Gamma surgery for vestibular schwannoma

OBJECT

The goal of this study was to assess the results of gamma surgery (GS) for vestibular schwannoma (VS) in 200 cases treated over the last 10 years and to review the role of this neurosurgical procedure in the management of VS.

METHODS

Follow-up reviews ranging from 1 to 10 years were available in 153 of these patients. Follow-up images in these cases were analyzed using computer software that we developed to obtain volume measurements for the tumors, and the clinical condition of the patients was assessed using questionnaires. Gamma surgery was the primary treatment modality in 96 cases and followed microsurgery in 57 cases. Tumors ranged in volume from 0.02 to 18.3 cm(3). In the group in which GS was the primary treatment, a decrease in volume was observed in 78 cases (81%), no change in 12 (12%), and an increase in volume in six cases (6%). The decrease was more than 75% in seven cases. In the group treated following microsurgery, a decrease in volume was observed in 37 cases (65%), no change in 14 (25%), and an increase in volume in six (11%). The decrease was more than 75% in eight cases. Five patients experienced trigeminal dysfunction; in three cases this was transient and in the other two it was persistent, although there has been improvement. Three patients had facial paresis (in one case this was transient, lasting 6 weeks; in one case there was 80% recovery at 18 months posttreatment; and in one case surgery was performed after the onset of facial paresis for presumed increase in tumor size). Over a 6-year period, hearing deteriorated in 60% of the patients. Three patients showed an improvement in hearing. No hearing deterioration was observed during the first 2 years of follow-up review.

CONCLUSIONS

Gamma surgery should be used to treat postoperative residual tumors as well as tumors in patients with medical conditions that preclude surgery. Microsurgery should be performed whenever a surgeon is confident of extirpating the tumor with a risk-benefit ratio superior to that presented in this study.

Progressive resistance training did not improve walking but can improve muscle performance, quality of life and fatigue in adults with multiple sclerosis: a randomized controlled trial

BACKGROUND

Few high-quality trials have examined the effects of progressive resistance training (PRT) on people with multiple sclerosis (MS).

OBJECTIVE

To determine the effectiveness of PRT for people with MS, focusing on improving the gait deficits common in this population.

METHODS

Using a single blind randomized controlled trial, people with relapsing-remitting MS were randomly allocated to either a PRT program targeting the lower limb muscles twice a week for 10 weeks (n = 36), or usual care plus an attention and social program conducted once a week for 10 weeks (n = 35). Outcomes were recorded at baseline, week 10 and week 22.

RESULTS

Participants attended 92% of training sessions, with no serious adverse events. At 10 weeks, no differences were detected in walking performance. However, compared with the comparison group PRT demonstrated increased leg press strength (16.8%, SD 4.5), increased reverse leg press strength (29.8%, SD 12.7), and increased muscle endurance of the reverse leg press (38.7%, SD 32.8). Improvements in favor of PRT were also found for physical fatigue (Mean difference -3.9 units, 95%CI -6.6 to -1.3), and the physical health domain of quality of life (Mean difference 1.5 units, 95%CI 0.1 to 2.9). At week 22 almost no between-group differences remained.

CONCLUSION

PRT is a relatively safe intervention that can have short-term effects on reducing physical fatigue, increasing muscle endurance and can lead to small improvements in muscle strength and quality of life in people with relapsing-remitting MS. However, no improvements in walking performance were observed and benefits do not appear to persist if training is completely stopped.

Direct electron transfer with yeast cells and construction of a mediatorless microbial fuel cell

The direct electron transfer exhibited by the yeast cells, Hansenula anomala has been demonstrated using the electrochemical technique cyclic voltammetry by immobilizing the microorganisms by two different methods viz., physical adsorption and covalent linkage. The analysis of redox enzymes present in the outer membrane of the microorganisms has been carried out in this work. This paper demonstrates that yeast cells with redox enzymes present in their outer membrane are capable of communicating directly with the electrode surface and contribute to current generation in a mediatorless biofuel cells. The efficiency of current generation has been evaluated using three anode materials.

