A mycobacterial extracytoplasmic sigma factor involved in survival following heat shock and oxidative stress

Extracytoplasmic function (ECF) sigma factors are a heterogeneous group of alternative sigma factors that regulate gene expression in response to a variety of conditions, including stress. We previously characterized a mycobacterial ECF sigma factor, SigE, that contributes to survival following several distinct stresses. A gene encoding a closely related sigma factor, sigH, was cloned from Mycobacterium tuberculosis and Mycobacterium smegmatis. A single copy of this gene is present in these and other fast- and slow-growing mycobacteria, including M. fortuitum and M. avium. While the M. tuberculosis and M. smegmatis sigH genes encode highly similar proteins, there are multiple differences in adjacent genes. The single in vivo transcriptional start site identified in M. smegmatis and one of two identified in M. bovis BCG were found to have -35 promoter sequences that match the ECF-dependent -35 promoter consensus. Expression from these promoters was strongly induced by 50 degrees C heat shock. In comparison to the wild type, an M. smegmatis sigH mutant was found to be more susceptible to cumene hydroperoxide stress but to be similar in logarithmic growth, stationary-phase survival, and survival following several other stresses. Survival of an M. smegmatis sigH sigE double mutant was found to be markedly decreased following 53 degrees C heat shock and following exposure to cumene hydroperoxide. Expression of the second gene in the sigH operon is required for complementation of the sigH stress phenotypes. SigH is an alternative sigma factor that plays a role in the mycobacterial stress response.

Fibrinolytic therapy in young women with acute myocardial infarction

STUDY OBJECTIVE

Previous studies found that women with acute myocardial infarction (AMI) receive less aggressive therapy compared with men. We sought to determine the percentage of young women (</=50 years) with an AMI eligible for fibrinolytic therapy who received it and explore factors resulting in the ineligibility of women for fibrinolytic therapy.

METHODS

A retrospective chart review was conducted for women 50 years of age or younger who were discharged from a tertiary cardiac care hospital with a diagnosis of AMI during the period 1990 to 1995. Women were included if they met the World Health Organization criteria for AMI.

RESULTS

There were 126 women meeting inclusion criteria with 54 (43%) receiving fibrinolytic therapy. Sufficient information to determine eligibility for fibrinolytic therapy was available for 118 (94%) of the women. Forty-one (91%) of the 45 women who met eligibility criteria received fibrinolytic therapy. Of the 73 women who were ineligible for fibrinolytic therapy, 52 (71%) had a nondiagnostic ECG, 28 (38%) presented 12 hours after symptom onset, and 19 (26%) had an absolute or relative contraindication to fibrinolytic therapy. Of the women not meeting eligibility requirements, 15% nonetheless received fibrinolytic therapy.

CONCLUSION

In this study, most young women with AMI who were eligible for fibrinolytic therapy received it. Nondiagnostic ECG and late presentation to the emergency department (>12 hours after symptom onset) were the most common reasons for ineligibility.

Genetic determination of islet cell autoimmunity in monozygotic twin, dizygotic twin, and non-twin siblings of patients with type 1 diabetes: prospective twin study

OBJECTIVE

To test the hypothesis that non-diabetic dizygotic and monozygotic twin siblings of patients with type 1 diabetes have a similar high prevalence of islet cell autoantibodies, thus suggesting that islet cell autoimmunity is mainly environmentally determined.

DESIGN

Prospective twin study.

SETTING

Two specialist centres for diabetes in the United States.

PARTICIPANTS

Non-diabetic monozygotic twin (n=53), dizygotic twin (n=30), and non-twin (n=149) siblings of patients with type 1 diabetes; 101 controls.

MAIN OUTCOME MEASURES

Analysis of progression to diabetes and expression of anti-islet autoantibodies.

RESULTS

Monozygotic twin siblings had a higher risk of progression to diabetes (12/53) than dizygotic twin siblings (0/30; P<0.005). At the last follow up 22 (41.5%) monozygotic twin siblings expressed autoantibodies compared with 6 (20%) dizygotic twin siblings (P<0.05), 16 (10.7%) non-twin siblings (P<0.0001), and 6 (5.9%) controls (P<0.0001). Monozygotic twin siblings expressed multiple (>/=2) antibodies more often than dizygotic twin siblings (10/38 v 1/23; P<0.05). By life table analysis the probability of developing positive autoantibodies was higher among the monozygotic twin siblings bearing the diabetes associated HLA DQ8/DQ2 genotype than in those without this genotype (64.2% (95% confidence interval 32.5% to 96%) v 23.5% (7% to 40%) at 10 years of discordance; P<0.05).

CONCLUSION

Monozygotic and dizygotic twins differ in progression to diabetes and expression of islet cell autoantibodies. Dizygotic twin siblings are similar to non-twin siblings. These two observations suggest that genetic factors play an important part in determination of islet cell autoimmunity, thus rejecting the hypothesis. In addition, there is a high penetrance of islet cell autoimmunity in DQ8/DQ2 monozygotic twin siblings.

