Hepatitis B virus reactivation risk varies with different chemotherapy regimens commonly used in solid tumours.

BACKGROUND: Hepatitis B virus (HBV) reactivation may occur with chemotherapy and has significant morbidity and mortality. The United States Centre for Disease Control and Prevention recommends pre-chemotherapy hepatitis B screening for all cancer patients, while the American Society of Clinical Oncology finds that there is insufficient evidence currently to support such a recommendation. Apart from anthracyclines, HBV reactivation rates from other commonly used chemotherapy regimens in solid tumours are not well described. METHODS: We compared HBV reactivation risk in patients receiving several commonly used chemotherapy regimens for solid tumours associated with different immunosuppression risk at a tertiary cancer centre in an HBV endemic region. RESULTS: A total of 1149 patients were identified, including 434, 196, 245 and 274, respectively, who received doxorubicin-based, oxaliplatin- or irinotecan-based, carboplatin/gemcitabine, and capecitabine chemotherapy. HBV screening rate was 39% overall. Thirty out of 448 (7%) screened patients were HBsAg positive and 28 out of 30 received prophylactic antiviral therapy with no reactivation. Three out of 1149 patients overall (0.3%) developed HBV reactivation, all from the unscreened doxorubicin group (3 out of 214, 1.4%). No unscreened patients (0 out of 487) in the other three treatment groups developed reactivation (P<0.001). CONCLUSION: Not all chemotherapy regimens result in HBV reactivation. Routine hepatitis B screening for low- or moderate-risk regimens may not be warranted.

A new feeding tube which is secure and easy to change.

Loss of a normal swallowing reflex as in dysphagic stroke is the commonest indication for long-term tube feeding. For this, either the nasogastric tube or the percutaneous endoscopic gastrostomy tube is used, with the former being uncomfortable. The latter tube is neither secure nor easy to change. A new feeding tube invented in Singapore uses a loop and lock configuration to make it comfortable for the patient, impossible to pull out accidentally, and easy to change. This third-generation feeding tube has the potential to be the new global standard.

An ecdysone-inducible putative "DEAD box" RNA helicase in the spruce budworm (Choristoneura fumiferana).

RNA helicases are a family of enzymes that unwind nucleic acid duplexes, such as RNA/RNA and RNA/DNA, in a 3' to 5' direction into single-stranded polynucleotides. A putative RNA helicase cDNA (CfrHlc64) was isolated from the spruce budworm, Choristoneura fumiferana. CfrHlc64 was 1998 nucleotides in length, and the deduced protein had 565 amino acids with a predicted molecular mass of 64 kDa. It contained eight functional motifs conserved in the "DEAD box" family of RNA helicases. The deduced amino acid sequence showed 10-50% identities to homologues of other species from bacteria to human. In vitro expression of the cDNA resulted in recombinant proteins of 64 kDa as expected from the deduced amino acid sequence. Northern blotting and RT-PCR analyses revealed the presence of CfrHlc64 mRNA in all developmental stages from embryo to adult. Higher levels of CfrHlc64 mRNA were detected in the fat body and midgut than in the epidermis of sixth instar larvae. The CfrHlc64 protein was distributed mainly in the fat body. Female adults expressed CfrHlc64 mRNA at higher levels than male adults. The nonsteroidal ecdysone agonist, tebufenozide, enhanced the expression of CfrHlc64 in a dose-dependent manner.

Glutathione S-transferase from the spruce budworm, Choristoneura fumiferana: identification, characterization, localization, cDNA cloning, and expression.

