Hydatiform mole with coexisting live fetus in dichorionic twin gestation

A case of dichorionic twin pregnancy was diagnosed in a 29-year-old, on routine ultrasound at 12 weeks. Subsequent ultrasounds for persistent vaginal bleeding at 16 weeks revealed molar placenta with viable fetus in both gestational sacs. The patient declined any invasive prenatal testing to confirm the karyotype of the fetus. The pregnancy was managed expectantly until 21 weeks, when she had a spontaneous abortion of twin fetuses and separate placentae with attached molar tissue. A final karyotype on cord blood samples confirmed 46XY and 46XX for both fetuses. Histopathology of molar tissue reported complete mole, with diploid chromosomal pattern on subsequent DNA flow cytometry. The clinical, ultrasound and chromosomal examination suggest that there has been a quadruplet pregnancy where two embryos developed into normal fetuses and other two degenerated to complete moles.

Evidence for new nuclear and mitochondrial genome organizations among high-frequency somatic embryogenesis-derived plants of allotetraploid Coffea arabica L. (Rubiaceae)

 The most important commercial species of coffee, Coffea arabica, which produces 73% of the world's coffee crop and almost all of the coffee in Latin America, is the only tetraploid (allotetraploid, 2n=4x=44) species known in the genus. High-frequency somatic embryogenesis, plant regeneration and plant recovery were achieved from leaf explants of a mature, elite plant of C. arabica cv. Cauvery (S-4347) using a two-step culture method. To assess the genetic integrity of the nuclear, mitochondrial and chloroplast genomes among the hardened regenerants, we employed multiple DNA markers (RFLP, RAPD, ISSR) for sampling various regions of the genome. Although the nuclear and mitochondrial genomes of the mother plant and five ramets derived from the mother ortet were similar in organization, this was not so in the somatic embryo-derived plants where both nuclear and mitochondrial genomes changed in different, characteristic ways and produced novel genome organizations. A total of 480 genetic loci, based on the data obtained from a total of 16 nuclear, mitochondrial and chloroplast gene probes, in combination with nine restriction enzyme digests, 38 RAPD and 17 SSR primers, were scored in 27 somatic embryo-derived plants and the single control. Among these, 44 loci were observed to be polymorphic. A relatively low level of polymorphism (4.36%) was found in the nuclear genome, while polymorphism in the mitochondrial genome (41%) was much higher. No polymorphism was detected in the chloroplast genome. The polymorphism in the mitochondrial genome was found in only 4 plants. Such selective polymorphism was not true for the nuclear genome. Thus, this in-depth and comprehensive study demonstrates, for the first time, the presence of subtle genetic variability and novel genome organizations in the commercially well-established somatic embryogenesis-derived plants of this important coffee species.

Mechanism of biochemical action of substituted 4-methylbenzopyran-2-ones. Part 7: Assay and characterization of 7,8-diacetoxy-4-methylcoumarin:protein transacetylase from rat liver microsomes based on the irreversible inhibition of cytosolic glutathione S-transferase

The enzymatic transfer of acetyl groups from acetylated xenobiotics to specific proteins is a relatively grey area in the evergreen field of biotransformation of foreign compounds. In this paper, we have documented evidence for the existence of a transacetylase in liver microsomes that catalyses the transfer of acetyl groups from 7,8-diacetoxy-4-methylcoumarin (DAMC) to glutathione S-transferase (GST), either purified or present in cytosol leading to the irreversible inhibition of GST. A simple procedure is described for the assay of transacetylase by preincubation of DAMC with liver microsomes and pure GST/liver cytosol, followed by the addition of 1-chloro-2,4-dinitrobenzene (CDNB) and reduced glutathione (GSH) in order to quantify GST activity by the conventional procedure. The extent of inhibition of GST by DAMC under the conditions of the assay is indicative of DAMC:protein transacetylase activity. Following the assay procedure described here, the transacetylase was shown to exhibit hyperbolic kinetics. The bimolecular nature of the transacetylase reaction was apparent by the demonstration of Km and vmax values. 7,8-Dihydroxy-4-methylcoumarin (DHMC), one of the products of transacetylase reaction was identified and quantified using the partially purified enzyme. The fact that p-hydroxymercuribenzoate (PHMB) and iodoacetamide abolished irreversible inhibition of GST upon the action of transacetylase on DAMC strongly characterized transacetylase as a protein containing thiol group at the active site. In addition, the relative specificities of acetoxy 4-methylcoumarins to transacetylase have been demonstrated.

Peritoneal dialysis in patients with abdominal vascular prostheses

Patients with intra-abdominal vascular catastrophes may develop acute and/or chronic renal failure requiring dialysis. To patients with in-situ vascular prostheses the use of peritoneal dialysis (PD) may offer considerable advantages including better hemodynamic control and avoidance of anti-coagulation in a critically ill patient. Institution of PD in such patients, however, often gives rise to concerns relating to peritonitis and subsequent infection of the prosthesis, fluid leaks, and abdominal wound dehiscence. A review of available literature suggests that PD has been utilized in both acute and chronic renal failure following intra-abdominal vascular procedures. PD appears to be an efficient mode of dialysis with a surprisingly small number of complications in these patients.