Thrombopoietin (Tpo) in the fetus and neonate: Tpo concentrations in preterm and term neonates, and organ distribution of Tpo and its receptor (c-mpl) during human fetal development

Little is known about thrombopoietin (Tpo) production in human fetuses and neonates. As a step toward determining whether Tpo is relevant to platelet production in the fetus and neonate, we hypothesized that: (1) like other cytokines, Tpo is present in the cord blood in higher concentrations than in adult plasma; (2) Tpo and its receptor (c-mpl) are expressed in fetuses at, and following, 5-6 weeks post-conception (when platelet production begins); and (3) the sites of Tpo and c-mpl production in the fetus are similar to those of adults. We quantified Tpo, by ELISA, in the plasma of 50 adults, as well as in the umbilical cord plasma of 50 preterm and term infants. We also characterized, by RT-PCR, the organ distribution of Tpo and c-mpl during fetal development (at 8 and 16 weeks). Tpo concentrations were measurable (> or =41 pg/ml) in only two of the 50 adult samples (44 and 46 pg/ml), but in 24 of the 50 cord plasma samples (of the 24 samples, the median was 62 pg/ml; mean+/-SD, 80+/-39 pg/ml). Tpo levels did not correlate with either gestational age or platelet count at birth. Similarly to adults, in the fetal tissues, Tpo transcripts were found in all organs tested, but the most dense bands were from liver. C-mpl transcripts were also predominantly from liver. We conclude that: (1) Tpo is present in higher concentrations in cord plasma than in venous plasma of adults; (2) Tpo and c-mpl transcripts are detected in human fetuses as early as the onset of platelet appearance; and(3) Tpo and c-mpl have a similar organ distribution in fetuses and adults.

Blunted thrombopoietin response to interferon alfa-induced thrombocytopenia during treatment for hepatitis C

Thrombocytopenia is common in advanced-stage liver disease and is partly caused by inadequate thrombopoietin (TPO) production in the failing liver. Treatment of chronic hepatitis C with interferon alfa (IFN-) often induces thrombocytopenia, sometimes even leading to discontinuation of treatment. TPO regulation in response to IFN--induced thrombocytopenia was studied in patients with chronic hepatitis C with and without cirrhosis (Child A). An in vitro culture system with HepG2 cells was used to demonstrate any direct effects of IFN- on TPO mRNA expression, TPO synthesis, or TPO secretion from liver cells. Thrombocyte count was lower (U test: P < .05) in patients with hepatitis C cirrhosis compared with patients with chronic hepatitis C without cirrhosis before IFN therapy, and decreased in both patient groups (Wilcoxon matched-pairs test: P < . 05) on IFN therapy, the median decrease in both groups being comparable (noncirrhotic patients, 35%; cirrhotic patients, 32%; U test: P = .57). TPO levels rose in noncirrhotic patients (Wilcoxon matched-pairs test: P < .05), but not in patients with cirrhosis (noncirrhotic patients' median increase: 43% vs. cirrhotic patients' median decrease: 5%; U test: P < .001). Even in patients without cirrhosis, the increase in TPO levels was relatively small for the decrease in platelet count. No effect of IFN- could be demonstrated on TPO mRNA expression in vitro, but TPO secretion from liver cells was significantly reduced. Lower platelet counts but similar TPO levels in patients with chronic hepatitis C and cirrhosis compared with noncirrhotic patients and a moderate increase in TPO levels in noncirrhotic patients with a missing increase in cirrhotic patients during IFN--induced thrombocytopenia provide further evidence for an impairment of TPO production in patients with cirrhosis and during IFN therapy. Recombinant human TPO could be of value in patients developing severe thrombocytopenia under IFN- therapy.

Inhibition of the growth and development of asexual and sexual stages of drug-sensitive and resistant strains of the human malaria parasite Plasmodium falciparum by Neem (Azadirachta indica) fractions

Neem (Azadirachta indica) has been shown to possess anti-malarial activity. In this study we systematically evaluated extracts of neem seeds and purified fractions further enriched in polar or non-polar constituents for their effect on in vitro growth and development of asexual and sexual stages of the human malaria parasite Plasmodium falciparum. Use of synchronized stages of parasites suggested trophozoites/schizonts as the susceptible target stages to various neem extracts. In addition, all the maturation stages of gametocytes were also killed by various neem fractions tested. The anti-plasmodial effect of neem components was also observed on parasites previously shown to be resistant to other anti-malarial drugs, i.e. chloroquine and pyrimethamine suggesting a different mode of action. Neem seed fractions are thus active not only against the parasite stages that cause the clinical infection but also against the stages responsible for continued malaria transmission.

Immunocontraceptive activity guided fractionation and characterization of active constituents of neem (Azadirachta indica) seed extracts

A novel approach for immunocontraception by intervention of local cell mediated immunity in the reproductive system by using single intrauterine application of neem oil has been described earlier. The reversible block in fertility was reported to last for 107-180 days in female Wistar rats (Upadhyay et al., 1990. Antifertility effects of neem oil by single intrauterine administration: A novel method of contraception. Proceedings Of The Royal Society Of London B 242, 175-180) and 7-11 months in monkeys (Upadhyay et al., 1994. Long term contraceptive effects of intrauterine neem treatment (IUNT) in bonnet monkeys: An alternative to intrauterine contraceptive devices. Contraception 49, 161-167). The present study, describes the identification and characterization of the biologically active fraction from neem seeds (Azadirachta indica A. Juss. Family Meliaceae), responsible for the above activity in adult female Wistar rats. Initial studies with the mechanically extracted oil and solvent extracts of neem seeds have revealed that the antifertility activity was present in constituents of low to intermediate polarity. A hexane extract of neem seeds was reported to be biologically active (Garg et al., 1994. Comparison of extraction procedures on the immunocontraceptive activity of neem seed extracts. Journal of Ethnopharmacology 22, 87-92). Subsequently, hexane extract was sequentially fractionated through the last active fraction using various separation techniques and tested for antifertility activity at each step. Preparative HPLC was used for isolating individual components of the active fraction in quantities, sufficient for characterization. An analytical HPLC method was developed for standardization of the fraction. The active fraction was identified to be a mixture of six components, which comprises of saturated, mono and di-unsaturated free fatty acids and their methyl esters. Dose response study was performed with the last active fractions. The antifertility activity with the active fraction was reversible in nature and it was completely active until 5% concentration. There was no systemic toxic effect following the administration of the active fraction. This study, for the first time, proposes an active fraction from neem seeds, responsible for long term and reversible blocking of fertility after a single intrauterine administration with high efficacy.