A 23-kDa protein that was present at higher levels in diapausing 2nd instar larvae than in feeding 2nd instar larvae of Choristoneura fumiferana was purified, and polyclonal antibodies were raised against this protein. The antibodies were subsequently used to screen a cDNA library that was constructed using RNA from 2nd instar larvae. Eight identical cDNA clones were isolated. The cDNA clone had a 665-bp insert and the longest open reading frame coded for a 203-amino acid protein with a predicted molecular mass of 23.37 kDa. The deduced amino acid sequence showed high similarity to glutathione S-transferases and therefore, the cDNA clone was named C. fumiferana glutathione S-transferase (CfGST). Identity of CfGST was confirmed by using affinity-purification as well as enzyme activity assay. CfGST was closer in similarity to insect GST2 members than GST1 members. The apparent Vmax of the purified CfGST towards the substrates glutathione and 1-chloro-2,4-dinitrobenezene (CDNB) were similar. However, the enzyme had a three-fold higher affinity towards CDNB than glutathione. Analyses using Northern blot, immunoblot and immunocytochemistry demonstrated that the fat body was the major tissue where the enzyme was synthesized and stored. Higher levels of CfGST protein were present in diapausing 2nd instar larvae compared to feeding 2nd and 6th instar larvae, suggesting that besides detoxification CfGST may have other roles during insect development that are not readily apparent at present. The CfGST cDNA was expressed in a recombinant baculovirus expression system and an active enzyme was produced.

Activation and fragmentation of Bacillus thuringiensis delta-endotoxin by high concentrations of proteolytic enzymes.

Commercial enzymes and insect gut juice at various concentrations were used to digest Bacillus thuringiensis subsp. sotto Cry1Aa protoxin and examine the fragmentation pattern and effect on insecticidal activity. Trypsin at both high (5 mg/mL) and low (0.05 mg/mL) concentrations converted protoxin to toxin with no difference in insecticidal activity against Bombyx mori larvae. In both cases, the toxin protein had an apparent M(r) of 58.4 kDa (SDS-PAGE). Active toxin of identical M(r) was also produced with low concentrations of Pronase and subtilisin, but at high concentration, it was degraded into two protease-resistant fragments of apparent M(r) 31.8 and 29.6 kDa, and exhibited no insecticidal activity. Sequencing data established the primary cleavage site to be in domain II, the receptor-binding region of the toxin, in an exposed loop between two beta-sheet strands. Fragmentation was not observed, however, when the digests were analyzed by native protein techniques, but rather the toxin molecule appeared to be intact. The amount of activated toxin produced by Choristoneura fumiferana gut juice was markedly reduced when the gut-juice concentration was increased from 1 to 50% and correlated with a loss in insecticidal activity. However, no lower M(r) protease-resistant fragments were evident in the SDS-PAGE of these digests.

Synthesis of the same two proteins prior to larval diapause and pupation in the spruce budworm, Choristoneura fumiferana.

Spruce budworm larvae produce large quantities of two proteins (Choristoneura fumiferana diapause associated proteins 1 and 2, CfDAP1 and CfDAP2) that are diapause related. These proteins appeared soon after hatching and increased in abundance, reaching maximum levels by four days into the 1st instar, and they remained at high levels until three days after the termination of diapause. These two proteins were purified to homogeneity and their NH2-terminal sequences were obtained. Oligonucleotide primers designed on the basis of these NH2-terminal sequences were used in RT-PCR to isolate the cDNA fragments coding for these proteins. These PCR fragments were then used as probes to isolate the cDNAs that contained the complete coding region. The 2.5kb mRNAs coding for these proteins started to appear 24hr after hatching and large quantities of these mRNAs were detected in 1st instar and 2nd instar larvae until the 2nd instar larvae entered diapause. Low levels of these mRNAs were detected in the 2nd instar larvae that were preparing to enter diapause, in those that were in diapause as well as in those that terminated diapause. Low levels of CfDAP1 mRNA were also detected on days 1 and 2 after ecdysis to the 3rd instar. However, no CfDAP1 and CfDAP2 mRNAs could be detected during the 4th and 5th instar larval stages. The mRNAs reappeared 24hr after the 5th instar larvae molted into the 6th instar and increased to reach maximum levels by 60hr after ecdysis. The mRNA levels remained high until 156hr after ecdysis into the 6th instar (36-48hr before pupal ecdysis), after which they disappeared once again. Immunocytochemical analyses showed that CfDAP1 protein was present in 2nd and 6th instar larval fat body but not in 5th instar larval fat body. Thus, the same two genes were expressed for the first time before C. fumiferana larvae entered diapause and for a 2nd time before pupation.

A protein complex from Choristoneura fumiferana gut-juice involved in the precipitation of delta-endotoxin from Bacillus thuringiensis subsp. sotto.

