Final Study Report of Andexanet Alfa for Major Bleeding With Factor Xa Inhibitors

BACKGROUND

Andexanet alfa is a modified recombinant inactive factor Xa (FXa) designed to reverse FXa inhibitors. ANNEXA-4 (Andexanet Alfa, a Novel Antidote to the Anticoagulation Effects of Factor Xa Inhibitors) was a multicenter, prospective, phase-3b/4, single-group cohort study that evaluated andexanet alfa in patients with acute major bleeding. The results of the final analyses are presented.

METHODS

Patients with acute major bleeding within 18 hours of FXa inhibitor administration were enrolled. Co-primary end points were anti-FXa activity change from baseline during andexanet alfa treatment and excellent or good hemostatic efficacy, defined by a scale used in previous reversal studies, at 12 hours. The efficacy population included patients with baseline anti-FXa activity levels above predefined thresholds (≥75 ng/mL for apixaban and rivaroxaban, ≥40 ng/mL for edoxaban, and ≥0.25 IU/mL for enoxaparin; reported in the same units used for calibrators) who were adjudicated as meeting major bleeding criteria (modified International Society of Thrombosis and Haemostasis definition). The safety population included all patients. Major bleeding criteria, hemostatic efficacy, thrombotic events (stratified by occurring before or after restart of either prophylactic [ie, a lower dose, for prevention rather than treatment] or full-dose oral anticoagulation), and deaths were assessed by an independent adjudication committee. Median endogenous thrombin potential at baseline and across the follow-up period was a secondary outcome.

RESULTS

There were 479 patients enrolled (mean age, 78 years; 54% male, 86% White; 81% anticoagulated for atrial fibrillation at a median time of 11.4 hours since last dose, with 245 (51%) on apixaban, 176 (37%) on rivaroxaban, 36 (8%) on edoxaban, and 22 (5%) on enoxaparin. Bleeding was predominantly intracranial (n=331 [69%]) or gastrointestinal (n=109 [23%]). In evaluable apixaban patients (n=172), median anti-FXa activity decreased from 146.9 ng/mL to 10.0 ng/mL (reduction, 93% [95% CI, 94-93]); in rivaroxaban patients (n=132), it decreased from 214.6 ng/mL to 10.8 ng/mL (94% [95% CI, 95-93]); in edoxaban patients (n=28), it decreased from 121.1 ng/mL to 24.4 ng/mL (71% [95% CI, 82-65); and in enoxaparin patients (n=17), it decreased from 0.48 IU/mL to 0.11 IU/mL (75% [95% CI, 79-67]). Excellent or good hemostasis occurred in 274 of 342 evaluable patients (80% [95% CI, 75-84]). In the safety population, thrombotic events occurred in 50 patients (10%); in 16 patients, this occurred during treatment with prophylactic anticoagulation that began after the bleeding event. No thrombotic episodes occurred after oral anticoagulation restart. Specific to certain populations, reduction of anti-FXa activity from baseline to nadir significantly predicted hemostatic efficacy in patients with intracranial hemorrhage (area under the receiver operating characteristic curve, 0.62 [95% CI, 0.54-0.70]) and correlated with lower mortality in patients <75 years of age (adjusted P=0.022; unadjusted P=0.003). Median endogenous thrombin potential was within the normal range by the end of andexanet alfa bolus through 24 hours for all FXa inhibitors.

CONCLUSIONS

In patients with major bleeding associated with the use of FXa inhibitors, treatment with andexanet alfa reduced anti-FXa activity and was associated with good or excellent hemostatic efficacy in 80% of patients.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02329327.

Can virtual reality technology be considered as a part of the surgical care pathway?

INTRODUCTION

Virtual reality (VR) is emerging as a new technology in the healthcare sector. It has been shown to enhance the patient's experience and satisfaction in various settings. This review aims to give a brief description of the use of VR and establish validity of its applications to improve the patient's pathway through surgery.

METHODS

A literature search was conducted using the PubMed and Embase™ databases to identify fields in which VR technology has been trialled in relation to surgery. The search terms 'virtual reality' and 'surgery' were employed.

RESULTS

Although benefits relating to VR use have been identified in mental health, obesity management, and physical and cognitive rehabilitation, those in surgery have been less well documented. There are, however, some important but limited benefits reported in managing surgery related stress and improving preoperative patient education as well as VR being an adjunct to some level of postoperative analgesia.

CONCLUSIONS

The current applications of VR in relation to surgical care fall into four main categories: preoperative education, supporting mental health, postoperative pain management, and pre and postoperative patient optimisation. Future studies and validation of VR applications should be carried out so the technology can be utilised throughout the entire patient pathway as VR surgical care bundles.

Isolation and characterization of synthetic pyrethroids-degrading bacterial strains from agricultural soil

Pyrethroid pesticides are commonly used for pest control in agriculture setup, veterinary and home garden. They are now posing increased risks to non-targeted organisms associated to human beings due to their considerable use. The present work deals with the isolation of bacteria with tolerance to high concentrations of bifenthrin and cypermethrin from contaminated soil. Enrichment culture technique (bifenthrin concentration = 50-800 mg/L) was used for bacterial isolation. Bacteria that showed growth on minimal media with bifenthrin were also sub-cultured on minimal media with cypermethrin. Bacteria showing luxurious growth on both the pyrethroid, were screened out based on their morphological, biochemical parameters and by API 20NE Kit. Phylogenetic studies revealed that, one bacterial isolate (MG04) belonging to Acinetobacter lwoffii and other five bacterial isolates (MG06, MG05, MG01, MG03 and MG02) cluster with Pseudomonas aeruginosa, Pseudomonas putida respectively. Isolated members of genera Pseudomonas and Acinetobacter could be used for further detailed degradation studies by using FTIR, HPLC-MS or GC-MS analysis.

Comparison of safety and efficacy between POLARx and Arctic Front cryoballoon ablation

Funding Acknowledgements

Type of funding sources: None.

Introduction

Pulmonary vein isolation (PVI) remains the cornerstone of atrial fibrillation (AF) ablation. The POLARx cryoballoon, which maintains a constant balloon pressure during ablation, was recently introduced for the treatment of AF. We present a comparison of acute and follow-up efficacy and safety outcomes between POLARx and Arctic Front, a frequently used second-generation used cryoballoon.

Methods

251 consecutive patients who underwent first-time cryoballoon AF ablation with POLARx (n=118) or Arctic Front (n=133) with a follow-up of at least 6 months, were retrospectively included.