The rationale for, and role of, heparin in peritoneal dialysis

The administration of intraperitoneal (i.p.) heparin enjoys time-honored use and is felt to be side-effect free. It is administered whenever fibrin is detected in the dialysate effluent. It is believed that there is no absorption of heparin across the peritoneal cavity. The aim of this article was to review the rationale behind the administration of i.p. heparin, to show that absorption and side effects may occur, and to present recent evidence that questions the routine use of this drug as an additive to dialysate fluid.

Temporary stoppage of peritoneal dialysis when laparoscopic procedures are performed on patients undergoing CAPD/CCPD: a change in policy

Laparoscopic surgery has been gaining in popularity. Prior to 1995, whenever our patients had a laparoscopic procedure it was carried out with the standard precautions, and the patient stayed on peritoneal dialysis (PD). We noticed a high incidence (71.4%) of peritonitis post laparoscopic surgery. Four of the peritonitis patients had cholecystectomies and 1 had a gastrostomy for placement of a feeding tube laparoscopically. The patients' ages ranged from 31 to 74 years; 4 (80%) were females. They had been on PD for a mean of 24 months (range 6-48 months). Peritonitis was diagnosed within a mean of 22.2 hours (r: 12-36 h) post procedure. The causative organisms were Klebsiella in two cases, Staph. aureus in one, Pseudomonas in one, with no growth observed in one. Following this, we instituted a deliberate policy of temporary cessation of PD for 2 weeks post laparoscopic procedure, maintaining the patient on hemodialysis during this period. Since the adoption of this policy, we have had no peritonitis in 7 patients who have undergone laparoscopic procedures.

Mechanism of biochemical action of substituted 4-methylbenzopyran-2-ones. Part 6: hydrolysis of 7,8-diacetoxy-4-methylcoumarin by a novel deacetylase in rat liver microsomes--a simple method for assay and characterisation

The existence of a novel microsomal deacetylase in rat liver catalysing deacetylation of diacetoxy 4-methylcoumarins has been reported. A simple method is outlined for the enzyme assay based upon the quantification of the dihydroxy derivative by measuring the UV absorption of its complex with ADP and Fe3+ at 600 nm. The enzyme can be routinely assayed using 7,8-diacetoxy-4-methylcoumarin (DAMC) as the substrate and demonstrated hyperbolic kinetics and yielded Km and vmax values of 1250 microM and 500 units, respectively. The pH optima was found to be 7.5 for the enzyme. No DAMC deacetylase activity was found in hepatic cytosol and the enzyme activity was not discernible in extrahepatic tissues.

Mechanism of biochemical action of substituted 4-methylbenzopyran-2-ones. Part 5: Pulse radiolysis studies on the antioxidant action of 7,8-diacetoxy-4-methylcoumarin

7,8-Dihydroxy-4-methylcoumarin (1, DHMC) and 7,8-diacetoxy-4-methylcoumarin (2, DAMC) were shown to possess radical scavenging property and strongly inhibit membrane lipid peroxidation. Although free polyphenolic compounds are known to be antioxidants, the antioxidant action of the acetoxy compound DAMC was intriguing. Hence, pulse radiolysis studies were undertaken to explain the antioxidant action of DAMC. Accordingly, DAMC and DHMC were separately reacted with the system generating azide radicals and the resulting transient spectra were recorded. The spectra so obtained in both the cases demonstrated peak at 410 nm, characteristic of phenoxyl radical. The rate constants for the formation of phenoxyl radical from DHMC and DAMC were 34 x 10(8) M(-1) s(-1) and 6.2 x 10(8) M(-1) s(-1), respectively. We propose that the free radical mediated oxidation of DAMC initially produces a radical cation that loses an acetyl carbocation to yield the phenoxyl radical. It is possible to conclude that the mechanism of the antioxidant action of DAMC follows the pathway similar to that of DHMC involving the formation of a stable phenoxyl radical.

Synthesis of E- and Z-pyrazolylacrylonitriles and their evaluation as novel antioxidants

A facile synthesis of (Z)- and (E)-2-(5-arylpyrazol-3-yl)-3-(pyrrol-2-yl)acrylonitriles and (Z)-2-(1,3-diarylpyrazol-5-yl)-3-pyrrol-2-yl)acrylonitriles, and isomerisation of (Z)-2-(5-arylpyrazolyl)acrylonitriles to (E)-2-(5-arylpyrazolyl)acrylonitriles under basic conditions have been reported. (Z)-2-(1,3-Diarylpyrazolyl)acrylonitriles did not undergo isomerisation under the similar conditions. New compounds were identified on the basis of their spectral data (1H-, 13C-, 1H-1H COSY, NOESY, NOE, HMQC NMR, IR, UV and EI mass). The structures of one acrylonitrile and five of their precursor 6-arylpyran-2-ones and cyanomnethylpyrazoles were confirmed by X-ray crystallographic studies. Effects of pyrazolylacrylonitriles and their precursors on rat liver-microsomal lipid peroxidation were evaluated in vitro with a view to establish structure activity relationship and to identify a lead compound.