A, B & H isoantigens in cervical lesions

Expression of A, B and H isoantigens in cervical mucosa was demonstrated by specific red cell adherence test in 92 cervical lesions (40 chronic cervicitis, 12 dysplasia and 40 carcinoma cervix). Eighty percent cases of chronic cervicitis showed a moderate reaction. On the contrary, in carcinoma cervix, 75% cases were found to be SRCA negative. In dysplasia, the intensity of red blood cell adherence was found to be directly related to the degree of cellular differentiation. Study of A, B and H isoantigens might help in deciding the prognosis of dysplasia and/or early detection of malignancy.

Emergence of a unique O3:K6 clone of Vibrio parahaemolyticus in Calcutta, India, and isolation of strains from the same clonal group from Southeast Asian travelers arriving in Japan

Active surveillance of Vibrio parahaemolyticus infection among hospitalized patients in Calcutta, India, was initiated in January 1994. The incidence of cases of V. parahaemolyticus infection suddenly increased in February 1996 and has remained high since then. One hundred thirty-four strains of V. parahaemolyticus isolated from January 1994 to August 1996 were examined for serovar, the presence of the thermostable direct hemolysin gene (tdh) and tdh-related hemolysin genes (trh1 and trh2), production of urease, and antibiogram. Strains of the O3:K6 serovar appeared for the first time in February 1996. The O3:K6 serovar strains accounted for 50 to 80% of the strains isolated during the high-incidence period (February to August 1996). All of the serovar O3:K6 strains carried the tdh gene but not the trh genes and did not produce urease. All of the isolates except two were sensitive to all of the antibiotics tested. These and the results of analysis by an arbitrarily primed PCR method indicated that the O3:K6 serovar strains belong to a unique clone. When the O3:K6 serovar strains, isolated from travelers arriving in Japan from Southeast Asian countries, were compared by the arbitrarily primed PCR method, the strains isolated between 1982 and 1993 were distinct from Calcutta O3:K6 while the strains isolated in 1995 and 1996 were indistinguishable from the Calcutta O3:K6 strains. The results suggest that this unique O3:K6 clone may have become prevalent not only in Calcutta but also in Southeast Asian countries very recently. Not only the O3:K6 strains but also the non-O3:K6, tdh-bearing strains isolated in 1996 produced thermostable direct hemolysin at high levels, and thus the level of hemolysin produced does not appear to have influenced the high incidence of serovar O3:K6 strains.

Status of chest X-ray in diagnosing right ventricular infarction

Right ventricular enlargement on left anterior oblique view at 60 degrees had low sensitivity (58.8%) but very high specificity (100 %) for diagnosing right ventricular infarction. Right ventricular and right atrial enlargement on other views had very low sensitivity (16.7-26.7%) but high specificity (80-90%). Thus chest X-ray in left anterior oblique view at 60% is useful in detecting right ventricular infarction when clinical examination and electrocardiogram are inconclusive.

Intravalvular implantation of aortic valve prosthesis

A simplified technique is described to overcome the problem of aortic valve replacement in a severely dilated aortic root (> 30-mm diameter). Intravalvular implantation of an inverted mitral prosthesis after imbrication of aortic cusps was performed in a patient with severe aortic regurgitation with gross annular dilatation. The technique may be applicable in a select subset of patients.

Health and nutritional status of boys aged 6 to 12 years in a children observation home

One hundred and ninety two boys in the age group 6 to 12 years, living in a Children Observation Home in Delhi were studied for their nutritional status and morbidity profile. Body Mass Index (BMI), an age-independent index was used to grade the nutritional status according to which, 36.7% of the boys were found to be malnourished. Signs of specific nutritional deficiencies were observed in 13.5% of the boys. Morbidity in some form or the other was present in 148 (60%) boys. Skin disease was the commonest morbidity (31.7%), followed by diseases of the oral cavity (16.1%), acute respiratory infections (8.6%) and diseases of the ear (9.9%). Need for health promotional activities is stressed to reduce the morbidity and improve the health status of these children.

Treatment of facial rhytides with a high-energy pulsed carbon dioxide laser

Facial rhytides are a common problem that often presents for treatment. Because of the tendency for rhytides to involve delicate tissue areas, traditional treatment modalities have been limited by complications of scarring or pigmentary alterations. With the advent of the new-generation high-energy pulsed carbon dioxide lasers, skin requiring resurfacing can now be treated successfully with minimal risk and side effects. This study included 259 patients with facial rhytides (104 perioral, 83 periorbital, 53 glabellar, and 17 forehead). Each patient received treatment with a high-energy pulsed CO2 laser system, and individual responses were evaluated independently by two blinded assessors at 1, 4, 8, 12, and 24 weeks postoperatively. While clinical response rates were uniformly excellent, they varied in different locations. On average, there was a 90 percent improvement in all areas under study. The periorbital regions responded best, an average 93 percent improvement being seen. The facial rhytides with the lowest response rates (86.8 percent) were those which were most severe and those caused by excessive muscle movement (i.e., frown lines at the glabella). No incidences of scarring were noted, but erythema persisting 1 to 3 months (mean 2.2 months) following laser irradiation was typical. Transient postinflammatory hyperpigmentation of 3 months' average duration was seen in 30 percent of patients and was not limited to those individuals with darker skin tones. The high-energy pulsed carbon dioxide laser is a safe and effective treatment for facial rhytides. Treatment can be delivered in an outpatient setting without the need for general anesthesia, and preliminary evidence suggests long-lasting results.