Results

Of the total 251 patients who were included, mean age was 63 ± 9 years and 161 (64%) participants were male. The majority of the patients suffered from paroxysmal atrial fibrillation (95%). Follow-up success rates did not significantly differ between the POLARx (79%) and Artic Front (75%) groups at 6 months. Antiarrhythmic drug-use after the blanking period of 3 months was 9% for the POLARx group. Complication rates, excluding groin complications, were low in both study groups and were not significantly different (4% in POLARx vs 3% in Arctic Front). Procedure times (71 ± 23 minutes vs. 120 ± 36 minutes) and fluoroscopy times (20 ± 10 minutes vs. 33 ± 18 minutes) were both more favourable in the POLARx group. Lastly, nadir balloon temperatures were significantly lower (-57 ± 7 ºC vs -51 ± 7 ºC) for the POLARx group for all pulmonary veins (p&lt;0.001).

Conclusion

Cryoballoon AF ablation with the POLARx cryoballoon results in similar success and complication rates at 6 months, in comparison with Arctic Front. Procedure and fluoroscopy times are shorter and balloon nadir temperatures are significantly lower for the POLARx cryoballoon. This can lead to optimal logistics and thus cost-effective use of lab and personnel.

Development, Characterization, and Evaluation of SLN-Loaded Thermoresponsive Hydrogel System of Topotecan as Biological Macromolecule for Colorectal Delivery

BACKGROUND

Chemotherapeutic drugs cause severe toxicities if administered unprotected, without proper targeting, and controlled release. In this study, we developed topotecan- (TPT-) loaded solid lipid nanoparticles (SLNs) for their chemotherapeutic effect against colorectal cancer. The TPT-SLNs were further incorporated into a thermoresponsive hydrogel system (TRHS) (TPT-SLNs-TRHS) to ensure control release and reduce toxicity of the drug. Microemulsion technique and cold method were, respectively, used to develop TPT-SLNs and TPT-SLNs-TRHS. Particle size, polydispersive index (PDI), and incorporation efficiency (IE) of the TPT-SLNs were determined. Similarly, gelation time, gel strength, and bioadhesive force studies of the TPT-SLNs-TRHS were performed. Additionally, in vitro release and pharmacokinetic and antitumour evaluations of the formulation were done.

RESULTS

TPT-SLNs have uniformly distributed particles with mean size in nanorange (174 nm) and IE of ~90%. TPT-SLNs-TRHS demonstrated suitable gelation properties upon administration into the rat's rectum. Moreover, drug release was exhibited in a control manner over an extended period of time for the incorporated TPT. Pharmacokinetic studies showed enhanced bioavailability of the TPT with improved plasma concentration and AUC. Further, it showed significantly enhanced antitumour effect in tumour-bearing mice as compared to the test formulations.

CONCLUSION

It can be concluded that SLNs incorporated in TRHS could be a potential source of the antitumour drug delivery with better control of the drug release and no toxicity.

Intraluminal Carotid Artery Thrombus in COVID-19: Another Danger of Cytokine Storm?

Coronavirus disease 2019 (COVID-19) is associated with a severe inflammatory response. Inflammation affects atherosclerotic plaque vulnerability and promotes a thrombogenic environment. We report a series of 6 patients with COVID-19 with acute ischemic stroke due to intraluminal carotid artery thrombus presenting during an 8-day period. Six patients were included (5 men) with a mean age of 65.8 years (range, 55-78 years). COVID-19 was diagnosed by detection of Severe Acute Respiratory Syndrome coronavirus 2 in 5 patients and was presumed due to typical clinical and imaging findings in 1 patient. All patients had vascular risk factors including diabetes (83%), hyperlipidemia (100%), and smoking (17%). Four patients presented with large infarcts with initial NIHSS scores of 24-30. During their hospitalization, all patients had elevated D-dimer and C-reactive protein levels, 5 patients had elevated lactate dehydrogenase and ferritin levels, 3 had elevated interleukin-6 levels, and 2 had elevated troponin levels. Inflammation related to COVID-19 may result in rupture of vulnerable atherosclerotic plaques, resulting in thrombosis and acute ischemic stroke.

An alternative approach to minimize the risk of coronavirus (Covid-19) and similar infections

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new strain that was discovered in 2019 and has not been previously identified in humans. On December 31st 2019 World Health Organization (WHO) was informed of a cluster of cases with pneumonia of unknown origin from Wuhan City, Hubei province of China. The WHO announced in February 2020 that COVID-19 is the official name of the coronavirus diseases. A total of 519,899 confirmed cases with 23,592 deaths linked to this pathogen as on March 27, 2020 have been reported. Due to increasing number of infected people across the continents and huge loss to human life, the WHO has declared the novel COVID-19 outbreak a pandemic. A pandemic is defined as the "worldwide spread" of a new disease. Currently, no COVID-19 specific treatments have been approved by the United States Food and Drug Administration (US-FDA). However, the current treatment options include hydroxychloroquine, tocilizumab, remdesivir, lopinavir-ritonavir (Kaletra®), and nitazoxanide. In recent past, some natural herbal compounds have demonstrated encouraging anti-viral properties. This article attempted to summarize available information on the reported anti-viral activity of some natural products.

Quantitative analysis of Fuller's earth using laser-induced breakdown spectroscopy and inductively coupled plasma/optical emission spectroscopy

Fuller's earth, most commonly known as Multani Matti (clay) in Urdu, among its various utilizations is traditionally used in skin care cosmetics, particularly for removing blackheads and to treat oily skin. It is also used for improving skin complexion. In this paper, laser-induced breakdown spectroscopy (LIBS) was effectively employed for the quantitative investigation of various clay samples for their special uses. To get the LIBS spectra with an optimal signal-to-noise as well as for a more robust and accurate analytical investigation, different experimental parameters (laser energy, gate delay time, and the distance between target and focusing lens) were optimized before the experiments on actual samples. The analysis of emission spectra revealed the presence of many different elements, including Al, Ca, Fe, Mg, Mn, Na, K, Li, S, Si, and Zn. The electron number density and plasma temperatures were determined using the Stark broadened line profile and Boltzmann plot method, respectively. To determine the relative concentration of observed elements, we used an integrated intensity ratio method, integrated intensity of every line from all elements, and calibration free (CF)-LIBS. The prevailing condition of local thermodynamic equilibrium during the experimental executions was verified with multiple criteria. The spectral lines used in CF-LIBS were characterized for the influence from the self-absorption phenomenon, but the same was found insignificant. The findings of our LIBS system were found to agree excellently with the outcomes of the inductively coupled plasma/optical emission spectroscopy, thereby yielding a high statistical correlation factor and hence enlighten the significance of LIBS as a safe and reliable tool for elemental analysis of clay samples.