Oligomerization of anthrax toxin protective antigen and binding of lethal factor during endocytic uptake into mammalian cells

The protective antigen (PA) protein of anthrax toxin binds to a cellular receptor and is cleaved by cell surface furin to produce a 63-kDa fragment (PA63). The receptor-bound PA63 oligomerizes to a heptamer and acts to translocate the catalytic moieties of the toxin, lethal factor (LF) and edema factor (EF), from endosomes to the cytosol. In this report, we used nondenaturing gel electrophoresis to show that each PA63 subunit in the heptamer can bind one LF molecule. Studies using PA immobilized on a plastic surface showed that monomeric PA63 is also able to bind LF. The internalization of PA and LF by cells was studied with radiolabeled and biotinylated proteins. Uptake was relatively slow, with a half-time of 30 min. The number of moles of LF internalized was nearly equal to the number of moles of PA subunit internalized. The essential role of PA oligomerization in LF translocation was shown with PA protein cleaved at residues 313-314. The oligomers formed by these proteins during uptake into cells were not as stable when subjected to heat and detergent as were those formed by native PA. The results show that the structure of the toxin proteins and the kinetics of proteolytic activation, LF binding, and internalization are balanced in a way that allows each PA63 subunit to internalize an LF molecule. This set of proteins has evolved to achieve highly efficient internalization and membrane translocation of the catalytic components, LF and EF.

Liposomes fuse with sperm cells and induce activation by delivery of impermeant agents

Sperm cell activation is a critical step in fertilization. To directly investigate the cell signaling events leading to sperm activation it is necessary to deliver membrane impermeant agents into the cytoplasm. In this study, the use of liposomes as possible agent-loading vectors was examined using (1) the octadecylrhodamine B (R18) and NBD phosphatidylethanolamine (NBD DHPE)/rhodamine phosphatidylethanolamine (rhod DHPE) fusion assays in bulk samples, (2) membrane transfer of fluorescence from liposome membranes labeled with R18 and rhodamine-tagged phosphatidylethanolamine (TRITC DHPE), and (3) lumenal transfer of impermeant calcium ions from liposomes to sperm cells, a process that stimulated sperm cell activation. Intermediate-sized unilamellar liposomes (98.17+/-15.34 nm) were prepared by the detergent-removal technique using sodium cholate as the detergent and a phosphatidylcholine/phosphatidylethanolamine/cholesterol (2:1:1 mole ratio) lipid composition. In the R18 fusion assays, self-quenching increased logarithmically with increasing concentrations of R18 in the liposome membranes; addition of unlabeled sperm to R18-labeled liposomes lead to a rapid release of self-quenching. In the NBD DHPE/rhod DHPE resonance energy transfer (RET) fusion assay, RET was rapidly reduced under similar conditions. In addition, individual sperm became fluorescent when TRITC DHPE-labeled liposomes were incubated with unlabeled sperm cells. Incubation of sperm cells with empty liposomes did not significantly affect sperm cell activation and did not alter cell morphology. However, incubation with Ca (10 mM)-loaded liposomes resulted in a time-dependent increase in sperm cell activation (7.5-fold over controls after 15 min). We conclude that liposomes can be used for direct loading of membrane-impermeant agents into sea squirt sperm cell cytoplasm, and that delivery occurs via fusion and content intermixing.

Mechanism of biochemical action of substituted 4-methylbenzopyran-2-ones. Part 4: hyperbolic activation of rat liver microsomal NADPH-cytochrome C reductase by the novel acetylator 7,8-diacetoxy-4-methylcoumarin

The effect of 7,8-diacetoxy-4-methylcoumarin (DAMC) has been studied on hepatic NADPH cytochrome C reductase-- an enzyme participating in the microsomal electron transport. The preincubation of liver microsomes with DAMC resulted in a time-dependent activation of NADPH cytochrome C reductase. The catalytic activity of the enzyme enhanced nearly 600% by 25 microM concentration of DAMC after 10 min of preincubation. The action of DAMC on the reductase resulted in enhanced v(max) while Km remained constant. A plot of 1/v(max) as a function of DAMC concentration resulted in a non-linear, but rectangular hyperbola indicative of hyperbolic activation. DAMC was also proved to be effective in significantly enhancing the activity of NADPH cytochrome C reductase in vivo. 7,8-Dihydroxy-4-methylcoumarin (DHMC), the deacetylated product of DAMC failed to irreversibly activate the enzyme. The activation effect of DAMC upon the enzyme was abolished by p-hydroxymercury benzoate. The role of a transacetylase in transferring the acetyl group of DAMC to the amino acid(s) of the active site of NADPH cytochrome C reductase causing irreversible enzyme activation is enunciated.