Temporal shifts in traits of Vibrio cholerae strains isolated from hospitalized patients in Calcutta: a 3-year (1993 to 1995) analysis

This study presents results of a surveillance on cholera conducted with hospitalized patients admitted to the Infectious Diseases Hospital, Calcutta, India, from January 1993 to December 1995. The O139 serogroup of Vibrio cholerae dominated in 1993 but was replaced by O1 as the dominant serogroup in 1994 and 1995. The isolation rate of V. cholerae non-O1 non-O139 did not exceed 4.9% throughout the study period, while the isolation rate of the O139 serogroup in 1994 and 1995 was below 9%. No temporal clustering of any non-O1 non-O139 serogroup was observed. With the exception of 1 strain, none of the 64 strains belonging to the non-O1 non-O139 serogroup hybridized with ctx, zot, and ace gene probes, while 97.3 and 97.7% of the O139 and O1 strains, respectively, hybridized with all the three probes. Multiplex PCR studies revealed that all the O1 strains belonged to the EIT or biotype. There was a progressive increase in the cytotoxic response on CHO and HeLa cells evoked by culture supernatants of strains of V. cholerae non-O1 non-O139 isolated during 1994 and 1995 compared with the response evoked by those isolated in 1993. Dramatic shifts in patterns of resistance to antibiotics between strains of V. cholerae belonging to different serogroups and within strains of a serogroup isolated during different time periods were observed. There was a discernible increase in the incidence of multidrug-resistant strains of V. cholerae O1 isolated in 1994 and 1995 compared with that in 1993. On the basis of the results of this study, we predict the possibility of newer variants of V. cholerae emerging in the future.

Electron microscopic studies on Vibrio cholerae O139

We conducted studies to investigate the surface architecture of V. cholerae O139 using electron microscopy and compared it with O1 and other serogroups of V. cholerae. The bacterium is comma-shaped and has a single polar flagellum and morphologically resembles the classical and E1Tor biotypes of V. cholerae O1. High power electron microscopy showed a few pili, 5 to 7 nm in diameter, and 2 to 3 in number per bacterium. The presence of a capsule on electron microscopy of ultrathin sections of V. cholerae O139 treated with polycationic ferritin clearly distinguished the O139 serogroup from the O1 serogroup which are not encapsulated. Immunoelectron microscopy further revealed that an anti-O139 monoclonal antibody of the IgG2a isotype bound specifically only to an O139 strain but not to any other serogroup of V. cholerae indicating that O139 has unique epitopes not found in other serogroups of V. cholerae.

Comparative analysis of factors promoting optimal production of cholera toxin by Vibrio cholerae O1 (classical & E1Tor biotypes) & O139

Various culture media [AKI, Brain heart infusion broth (BHI), Casamino acid-yeast extract broth (CAYE), Casamino acid-yeast extract broth supplemented with 90 micrograms/ml of lincomycin (CAYE-L), Tryptic soy broth (TSB) and Yeast extract peptone (YEP)], cultural conditions (stationary and shaking) and incubation temperatures (30 degrees C and 37 degrees C) were evaluated to determine optimal conditions for production of cholera toxin (CT) by different biotypes (classical and E1Tor) and serogroups (O1 and O139) of V. cholerae. It was found that V. cholerae O1 E1Tor grown in CAYE-L and incubated at 30 degrees C with constant shaking was optimal for production of CT, while for the classical biotype and for the O139 serogroup, CT was maximally produced when grown in YEP and incubated at 30 degrees C in a shaker. Temperature appeared to be a prominent factor affecting the production of CT by the O1 E1Tor biotype when the media used were AKI, CAYE-L and YEP and also for the classical biotype when the media used were the AKI, BHI, CAYE and YEP. In the case of the O1 E1Tor biotype, CAYE-L was the best medium for CT production whereas for the classical biotype, CAYE-L was a poor medium as far as CT production was concerned. Irrespective of the media used, 30 degrees C shake culture condition seemed to be more favourable for supporting CT production except in CAYE medium for the O1 E1Tor biotype where incubation at 37 degrees C in a shaker was as good as incubation at 30 degrees C.

Effect of volatiles from neem and other natural products on gonotrophic cycle and oviposition of Anopheles stephensi and An. culicifacies (Diptera: Culicidae)

The gonotrophic cycle of female Anopheles was impaired by exposure to volatiles of neem, (Azadirachta indica), reetha, (Sapindus mukorossi), and garlic, (Allium sativum), but not to castor seeds and cotton seed oil. A brief exposure to contact or volatile extracts from neem suppressed rather than inhibited oviposition. Complete inhibition of oviposition was observed by exposure of mosquitoes to neem oil and 1 fraction containing volatile components. Vitellogenesis was impaired irreversably by long-term exposure to neem odor and some extracts. The effect of volatiles on oviposition seems to be regulated by absorption through the cuticle, although passage through the spiracles could not be excluded.

Jugular venous pressure and pulse wave form in the diagnosis of right ventricular infarction

Jugular venous pressure (measured clinically) and pulse wave form (recorded at 100 mm/s) were analysed in 44 cases of first acute myocardial infarction and 10 age-matched controls. Patients were divided into different groups according to site of infarction decided by detailed 2-D echocardiography. Raised jugular venous pressure had high specificity (96.8%) but low sensitivity (39%) in diagnosing right ventricular infarction. Positive Kussmaul's sign had equal specificity but lower sensitivity (26.1%). Rapid 'y' descent had high specificity (100%) but low sensitivity (17.3%) in diagnosing right ventricular infarction. Jugular venous pressure and pulse wave form are significantly affected by the magnitude of damage to interventricular septum and left ventricular free wall.

