Optimal prefixation of cells to demonstrate apoptosis by the TUNEL method

OBJECTIVE

To determine the optimal fixation method for cultured human ovarian cancer cell line SHIN-3 to document cisplatin-induced apoptosis by the terminal deoxynucleotidyl transferase-mediated biotinylated dUTP nick end-labeling (TUNEL) assay.

STUDY DESIGN

Cisplatin-treated cancer cell suspensions were (1) fixed in 4% buffered formalin for 10 minutes (BF group); (2) treated with 2% Carbowax in 50% ethanol (CW) for 10 minutes and then fixed in 100% ethanol for one hour (CW + ET); or (3) treated with CW for 10 minutes and then fixed in 4% buffered formalin for one hour (CW + BF). Cell morphology, adhesion to the glass slides and TUNEL reactivity were compared among the three groups. The effects of prolonged prefixation of cell suspensions in CW and of the postfixation of cell smears in BF for one, three and seven days were also examined.

RESULTS

CW + BF treatment yielded satisfactory cell morphology, minimum cell loss and an excellent TUNEL reaction. However, prolonged prefixation in CW resulted in cell shrinkage.

CONCLUSION

CW + BF treatment can be widely recommended for use with cytologic preparations for the TUNEL assay.

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.

Diagnosis of hydatid disease of abdomen and thorax by ultrasound guided fine needle aspiration cytology

Five cases of hydatid disease of abdomen and thorax were diagnosed by fine needle aspiration cytology (FNAC) under ultrasound guidance. The age of patients ranged from 25-50 years, with a median age of 37 years. Male to female ratio was 2:3. None of the cases were clinically diagnosed as hydatid disease, but ultrasonography raised suspicion in two cases. The location of cyst in four cases was liver and one aspiration was done from lung. Smears from all cases showed features consistent with hydatid disease. None of the patients showed any untoward allergic reaction following FNAC.

Atrial fibrillation: prevalence and management in an acute general medical unit

BACKGROUND

Atrial fibrillation (AF) is a common comorbid condition in patients admitted to hospital. In managing patients with AF, recent research has highlighted the importance of heart rate control, cardioversion, maintenance of sinus rhythm and anticoagulation for the prevention of thromboembolism.

AIM

To determine the prevalence of AF in patients admitted acutely to the general medical service at Auckland Hospital and to assess the adequacy of heart rate control, the number cardioverted and the use of warfarin to prevent thromboembolism.

METHODS

Prospective review of all acute admissions to the general medical service over a 12 week period. Information was collected from hospital notes on the patients' present and past medical conditions, admission and discharge cardiac medication and the use of investigations, particularly thyroid function tests and echocardiography. The heart rate on discharge, number cardioverted either during the admission or after discharge and the number given warfarin and aspirin were recorded.

RESULTS

One hundred and forty-seven patients (aged 38-96, mean age 76 years and 52% male) were admitted in AF 165 times out of the 1637 admissions over the study period (a prevalence of 10.4%, 95% CI 8.6-11.5%). The main causes of admission were heart failure (23%), pneumonia or sepsis (17%), cerebrovascular accident (CVA) or transient ischaemic attack (TIA) (14%) and ischaemic heart disease (11%). Past medical history included hypertension (46%), ischaemic heart disease (39%), congestive heart failure (58%), valvular heart disease (12%), chronic obstructive airways disease (24%), CVA, TIA or thromboembolic event (24%) and diabetes (17%). Thyroid function tests were performed in 50% of patients and echocardiograms in 38%. Heart rate control at discharge could not be assessed, as this was not recorded prior to any patient's discharge. Seventy-eight per cent of patients were discharged on digoxin but only 29% on drugs that control the heart rate with exercise. Five patients out of 11 considered for cardioversion had a successful cardioversion in hospital and two were later cardioverted as outpatients. Twenty-eight per cent were discharged on warfarin, 33% on aspirin and one patient on both. Fifty-two per cent were considered to have contraindications to warfarin therapy. Prescribing rates for warfarin did not vary according to the patients' clinical risk for thromboembolism.

CONCLUSION

AF is a common comorbid condition in the acute general medical ward. Standard investigations were under-utilised. Attention needs to be paid to the recording and control of heart rate at rest and on exercise. Cardioversion is considered infrequently. This patient group had a high risk for thromboembolism and after excluding the large group in whom warfarin was contraindicated, warfarin was still under-utilised.

