Histochemical studies of the development of alkaline and acid phosphatase activities in the ovary and oviduct of the fowl (Gallus domesticus)

Alkaline and acid phosphatase activities were studied in the ovary and oviducts of pullets from the age of 2-32 weeks. Adult fowls were similarly studied. Alkaline phosphatase activity was present only in the glandular grooves and crypts of the immature oviducts. Alkaline phosphatase activity appeared at the pits of epithelial evaginations as glandular formation commenced. The young, non-secreting glands also showed the enzyme activity. But in the mature oviduct, alkaline phosphatase activity was confined to only the uterovaginal glands or sperm host glands and the epithelium of the vagina. In the ovary, alkaline phosphatase activity in the theca interna increased as the diameter of the follicles increased. Acid phosphatase activity was not present in the ovary, but in the oviduct, the enzyme activity was present in the uterine (shell gland) glands and in the uterovaginal epithelium and glands (sperm host glands). Alkaline phosphatase activity in the ovarian follicles and in the immature oviduct is thought to be related to histodifferentiation of these structures.     

Reevaluation of the linkage between acute hemorrhagic shock and bacterial translocation in the rat

The present study was undertaken to determine the conditions under which acute periods of hemorrhagic shock induce bacterial translocation. Rats (at least six per group) were anesthetized intraperitoneally with the barbiturate, pentobarbital (50 or 65 mg/kg), or the inhalation anesthetic methoxyflurane. Following anesthesia, the femoral artery was catheterized, from which blood was withdrawn to maintain a mean arterial blood pressure of 30 mmHg for 30, 60, or 90 min, followed by reinfusion of shed blood. Instrumented, but nonshocked animals served as controls. Rats were sacrificed at 0, 2, or 24 hr postshock, and quantitative bacterial cultures of the mesenteric lymph node complex (MLN), liver, and spleen were made. Within groups, the effects of heparinization were also determined. In pentobarbital-treated animals, regardless of the extent of heparinization, consistent translocation to both MLN and distant organs occurred when shock was prolonged for 90 min, and assessment of translocation was made 24 hr after reinfusion of shed blood. Furthermore, a mortality rate of approximately 30% was found in rats subjected to this protocol. The magnitude of translocation was less consistent, and did not differ from that in sham shock controls, under other conditions of shock and evaluation. In rats anesthetized with methoxyflurane, no mortality occurred, and no statistical significance between the incidence or degree of translocation in shocked animals vs. sham shock controls could be demonstrated, regardless of the shock protocol. In additional studies, effects of these anesthetics on intestinal morphology and superior mesenteric arterial (SMA) flow in the context of hemorrhagic shock were assessed.(ABSTRACT TRUNCATED AT 250 WORDS)     

An improved method for detecting passive pills

One of the principal disadvantages of the passive pill as a telemetric method for measuring various physiological parameters has been its resticted range. The reasons for the restricted range with existing detection methods are discussed. An improved method using a locking spectrometer based on third-order phase-sensitive detection is described and its performance is assessed. A significant increase in the usable range of a high sensitivity passive pill is obtained.     

Shiga toxin binds human platelets via globotriaosylceramide (Pk antigen) and a novel platelet glycosphingolipid

Hemolytic-uremic syndrome is a clinical syndrome characterized by acute renal failure, microangiopathic hemolytic anemia, and thrombocytopenia that often follows infection by Shiga toxin- or verotoxin-producing strains of Escherichia coli. Because thrombocytopenia and platelet activation are hallmark features of hemolytic-uremic syndrome, we examined the ability of Shiga toxin to bind platelets by flow cytometry and high-performance thin-layer chromatography (HPTLC) of isolated platelet glycosphingolipids. By HPTLC, Shiga toxin was shown to bind globotriaosylceramide (Gb3) and a minor platelet glycolipid with an Rf of 0.03, band 0.03. In a survey of 20 human tissues, band 0.03 was identified only in platelets. In individuals, band 0.03 was expressed by 20% of donors and was specifically associated with increased platelet Gb3 expression. Based on glycosidase digestion and epitope mapping, band 0.03 was hypothesized to represent a novel glycosphingolipid, IV3-beta-Galalpha1-4galactosylglobotetraosylceramide. Based on incidence, structure, and association with increased Gb3 expression, band 0.03 may represent the antithetical Luke blood group antigen. By flow cytometry, Shiga toxin bound human platelets, although the amount of Shiga toxin bound varied in donors. Differences in Shiga toxin binding to platelet membranes did not reflect differences in platelet Gb3 expression. In contrast, there was a loose association between Shiga toxin binding and decreasing forward scatter, suggesting that Shiga toxin and verotoxins bind more efficiently to smaller, older platelets. In summary, Shiga and Shiga-like toxins may bind platelets via specific glycosphingolipid receptors. Such binding may contribute to the thrombocytopenia, platelet activation, and microthrombus formation observed in hemolytic-uremic syndrome.     