Para-[18F]fluorobenzylguanidine kinetics in a canine coronary artery occlusion model

BACKGROUND

The kinetics of para-[18F]fluorobenzylguanidine ([18F]PFBG) were investigated in a canine coronary artery occlusion model.

METHODS AND RESULTS

Five dogs were imaged by positron emission tomography (PET) before and after complete surgical ligation of the left anterior descending coronary artery. PET studies included a 10-minute dynamic [13N]NH3 perfusion scan, followed 1 hour later by 3-hour dynamic [18F]PFBG scanning. [18F]PFBG and [13N]NH3 images demonstrated homogeneous myocardial uptake/perfusion before infarction. One hundred eighty minutes after [18F]PFBG administration, myocardial accumulation was decreased by 60% (day 2, 0.0065% +/- 0.0015% injected dose/ml) and 58% (day 16, 0.0069% +/- 0.003% injected dose/ml) compared with a similar myocardial region of interest from the preinfarction (0.016% +/- 0.005% injected dose/ml) study. Myocardial accumulation of [13N]NH3 at 9 minutes showed a 52% (day 2) and 7% (day 16) decrease compared with the preinfarction study. The accumulation of [18F]PFBG in the infarction was decreased significantly at 120 and 180 minutes on all postinfarction studies (p = 0.01). In three dogs a significant decrease in the myocardial norepinephrine concentration was documented in the area of infarction (237 +/- 94 ng/gm) versus the noninfarcted (1018 +/- 48 ng/gm) myocardium (p = 0.001).

CONCLUSIONS

A decreased accumulation of [18F]PFBG was observed in the area of myocardial infarct in this canine model. The magnitude of the decrease in [18F]PFBG was larger than that seen with [13N]NH3 on day 16 after infarction, suggesting reperfusion and persistent sympathetic neuronal dysfunction.

Biotype traits and antibiotic susceptibility of Vibrio cholerae serogroup O1 before, during and after the emergence of the O139 serogroup

Sixty-nine strains of Vibrio cholerae O1 isolated at different times were analysed to investigate if there were any differences among the O1 strains isolated before, during and after the advent of the O139 serogroup. Of the 69 O1 strains examined, 68 belonged to the Ogawa serotype while one belonged to the Inaba serotype. With the exception of one strain all other strains of V. cholerae O1 belonged to the eltor biotype. A single O1 strain isolated before the emergence of the O139 serogroup could not be classified as either eltor or classical biotype because it was resistant to both classical and eltor specific bacteriophages. Marked variations in the susceptibility to antibiotics of V. cholerae O1 isolated during the different periods were observed. In addition, strains of V. cholerae isolated after the epidemic of serogroup O139 in Calcutta showed an expanding R-type with resistance to a variety of drugs as compared to the O1 strains isolated before the advent of the O139 serogroup. From this study, it is clear that there is a substantial mobility in genetic elements of V. cholerae O1 which necessitates a continuous monitoring to keep abreast of the changing traits of the etiologic agent of cholera.

Development and testing of monoclonal antibody-based rapid immunodiagnostic test kits for direct detection of Vibrio cholerae O139 synonym Bengal

We report on the development and testing of two monoclonal antibody-based rapid immunodiagnostic test kits, BengalScreen, a coagglutination test, and Bengal DFA, a direct fluorescent-antibody test, for direct detection of Vibrio cholerae O139 synonym Bengal in clinical and environmental specimens. The BengalScreen test requires less than 5 min to complete and can be used in the field. Bengal DFA, being more sensitive than BengalScreen, requires only one reagent and less than 20 min for detection and enumeration of V. cholerae O139 synonym Bengal. In tests for specificity, all 40 strains of V. cholerae O139 reacted with both test kits, whereas 157 strains of heterologous species examined did not, yielding 100% specificity in this study. A field trial was conducted in with both BengalScreen and Bengal DFA, and the results were compared with those obtained by conventional culture methods. BengalScreen demonstrated a sensitivity of 95%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 94%. Results obtained by Bengal DFA, on the other hand, were 100% sensitive and 100% specific and yielded 100% positive and negative predictive values compared with culture methods. In a second evaluation, 93 stool specimens from Mexico that were negative for V. cholerae O139 by culture were also tested with both the BengalScreen and Bengal DFA kits. None of the 93 specimens were positive for V. cholerae O139 by both tests. A concentration method was optimized for screening of environmental water samples for V. cholerae O139 synonym Bengal with rapid test kits. BengalScreen results were unequivocally positive when water samples contained at least 2.0 x 10(3) CFU/ml, whereas Bengal DFA demonstrated an unequivocally positive reaction when the water sample contained at least 1.5 x 10(2) CFU/ml. When Bengal DFA was compared with conventional culture methods for enumeration of V. cholerae O139 synonym Bengal organisms, no difference was observed.