Cytoprotective and antioxidant activity of Rhodiola imbricata against tert-butyl hydroperoxide induced oxidative injury in U-937 human macrophages

The present study reports cytoprotective and antioxidant activity of aqueous and alcoholic extracts of Rhodiola imbricata rhizome on tert-butyl hydroperoxide (tert-BHP) induced cytotoxicity in U-937 human macrophages. There was an increase in cytotoxicity and apoptosis significantly in the presence of tert-BHP over control cells. The tert-BHP induced cytotoxicity can be attributed to enhanced reactive oxygen species (ROS) production which in turn is responsible for fall in reduced glutathione (GSH) levels; further there was a significant decrease in mitochondrial potential and increase in apoptosis and DNA fragmentation. Both aqueous and alcoholic extracts of Rhodiola rhizome at a concentration of 250 microg/ml were found to inhibit tert-BHP induced free radical production, apoptosis and to restore the anti-oxidant levels to that of the control cells. The alcoholic extract of Rhodiola showed higher cytoprotective activities than aqueous extract. These observations suggest that the alcoholic and aqueous extracts of Rhodiola have marked cytoprotective and antioxidant activities.

Progressive resistance exercise for people with multiple sclerosis

PURPOSE

This study aimed to determine if participation in a progressive resistance exercise (PRE) programme can: (1) increase the ability to generate maximal muscle force, (2) increase muscle endurance, (3) increase functional activity, and (4) improve overall psychological function of people with multiple sclerosis (MS).

METHODS

A pre-post single group research design with a 4-week baseline familiarisation phase was used. Nine people (mean age 45.6 years, SD 10.7) with MS attended a gymnasium three times over 4 weeks for familiarization. Participants then completed a twice-weekly 10-week PRE programme, with two sets of 10 - 12 repetitions of each exercise. Outcome measures of muscle strength (1RM for arms and legs), muscle endurance (repetitions at half 1RM), walking speed, the 2-min walk test (2MWT), a timed stairs test, and the impact of MS on physical and psychological function were taken at weeks 2, 4, and 14.

RESULTS

Participants attended 94.3% (SD 8.2%) of the training sessions, with no adverse events. After accounting for baseline stability, significant improvements (P < 0.05) were found in arm strength (14.4%), leg endurance (170.9%), fast walking speed (6.1%), and there was a trend for increased distance in the 2MWT (P = 0.06). The perceived impact of MS on physical function was reduced (P = 0.02).

CONCLUSIONS

Adults with MS benefited from a PRE programme by improving muscle performance and physical activities, without adverse events. These findings suggest that PRE may be a feasible and useful fitness alternative for people with mild to moderate disability due to MS.

A qualitative analysis of a progressive resistance exercise programme for people with multiple sclerosis

PURPOSE

This qualitative study explored the perceptions of adults with multiple sclerosis about the positive and negative effects of a progressive resistance strengthening programme; and identified factors that might facilitate or create barriers to participation.

METHODS

Seven women and two men (mean age 45.6 years, SD 10.7) with multiple sclerosis participated in a 10-week gymnasium based progressive resistance strengthening programme held twice a week. Participants were interviewed at the end of the programme. The recorded interviews were transcribed and then independently coded by three researchers. From these codes, the main themes emerged.

RESULTS

Reports about the programme were very positive with physical, psychological and social benefits noted. Most participants said that they had less fatigue as a result of the programme. Few negative outcomes were reported and these were minor such as aches and pains. Key extrinsic factors for programme completion were the leaders' encouragement and knowledge of exercise; and the group aspect of the programme. Key intrinsic factors were enjoyment, determination, seeing the signs of progress, and a previously held positive attitude about the benefits of exercise.

CONCLUSIONS

The results of this study suggest that progressive resistance strength training is a feasible fitness option for some people with multiple sclerosis. Factors perceived to be important for programme completion suggest that choosing encouraging leaders with knowledge of exercise, and exercising in a group may contribute to programme success.

Early adolescent suicide: a comparative study

A study was undertaken of suicides in children and adolescents aged 16 years and under in South Australia, (Australia), and in San Diego County (USA) from January 1985 to December 1997. In South Australia there were 48 cases of youth suicide, representing 2% of the total number of 2251 suicides over that time. There were 34 males and 14 females (age range 13 to 16 years; mean = 15.3 years), with 22 hangings (46%), six gunshot wounds (13%), five train deaths (10%), four drug overdoses (8%), four jumping deaths (8%), three self immolations (6%), three carbon-monoxide inhalations (6%) and one electrocution (2%). In San Diego County there were 70 cases, representing 1.6% of the total number of 4492 suicides. There were 48 males and 22 females (age range 11 to 16 years; mean = 14.7 years), with 41 gunshot wounds (59%), 21 hangings (30%), six drug overdoses (9%), and two jumping deaths (3%). Preferred methods of suicide differed between the two areas, with significantly more gunshot suicides in San Diego compared to South Australia. The methods of suicide also differed in South Australia from older age groups, with more hangings, jumping deaths and self immolations, and fewer firearm and carbon monoxide inhalation deaths. Suicides in adolescents under the age of 17 years in both populations were, however, rare, with no demonstrable increase in numbers over the time of the study.