Tongue papillae in goat: a scanning electron-microscopic study

The tongue papillae of 6-9-month-old Jamunapari goats were studied by scanning electron-microscopy. The conical-shaped filiform papillae had 3-6 pointed projections and 6-8 secondary papillae at the free tip and the base of the dorsal surfaced of the tongue, respectively. The convex surfaced fungiform papillae were raised above the lingual mucosa. The vallate papilla was characterized by a papillary groove and an annular pad. The large conical papilla had a round base and a blunt tip without any projection. Two types of lenticular papillae could be distinguished. The irregular surface of all types of papillae revealed microplicae in the form of microridges and micropits. The fungiform papilla was studded with microvilli. The taste pores were oriented on the dorso-lateral surface of the vallate papilla.

Effect of prenatal diazepam, phenobarbital, haloperidol and fluoxetine exposure on foot shock induced aggression in rats

Different groups of pregnant rats were treated with diazepam (10 mg/kg), phenobarbital (10 mg/kg), haloperidol (0.1 mg/kg), fluoxetine (10 mg/kg) and vehicle (normal saline) intraperitoneally once a day during gestation days 13 to 21. After birth these pups were culled to 8 pups/dam and foster-nursed by lactating mothers for 3 weeks and were reared in colony cages thereafter. Sex and weight matched pairs of rat offsprings were subjected to foot shock induced aggression test at 8 weeks of age. Two parameters of aggressive behaviour were recorded namely, the latency to fight and total number of fighting bouts. The results indicate that prenatal exposure to diazepam, phenobarbital, haloperidol and fluoxetine caused significantly enhanced aggression in terms of number of fighting bouts.

Study of immunization against anthrax with the purified recombinant protective antigen of Bacillus anthracis

Protective antigen (PA) of anthrax toxin is the major component of human anthrax vaccine. Currently available human vaccines in the United States and Europe consist of alum-precipitated supernatant material from cultures of toxigenic, nonencapsulated strains of Bacillus anthracis. Immunization with these vaccines requires several boosters and occasionally causes local pain and edema. We previously described the biological activity of a nontoxic mutant of PA expressed in Bacillus subtilis. In the present study, we evaluated the efficacy of the purified mutant PA protein alone or in combination with the lethal factor and edema factor components of anthrax toxin to protect against anthrax. Both mutant and native PA preparations elicited high anti-PA titers in Hartley guinea pigs. Mutant PA alone and in combination with lethal factor and edema factor completely protected the guinea pigs from B. anthracis spore challenge. The results suggest that the mutant PA protein may be used to develop an effective recombinant vaccine against anthrax.

Value of computed tomography in the evaluation of retroperitoneal organ injury in blunt abdominal trauma

Computed tomography (CT) is widely used in the evaluation of blunt abdominal trauma. One of its purported advantages is in the evaluation of the retroperitoneum. This study was undertaken to determine the utility of CT in diagnosing retroperitoneal organ injury. A retrospective chart review of 466 stable patients with blunt abdominal trauma who received abdominal CT was conducted. Twelve percent of the patients had CT scans showing retroperitoneal organ injury. There were 58 total injuries, with the kidney being the most frequently injured organ. Twenty-four patients required laparotomy, confirming the CT diagnosis in 8 patients (7 renal and 1 pancreatic). Two duodenal injuries were found at laparotomy that had not been seen on CT scan. Fourteen percent of the patients with positive CT scans had a positive laparotomy, and of those, 38% were therapeutic. Five percent of the patients with positive scans had therapeutic laparotomies. These data infer that the utility of CT to define retroperitoneal organ injury is lower than previously suspected.

Factors related to axillary lymph node metastasis in T1 breast carcinoma

The current study was performed on 38 cases of T1 breast cancers ( 2 cm in greatest diameter) to identify the factors related to recognition of axillary lymph node (AxLN) metastasis. Ten patients (26.3%) had lymph node metastases. Comparing the AxLN positive (+) group with the AxLN negative (-) group revealed that tumor size and hormone receptor status as well as age of the patients were not significantly different. However, the Ki-67 labeling index (22.2 +/- 5. 9% vs. 12.5 +/- 2.8%), the microvessel count (43.8 +/- 12.4/0.785 mm2 vs. 27.0 +/- 8.4/0.785 mm2) and bcl-2+ cases (70% vs. 29%) were significantly higher in the AxLN+ cases. These results suggest that the Ki-67 labeling index, microvessel count and Bcl-2 expression, especially when combined, are useful predictors of AxLN metastases in T1 breast cancers.