Should vitamin D be routinely checked for all chronic obstructive pulmonary disease patients?

Aims and Objectives:

This study aimed to compare the vitamin D levels between chronic obstructive pulmonary disease (COPD) patients and healthy controls and to describe the correlation between vitamin D levels and lung functions.

Methods:

Fifty COPD patients (cases) and 30 healthy volunteers (controls) were recruited and their serum vitamin D level was measured together with lung function (forced vital capacity and forced expiratory volume in 1 s [FEV1]) by spirometry. vitamin D was categorized as ≤20 nmol/l: deficient, 21–50 nmol/l: inadequate, and ≥51 nmol/l as sufficient.

Results:

In this case–control cross-sectional study, lower vitamin D levels were associated with lower lung function in both cases as well as controls, the effect being more pronounced in cases. Mean FEV1 at vitamin D ≤20 nmol/l (0.98 ± 0.40 vs. controls 1.93 ± 0.24 with P = 0.006), mean FEV1 at vitamin D 21–50 nmol/l (1.55 ± 0.54 vs. 2.20 ± 0.31 with P = 0.000), and mean FEV1 at vitamin D ≥51 nmol/l (2.06 ± 0.54 vs. 2.20 ± 0.31 with P = 0.002). Moreover, the severity of predicted postbronchodilator FEV1% was also much lower among COPD cohort versus healthy volunteers (mean FEV1%: cases 47.88 ± 14.22 vs. controls 58.76 ± 15.05 with P = 0.002).

Conclusions:

Importantly, lung function in both the groups was affected by decreased vitamin D level; decrease in FEV1 was more pronounced among COPD patients compared to controls showing more expiratory airflow limitation. Vitamin D levels are associated with changes in lung function in cases of COPD as well as healthy controls. Larger studies to confirm the association in Indian context are required and routine assessment of vitamin D may be undertaken to obviate the effects of low vitmain D level on lung function.

Role of Angiopoietin-like 4 on Bone Vascularization in Chickens Exposed to High-altitude Hypoxia

The aim of this study was to investigate the role and expression of a novel angiogenic factor (angiopoietin-like 4, ANGPTL4) in tibial growth plates of broiler chickens exposed to high-altitude hypoxia. One-day-old healthy broiler chickens (n = 120) were transported from lowland to a high-altitude hypoxic region (nearly 3,000 m above sea level) and were reared under hypoxic- (natural lower oxygen content) and normoxic conditions (nearly 21% oxygen content) for 14 days. The effect of hypoxia on angiogenesis in the tibial growth plates and hypoxia-inducible factor (HIF)-1α and ANGPTL4 expressions were determined by histological examination, quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), western blot and enzyme-linked immunosorbent assay (ELISA) techniques. The increase in vascular distribution to the hypertrophic chondrocyte zone of tibial growth plates contributed to promoting growth and development of the tibia under hypoxic conditions, which was highly correlated with the upregulation of ANGPTL4 at both the mRNA and protein levels together with activation of HIF-1α under hypoxic conditions. These findings demonstrate that angiogenic factor ANGPTL4 upregulation is involved in tibial growth plate angiogenesis to promote the development of the tibia in broiler chickens under hypoxic conditions. They also suggest that ANGPTL4 may serve as a new molecular therapeutic target for ameliorating tibial dyschondroplasia chicken bone vascularization.

FK228 recovers thiram-induced tibial dyschondroplasia in chicken via hypoxia inducible factor-1α

Tibial dyschondroplasia (TD) is a disease of many avian species characterized by an enlarged and avascular lesion in the proximal tibiotarsal bone. The aim of present study was to evaluate the effects of hypoxia-inducible factor-1α(HIF-1α) inhibition on thiram- induced TD using synthetic medicine FK228 and the association between HIF-1α and heat-shock protein 90 (Hsp90). One hundred and fifty broiler chicks were equally divided into 3 groups: control; thiram fed; and FK228 treatment. Expressions of HIF-1α and Hsp90 genes were analyzed by real-time quantitative polymerase chain reaction (RT-qPCR) on day 10 and 14 post-hatch. Western blot analysis of HIF-1α and Hsp90 gene was performed to measure the protein levels at the end of the experiment. Results showed that HIF-1α and Hsp90 levels were significantly (P less than 0.05) up-regulated in the thiram group as compared to the control group. Meanwhile, FK228 (HIF-1α inhibitor) significantly (P less than 0.05) down- regulated the mRNA and protein levels of HIF-1α and Hsp90, restored the size of growth plate and diminished lameness. In conclusion, HIF-1α and Hsp90 play an important role in the formation of avascular growth plate and there is a direct relationship between HIF-1α and Hsp90 for the progression of TD pathogenesis. Therefore, HIF- 1α may prevent and control TD in broiler chickens.

Protective effects of Nano-elemental selenium against chromium-vi-induced oxidative stress in broiler liver

The valuable role of selenium in mitigation of oxidative stress and heavy metal toxicity is well-known. Thus, the aim of the current study on broiler chickens was to examine whether nano elemental selenium (Nano-Se) supplementation can reduce the effects of chromium VI (K2Cr2O7) toxicity. For this purpose, a total of 150, one-day-old broiler chickens were allotted to five groups with three replicates: control group (standard diet), poisoned group (K2Cr2O7 via drinking water), protection group (K2Cr2O7 + Nano- Se), cure group (K2Cr2O7 for initial 2 weeks and then Nano-Se), and prevention group (opposite to the cure group). The broilers were detected by the activities of marker enzymes and oxidative stress markers including, aspartate aminotransferase (AST), alanine transaminase (ALT), gamma-glutamyl transferase (GGT) and superoxide dismutase (SOD), glutathione peroxidase (GSH-px), malondialdehyde (MDA), respectively. The (K2Cr2O7 administration caused histopathological damage in the liver of the chickens. Moreover, changes in serum biochemical indicators and oxidative stress parameters were also observed. Nano-Se supplementation increased the levels of GSH-px but reduced the activities of SOD, MDA, GGT, ALT and AST in the experimental groups (P less than 0.05). Our results showed that Nano-Se plays a protective role by preventing the oxidative stress induced by the chromium VI in broiler chickens.