Anticonvulsant effects of gamma surgery in a model of chronic spontaneous limbic epilepsy in rats

OBJECT

The management of intractable epilepsy remains a challenge, despite advances in its surgical and nonsurgical treatment. The identification of low-risk, low-cost therapeutic strategies that lead to improved outcome is therefore an important ongoing goal of basic and clinical research. Single-dose focal ionizing beam radiation delivered at necrosis-inducing and subnecrotic levels was investigated for its effects on seizure activity by using an established model of chronic recurrent spontaneous limbic seizures in rats.

METHODS

A single 90-minute period of repetitive electrical stimulation (inducing stimulus) of the hippocampus in rats elicited a single episode of status epilepticus, followed by a 2- to 4-week seizure-free period. Spontaneous recurrent seizures developed subsequently and persisted for the duration of monitoring (2-10 months). Simultaneous computerized electroencephalography and video recording were used to monitor the animals. After the establishment of spontaneous recurrent seizures, bilateral radiation centered in the ventral hippocampal formation was administered with the Leksell gamma knife, aided by a stereotactic device custom made for small animals. A center dose of 10, 20, or 40 Gy was administered using a 4-mm collimator. Control animals were subjected to the same seizure-inducing stimulus but underwent a sham treatment instead of gamma irradiation. In a second experiment, the authors examined the effects of gamma irradiation on the proclivity of hippocampal neurons to display epileptiform discharges. Naive animals were irradiated with a single 40-Gy dose, as already described. Slices of the hippocampus were prepared from animals killed between 1 and 178 days postirradiation. Sensitivity to penicillin-induced epileptiform spiking was examined in vitro in slices prepared from control and irradiated rat brains.

CONCLUSIONS

In the first experiment, single doses of 20 or 40 Gy (but not 10 Gy) reduced substantially, and in some cases eliminated, behaviorally and electrographically recognized seizures. Significant reductions in both the frequency and duration of spontaneous seizures were observed during a follow-up period of up to 10 months postradiation. Histological examination of the targeted region did not reveal signs of necrosis. These findings indicate that single-dose focal ionizing beam irradiation at subnecrotic dosages reduces or eliminates repetitive spontaneous seizures in a rat model of temporal lobe epilepsy. In the second experiment, synaptically driven neuronal firing was shown to be intact in hippocampal neurons subjected to 40-Gy doses. However, the susceptibility to penicillin-induced epileptiform activity was reduced in the brain slices of animals receiving 40-Gy doses, compared with those from control rats that were not irradiated. The results provide rational support for the utility of subnecrotic gamma irradiation as a therapeutic strategy for treating epilepsy. These findings also provide evidence that a functional increase in the seizure threshold of hippocampal neurons contributes to the anticonvulsant influence of subnecrotic gamma irradiation.

Gamma surgery for intracranial metastases from renal cell carcinoma

OBJECT

The goal of this study was to evaluate the effectiveness and limitations of gamma surgery (GS) in the treatment of renal cell carcinoma that has metastasized to the brain.

METHODS

The authors performed a retrospective analysis of a consecutive series of 21 patients with 37 metastatic brain deposits from renal cell carcinoma who were treated with GS at the University of Virginia from 1990 to 1999. Clinical data were available in all patients. No patient died of progression of intracranial disease or deteriorated neurologically following GS. Eight patients clinically improved. Follow-up imaging studies were available for 23 tumors in 12 patients. Nine patients did not undergo follow-up imaging. One patient lived 17 months and succumbed to systemic disease: no brain imaging was performed in this case. Another patient refused further imaging and lived 7 months. Seven patients lived up to 4 months after the procedure; however, their physicians did not require these patients to undergo follow-up imaging examinations because of their general conditions-all had systemic progression of disease. Of the 23 tumors that were observed posttreatment, one remained unchanged in volume, 16 decreased in volume, and six disappeared. No tumor progressed at any time, and there were no radiation-induced changes on follow-up imaging an average of 21 months after GS (range 3-63 months).