Isolation and characterization of Salmonella enterica Weltevreden cytotoxin

Cytotoxin of Salmonella enterica subspecies enterica serovar Weltevreden (BM-1643), isolated from buffalo meat, was purified and characterized physicochemically and immunologically. Cell-free culture supernatant (CFCS) of the organism showing marked cytotoxicity to Vero cells and least enterotoxicity to rabbit ligated ileal loop (RLIL) model, was salt precipitated with ammonium sulphate (60% saturation level) and dialysed. Precipitated dialysed preparation (60% PDP) when filtered through Sephadex G-100 column yielded two peaks, of which second peak (SG-100 SP) contained the cytotoxic activity. Upon filtration of SG-100 SP through SG-200 column, three peaks were obtained. Second peak (SG-200 SP), which was cytotoxic, yielded a single protein band of approximately 60-70 kDa in polyacrylamide gel electrophoresis and 3 protein bands of lower, molecular weight (13.5-56 kDa) in SDS-PAGE analysis. Cytotoxic preparation was maximally active at pH 7 to 8. On heating above 60 degrees C, cytotoxicity decreased gradually with insignificant activity left after treatment at 121 degrees C (15 min). Cytotoxin was inactivated by treatment with trypsin and protease but not by papain or lipase enzymes. It was immunogenic in rabbit and antiserum neutralized the cytotoxicity of cytotoxic preparations of homologous as well as heterologous Salmonella serovars.

Expression and purification of the recombinant lethal factor of Bacillus anthracis

The structural gene for the 90-kDa lethal factor (LF) isolated from Bacillus anthracis was expressed as a fusion protein with six histidine residues in Escherichia coli. Expression of LF in E. coli under the transcriptional regulation of the T5 promoter yielded a soluble cytosolic protein with an apparent molecular mass of 90 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Recombinant LF reacted with anti-LF antibodies. The protein was purified to homogeneity by nickel nitrilotriacetic acid affinity chromatography and gel filtration on a Sephacryl S-200 column followed by anion exchange on a fast-performance liquid chromatograph with a Resource-Q column. The yield of purified LF from this procedure was 1.5 mg/liter. In solution, trypsin cleaved protective antigen bound to native and recombinant LF with comparable affinities. In macrophage lysis assays, native and recombinant LF exhibited identical potencies. The results suggest that large amounts of biologically active LF can be purified by this procedure.

Effect of prenatal haloperidol administration on anxiety patterns in rats

Haloperidol (0.1 mg/kg, i.p.) treatment was given from day 12 to 20 of gestation to pregnant rats, this being the critical period for neural development in this species. The pups born were subjected to open-field exploratory behaviour, tunnel-board exploratory behaviour, elevated zero-maze and elevated plus maze behaviour tests at 7-8 weeks of age. The results indicate that prenatal haloperidol treatment induces a significant increase in open-field ambulations and rearings, decrease in scratching and licking/washing behaviours whereas grooming and faecal droppings remain unchanged. Significantly reduced activity in the centre and increased activity in the periphery of the tunnel board was noted. These suggest presence of anxiety in these animals. Significant anxiogenic behavioural patterns were also observed on elevated zero-maze and plus-maze in the prenatally haloperidol treated offsprings. The results suggest that prenatal exposure of haloperidol leaves a lasting effect on offsprings resulting in hyper-emotional responsiveness and anxiety state.

Inhibition of tumor growth and metastasis by angiogenesis inhibitor TNP-470 on breast cancer cell lines in vitro and in vivo

Antitumor and antimetastatic activity of the angiogenesis inhibitor O-(chloroacetyl-carbamoyl) fumagillol (TNP-470), a semisynthetic analogue of fumagillin, was evaluated in breast cancer cell lines. In an in vitro MTT assay, after 72 hrs continuous exposure to TNP-470, growth inhibition was observed in all seven cell lines of murine (JYG-A, JYG-B, DD-762, and BALB/c-MC) or human (KPL-1, MDA-MB-231, and MKL-F) origin, in which the 50% inhibitory concentrations (IC50) at 72 hrs treatment were 4.6, 4.4, 4.6, 10.1, 35.0, 25.3, and 33.4 micrograms/ml, respectively. In an in vivo assay using JYG-A, JYG-B, KPL-1, and MDA-MB-231 cells by orthotopic (right thoracic mammary fat pad) transplantation in female nude mice, TNP-470 at 30 or 50 mg/kg body weight was injected s.c. every other day from the day of tumor cell inoculation until the end of the experiment. The inhibitory effect on primary tumor growth was obtained in all four cell lines in a dose-dependent manner. In the 50 mg/kg TNP-470-treated group, the reductions in tumor weight of the JYG-A, JYG-B, KPL-1, and MDA-MB-231 cells with respect to the controls were 50%, 30%, 4%, and 49%, respectively. Metastasis was seen in the JYG-A, JYG-B, and KPL-1 cells. The numbers of mice bearing pulmonary metastases of JYG-A and JYG-B cells and regional axillary lymph node metastases of KPL-1 cells were reduced, and TNP-470 at the 50 mg/kg dose to KPL-1 cells significantly reduced lymph node metastases compared with the control. Although the weight gain was retarded in the TNP-470-treated mice, weight loss was not seen. TNP-470 was highly effective in the treatment of breast cancer cells. These results suggest that the clinical use of TNP-470 may be a promising treatment for breast cancer patients.