A 75 kDa protein from spruce budworm (Choristoneura fumiferana) gut-juice has been isolated and shown to cause a specific precipitation of the delta-endotoxin from Bacillus thuringiensis subsp. sotto. This 75 kDa protein, separated by either column chromatography or SDS-PAGE, caused precipitation of the sotto toxin in both agarose diffusion gels and the PAGE gels. The precipitation event leads to limited proteolysis of the toxin and loss of larval toxicity. SDS-PAGE analysis of the precipitated toxin indicates that proteolysis of the toxin is not a prerequisite for precipitation. The protein responsible for precipitation, exhibits elastase-like activity and appears to be a complex which partially dissociates during boiling in SDS-PAGE sample buffer. Gut-juice from gypsy moth, forest tent caterpillar and white mark tussock moth also precipitated delta-endotoxin, but silkworm gut-juice gave a much weaker response. These results provide further evidence that, in the larval gut, differential processing of delta-endotoxin may play a role in the expression of activity towards various insect larvae.

Necrotising soft tissue infections as a complication of chickenpox.

Varicella gangrenosum, in which a necrotising soft tissue infection complicates the vesicular eruption of chickenpox, is rare. The condition may have devastating sequelae including disseminated intravascular coagulation and death. Survival is dependent on early diagnosis, adequate antibiotic coverage and, particularly, early surgical debridement. Three cases of varying severity are presented here together with a review of the available literature.

Production of antibodies against Bacillus thuringiensis delta-endotoxin by injecting its plasmids.

Bacillus thuringiensis insecticidal crystalline delta-endotoxin proteins are plasmid encoded. Specific antibodies against the delta-endotoxin were obtained in mice and rabbits by injecting isolated B. thuringiensis DNA plasmids into their muscles. Antibodies could be detected by ELISA as early as two weeks after the first injection. They formed immunoprecipitin lines with the toxin in the Ouchterlony agarose plate and neutralized the toxicity of the toxin. Because no special equipment, delivery mechanism or purification of the protein is required, this technique may provide a way to raise polyclonal antibodies to proteins encoded by bacterial plasmids and recombinant products.

Lymphocytic infiltration in focal thyroiditis: an ultrastructural case study.

In autoimmune thyroiditis, infiltrating lymphocytes play an important role in the disease process since they are known to release cytokines which can alter thyroid functions. The degree and site of lymphocytic infiltration in the thyroid gland have been used to differentiate between Hashimoto's disease and focal lymphocytic thyroiditis. Intraluminal lymphocytes have been reported to be absent in focal thyroiditis but present in Hashimoto's disease. However, we demonstrate here by transmission electron microscopy, that extrafollicular and intrafollicular lymphocytes could be present in focal lymphocytic thyroiditis. This seems to support the notion that focal lymphocytic thyroiditis could represent part of the spectrum of autoimmune thyroiditis and Hashimoto's thyroiditis.

Detection of Choristoneura fumiferana brush border membrane-binding molecules specific to Bacillus thuringiensis delta-endotoxin by crossed affinity immunoelectrophoresis.

Brush border membrane vesicles (BBMVs) prepared from midguts of Choristoneura fumiferana larvae were pretreated separately with the three CryIA delta-endotoxins from Bacillus thuringiensis subsp. kurstaki HD-1. Crossed affinity immunoelectrophoresis of the solubilized toxin-BBMV complexes, using antibodies raised against the toxins, revealed at least two peaks for each toxin. All complexes (BBMV bound toxin) migrated in the opposite direction to that of the free toxins. It is concluded that the toxins form stable complexes with membrane acceptor molecules, possibly receptors, and that there are at least two types of acceptor molecules present in the midgut epithelial cells of C. fumiferana that bind to all three toxins. The relative size of one of the BBMV-toxin peaks correlates with the in vivo potency of the toxins against C. fumiferana.

An analysis of 50 cases of restorative proctocolectomy.

Restorative proctocolectomy with ileal pouch-anal anastomosis is clearly the operation of choice for ulcerative colitis and polyposis coli. Not so clear is the best way to perform this operation. The technique used at the University of Pittsburgh is described. Utilising a meticulous mucosectomy with the patient in a prone jack-knife position, the ileal pouch-anal anastomosis was successfully performed in a series of 50 consecutive patients which included six with orthotopic liver graft, nine with a prior Hartmann procedure, ten with fulminant colitis and six with cancer. All patients were fully continent of stools, and except for one, had a good functional result. Complications were minor and included pelvic sepsis (n = 2), ileostomy-related complications (n = 6) and pouchitis (n = 7).