CONCLUSIONS

Gamma surgery provides an alternative to surgical resection of metastatic brain deposits from renal cell carcinoma. Neurological side effects were seen in only one case; freedom from progression of disease was achieved in all cases.

Gamma surgery for hemangiopericytomas

A retrospective analysis of a consecutive series of 12 patients with 15 intracranial hemangiopericytomas treated at the University of Virginia using Gamma surgery is presented. Clinical and radiographic follow up of 3 to 56 months is available for 10 patients with 12 tumors. There was one tumor present at the time of initial Gamma surgery in each patient. Two new tumors occurred in patients previously treated. Nine of the tumors decreased in volume and three remained stable. Four of the nine tumors that shrank later progressed at an average of 22 months after treatment. Of the tumors that decreased in volume and have not progressed, the response has been for an average of 11 months. The follow-up for two tumors that remained unchanged was 10 and 34 months (average 22 months). A third tumor was unchanged at 42 months but the patient died of new disease adjacent to the treated area in the anterior skull base. There were no complications and the quality of life following the procedure was maintained or improved in every case. Gamma surgery is effective in palliating the patients by decreasing tumor volume and delaying recurrence.

Acetyl-l-carnitine (ALCAR) prevents hypobaric hypoxia-induced spatial memory impairment through extracellular related kinase-mediated nuclear factor erythroid 2-related factor 2 phosphorylation

Exposure to hypobaric hypoxia, a condition involving decreased availability of oxygen is known to be associated with oxidative stress, neurodegeneration and memory impairment. The multifactorial response of the brain and the complex signaling pathways involved therewith limits the therapeutic efficacy of several antioxidants in ameliorating hypobaric hypoxia-induced memory impairment. The present study was therefore aimed at investigating the potential of acetyl-l-carnitine (ALCAR), a known antioxidant that has been reported to augment neurotrophin-mediated survival mechanisms, in ameliorating hypoxia-induced neurodegeneration and memory impairment. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor involved in the cellular defense mechanism against oxidative stress related to brain injury and neurological disorders. The study was designed to understand the mechanisms involving Nrf2 stabilization following exposure to hypobaric hypoxia. The results displayed reference memory impairment in Sprague-Dawley rats exposed to hypobaric hypoxia (7620 m) for 14 consecutive days which however improved on administration of ALCAR during hypoxic exposure. The study also revealed Nrf2 regulated augmented antioxidant response on administration of ALCAR which was through a novel tyrosine kinase A (TrkA) receptor-mediated mechanism. A decrease in free radical generation, lipid peroxidation and protein oxidation was also observed along with a concomitant increase in thioredoxin and reduced glutathione levels on administration of ALCAR during exposure to hypobaric hypoxia. The present study therefore reveals the therapeutic potential of ALCAR under conditions of hypobaric hypoxia and elucidates a novel mechanism of action of the drug.

Mechanism of tert-butylhydroperoxide induced cytotoxicity in U-937 macrophages by alteration of mitochondrial function and generation of ROS

tert-Butylhydroperoxide has been reported to inhibit growth and induce apoptosis in number of cell types, but little is known about the molecular mechanism mediating these effects. In the present study, we determined the molecular pathways that lead to apoptosis after treatment of cells with t-BOOH. The cells were exposed to different concentrations of t-BOOH (100-750 microM) for 1-4 h and various parameters such as cytotoxicity, ROS (reactive oxygen species) generation, MMP (mitochondrial membrane potential), intracellular Ca++ levels and expression of various proteins involved in apoptosis were determined. Exposure of U-937 cells to t-BOOH induced cytotoxicity in a time dependent manner with about 50% toxicity at 400 microM t-BOOH in 4h. t-BOOH treatment resulted in a time dependent increase in reactive oxygen species levels, Ca++ influx and annexin V positive cells. There was a significant fall in MMP following exposure to t-BOOH with time. t-BOOH treatment of U-937 cells leads to apoptosis, which is accompanied by activation of caspase-3. The caspase-3 inhibitor (Ac-DEVD-CHO) inhibits the cytotoxicity induced by t-BOOH, indicating a direct link between caspase-3 activation and cell death. This activation of apoptosis is accompanied by release of cytochrome c, down regulation of anti-apoptotic protein Bcl-2 levels with concurrent increase in pro-apoptotic proteins Bax and Bad levels. These observations indicate that t-BOOH induces cell death in U-937 macrophages by apoptosis, which is mediated through mitochondrial pathway.