Safety of intrauterine administration of purified neem seed oil (Praneem Vilci) in women & effect of its co-administration with the heterospecies dimer birth control vaccine on antibody response to human chorionic gonadotropin

Praneem Vilci (PV), purified neem oil was reported to exercise a reversible antifertility effect after a single intrauterine instillation in rodents and primates without any adverse effects. After toxicology, drug regulatory and ethical clearances, a phase I clinical trial was conducted on PV. Eighteen healthy tubectomised women were enrolled to evaluate the safety of a single intrauterine instillation of PV and to determine the effect of its co-administration on anti-hCG response to the heterospecies dimer (HSD) hCG vaccine. Eight women received PV alone and ten women were given the HSD-hCG vaccine in addition. Base-line and post-treatment haematological and biochemical profiles were determined as also the mid-luteal serum progesterone. Endometrial biopsies were examined to assess ovulatory status and the effect of intrauterine treatment with PV on the endometrium. Anti-hCG antibody titres were estimated in women who were concurrently immunized with the HSD vaccine. No untoward reaction was observed in any woman. Menstrual pattern and ovulatory status remained unaltered. Endometrial biopsy after PV instillation in one woman showed non-specific endometritis but she remained asymptomatic. Mild eosinophilia was seen in two women and this reverted to normal on its own. All women receiving PV and the HSD vaccine generated antibodies against hCG. Our data show that intrauterine administration of PV is safe and does not prevent the antibody response to HSD-hCG vaccine.

Distribution and virulence of Vibrio cholerae belonging to serogroups other than O1 and O139: a nationwide survey

The distribution and virulence of Vibrio cholerae serogroups other than O1 and O139 in India before, during and after the advent of O139 serogroup was investigated. A total of 68 strains belonging to 31 different 'O' serogroups were identified during the study period. With the exception of O53, there was no spatial or temporal clustering of any particular non-O1 non-O139 serogroup at any given place. Two of the 68 strains examined produced cholera toxin (CT) which could only be partially absorbed with anti-CT immunoglobulin G. Tissue culture assay revealed that some of the non-O1 non-O139 strains produced factors which evoked either a cell rounding or cell elongation response depending upon the medium used. This study indicates that serogroups other than O1 and O139 should also be continuously monitored.

Monoclonal antibodies against Ogawa specific & Ogawa-Inaba common antigenic determinants of Vibrio cholerae O1 & their diagnostic utility

Monoclonal antibodies to Ogawa-Inaba common antigenic determinant and Ogawa specific antigenic determinant of V. cholerae belonging to the serogroup O1 were generated from BALB/c mice immunized with V. cholerae O1 Eltor Ogawa strain. Reactivity and specificities of the monoclonal antibodies were examined by slide agglutination method. The monoclonal antibodies agglutinated all the V. cholerae O1 strains tested but did not agglutinate with any of the other currently recognized 140 serogroups of V. cholerae non-O1 as well as with a variety of other enteric pathogens. Diagnostic utility of the MAbs produced in this study as compared to polyclonal O1 and monospecific antisera showed that the MAbs were as good as the latter for serological diagnosis of the two serotypes of V. cholerae O1.

Outbreak of cholera due to Vibrio cholerae 01 in Orissa state

During May-June 1993, an outbreak of acute diarrhoea resulting in deaths primarily in adults was reported in two districts of Orissa state. Epidemiological and microbiological investigations revealed that this outbreak was caused by V. cholerae 01 biotype EITor. V. cholerae 01 strains were uniformly resistant to furazolidone.

Characterization of phenotypic, serological, and toxigenic traits of Vibrio cholerae O139 bengal

Biochemical and physiological traits of a collection of strains of Vibrio cholerae O139 Bengal isolated from India, Bangladesh, and Thailand showed that these strains formed a phenotypically homogeneous group with identical characteristics that were essentially similar to those of the O1 serogroup. Resistance to 150 micrograms of the vibriostatic agent O/129 (2,4-diamino-6,7-diisopropylpteridine) and Mukherjee's El Tor phage 5 and classical phage IV and the nonagglutinability of the strains with O1 antiserum were the only discernible differences between the O139 and O1 serogroups. Extensive serological characterization further revealed the O139 serogroup to be distinct from the existing 138 serogroups of V. cholerae. Antiserum raised against the O139 serogroup required absorption with the R reference strain CA385 and with the reference strain representing serogroup O22 to remove cross-reacting agglutinins. All of the 223 representative strains of V. cholerae O139 examined hybridized with DNA probes specific for the cholera toxin (CT) gene, zonula occludens toxin gene, and El Tor hemolysin gene but not with the probe specific for the heat-stable enterotoxin gene. The amount of CT present in stool samples of patients infected with the O139 serogroup was higher than that found in stools of patients infected with O1 El Tor, and this echoed findings that the amount of CT produced by O139 strains in vitro was higher than that produced by the O1 El Tor strains. The nucleotide sequences of the genes encoding the A and B subunits of CT of the O139 serogroup were identical to the sequences reported for the CT gene of O1 El Tor. The CT gene of O139 strains could be amplified by using primers developed for detection of the CT gene of the O1 serogroup by a PCR assay, which could also be used to detect the CT gene in stool samples of patients infected with strains of the O139 serogroup.

Comparison of extraction procedures on the immunocontraceptive activity of neem seed extracts

Azadirachta indica (Neem) seed extracts are known to activate the local cell-mediated immune reactions after a single intrauterine administration, leading to a long term reversible block of fertility. In order to identify and characterize the active fraction responsible for this activity, neem seeds were extracted by both mechanical expression and solvent extraction using a range of polar to non-polar solvents which yielded 3 broad fractions. The mechanically expressed oil was fractionated using different approaches and studied for antifertility activity. The hexane extract and a corresponding column fraction showed potent and reproducible antifertility activity. Other fractions were less stable with regard to reproducibility of effects and composition. It is our conclusion that for subsequent fractionation to reach the last active fraction, the hexane extract is the most useful starting material.

PET imaging of osteosarcoma in dogs using a fluorine-18-labeled monoclonal antibody Fab fragment

Four dogs with histologically confirmed osteogenic sarcoma were studied with PET following intravenous injection of the 18F-labeled Fab fragment of TP-3, a monoclonal antibody specific for human and canine osteosarcomas.