Complications of 32% dextran-70 in 10% dextrose. A case report

BACKGROUND: Thirty-two percent dextran-70 in 10% dextrose is a useful distention medium for hysteroscopic surgery. However, the side effects profile is considerable. CASE REPORT: A young woman underwent hysteroscopic evaluation for menorrhagia. Postoperatively, she suffered severe noncardiogenic pulmonary edema, disseminated intravascular coagulopathy and acute anuric renal failure. CONCLUSION: Precautions must be taken when using 32% dextran-70 in 10% dextrose to avoid its potentially life-threatening complications.     

Base miscoding and strand misalignment errors by mutator Klenow polymerases with amino acid substitutions at tyrosine 766 in the O helix of the fingers subdomain

A mutant derivative of Klenow fragment DNA polymerase containing serine substituted for tyrosine at residue 766 has been shown by kinetic analysis to have an increased misinsertion rate relative to wild-type Klenow fragment, but a decreased rate of extension from the resulting mispairs (Carroll, S. S., Cowart, M., and Benkovic, S. J. (1991) Biochemistry 30, 804-813). In the present study we use an M13mp2-based fidelity assay to study the error specificity of this mutator polymerase. Despite its compromised ability to extend mispairs, the Y766S polymerase and a Y766A mutant both have elevated base substitution error rates. The magnitude of the mutator effect is mispair-specific, from no effect for some mispairs to rates elevated by 60-fold for misincorporation of TMP opposite template G. The results with the Y766S mutant are remarkably consistent with the earlier kinetic analysis of misinsertion, demonstrating that either approach can be used to identify and characterize mutator polymerases. Both the Y766S and Y766A mutant polymerases are also frameshift mutators, having elevated rates for two-base deletions and a 276-base deletion between a direct repeat sequence. However, neither mutant polymerase has an increased error rate for single-base frameshifts in repetitive sequences. This error specificity suggests that the deletions generated by the mutator polymerases are initiated by misinsertion rather than by strand slippage. When considered with recent structure-function studies of other polymerases, the data indicate that the nucleotide misinsertion and strand-slippage mechanisms for polymerization infidelity are differentially affected by changes in distinct structural elements of DNA polymerases that share similar subdomain structures.     

Determination of antibiotics in different water compartments via liquid chromatography-electrospray tandem mass spectrometry

The mechanisms by which BCG exerts its antitumour activity remain unclear. Attachment of BCG to the bladder via FN has been shown to be an important step in initiating its antitumorigenic activity. The mechanism(s) by which BCG operates requires LAK cells, BCG-activated killer cells, T lymphocytes (CD4) helper cells and CD8 suppressor/cytotoxic cells) and monocytes. The optimal route of administration is intravesical. The efficacy of a BCG vaccine depends on the viability, dose and strain. Differences in efficacy and side-effects have not been shown between different strains. Low-dose regimens successfully protect from recurrences, with fewer side-effects. The initial schedule of BCG is a course of six instillations in 6 weeks; when the patient fails this course, two possibilities arise. The first is maintenance therapy; response rates improve but there is more local and systemic toxicity. The second is a further 6-week course, and this seems most useful in those with a sustained response to the initial treatment. The clinical response to BCG therapy can be monitored using cytokine measurements or p53 determinations. Toxicity remains a major problem in BCG treatment and triple antituberculosis combination therapy should be given for 3 months in those with severe systemic side-effects. The use of prophylactic isoniazid is not recommend to decrease side-effects. The clinical results of BCG have been good, with success rates of 58-100%, with a minimal follow-up of one year in prophylaxis. BCG seems superior to intravesical therapy, but at the cost of inducing more adverse effects. BCG is not indicated for low- and intermediate-risk patients, in whom chemotherapy is the first choice. BCG can also be used to eliminate tumour after an incomplete TUR, or in patients who are unfit for surgery, with a 60-70% success rate. The primary and best treatment for CIS is intravesical BCG; encouraging results have been reported, with success rate of 42-83% after a minimal follow-up of one year. Although currently BCG seems to be the choice for high-risk superficial TCC, many questions remain unanswered, especially about the mechanism(s) of action, the optimal dose and clinical schedule.