Mechanism of biochemical action of substituted 4-methylbenzopyran-2-ones. Part 3: A novel mechanism for the inhibition of biological membrane lipid peroxidation by dioxygenated 4-methylcoumarins mediated by the formation of a stable ADP-Fe-inhibitor mixed ligand complex

7,8-Dihydroxy-4-methylcoumarin (DHMC) and 7,8-diacetoxy-4-methylcoumarin (DAMC) have been reported to effectively inhibit in-vivo lipid peroxidation in rat tissues induced by CCl4 and paraquat. DHMC was found to readily impart green colour to the lipid peroxidation incubation mixture containing ADP and Fe3+, whereas DAMC formed green complex only upon incubation with liver microsomes, confirming our earlier observation that liver microsomal deacetylase hydrolyses DAMC to DHMC. Sensitive pH metric technique revealed the formation of ADP-Fe-DHMC ternary complex with highest stability, while Fe-DHMC and ADP-DHMC had negligible stabilities concluding that ADP-perferryl ion formation is prevented by DHMC resulting in the production of stable ternary mixed ligand complex (ADP-Fe-DHMC), thereby inhibiting the formation of O2-, and eventually other reactive oxygen species (ROS) responsible for membrane lipid peroxidation.

Effects of fumonisin B1-contaminated feeds on weanling angora goats

Two diets containing no (<1.0 mg/ kg) or 95 mg of fumonisin B1 (FB1)/kg were fed to eight weanling Angora goats for 112 d. Dry matter intake, apparent nutrient digestibilities, serum chemistry profiles, sphingolipid concentrations, and persistency of FB1 in tissues were evaluated. No differences (P>.10) were found between control and treated goats in terms of DMI, apparent nutrient digestibilities, or ADG. Elevated concentrations (P<.10) of blood-borne enzymes such as aspartate aminotransferase, lactate dehydrogenase, and gamma glutamyl transpeptidase and increased concentrations of cholesterol and triglycerides indicated mild liver damage and kidney dysfunction in treated goats. Linear relationships (P<.10) were observed between these serum constituents and duration of FB1 exposure. The sphingolipid analysis of liver, kidney, and heart tissues showed elevated free sphinganine:free sphingosine ratios in the treated group. The elevated sphingolipid ratios were mainly due to increased concentrations of free sphinganine in tissues. However, without serum profile and sphingolipid analyses, fumonisin toxicosis would not have been recognized because treated animals showed no clinical signs of toxicosis throughout the trial. No measurable FB1 was present in liver, kidney, and heart tissues (detection limit of 1 ppm). However, further research is needed to analyze tissues for FB1 or its metabolites with a lower detection limit. In conclusion, goats can be fed for up to 112 d with diets containing 95 mg FB1/kg of diet without any overt signs of toxicosis and also without any effect on live weight gain.

Mechanism of biochemical action of substituted 4-methylbenzopyran-2-ones. Part II: Mechanism-based inhibition of rat liver microsome-mediated aflatoxin B1-DNA binding by the candidate antimutagen 7,8-diacetoxy-4-methylcoumarin

7,8-Diacetoxy-4-methylcoumarin (DAMC), with no prerequisite for oxidative biotransformation has been reported to produce suicide inactivation of microsomal cytochrome P-450-catalysed formation of aflatoxin B1-8,9-oxide that binds to DNA. Parenteral administration of DAMC to rats caused significant inhibition of AFB1 binding to hepatic DNA in vivo as well as AFB1-induced micronuclei formation in bone marrow cells. These results highlight the antimutagenic potential of DAMC.

Mechanism of biochemical action of substituted 4-methylbenzopyran-2-ones. Part I: Dioxygenated 4-methyl coumarins as superb antioxidant and radical scavenging agents

Twenty-three 4-methylcoumarins bearing different functionalities have been examined for the first time for their effect on NADPH-catalysed liver-microsomal lipid peroxidation with a view to establish structure-activity relationship. Dihydroxy- and diacetoxy-4-methylcoumarins produced dramatic inhibition of lipid peroxidation. 7,8-Diacetoxy-4-methylcoumarin and 7,8-dihydroxy-4-methylcoumarin were found to possess superb antioxidant and radical scavenging activities.

Endogenous apolipoprotein E suppresses LPS-stimulated microglial nitric oxide production

The human apolipoprotein (apo) E4 isoform is associated with an increased risk for Alzheimer's disease (AD) and poor prognosis after acute CNS injury. Addition of human apoE inhibits murine microglial activation in culture, suggesting that microglia might be an important physiological target of apoE. In the present study, we examined the role of endogenous murine apoE in modulating microglial nitric oxide (NO) production following lipopolysaccharide (LPS) stimulation. Brain cultures from apoE-deficient mouse pups showed enhanced NO production relative to cultures from wild-type mice and from transgenic mice expressing the human apoE3 isoform, demonstrating that endogenous apoE produced by glial cultures is capable of inhibiting microglial function. ApoE produced within the brain may suppress microglial reactivity and thus alter the CNS response to acute and chronic injury.

The effect of antibiotic prophylaxis on the healing of exit sites of peritoneal dialysis catheters in rats

OBJECTIVE

To evaluate the influence of intraperitoneal (i.p.) antibiotic (AB) prophylaxis on the quality of healing and infection rates of exit sites in peritoneal dialysis catheters.