Enhanced blood brain barrier permeability and glioblastoma cell targeting via thermoresponsive lipid nanoparticles

Thermoresponsive targeting is used to deliver therapeutic agents at hyperthermic conditions (39-45 °C). However, available thermoresponsive drug delivery systems (TDDS), including liposomes, have a complex method of preparation involving toxic solvents and reagents. The objective of this in vitro study was to prepare and characterize thermoresponsive lipid nanoparticles (TLN) for treating glioblastoma, the most aggressive brain tumor whose treatment is limited by a low blood brain barrier (BBB) permeability of drugs. Thermoresponsive lipids were prepared by mixing liquid and solid fatty acids (0.1 : 1 to 2 : 1 ratio) and lipid mixtures exhibiting a solid-liquid phase transition at 39 °C were identified by plotting melting point against liquid contents. TLN were prepared by a hot melt encapsulation method using mono- or double-surfactant systems. TLN showed desirable size (<270 nm), zeta potential (-35 to -50 mV), spherical morphology and stability by FTIR studies. In the drug release studies, paclitaxel release was slow at 37 °C, however, it was released abruptly at 39 °C due to the faster diffusion rate from liquid state nanoparticles. During cytotoxicity studies, the unloaded TLN were non-toxic whereas paclitaxel loaded TLN showed higher cytotoxicity to glioblastoma cells at 39 °C (69% cell viability after one hour) compared to 37 °C (82% cell viability). The TLN showed higher permeability across an in vitro model of BBB at 39 °C due to a deformable liquid state which can squeeze through the tight junctions of the BBB. In conclusion, this study demonstrated that the TLN can be used as a safe and effective alternative to traditional TDDS with higher potential to target glioblastoma cells across the BBB.

Comparison of biological effects of modulated electro-hyperthermia and conventional heat treatment in human lymphoma U937 cells

Loco-regional hyperthermia treatment has long history in oncology. Modulated electro-hyperthermia (mEHT, trade name: oncothermia) is an emerging curative treatment method in this field due to its highly selective actions. The impedance-matched, capacitive-coupled modulated radiofrequency (RF) current is selectively focused in the malignant cell membrane of the cancer cells. Our objective is studying the cell-death process and comparing the cellular effects of conventional water-bath hyperthermia treatment to mEHT. The U937 human histiocytic lymphoma cell line was used for the experiments. In the case of conventional hyperthermia treatment, cells were immersed in a thermoregulated water bath, whereas in the case of mEHT, the cells were treated using a special RF generator (LabEHY, Oncotherm) and an applicator. The heating dynamics, the maximum temperature reached (42 °C) and the treatment duration (30 min) were exactly the same in both cases. Cell samples were analysed using different flow cytometric methods as well as microarray gene expression assay and western blot analysis was also used to reveal the molecular basis of the induced effects. Definite difference was observed in the biological response to different heat treatments. At 42 °C, only mEHT induced significant apoptotic cell death. The GeneChip analysis revealed a whole cluster of genes, which are highly up-regulated in case of only RF heating, but not in conventional heating. The Fas, c-Jun N-terminal kinases (JNK) and ERK signalling pathway was the dominant factor to induce apoptotic cell death in mEHT, whereas the cell-protective mechanisms dominated in case of conventional heating. This study has clearly shown that conventional hyperthermia and RF mEHT can result in different biological responses at the same temperature. The reason for the difference is the distinct, non-homogenous energy distribution on the cell membrane, which activates cell death-related signalling pathways in mEHT treatment but not in conventional heat treatment.

18-β Glycyrrhetinic acid alleviates 2-acetylaminofluorene-induced hepatotoxicity in Wistar rats

2-Acetylaminofluorene (2-AAF) is a known hepatic carcinogen which leads to tumour formation in rodents. 18-β Glycyrrhetinic acid (18 β-GA) derived from liquorice plant has various pharmacological properties such as anti-ulcer, anti-inflammatory, antiviral, hepatoprotective and antioxidant. This study is designed to elucidate the chemopreventive properties of 18 β-GA against 2-AAF-induced liver toxicity in Wistar rats and evaluated its effect on inflammatory and tumour promotion marker and activities of different oxidative stress enzymes. Administration of 2-AAF at the dose of (50 mg/kg body weight (b.w.) intraperitoneally (i.p.)) for five consecutive days induces hepatic toxicity, inflammation, oxidative stress and hyperproliferation. Pretreatment with 18 β-GA at two different doses (45 and 75 mg kg−1 b.w.) significantly ameliorates 2-AAF-induced increased lipid peroxidation, alanine transaminase and aspartate transaminase, xanthine oxidase activities and activities of phase-II detoxifying enzymes along with the levels of glutathione content. Administration of 18 β-GA also significantly restored the expressions of proliferating cell nuclear antigen, cyclooxygenase 2, inducible nitric oxide synthase and nuclear factor κB. Furthermore, histological observations also support the preventive effects of 18 β-GA. Our findings suggest that pretreatment with 18 β-GA showed potential hepatoprotective effects via attenuation of oxidative stress, inflammation and hyperproliferation.

Chemopreventive effects of aloin against 1,2-dimethylhydrazine-induced preneoplastic lesions in the colon of Wistar rats

Chemoprevention opens new window in the prevention of all types of cancers including colon cancer. Aloin, an anthracycline in plant pigment, can be utilized as a protective agent in cancer induction. In the present study, we have evaluated the chemopreventive efficacy of aloin against 1,2-dimethylhydrazine (DMH)-induced preneoplastic lesions in the colon of Wistar rats. DMH-induced aberrant crypt foci (ACF) and mucin-depleted foci (MDF) have been used as biomarkers of colon cancer. Efficacy of aloin against the colon toxicity was evaluated in terms of biochemical estimation of antioxidant enzyme activities, lipid peroxidation, ACF, MDF, histopathological changes, and expression levels of molecular markers of inflammation and tumor promotion. Aloin pretreatment ameliorates the damaging effects induced by DMH through a protective mechanism that involved reduction in increased oxidative stress enzymes (p < 0.001), ACF, MDF, cyclooxygenase-2, inducible nitric oxide synthase, interleukin-6, proliferating cell nuclear antigen protein expression, and tumor necrosis factor-α (p < 0.001) release. From the results, it could be concluded that aloin clearly protects against chemically induced colon toxicity and acts reasonably by inducing antioxidant level, anti-inflammatory and antiproliferative markers.