METHODS

The antibody fragment was labeled using the N-succinimidyl 8-[(4'-[18F]fluorobenzyl)amino]suberate acylation agent. Blood clearance of activity was biphasic in all dogs but half-times were variable (T1/2 beta = 2-13 hr). Catabolism of labeled Fab was reflected by the decrease in protein-associated activity in serum from more than 90% at 1 min to 60%-80% at 4 hr.

RESULTS

PET images demonstrated increased accumulation of 18F at the primary tumor site relative to normal contralateral bone in one dog as early as 15 min after injection. Biopsies obtained after euthanasia indicated higher uptake at the edges of the tumor as observed on the PET scans. Tumor uptake was 1-3 x 10(-3)% injected dose/g, a level similar to that reported for other Fab fragments in human tumors. In the three dogs with metastatic disease, early PET images reflected activity in the blood pool but later uptake was observed in suspected metastatic sites.

CONCLUSIONS

These results, although preliminary, suggest that PET imaging of 18F-labeled antibody fragments is feasible and that dogs with spontaneous tumors could be a valuable model for preclinical research with radioimmunoconjugates.

Synergistic spermicidal activity of neem seed extract, reetha saponins and quinine hydrochloride

In order to identify potent spermicidal agents which are free from the side effects of currently available agents, spermicidal activity of purified neem seeds extract (Praneem), reetha saponins and quinine hydrochloride was studied individually and in combination. Sander-Cramer test was used to assess the activity on human sperm. Under the test conditions, minimum effective spermicidal concentrations for Praneem, reetha saponins and quinine hydrochloride were 25%, 0.05% and 0.346%, respectively. At these concentrations, 100% of the sperm were immobilised within 20 seconds. A positive synergistic effect in the spermicidal activity of these components, if used in combination, was observed which implies the use of reduced concentrations of each to bring about the desired action. The selected combination formulated into a suitable dosage form is likely to offer dual benefit of a potent contraceptive and an antimicrobial preparation.

Vibrio cholerae O139 in Calcutta

Vibrio cholerae O139 was recovered from 28 of 79 children with acute watery diarrhoea. Clinically, they presented with watery diarrhoea (100%), vomiting (79%), abdominal cramps (61%), anorexia (61%), dehydration (100%), and absence of fever. Both clinical and blood biochemical parameters of these cases were similar to the illness caused by the new strain in adults. Hypoglycaemia was seen in 40% of those screened.

Production and cross-reactivity patterns of a panel of high affinity monoclonal antibodies to Vibrio cholerae O139 Bengal

A series of monoclonal antibodies of different isotypes specific for Vibrio cholerae O139, the new pandemic strain of cholera, was produced. These mAbs reacted only with the reference strain (MO45) representing serovar O139 but did not react with any of the other reference strains representing serovars O1 to O140. Significantly, the mAbs did not agglutinate the R-cultures of V. cholerae (CA385, 20-93) which demonstrated the exceptional specificity of these mAbs and indicated that the mAbs recognized antigenic determinants unique for the O139 serovar. There was heterogeneity in the intensity of reactivity of the mAbs with strains of V. cholerae O139 isolated from diverse sources. Apart from 4H6, the other mAbs agglutinated all the O139 strains examined. 2D12 and 2F8 were the best mAbs based on the intensity of agglutination with all the O139 strains. Evaluation of 3A10 in comparison with a polyclonal anti-O139 antibody raised in rabbit using the slide agglutination format revealed that 3A10 fared as well as the polyclonal antibody for the laboratory identification of the O139 serovar. The acquisition of these mAbs provide reagents which would be very useful in the development of simple immunodiagnostic assays for the diagnosis of V. cholerae O139 infections.

Spread of Vibrio cholerae O139 Bengal in India

Vibrio cholerae serogroup O139 Bengal, a novel strain with epidemic potential, completely displaced V. cholerae serogroup 01 in Calcutta in January 1993, which was followed by an epidemic caused by V. cholerae O139 in March-May 1993. From November 1992 to July 1993, 95.6% of 916 V. cholerae isolates submitted to the National Institute of Cholera and Enteric Diseases from 28 locations in India were confirmed as serogroup O139. As of July 1993, V. cholerae O139 had been isolated from 13 Indian states and a union territory, and large outbreaks of cholera caused by the O139 serogroup had occurred in several cities. The extent of spread of V. cholerae O139 Bengal in India and its ability to swiftly disseminate leaves little doubt that this is the beginning of the eighth pandemic of cholera.

Synthesis and preliminary evaluation of para- and meta-[18F]fluorobenzylguanidine

meta-[18F]Fluorobenzylguanidine ([18F]MFBG) and para-[18F]fluorobenzylguanidine ([18F]PFBG) were synthesized in three steps beginning with a fluoro for nitro exchange reaction on 3- and 4-nitrobenzonitrile, respectively. Overall radiochemical yields were 10-15% for [18F]MFBG and 50-55% for [18F]PFBG in a total synthesis time of 60 min. However, impurities interfered with the binding of the product to target cells. A new route was adopted for the synthesis of [18F]PFBG using 4-nitrilophenyl trimethylammonium trifluoromethanesulfonate (Q.S.) as the starting material. In addition to shortening the overall synthesis time by 10 min, this precursor also eliminated problems associated with the presence of small amounts of starting material in the preparation. In vitro binding of [18F]PFBG prepared by the Q.S. method to SK-N-SH, human neuroblastoma cells was 26.5 +/- 1.1%, compared to 16.9 +/- 1.6% when the nitro precursor was used. Selective uptake of both 18F-labeled isomers in the heart and adrenal was seen in mice. At 4 h, adrenal and heart uptake of [18F]PFBG prepared using Q.S. was 20.3 +/- 4.8 and 5.9 +/- 0.8% ID/g respectively, compared to 23.8 +/- 5.0 and 10.5 +/- 1.7% ID/g for [18F]MFBG. Based on the 5-fold higher radiochemical yields obtained with [18F]PFBG, this isomer would appear to be the more practical choice; however, in vitro and in vivo results suggest that [18F]MFBG exhibits greater similarities to MIBG.