Gamma knife surgery for craniopharyngioma

We present our results of Gamma Knife surgery for craniopharyngioma in nine patients. The current status of surgery, radiation therapy, intracavitary instillation of radionucleides and Gamma Knife surgery in the management of craniopharyngiomas is discussed.

A new secoiridoid glycoside from Lonicera angustifolia

A new secoiridoid glycoside, 6'-O-beta-apiofuranosylsweroside (1), together with the known compounds sweroside, loganin, beta-sitosterol, oleanolic acid, ursolic acid and methyl-4-hydroxy benzoate have been identified from the leaves of Lonicera angustifolia. The structure of the new compound has been elucidated on the basis of spectroscopic and chemical evidence.

Gamma surgery for vein of Galen malformations

OBJECT

The goal of this study was to evaluate the results of gamma surgery in nine patients treated for vein of Galen malformations (VGMs).

METHODS

A consecutive series of nine VGMs in eight children aged 4 to 14 years and in one adult were treated with gamma surgery. Six of the patients were male, including the adult, and three were female. Among these patients there were three Yasargil Type I, one Type II, two Type III, and three Type IV malformations. Previous embolization had failed in four cases. Three VGMs were treated with gamma surgery twice. An additional patient with a Type III VGM underwent stereotactic angiography in preparation for gamma surgery but was judged to be suitable for direct embolization. Follow-up angiograms were obtained in eight of the VGMs treated. Four no longer filled; one has probably been obliterated, but this cannot be confirmed because the patient refused to undergo final angiography; one patient has residual fistulas not included in the initial treatment field, which were retreated recently; and two other patients have marked reduction of flow through their VGMs.

CONCLUSIONS

Gamma surgery is a viable option in the treatment of VGMs in clinically stable patients. Combined endovascular therapy and gamma surgery is of benefit in complex malformations.

Accuracy and applicability of the revised WHO classification (2009) of dengue in children seen at a tertiary healthcare facility in northern India

BACKGROUND

Revised case definitions of dengue into dengue with/without warning signs (DWS/D) and severe dengue (SD) was proposed by the World Health Organization (WHO)/Tropical Disease Research (TDR) in 2009. To date, there has been no Indian study that has applied this classification.

AIMS AND OBJECTIVES

To assess the accuracy and applicability of the revised WHO classification (2009) of dengue in children seen at a tertiary healthcare facility in India.

MATERIALS AND METHODS

Over a period of 1 year children from the pediatric ward and Out Patient Department (OPD) of the King George Medical University Hospital, Lucknow were enrolled in the study according to predefined criteria and tested for dengue. Each dengue-positive patient was classified according to both the older system [dengue fever (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS)] and the new system (D, DWS, and SD). The severity of dengue was compared to the level of treatment received.

RESULTS

A total of 56 patients tested positive for dengue--51 from the pediatric ward and five from the OPD. According to the older WHO classification, 42 (75 %) patients were classified as DF and 13 (23.2 %) as DHF/DSS; one patient was unclassifiable. Five patients (8.9 %) received level 1 treatment, ten (17.8 %) received level 2 treatment, and 41 (73.2 %) received level 3 treatment. According to the new WHO/TDR classification, 46 (82.1 %) patients were classified as SD, nine (16 %) as DWS, and only one (1.7 %) as D. Many of the severe manifestations (encephalopathy, shock, mucosal bleed, platelet count <20,000, respiratory distress, liver enzymes >1,000 U/L) were seen in patients who were classified as DF according to old classification, whereas these patients were mostly classified as SD by the new classification. Sensitivity of the older and new classifications was 24.8 and 98 %, respectively.

CONCLUSIONS

The revised WHO/TDR (2009) classification has very high sensitivity for identifying severe dengue and is easy to apply.