Efficacy of Quinine versus Artemether in the treatment of severe malaria

BACKGROUND

For centuries Quinine has been used as very effective antimalarial drug and with advent of Artemisinin and its derivative Artemether there stands a concern about the superiority among these drugs especially in case of severe malaria in paediatric population. This study compares these drugs to explore their effectiveness.

METHODS

A randomized prospective study was conducted with a view to compare efficacy regarding fever clearance, parasitaemia clearance and coma resolution between Quinine (10 milligrams per kilogram per dose diluted in 100 ml of 10 % dextrose solution T.D.S for seven days) and Artemether (3.2 milligrams per kilogram per day I.M on the first day and 1.6 milligrams per kilogram per day from second to fifth day of treatment) among 138 children with severe malaria in Bolan Medical College, Quetta, Pakistan. Study was conducted from December 2009 to December 2011. Ethical clearance was taken from Ethical clearance committee, Bolan Medical College, Quetta, Pakistan.

RESULTS

Parasitaemia clearance was better with Artemether than Quinine. Parasitaemia clearance was 68 (98.55%) and 69 (100%) on third and fifth day respectively in Artemether group while Quinine group had 64 (92.75%) and 67 (97.1%) on third and fifth day respectively [third day [RR=0.9412 (95%CI, 0.8759-1.0113) P=0.2084 and fifth day respectively [RR=0.9571 (95%CI 0.9109-1.0058) P=0.2446]. Between 24-72 hours the coma recovery rate for Quinine and Artemether were 49 (98%) and 41 (85.41%) respectively [RR=1.1473 (95%CI 1.0141-1.298) P=0.029203 but after 72 hours of treatment the coma recovery remained 49 (98%) for quinine while it was 42 (87.5%) for artemether; RR=1.12 (95%CI 0.9993-1.2553) P=0.0568. The rapid resolution of coma with Quinine within 24 to 72 hours and after 72 hours were statistically significant than Artemether.

CONCLUSIONS

In severe paediatric malaria intravenous Quinine or intramuscular Artemether therapy does not have any statistically significant difference in terms of fever clearance but Quinine has statistically significant shorter duration of coma resolution than with Artemether therapy after 24 hours of treatment.

The role of surgical therapy for pulmonary vein atresia in childhood

The outcome for children with pulmonary vein atresia has been historically poor. This report describes clinical outcomes after surgical treatment of primary and secondary pulmonary vein atresia. All patients undergoing surgery for pulmonary vein atresia at Children's Hospital Boston from 1 January 2005 to 1 January 2009 were identified. The data available for analysis included demographic characteristics, findings based on cardiac catheterization and other imaging, clinical information, operative surgical intervention, and pulmonary vein histology. The study-specific information included the calculated number of atretic pulmonary veins as well as surgical interventions performed during the study period. The study end points included successful relief of pulmonary vein atresia, recurrence of pulmonary atresia or stenosis, overall pulmonary vein disease progression, and patient survival. A total of 16 patients with one or more pulmonary vein atresias were identified in the cardiac surgery registry database. Of these 16 patients, 5 had primary pulmonary atresia, and 11 had secondary atresia after repair of anomalous pulmonary venous drainage. Surgical recanalization of atretic pulmonary veins was achieved for more than 80% of the patients. At the most recent follow-up assessment, 7 (44%) of the 16 patients had recurrence of atresia. Five of the patients had development of new atresia in other previously healthy pulmonary veins. The median follow-up period was 4 months for primary and 17 months for secondary pulmonary vein atresia. The three main predictors of pulmonary vein disease progression after surgery were the presence of underlying lung disease (P = 0.036), prematurity (P = 0.035), and a history of recurrent pulmonary vein atresia. The overall mortality rate for the patients with primary or secondary pulmonary vein atresia was 56% at the most recent follow-up assessment (100% for the patients with primary vein atresia and 36% for the patients with secondary vein atresia).

CONCLUSIONS

Surgical recanalization of pulmonary vein atresia is possible, but prognosis remains poor. Recurrence of atresia can take place as early as a few months in the presence of underlying lung disease, prematurity, or history of recurrent pulmonary vein atresia. Further research is needed to identify mechanisms for attaining and sustaining pulmonary vein patency after surgery.

Concomitant hypertension, bradycardia, and loss of transcranial electric motor evoked potentials during pedicle hook removal: report of a case

Neurophysiologic monitors in the form of transcranial electric motor evoked potentials (tceMEPs) and somatosensory evoked potentials (SSEPs) have become widely used modalities to monitor spinal cord function during major orthopedic spine procedures. In combination with invasive and non-invasive clinical monitoring and an anesthesia information management system (AIMS), we promptly recognized an acute change in hemodynamic and neurophysiologic parameters, managed intraoperative spinal cord contusion, and successfully minimized iatrogenic injury to the spinal cord during corrective spine surgery.

First Report of "Candidatus Liberibacter psyllaurous" or "Ca. Liberibacter solanacearum" Associated with Severe Foliar Chlorosis, Curling, and Necrosis and Tuber Discoloration of Potato Plants in Honduras