Evaluation of various diagnostic techniques for Trypanosoma evansi infections in naturally infected camels

One hundred and eight camels (Camelus dromedarius) from Trypanosoma evansi endemic areas of the Thar Desert of Rajasthan State, India, were evaluated by various diagnostic tests including parasitological tests (wet blood film-WBF, stained thick blood film), chemical test (mercuric chloride), biological test (mouse subinoculation-MSI), and immunodiagnostic tests based on antibody detection (double immunodiffusion test-DID, card agglutination test-CATT), antigen detection (double antibody sandwich enzyme linked immunosorbent assay-Ag-ELISA). Of the tested camels 49 were found infected using the WBF of which nine gave false negative results with the mercuric chloride test. The efficacy of MSI was 87.03 percent, while the mercuric chloride test was 60.18 percent efficient. The diagnostic efficacy of CATT (72.22 percent) was found to be much better than DID (28.70 percent). Ag-ELISA was 86.11 percent efficient in detecting trypanosomal antigens. A good correlation was found between the positive results obtained by wet blood film, CATT and Ag-ELISA. It was inferred that CATT can be used to study the seroprevalence of T. evansi with great ease, however, trypanosome antigen detection may give a more accurate idea of the prevalence of T. evansi in an endemic area.

Characterisation of virulence factors of Serratia strains isolated from foods

Out of 21 Serratia strains isolated from fresh juice and fish samples, five S. marcescens and two S. rubidaea caused lethality in mice on parenteral inoculation, but none through oral feeding. Three S. marcescens and one S. rubidaea produced heat-labile enterotoxin, detectible with the rabbit ligated ileal loop test, the mouse foot pad test and the vasopermeability factor test. Cell free culture filtrate (CFCF) of two enterotoxigenic S. mearcescens strains induced cytotoxic effect on a monolayer of Vero-cells, but CFCF of other enterotoxigenic strains could only induce cytotonic changes in Vero-cells. All strains possessed fimbriae type 3 while, only pathogenic strains had type 4 fimbriae and a colonization factor. All pathogenic Serratia strains were agglutinated at comparatively lower salt concentrations than non pathogenic strains (< 1.3 M), and had multiple drug resistance. Their public health significance is also discussed.

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.

Behavioural effects of prenatal diazepam administration on anxiety patterns in rats

Diazepam (10 mg/kg, ip) treatment was given from day 13 to 20 of gestation to pregnant rats, this being the critical period for neural development in this species. The pups born were subjected to open-field exploratory behaviour, tunnel-board exploratory behaviour, elevated zero maze behaviour and social interaction tests at 8-9 weeks of age. The results indicate that prenatal diazepam treatment induces a significant increase in open-field ambulation, grooming, scratching and licking/washing, whereas rearing and faecal dropping remain unchanged. Significant reduction in tunnel-board exploratory activity, activity on zero-maze and social interaction were also observed in the prenatally diazepam treated offsprings. The results suggests that prenatal interference in the form of diazepam leaves a lasting imprint on offsprings resulting in hyper-emotional responsiveness and anxiety state.

Effect of ethanol on esophageal cell proliferation and the development of N-methyl-N'-nitro-N-nitrosoguanidine induced-esophageal carcinoma in shrews

The effect of ethanol (EtOH) on esophageal cell proliferation and the development of esophageal cancers induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in shrews were investigated. Sequential histological examination was done, and cell proliferation was assessed by BrdU labeling. At 5 weeks of age, animals were given tap water, 2% EtOH, 50 ppm MNNG, or 50 ppm MNNG plus 2%, 5% or 10% EtOH in the drinking water. Administration of 10% and 5% EtOH simultaneously with MNNG caused death in 40% (10/25) within 4 days and in 20% (6/30) within 7 days respectively, whereas other treatment were well tolerated with no sudden deaths. Administration of 2% EtOH for 30 weeks caused a 2-fold increase, and that of MNNG caused a 4.5-fold increase in the proliferation index of the basal cells of the esophagus compared with control shrews, and MNNG plus 2% EtOH caused a 5.5-fold increase. In MNNG-treated shrews, with or without 2% EtOH administration, sequential histological examination of esophageal tissue revealed a similar change; dysplasia appeared at 30 weeks of age, squamous cell carcinoma occurred at 35 weeks of age, and the depth of invasion extended to adventitia at 45 weeks of age. These finding indicate that treatment with 2% EtOH promoted the proliferation of esophageal basal cells but did not alter the tumor induction period and did not have tumor-promoting activity. EtOH per se was not carcinogenic; no tumors were seen in shrews not administered MNNG.