Targeted cybridization in citrus: transfer of Satsuma cytoplasm to seedy cultivars for potential seedlessness

CMS (cytoplasmic male sterility) can be controlled by the mitochondrion genome in higher plants, including Satsuma mandarin. Somatic fusion experiments in citrus combining embryogenic callus protoplasts of one parent with leaf protoplasts of a second parent often produce cybrid plants of the leaf parent, a phenomenon occurring most often with interspecific fusion combinations. In an attempt to practically exploit this cybridization phenomenon, we conducted somatic fusion experiments combining embryogenic suspension-derived protoplasts of Satsuma mandarin, Citrus unshiu Marc. cv. Guoqing No. 1 (G1), a male-sterile cultivar, with leaf protoplasts of other seedy types--Hirado Buntan Pink pummelo (HBP) [Citrus grandis (L.) Osbeck], Sunburst mandarin (C. reticulata Blanco), Orie Lee hybrid (C. reticulata cv. Clementine x Murcott tangor), and Murcott tangor [C. reticulata x C. sinensis (L.) Osbeck], respectively--in an attempt to generate seedless cybrids by the targeted transfer of CMS. The genetic identities of regenerated plants from all four parental combinations were determined by flow cytometry, SSR, CAPS (or PCR-RFLP), RFLP, and chloroplast-SSR analyses. Regenerated plants from the first three parental combinations were diploids, and the cybrid nature of G1 + HBP with the mitochondrion genome from G1 and the chloroplast genome from HBP was confirmed, whereas the cybrid nature of the remaining two combinations was difficult to confirm because of the close phylogenetic relatedness of both fusion parents, as expected. Plants from G1 + Murcott were confirmed as tetraploid somatic hybrids. This is the first report of targeted citrus cybrid production by symmetric fusion with male-sterile Satsuma as the callus parent and other seedy cultivars as the leaf parents.

High prevalence and early onset of cardiac autonomic neuropathy among South Indian type 2 diabetic patients with nephropathy

OBJECTIVE

This study was conducted to assess the adverse effects of diabetic nephropathy on cardiovascular autonomic neuropathy (CAN) in South Indian Type 2 diabetic patients.

METHODS

Comparison was made between Type 2 diabetic patients with nephropathy (group 1, n=25), Type 2 diabetic patients without nephropathy (group 2, n=25) and non-diabetic, non-hypertensive control subjects (n=20). All had a detailed clinical and biochemical work-up and cardiac assessment by ECG. Cardiac dysautonomia was assessed by a battery of five non-invasive autonomic function tests (ANF) as recommended by Ewing and Clarke [D.J. Ewing, B.F. Clarke, Diagnosis and Management of autonomic neuropathy. Br. Med. J. 285 (1982) 916-918].

RESULTS

Group 1 patients showed a higher percentage of abnormal CAN function and a more severe form of CAN compared with patients in group 2. Group 1 patients showed early development of the abnormalities. They also had a higher prevalence of peripheral neuropathy compared with the patients without nephropathy.

CONCLUSIONS

The present study showed that the presence of nephropathy was associated with the risk of cardiac autonomic neuropathy in Type 2 diabetic patients and it probably had an earlier onset also in them.

Secretory nucleoside diphosphate kinases from both intra- and extracellular pathogenic bacteria are functionally indistinguishable

Nucleoside diphosphate kinase (NDK), responsible for the maintenance of NTP pools, is an ATP-utilizing enzyme secreted by different pathogens. We found that NDK from Salmonella enterica serovar Typhimurium (S. Typhimurium) is also secretory in nature. Secretory NDK is known to play a crucial role in the survival of pathogenic microbes within host cells through their interaction with extracellular ATP. To elucidate this aspect, we assessed the contribution of secretory products containing NDK from intracellular (Mycobacterium tuberculosis and S. Typhimurium) and extracellular (Vibrio cholerae) pathogens to the process of ATP-induced J774 mouse macrophage cell lysis by monitoring lactate dehydrogenase (LDH) release in the culture medium. Compared with an untreated control, our results demonstrate that S. Typhimurium secretory products caused a greater than twofold decrease in LDH release from J774 macrophage cells treated with ATP. Furthermore, the secretory products from an ndk-deleted strain of S. Typhimurium did not display such behaviour. Contrary to this observation, the secretory products containing NDK of V. cholerae were found to be cytotoxic to J774 cells. At the amino acid level, the sequences of both the NDKs (S. Typhimurium and V. cholerae) exhibited 65 % identity, and their biochemical characteristics (autophosphorylation and phosphotransfer activities) were indistinguishable. However, to our surprise, the secretory product of an ndk-deleted strain of S. Typhimurium, when complemented with V. cholerae ndk, was able to prevent ATP-induced cytolysis. Taken together, our results unambiguously imply that the intrinsic properties of secretory NDKs are identical in intra- and extracellular pathogens, irrespective of their mode of manifestation.