From 2006 to 2009, all commercial potato fields in Azacualpa F.M. Honduras were heavily infested with the potato psyllid Bactericera cockerelli (Sulc.). Plants exhibited interveinal chlorosis, vein-greening, downward curling, stunting, above ground tuber formation, and brownish flecks in some tubers. Disease incidence ranged from 50 to 95%. Leaf samples and psyllids were collected from seven fields in two potato-growing regions of Honduras. Total DNA was purified from the leaves of 30 symptomatic and three asymptomatic plants. DNA was extracted from 20 adult and 10 immature (4th to 5th instar) psyllids according to Frohlich et al (1). PCR primers, PSY680F 5'-GTTCGGAATAACTGGGCGTA-3' and PSY1R 5'-CCCATAAGGGCCATGAGGACT-3', were used to amplify a 680-bp fragment of the 16S rDNA for the recently described "Candidatus Liberibacter physallaurous" (2) and "Ca. L. solanacearum" (3). PSY1R/PSY680F primer design was based on the association of a previously undescribed liberibacter with vein-greening symptoms in greenhouse tomato plants in Arizona from 2006 to 2007 (GenBank Accession No. GQ926918) that lead to the hypothesis that a similar bacterium could be associated with symptomatic potato plants in Honduras. PCR amplification, cloning, and sequencing of the resultant 16S rDNA amplicons indicated that 17 of 30 potato plants, 8 of 20 adult and 7 of 10 third to fourth instar psyllids, respectively, were positive for liberibacter based on 99 to 100% shared nucleotide sequence (nt) identity with the analogous sequence from liberibacter (EU812558 [2]). To substantiate these results, a second molecular marker was targeted using the 1611F and 480R primers (~980 bp) that amplify the 16S-23S-ITSrDNA of liberibacter (2) for selected liberibacter-positive samples (above). Amplicons of the expected size were obtained from 12 of 17 potato and 7 of 10 immature psyllids. No PCR product of the expected size was obtained from asymptomatic potato samples or the PCR negative (water) control. The resultant PCR amplicons were cloned and 12 to 15 clones per amplicon were sequenced. The sequences were aligned and the percentage pair wise nt identity was calculated by Clustal W revealing that the 16S rDNA and 16S-23S-ITS sequences, respectively, shared 99 to 100% nt identity with each other. BLAST analysis against the NCBI database indicated that the 16S rRNA sequences from potato plants (GQ926922) and immature psyllids (GQ926923), and the 16S-ITS-23S sequence from potato plants (GQ926924) and immature psyllids (GQ926925), shared 98.5 to 100% nt identity with 'Ca. Liberibacter' reported from potato (EU812556; [2,4]) and tomato (EU812558, EU812559, EU935005; [2,3]). Evidence for the widespread presence of liberibacter and the potato psyllid in potato fields in Honduras, together with foliar and tuber symptoms that are reminiscent of those recently described in potato plants in the United States affected with 'zebra chip' disease (4), suggest that a similar or identical disease of the potato also occurs in Honduras. This emergent disease poses a serious threat to potato production in Honduras and elsewhere in Central America. References: (1) D. R. Frohlich et al., Mol. Ecol. 8:1683, 1999. (2) A. K. Hansen et al. Appl. Environ. Microbiol. 78:5862, 2008. (3) L. W. Liefting et al. Plant Dis. 93:208, 2009. (4) J. E. Munyaneza et al. J. Econ. Entomol. 100:656, 2007.

First Report of "Candidatus Liberibacter psyllaurous" (synonym "Ca. L. solanacearum") Associated with 'Tomato Vein-Greening' and 'Tomato Psyllid Yellows' Diseases in Commercial Greenhouses in Arizona

During the winter of 2006-2007, plants in commercial tomato greenhouses (GH-1 and GH-2; total 320 acres [129.5 ha]) in Arizona were infested with the potato psyllid Bactericera cockerelli (Sulc) and more than 60% and ~20% of the plants, respectively, exhibited leaf curling, chlorosis, and shortened internodes. In addition, some plants in GH-1 developed an unusual 'vein-greening' phenotype. Nucleic acids were isolated from 10 symptomatic and three asymptomatic plants from each greenhouse. PCR primers designed to amplify a phytoplasma-like 16S rDNA (850 bp) yielded the expected size product from GH-1 samples, whereas samples from GH-2 and the asymptomatic samples from both greenhouses did not. Several 16S rDNA PCR products (3 of 60) when cloned and sequenced, surprisingly shared 97% homology with 'Candidatus Liberibacter asiaticus' (GenBank No. GQ926917). PCR primers PSY680F 5'-GTTCGGAATAACTGGGCGTA-3' and PSY1R 5'-CCCATAAGGGCCATGAGGACT-3', based on the resultant 16S rDNA sequences, were used to amplify a 680-bp fragment from plant DNA extracts and psyllid lysates (1). A robust PCR product (~680 bp) was obtained from 10 of 10 GH-1 plant extracts (GQ926918) and from a GH-1-derived psyllid colony (28 of 35 adults) (GQ926919) and the tomato plants on which they were reared. In contrast, no 680-bp product was obtained from GH-1 asymptomatic plants (0 of 3), GH-2 plants (0 of 10 symptomatic; 0 of 3 asymptomatic), GH-2-derived psyllid colonies (0 of 35 adults), or psyllid colony tomato plants (data not shown). At least three 680-bp amplicons for each sample type were cloned and 8 to 10 inserts were sequenced for each. BLAST analysis revealed that all 680-bp sequences shared 99 to 100% nt identity with the analogous 16SrDNA from "Ca. Liberibacter psyllaurous" (2) and synonym "Ca. L. solanacearum" (3). A second molecular marker was obtained with the 1611F and 480R primers (2) to amplify the 16SrDNA-23S-ITS (980 bp) from >3 plant extracts and psyllid lysates that tested positive for liberibacter. Clustal W alignment of the 16S-23S-ITS sequences from GH-1 original tomato plants and psyllid colony plants (GQ926920) and psyllids (GQ926921) indicated they were 100% identical to each other and BLAST analysis indicated 99 to 100% shared identity with "Ca. L. psyllaurous" (EU812558) (synonym "Ca. L. solanacearum"). Transmission electron microscopy examination of GH-1 and GH-2 psyllids revealed rod and pleomorphic-shaped bacteria (0.5 to 2.0+ μm) at the brain-salivary gland interface in psyllids from the GH-1 liberibacter-positive colony. No such bacteria were observed in GH-2 liberibacter-negative psyllids. These results support an etiological role of a new liberibacter spp. in the development of the 'vein-greening' symptom phenotype. In contrast, the GH-2 'yellows' phenotype is reminiscent of 'psyllid toxicity' in tomato colonized by B. cockerelli (4). To our knowledge, this is the first report of distinct psyllid-associated diseases in greenhouse tomato in Arizona, one associated with a new 'Ca. Liberibacter' spp., manifest as 'vein-greening' disease, and the other associated with psyllid feeding, in which liberibacter is undetectable in plants and psyllids, and is manifest as the 'tomato psyllid yellows' disease. References: (1) D. R. Frohlich et al. Mol. Ecol. 8:1683, 1999. (2) A. K. Hansen et al. Appl. Environ. Microbiol. 74:5862, 2008. (3) L. W. Liefting et al. Plant Dis. 93:208, 2009. (4) H. J. Pack. Utah Agric. Exp. Stn. Bull. 209, 1929.