Treatment of low rectal cancers and pre-cancerous lesions with proctectomy and pullthrough colo-anal anastomosis.

There are conflicting reports on the functional outcome of the sphincter after a pullthrough colo-anal anastomosis. We report a series of 21 consecutive patients treated with this technique. Thirteen patients underwent operation for cancer, seven for villous adenoma and one for benign stricture. They were interviewed for stool frequency, continence and gas/stool discrimination, and the clinical records were reviewed. At 19 +/- 9 months (mean +/- SD) post-operation, 15 patients (71%) were perfectly continent, five (24%) had minor impairment in continence, and one (5%) was incontinent. Thirteen patients (62%) had two or less bowel actions per day, six (28%) had three to five bowel actions, and two (10%) had more than five bowel actions. Eighteen patients (85%) had normal gas/stool discrimination, two (10%) had partial but improving discrimination, and one (5%) was unable to discriminate. There was no local recurrence in any of the cancer patients. This series corroborates the findings of other investigators who report good functional outcome with the pullthrough technique.

Oncocytes of the thyroid: a neutral red dye uptake study.

Oncocytosis and oncocytomas have attracted attention because on the one hand there have been reports of the favourable prognosis and generally benign nature of oncocytic tumours, while on the other hand, Hurthle cell change in thyroid neoplasms have been reported to be correlated with aggressive biological behaviour and a significantly worse clinical course. Presently, there appear to be two schools of thought on the significance of oncocytosis: (i) a process where there is redifferentiation of cells with involvement in the pathogenesis of cancer; and (ii) a compensatory process for 'functional exhaustion' of the cell. Many aspects of oncocytosis seem unclear. In this study, transmission electron microscopy is used to demonstrate the presence of thyroid oncocytes in the hemithyroidectomy specimen of a patient with focal lymphocytic thyroiditis. Tissue sections from this specimen did not display preferential uptake of neutral red dye, a distinctive characteristic of M-phase cancer cells which was previously reported. The findings seem to suggest that oncocytes are not cells with distinctive proliferative potentials. If that were the case, then oncogenesis or cancer cell progression and oncocytosis may not be convergent processes.

Use of synthetic peptides to probe functional domains of a Bacillus thuringiensis toxin.

Two 10-residue peptides exhibiting sequence homology to CryIA(a) toxin were chemically synthesized. One corresponds to a segment from residues 48-57 (peptide A) and is common to all CryIA toxins and the second corresponds to a segment from residues 348-357 (peptide B) and is specific to the CryIA(a) toxin. Antibodies were raised in rabbits against both peptides. Antipeptide A did not protect either Bombyx mori or Choristoneura fumiferana larvae against CryIA(a) toxin. However, antipeptide B offered significant protection to B. mori and somewhat less protection to C. fumiferana larvae. Neither antiserum interfered with the binding of CryIA(a) toxin to brush border membrane vesicles of either insect. The results suggest that the segment from residues 348-357 in CryIA(a) toxin is important for expression of toxicity in both insects but not for binding.

A successful peritoneovenous shunting of ascites using the great saphenous vein.

For the surgical palliation of massive ascites, a LeVeen or Denver shunt may be implanted to drain ascitic fluid from the peritoneal cavity into the circulation. But all commercial shunts are costly and depend on a synthetic valve to prevent blood refluxing into the peritoneal cavity. We report here the first patient with a malignant ascites that was successfully palliated by peritoneovenous shunting using the great saphenous vein as a biological valve.

Jejunal diverticulosis: case report of a rare cause of mechanical intestinal obstruction.

Jejunal diverticulosis is a rare condition and usually discovered incidentally at laparotomy for an unrelated pathology. When inflamed or perforated, jejunal diverticulosis may present with paralytic ileus. In contrast, mechanical bowel obstruction is an unusual presentation. This paper reports the first local case of jejunal diverticulosis presenting with mechanical bowel obstruction due to impaction at the terminal ileum by an enterolith originating from a diverticulum, and reviews the recent literature on the subject.