STUDY DESIGN

Twenty-one Sprague-Dawley rats were dialyzed 3 times per day for 6 weeks. Dianeal solution containing AB was used for all the rats during the first 5 days. The animals were randomized on the sixth day into three groups: group A (AB-free after randomization), group B (AB for 3 weeks), and group C (AB during 6 weeks). Scores were given to each exit site according to the observation. Mean scores from each group were compared in an attempt to find significant differences between the groups. Dialysate and exit-site drainage samples were taken weekly for microbiology.

RESULTS

Eight episodes of peritonitis were diagnosed, six in group A and two in group B. The most common bacteria causing peritonitis were gram-negative rods. The mean scores were not significantly different between groups C and B throughout the study, even after the discontinuation of the prophylaxis. Group A, when compared to the other two groups, had significantly higher scores after the second week and throughout the rest of the study.

CONCLUSION

Intraperitoneal antibiotic prophylaxis for 3 weeks after catheter implantation is an effective way to prevent early colonization of exit sites, providing a better healing quality and lower incidence of catheter-related infection. Although the extension of the prophylaxis for 6 weeks seems to be beneficial, it was not statistically proven in this study.

Idiosyncratic pacing with a commercial pacing system analyzer

An idiosyncratic response of the Medtronic AV Pacing System Analyzers (models 5311 [unipolar] and 5311B [bipolar]) during high output AAI pacing is reported. Using the bipolar analyzer with unipolar cables and a 2734 adaptor, ventricular capture was noted during high output AAI pacing when the ground was displaced from the patient. Using the unipolar analyzer with bipolar cables also resulted in ventricular capture with high output AAI pacing. Implanting physicians should be aware of this phenomenon to avoid false conclusions.

Effect of dialysis modality and membrane transport characteristics on dialysate protein losses of patients on peritoneal dialysis

OBJECTIVE

To determine if peritoneal dialysis modality has an impact on protein losses in dialysate.

DESIGN

Retrospective, cross-sectional study.

PATIENTS

190 patients who had selected peritoneal dialysis were classified into one of four transport categories (high, high-average, low-average, or low) based on standard peritoneal equilibration test results. Patients were then assigned to continuous ambulatory peritoneal dialysis (CAPD) or nightly intermittent peritoneal dialysis (NIPD) based on membrane transport characteristics and individual preferences.

RESULTS

Patients with similar membrane transport characteristics had essentially no differences in dialysate protein and albumin losses whether treated with CAPD or NIPD.

CONCLUSIONS

Although high transporters may be better managed with short-dwell therapies such as nocturnal intermittent peritoneal dialysis or daily ambulatory peritoneal dialysis, consistent marked decreases in protein losses cannot be cited as a benefit of NIPD over CAPD.

Benzodiazepine receptors in the post-mortem brain of suicide victims and schizophrenic subjects

To examine the role of benzodiazepine (BZ) receptors in suicide and schizophrenia, we determined BZ receptors in post-mortem brain (Brodmann's area 10) obtained from suicide victims, schizophrenic patients, and control subjects using [3H]RO15-1788 as the radioligand. The maximum number of binding sites (Bmax) of BZ receptors in the cortex of suicide victims was significantly higher compared with controls, but this increase was mainly due to those suicide victims who died by violent means and whose Bmax was significantly higher than of those who died by non-violent means or control subjects. In schizophrenic patients, Bmax was not significantly different from that of control subjects. When the schizophrenic subjects were separated into two groups, those on neuroleptics and those off neuroleptics for at least 12 months, however, the mean Bmax of BZ receptors in the prefrontal cortex in post-mortem brain obtained from schizophrenic patients on neuroleptics was significantly lower than Bmax in drug-free schizophrenic patients or normal controls. There were no significant differences among groups in values of the apparent dissociation constant (KD) of [3H]RO15-1788 binding. These results suggest that BZ receptors are up-regulated in the cortex of suicide victims, specifically those who used violent means, and that neuroleptic treatment may result in decreased central BZ receptor binding in the cortex of schizophrenic patients. Thus, the method of suicide and previous exposure to neuroleptics should be considered in the interpretation of data on BZ receptors.

Apolipoprotein E suppresses glial cell secretion of TNF alpha

Apolipoprotein E (apoE) is a 299 amino acid protein with multiple biological functions. Initially described in the context of cholesterol metabolism, apoE also has immunomodulatory properties and recent evidence has implicated a role for apoE in neurological disease. One possibility is that apoE, which is the predominant apolipoprotein produced intra-axially, may modify the CNS response to acute and chronic injury. We prepared mixed neuronal-glial cultures from apoE deficient mouse pups and measured secretion of TNF alpha after stimulation with lipopolysaccharide (LPS) in the presence and absence of human recombinant apoE3 and E4. We demonstrate that preincubation with apoE blocks glial secretion of TNF alpha in a dose-dependent manner. This effect is independent of any direct effect of apoE on cell viability and is greatest when apoE is preincubated with the cell culture for 24 h.