Notch1 regulates the functional contribution of RhoC to cervical carcinoma progression

BACKGROUND

The role of Notch signalling in human epithelial cancers is of immense interest. In this study, we examine the interplay between Notch signalling and RhoC, a well-established molecular factor in metastasis. By linking the function of Notch and RhoC, we further strengthen the notion that there is a pro-oncogenic role of Notch signalling in human cervical cancers.

METHODS

RhoC protein expression in cervical carcinoma cell lines was assessed by western blotting. Using CaSki and SiHa cells (cervical carcinoma cells lines), we show that RhoC contributes to wound healing, invasion and migration, anoikis resistance, colony formation, in vitro tube formation and tumour formation. Immunohistochemical studies were carried out to assess the co-expression of RhoC, pAkt and Notch1 in clinical sections.

RESULTS

An assessment of the changes associated with epithelial-to-mesenchymal transition (EMT) shows that both Notch1 and RhoC have similar phenotypic contribution to EMT. Rho activity assessment on Notch1 inhibition with DAPT shows decreased RhoC activity. We further show that constitutively active RhoC rescues the phenotypic effect of Notch1 inactivation, and a comparison of Notch1 with RhoC expression shows an overlap between the two proteins in the same areas of the tissue.

CONCLUSION

This study has provided evidence to suggest that RhoC is an effector of Notch1 in cervical carcinoma.

Ventricular free wall rupture

BACKGROUND

Left ventricular free wall rupture (FWR) is reported to occur in 2-6% of cases presenting with acute myocardial infarction. Mortality of this complication is very high, accounting for 20-30% of all infarct related deaths. The objective of our study was to present our surgical experience of free wall rupture over a period of five years from 2004-2009.

METHODOLOGY

A review of our records over this period of time was undertaken.

RESULTS

In our series of six patients collected over this time period, 3 (50%) presented with hypotension and 3 (50%) with persistent chest pain ECG evidence of myocardial infarction was present in 4 (67%) cases, LVH in 2 (33.3%) cases and 2 (33.3%) showed diffuse ST and T changes. Echocardiogram was useful in the diagnosis of rupture but was not confirmatory. Coronary angiography and left ventriculography was performed in all the patients. Surgery was performed in all cases confirming the FWR.

CONCLUSION

In this sma I s,ries there was no surgical mortality which may reflect the favourable prognosis in sub acute rupture where haemodynamic stability is achieved with medical therapy prior to surgery.

Estrogen receptor genotypes, menopausal status, and the lipid effects of tamoxifen

Tamoxifen induces important changes in serum lipid profiles in some women; however, little information is available to predict which women will experience improved lipid profiles during tamoxifen therapy. As part of a multicenter prospective observational trial in 176 breast cancer patients, we tested the hypothesis that tamoxifen-induced lipid changes were associated with genetic variants in candidate target genes (CYP2D6, ESR1, and ESR2). Tamoxifen lowered low-density lipoprotein cholesterol (P<0.0001) by 23.5 mg/dl (13.5-33.5 mg/dl) and increased triglycerides (P=0.006). In postmenopausal women, the ESR1-XbaI and ESR2-02 genotypes were associated with tamoxifen-induced changes in total cholesterol (P=0.03; GG vs GA/AA) and triglycerides (P=0.01; gene-dose effect), respectively. In premenopausal women, the ESR1-XbaI genotypes were associated with tamoxifen-induced changes in triglycerides (P=0.002; gene-dose effect) and high-density lipoprotein (P=0.004; gene-dose effect). Our results suggest that estrogen receptor genotyping may be useful in predicting which women would benefit more from tamoxifen.

Abnormalities of conduction after total correction of Fallot's tetralogy: a prospective study

OBJECTIVE

To determine the frequency of post-operative conduction abnormalities in Pakistani patients undergoing total correction for Fallot's Tetralogy.

PATIENTS AND METHODS

One hundred and fifteen patients of Fallot's Tetralogy underwent definitive repair between January, 1999 and April, 2000. Their mean age was 12.89 years (range 3-30 years). One hundred nine patients (94.78%) had severe cyanosis and 6 patients (5.21%) were moderately cyanotic due to mild right ventricular outflow tract (RVOT) obstruction. Thirty percent patients required frequent hospital admissions within 6 months before the time of operation due to -hyper-cyanotic spells. The mean haematocrit was 50.83 (range 28-71). The majority of patients were in NYHA class-III (57%) and 45% had previous palliative shunt procedures done. Surgical access was through the RVOT in 90% cases and trans-atrial in 10%. RVOT patch was used in 55.9%, Pulmonary artery patch in 13.5% and trans-annular patch in 17.1% of cases.

RESULTS

The mean bypass time was 79.15 min and the mean cross clamp time 51.23 min. Average stay in the intensive care unit was 4.48 days. Twenty-three patients required re-exploration for bleeding. Sixty-nine patients required inotropic support. Fifteen patients had transient heart blocks and two had complete heart block requiring permanent pace-maker. Nineteen patients had various transient arrhythmias which were managed medically. Univariate analysis showed that higher age at operation, low preoperative heart rate, prolonged bypass time, prolonged cross clamp time and presence of patch on pulmonary artery were more common in patients who developed various heart blocks. However, none of these factors had statistical significance or definitive cause-effect relationship with heart blocks.

CONCLUSION

With careful surgical technique, total correction of Fallot's tetralogy can be conducted in children and young adults, with a very low risk of conduction abnormalities.

Solubility and precipitation of nicotinic acid in supercritical carbon dioxide

Solubilities of a model compound (nicotinic acid) in pure supercritical carbon dioxide (SC-CO(2)) and SC-CO(2) modified with methanol have been measured in the pressure range of 80-200 bar and between temperatures of 35 and 90 degrees C. On-line ultraviolet detection enabled a simple and relatively fast measurement of very low levels of solubility (10(-7) mol fraction) with good accuracy in pure and modified SC-CO(2). The solute solubility in both pure SC-CO(2) and SC-CO(2) modified with methanol increased with pressure at all investigated temperatures. A retrograde solubility behavior was observed in that, at pressures below 120 bar, a solubility decrease on temperature increase occurred. Solubility data were used to calculate supersaturation values and to define optimum operating conditions to obtain crystalline particles 1-5 microm in diameter using the solution-enhanced dispersion by supercritical fluids (SEDS) process, thereby demonstrating the feasibility of a one-step production process for particulate pharmaceuticals suitable for respiratory drug delivery.

