preoperative value, in the integrated surface electromyogram recorded during maximal voluntary isometric contractions with the knee in extension. Pain during each contraction was recorded on a linear analogue scale. Unoperated limbs showed no evidence of quadriceps inhibition. In the operated limbs, at 1-2 h post-operatively, controls had both severe inhibition (median = 62%) and severe pain on attempting a maximal quadriceps contraction. The B10 group had similar inhibition but less pain (P less than or equal to 0.005, Wilcoxon 2-sample, 1-tailed test). In the B15 group both inhibition (P less than or equal to 0.05) and pain (P less than or equal to 0.01) were less than in the controls. These effects of bupivacaine had been lost by 4-5 h post-operatively. At 3-4 days, inhibition was still severe (median = 75%) in all three groups of patients but pain was only mild or absent. At 10-15 days, median inhibition was still 35%, but there was little or no pain. We conclude that postmeniscectomy inhibition is not simply due to perceived pain but is due, at least in part, to stimuli from the knee.