Cytotoxicity of anthrax lethal factor microinjected into macrophage cells through Sendai virus envelopes

Lethal toxin (LT) secreted by Bacillus anthracis consists of two proteins, protective antigen (PA) and lethal factor (LF). LT causes lysis of macrophages and derived cell lines at low concentrations. PA binds to the cell surface receptors and mediates translocation of LF into cytosol of mammalian cells. Internalization of LF into cytosol by osmotic lysis of pinocytic vesicles requires high concentration of LF for cell lysis. To examine the possible cell lysis by LF at low concentration, we introduced LF directly into cytosol of J774A.1 cells through reconstituted Sendai virus envelopes. The introduction of LF lysed J774A.1 cells in a concentration dependent manner. Internalization of PA alone through virosome had no toxic effect on J774A.1 cells. In the process of cytotoxicity LF was not cleaved by cellular proteases. Unlike many protein toxins, golgi was not involved in the expression of lethal toxin activity. These results indicate that LF is the toxic component of anthrax lethal toxin and prior proteolytic processing or trafficking through golgi is not required for its activity.

Carbamylated hemoglobin: a potential marker for the adequacy of hemodialysis therapy in end-stage renal failure

Urea can dissociate in vivo to form isocyanic acid which can react with hemoglobin to form carbamylated hemoglobin. Previous work has shown that formation of carbamylated hemoglobin depends upon both the severity and the duration of renal failure. To determine whether carbamylated hemoglobin can be used as an assessment of the adequacy of hemodialysis treatment, we prospectively studied 55 stable patients who regularly attended our hospital dialysis program. Carbamylated hemoglobin was greater in those patients with a Kt/V of < or = 1.1 compared to those with a Kt/V of > 1.1 (120 +/- 8 micrograms VH/gHb versus 99 +/- 7, P < 0.01), and there was a negative correlation with Kt/V (r = -0.37, P = 0.007). There were positive correlations between carbamylated hemoglobin and the time-averaged urea concentration (r = 0.4, P = 0.004), and a negative correlation with the urea reduction ratio (r = -0.37, P = 0.01). Carbamylated hemoglobin may therefore be a useful marker of the degree of uremia, just as glycosylated hemoglobin is used in the assessment of patients with diabetes mellitus.

Wegener's granulomatosis involving the urogenital tract

OBJECTIVE

To report eight cases of limited Wegener's granulomatosis (WG) affecting the urogenital tract (testis, ureter, bladder, urethra and penis) and to emphasize the importance of the anti-neutrophil cytoplasm antibody (ANCA) test in establishing the diagnosis.

PATIENTS AND METHODS

Eight patients (six men and two women, aged 41-77 years) were diagnosed with WG, based on their previous medical history, the ANCA test and by biopsy.

RESULTS

In each case, there were difficulties and delay in establishing the diagnosis of WG and starting appropriate treatment. The ANCA test was positive in seven cases and helped in establishing the diagnosis, in conjunction with the confirmation of vasculitis and granulomata by biopsy.

CONCLUSION

We advocate ANCA testing in patients presenting with limited urogenital disease in association with a past or present relevant history of arthritis, skin vasculitis and/or biopsies showing necrosis or non-specific inflammation.

Effects of fusarium moniliforme isolates on tissue and serum sphingolipid concentrations in horses

Disruption in sphingolipid (SL) metabolism is a biomarker of exposure to fumonisins. The role of altered SL metabolism in the pathogenesis of fumonisin toxicoses is not understood. A 27-d feeding trial in horses compared the toxic effects of 3 strains of Fusarium moniliforme: RRC 415, cultured from corn in MS; AU 2/3, cultured from feed associated with clinical signs of duodenitis-proximal jejunitis (DPJ) in horses in AL; and MRC 826, cultured from corn in South Africa and shown to cause equine leukoencephalomalacia (ELEM). These were cultured on corn and diluted with clean corn and grain mixed with molasses (sweet feed) to final concentrations of < 1, 65-130 and 200 mg fumonisin B1 (FB1)/kg, respectively. None of the horses developed DPJ, but horses fed MRC 826 had intestinal lesions consistent with DPJ and horses fed AU 2/3 and MRC 826 developed ELEM. Serum SL concentrations were analyzed in horses fed control and F moniliforme culture material, in brain and/or intestinal tissues in healthy horses (euthanized in AL and IL), and in horses fed AU 2/3 and MRC 826. Serum sphinganine (Sa): sphingosine (Szero) ratios were significantly elevated in horses fed AU 2/3 and MRC 826. Sphinganine concentrations were significantly elevated in the hypothalamus-dentate gyrus and brain stem in horses fed AU 2/3, compared to healthy horses. Sphingosine concentrations were significantly elevated in the proximal duodenum and ileum of MRC 826 horses compared to healthy horses. The brain and intestinal tissues in horses with and without pathological lesions did not have changed Sa:S(zero).

Role of transabdominal pelvic ultrasound and computed tomography in the detection of bladder involvement in advanced cancer of the cervix

The imaging data of 125 advanced cancer cervix patients attending the Institute Rotary Cancer Hospital between June 1992 and June 1994 was reviewed. The aim of the study was to assess the role of transabdominal pelvic ultrasound (TAPUS) and computed tomography (CT) in the detection of bladder involvement. TAPUS was performed in 65 patients (group I) and CT in 60 patients (group II). With respect to clinical stage, both groups were comparable. Cystoscopy was performed in all patients and the findings were taken as the gold standard for comparison of imaging data. The sensitivity, specificity and accuracy of TAPUS were 65, 94 and 75%, respectively, while those for CT were 80, 92 and 85%, respectively. Results of the present study reveal that the accuracy of TAPUS is comparable to the accuracy of other imaging modalities in the detection of bladder involvement in cervical cancer and that it should be used more frequently in developing countries that deal with a large number of cervical cancer patients in view of its easy availability, low cost and absence of exposure to radiation.