Prognostic indicators of childhood acute viral encephalitis

OBJECTIVE

To devise a set of clinical signs and laboratory parameters that would help clinicians assess prognosis in patients and plan appropriate management.

METHODS

Medical records of 147 paediatric cases (with a discharge diagnosis of acute viral encephalitis) admitted over a ten year period from 1987 to 1997 were reviewed and relevant information collected on a data extraction form.

RESULTS

Of 147 patients, 24 (16.3%) died and 48 (32.7%) were left with severe neurological deficits. A GCS (Glasgow Coma Scale) score between 6-10 had an association with poor outcome (OR = 2.62, Chi-square = 5.57, p-value = 0.018) and that a GCS score of > or = 5 was even more strongly suggestive of poor outcome (OR = 5.49, Chi-square = 12.08, p-value = 0.0005). A history of having seizures, for more than 3 days, also showed a strong association with poor outcome (OR = 3.66, Chi-square = 5.46, p-value = 0.019).

CONCLUSION

Patients with an increased risk of death and severe disability can be identified using a few guidelines. Of these, a history of seizures of > 3 days and/or impaired consciousness (GCS < or = 10), at the time of presentation to the hospital, constitute high risk. These cases must be identified promptly and aggressive therapy initiated in order to improve long term outcome.

Anesthetic management of living liver donors

PURPOSE

Living organ donation is being performed with increasing frequency to overcome the shortage of organs for transplantation. Our experience in the anesthetic management of donors with relevant issues is discussed and complications encountered are recorded.

METHODS

Data were collected retrospectively and analyzed on all 22 left lateral hepatectomies performed at our institution between 1993 to 1997 for transplantation.

RESULTS

Major ethical concern was the risk to the donors and anesthetic issues were those of a major abdominal procedure. All except four donors were parents (mother/father). Average blood loss was 805 +/- 479 ml and only two donors required blood transfusion. Mean operative time was 8.2 +/- 1.5 hr. Thoracic epidural analgesia was the most commonly adopted mode of pain relief. Average time to return of bowel sound postoperatively was 3.1 +/- 1.0 days and was not influenced by the postoperative analgesic technique used. Total duration of hospital stay was 8.4 +/- 1.1 days. Three donors developed minor postoperative complications atrial fibrillation and retained JP drain; left lower lobe pneumonia; and incisional hernia. All patients recovered uneventfully.

CONCLUSION

Living organ donors contribute towards decreasing the shortage of organs for transplantation. Minimizing the discomfort associated with the surgical intervention and providing a complication-free perioperative course will positively influence the continued availability of such donations. On review of the first 22 left lateral hapatectomies performed, we observed only minor complications. Postoperative pain was a serious problem and thoracic epidural provided satisfactory analgesia.

Unexpected difficult intubation in the patient with Morning Glory syndrome

Morning Glory syndrome is an uncommon congenital optic disc anomaly with occasional systemic associations. A case of unsuspected difficult intubation in a three-year old patient is described in this case report.

Inflammatory disease in HLA-B27 transgenic rats

A spontaneous inflammatory disease in rats transgenic for HLA-B27 resembles the B27-associated human spondyloarthropathies. Colitis and arthritis, the two most important features, require T cells, gut bacteria, and high expression of B27 in bone marrow-derived cells. Control rats with HLA-B7 remain healthy. Most rats with HLA-Cw6 (associated with psoriasis vulgaris) remain healthy; a minority develop mild and transient disease. Rats with a mutant B27 with a Cys67-->Ser substitution resemble wild-type B27 transgenics, but with a lower prevalence of arthritis. A similar phenotype is seen in B27 rats co-expressing a viral peptide that binds B27. Disease-prone LEW but not F344 B27 rats develop high serum IgA levels concurrent with disease progression. Colitis is associated with high interferon-gamma, arthritis with high interleukin-6. Disease is similar in B27 LEW, F344, and PVG rats, but the DA background is protective.

CONCLUSIONS

The spondyloarthropathy-like disease in rats is specific for HLA-B27 but does not require Cys67. Arthritis but not colitis is particularly sensitive to B27 peptide-binding specificity. Genetic background exerts a strong influence, but some phenotypic differences exist between permissive strains that do not influence disease susceptibility. The data favor a role for B27 peptide presentation in arthritis, but other mechanisms to explain the role of B27 have not been excluded.

The use of lidocaine for preventing the withdrawal associated with the injection of rocuronium in children and adolescents

We designed this study to examine the incidence and degree of movement after the administration of rocuronium in children and adolescents and to measure the treatment effect of lidocaine for its prevention. One hundred patients (aged 5-18 yr) were randomly assigned to two groups. After general anesthesia was induced with 5 mg/kg thiopental sodium and manual occlusion of venous outflow was performed, one group of patients received 0.1 mL/kg 1% lidocaine i.v.. A second group received 0.1 mL/kg of isotonic sodium chloride solution as a placebo control. Venous outflow occlusion was held for 15 s, released, and immediately followed by the administration of rocuronium 1 mg/kg i.v.. The patient's response to rocuronium injection was graded using a 4-point scale. We observed that the incidence of withdrawal was 84% in the placebo group and was significantly decreased to 46% in patients pretreated with lidocaine (P < 0.001). This study demonstrates that the i.v. injection of rocuronium is commonly associated with a withdrawal reaction in anesthetized pediatric patients and that this reaction can be attenuated or eliminated by pretreatment with i.v. lidocaine.

IMPLICATIONS

Pain on injection of rocuronium in pediatric patients can be alleviated by pretreatment with i.v. lidocaine.

Heat shock protein hsp70 protects cells from thermal stress even after deletion of its ATP-binding domain

Retroviral-mediated gene transfer experiments show that rodent cells become heat resistant when stably and constitutively expressing a cloned human gene encoding an intact human 70-kDa heat shock protein (hsp70). Cells expressing higher levels of the hsp70 protein generally tolerate thermal stress better, whereas cells expressing either of two mutated hsp70-encoding genes, one with a 4-base pair out-of-frame deletion and one with an in-frame deletion of codons 438-618, are heat sensitive. These results provide strong evidence that expression of hsp70 leads directly to thermal tolerance. Surprisingly, cells expressing a mutant hsp70 of a human gene missing codons 120-428 are, nevertheless, heat resistant. Because the deleted region of this mutant contains the ATP-binding domain of human hsp70, this domain appears dispensable in the hsp70-mediated protection of cells from thermal stress.