Acrochordon, diabetes and associations

A study of clinical profile of acrochordons was carried out in 100 patients. Their association with diabetes mellitus and other disorders was studied. Acrochordons were found to be closely associated with pseudo-acanthosis nigricans, seborrhoeic keratosis, obesity and non-insulin dependent diabetes mellitus.

The visiting lectureship on aboriginal health: an educational initiative at the University of Toronto

Many recent reports on Aboriginal issues have identified three major deficits in Canadian universities: a lack of Aboriginal curriculum content, a lack of faculty role models, and low student enrollment. Many health professional schools have responded by recruiting more Aboriginal students and by introducing Native content into their curricula. This paper describes the six-year experience of the annual program of the Visiting Lectureship on Native Health at the University of Toronto as one of the ways to increase the Aboriginal curricular content. The three-week program covers the selected Aboriginal health issue by sequentially exploring its historical background, the extent of the current problem and its future solutions. Over six years, 37 Native speakers delivered 83 lectures, 19 public fora and 98 seminars and workshops to 3 universities and 12 professional and community agencies. Over 7,900 individuals have participated in the program and the response has been very positive.

Adequacy of solar energy to keep babies warm

OBJECTIVE

Solar energy could be used as an alternate energy source for keeping neonates warm especially in tropical countries. The present study investigated the efficacy of solar powered room heating system.

SETTING

Referral center for neonatal care.

INTERVENTION

A fluid system heated by solar panels and circulated into a room was used to maintain room temperature. A servocontrolled heating device was used to regulate and maintain desired room temperature.

MAIN OUTCOME MEASURES

Neonatal rectal temperature and room temperature.

RESULT

Infants between 1750-2250 g were observed to require a mean room temperature of 32.5 degrees C to maintain normothermia. In 85 infants less than 1500 g, of the 5050 infant temperature records, only 3% showed a record less than 36 degrees C.

CONCLUSIONS

Solar powered room heating is effective in maintaining infant temperature and is cost-effective as compared to the existing warming devices.

Clinical features and outcome of patients with thin and ultrathin glomerular membranes

There is considerable disagreement regarding the natural history of renal disease associated with thin glomerular basement membranes (TGBM). We followed 43 patients (19 male), mean age 41.6 years (range 19-73) for a mean of 88 months (48-140). TGBM was recognized in adults when glomerular basement membrane thickness, measured from multiple sites in electronmicrographs of renal biopsy tissue as the harmonic mean, was < 320 nm. At presentation, 95% had microscopic haematuria, 12% macroscopic haematuria, 14% loin pain, 28% proteinuria, and 14% hypertension. There was no difference in GBM width between the sexes (male 258 nm vs. female 251 nm) but there was a significant negative correlation between age and GBM width (r = -0.53, p < 0.001), with older patients having the thinnest membranes. Twenty six patients had ultrathin GBM (< 270 nm), of whom 54% had 3+ haematuria vs. 12% of the group with BM > 270 nm (p < 0.01). In the ultrathin group, 71% had loss of anionic charge from the GBM, vs. 17% in those with membranes which were thin but > 270 nm (p < 0.05). Proteinuria occurred more frequently in those with GBM > 270 nm, 65% vs. 8% in the ultrathin group (p < 0.01). Thin GBM were associated with a benign prognosis, as after a mean follow-up of 85 months (48-140), there was no significant change in either serum creatinine or mean arterial blood pressure. Patients with ultrathin GBM had greater loss of GBM anionic charge, which might result in both an alteration of flow characteristics within the glomerular capillaries and also increased fragility of the glomerular basement membrane with likelihood of rupture and resultant macroscopic haematuria.

A prospective study of the effect of noncompliance on small solute removal in continuous ambulatory peritoneal dialysis. Preliminary report

In nine patients on continuous ambulatory peritoneal dialysis (CAPD) who were in stable condition, the authors measured the effects of an extra daily exchange on small solute removals and clearances and the measured/predicted creatinine production (M/P). The goal was to evaluate the sensitivity of M/P to single exchange noncompliance. Daily collections of urine and dialysate were performed on the usual prescribed program and on the next day with an extra exchange of usual exchange volume. The average increase in drain volume of 26% was associated with an average increase in M/P of 6%. The maximum M/P increase was 15%; the percentage increase in M/P correlated inversely with renal creatinine clearance. Daily total urea clearance normalized to total body water by dialysis and renal function increased 12%. Extrapolating these findings suggests that an average patient with a baseline M/P near 1.0 and renal creatinine clearance of 5 ml/min would require more than 50% drain volume noncompliance to yield a M/P of 1.24 on the complaint day. A 50% noncompliance may not yield a M/P greater than 1.0 on the first compliant day if baseline M/P is less than 0.94. The authors suggest monitoring daily urine and dialysis creatinine output because M/P creatinine is relatively insensitive to noncompliance (particularly in patients with residual renal function) and because there are questions about the accuracy of predictions in patients with renal failure using formulae established in different populations. The authors recommend simply monitoring total daily creatinine output and establishing patients as their own controls. The authors provide a table for the interpretation of changes in creatinine output in conjunction with changes in other routinely monitored parameters.

Aortic valve disease in patients with Wegener's granulomatosis

Wegener's granulomatosis usually affects the upper and lower respiratory tract as well as the kidney. Cardiac involvement is rare, although electrocardiographic abnormalities, coronary artery vasculitis, cardiac arrhythmias, and myocardial infarction have been described. We report two cases of aortic valve disease associated with Wegener's granulomatosis that were progressive despite clinical remission of Wegener's disease in both patients. One patient has undergone successful valve replacement and the other is currently awaiting surgery. Aortic valve histopathology showed myxoid degeneration that was most likely due to previously active vasculitis affecting the vessels of the aortic wall and valvular necrosis with subsequent progressive degeneration of the cusps.

Plasmacytoma of the hyoid

A case of plasmacytoma arising from the hyoid bone is described, this is a distinctly unusual site, as the marrow-containing flat bones are more commonly affected. On a review of the literature this appears to be the first report of plasmacytoma occurring in the hyoid bone. The patient underwent a CT scan and plain radiographs. Histopathology was diagnostic.

Treatment of hypercalcaemia with pamidronate in patients with end stage renal failure

Pamidronate was given to 10 patients with end stage renal failure who had become symptomatically hypercalcaemic due to the use of calcium based phosphate binders and alphacalcidol. All patients were initially treated with rehydration, increased dialysis and withdrawal of drugs, however despite this they remained symptomatic and the serum calcium remained elevated, mean 3.89 mmol/l (range 3.44-4.74). Pamidronate was given, and the serum calcium had declined to 2.92 mmol/l (2.79-3.84), p < 0.01 by the third day. The reduction in serum calcium observed with pamidronate was more rapid than that in 9 patients who developed asymptomatic hypercalcaemia, mean serum calcium 3.45 mmol/l (3.4-3.56), with an actual median reduction of 0.72 mmol/l (0.37-1.30) in the pamidronate group after 3 days compared to 0.20 mmol/l (0.10-0.52) in the conservatively treated asymptomatic group, p < 0.01, and a median percentage decrease of 19% (10-30) in the pamidronate group and 6% (3-15) in the asymptomatic group, p < 0.01. In this study pamidronate was a safe and effective agent in reducing serum calcium in a group of hypercalcaemic dialysis patients.

Differentiation of acute from chronic renal impairment by detection of carbamylated haemoglobin

Detection of carbamylated haemoglobin, measured as valine hydantoin per g haemoglobin (VH/g Hb), may be useful in differentiating between patients with acute or chronic renal failure. To assess this test, we measured carbamylated haemoglobin prospectively in 42 consecutive patients referred to the regional renal unit with a serum creatinine in excess of 500 mumol/L and a provisional diagnosis of acute renal failure (ARF). Patients were subsequently classed on clinical criteria as having ARF (20) or acute on chronic renal failure (AonCRF, 22). 24 patients with stable chronic renal failure (CRF), matched for degree of renal impairment, were also studied. Standard biochemical tests and haemoglobin were similar among the three groups. Patients with ARF of 10 or less days duration had a lower median (interquartile range [IQR]) carbamylated haemoglobin concentration than those with a longer duration of ARF (29 [27-35] vs 72 [60-83] micrograms VH/g Hb; p < 0.01). Carbamylated haemoglobin concentration was lower in the ARF group than in the AonCRF or CRF groups (42 [31-67], 116 [83-119], and 148 [122-210] micrograms VH/g Hb, respectively; p < 0.001). All patients with a degree of acute and potentially, reversible renal failure (ARF and AonCRF) had a carbamylated haemoglobin concentration below 190 micrograms VH/g Hb (sensitivity 100%, positive predictive value 62% for this cut-off). When the ratio of carbamylated haemoglobin to serum creatinine was calculated, to correct for degree of renal failure, a value of less than 0.2 had a 100% sensitivity and 80% positive predictive value for dividing patients with potentially reversible renal failure from those with CRF. Measurement of carbamylated haemoglobin was useful in identifying patients with acute and potentially reversible forms of renal failure. This test could be of clinical value in deciding which patients require urgent referral for further management and treatment in hospitals without specialist nephrological care.

Double V-groove ridge waveguides on a silicon substrate

A new design for fabricating low-loss ridge waveguides by anisotropically etching two parallel V-grooves on a silicon substrate is proposed and demonstrated. Polymethyl methacrylate is used as the waveguide medium, with silicon dioxide and air as the lower and upper cladding, respectively. Because of the smooth sidewalls of the ridge structure, transverse confinement within the double V-groove ridge waveguide, with scattering losses of ~ 1.0 dB/cm are observed.