Engineering Fab' fragments for efficient F(ab)2 formation in Escherichia coli and for improved in vivo stability

We previously developed an efficient route to humanized F(ab')2 fragments by high level secretion of the Fab' arms from Escherichia coli followed by directed chemical coupling in vitro. Here the number and type of interchain linkages in F(ab')2 molecules has been modified to simplify their production and improve their serum stability. All F(ab')2 variants had comparable binding affinity for the p185HER2 Ag and antiproliferative activity against p185HER2-overexpressing tumor cells. This was anticipated since the modifications are distant from the Ag-binding loops. Replacement of a single disulfide bridge between Fab' arms with a more stable thioether bridge increased the serum permanence time in normal mice by threefold to 2.1 h. Removal of the disulfide bond between L and H chains in the thioether-bridged F(ab')2 did not affect the pharmacokinetics, suggesting that the L chain remains associated with the H chain. An additional Fab' variant containing three repeats of the motif, CysProPro, was constructed with the aim of promoting efficient formation of F(ab')2 in E. coli. This Fab' (CPP)3 variant was recovered predominantly (up to 70%) as F(ab')2 directly from fermentation cell pastes, thus circumventing the need for in vitro coupling. The F(ab')2 (CPP)3 variant has a similar serum pharmacokinetics to the thioether-bridged molecules. The improvements described here for deriving F(ab')2 fragments from E. coli should enhance the clinical potential of these molecules.

Engineering Fab' fragments for efficient F(ab)2 formation in Escherichia coli and for improved in vivo stability

We previously developed an efficient route to humanized F(ab')2 fragments by high level secretion of the Fab' arms from Escherichia coli followed by directed chemical coupling in vitro. Here the number and type of interchain linkages in F(ab')2 molecules has been modified to simplify their production and improve their serum stability. All F(ab')2 variants had comparable binding affinity for the p185HER2 Ag and antiproliferative activity against p185HER2-overexpressing tumor cells. This was anticipated since the modifications are distant from the Ag-binding loops. Replacement of a single disulfide bridge between Fab' arms with a more stable thioether bridge increased the serum permanence time in normal mice by threefold to 2.1 h. Removal of the disulfide bond between L and H chains in the thioether-bridged F(ab')2 did not affect the pharmacokinetics, suggesting that the L chain remains associated with the H chain. An additional Fab' variant containing three repeats of the motif, CysProPro, was constructed with the aim of promoting efficient formation of F(ab')2 in E. coli. This Fab' (CPP)3 variant was recovered predominantly (up to 70%) as F(ab')2 directly from fermentation cell pastes, thus circumventing the need for in vitro coupling. The F(ab')2 (CPP)3 variant has a similar serum pharmacokinetics to the thioether-bridged molecules. The improvements described here for deriving F(ab')2 fragments from E. coli should enhance the clinical potential of these molecules.

Studies on the contraceptive efficacy of Praneem polyherbal cream

Praneem polyherbal cream, a spermicidal formulation, has been developed at the National Institute of Immunology, which makes use of Praneem, a purified extract from the dried seeds of an ancient Indian plant Azadirachta indica (Neem), extract from the pericarp of fruits of Sapindus species and quinine hydrochloride. These ingredients have a synergistic spermicidal activity and an optimised formula was derived. The components were made into a water-soluble cream base prepared by using pharmaceutically acceptable base and stabilised by addition of IP grade antioxidant and preservatives. The cream is devoid of irritation and sensitization potential, as seen with standard Draize test on normal and abraded skin of rabbits and by 21-day cumulative skin sensitivity in human volunteers. The formulation was found to be safe under subacute toxicity studies in monkeys. The formulation has shown high contraceptive efficacy in rabbits and in monkeys after intravaginal application. The shelf-life of the cream at room temperature is estimated to be 18 months by accelerated stability studies.

Quantitative two-site enzyme-linked immunosorbent assays for inhibin A, activin A and activin B

We have developed three specific enzyme-linked immunosorbent assay (ELISA) formats which quantitate inhibin A in conditioned media and serum. The assays are sensitive in a range 0.078-5.0 ng/ml and have been characterized in terms of cross-reactivity to inhibin related proteins. The CK:CK assay format recognizes inhibin A, inhibin B and inhibin-related molecules, while the 9A9:CK assay format recognizes inhibin A and inhibin A precursors, but not free alpha-subunit. The 11B5:CK assay appears to recognize only mature 32 kDa inhibin A. Additionally, we have developed separate, specific ELISA formats which quantitate activin A and activin B. The assays have a range of 0.2-50 ng/ml and 0.4-50 ng/ml for activin A and recombinant activin B, respectively. These assays are presently being used to examine the concentration of inhibin A, activin A and activin B in clinical serum samples.

Magnitude of acute respiratory infections in under five

A community-based study was carried out in a rural area of Delhi to measure the prevalence and incidence of acute respiratory infections among children below the age of 5 years. The prevalence of 12.1%, was similar in boys and girls and was seen to decline with age. The incidence of acute respiratory infections was 2.5 episodes per child per year; it was not different in boys and girls. There was a statistically significant decline in the incidence with age. Upper respiratory tract infections comprised 87.5% of total acute respiratory infection morbidity while lower respiratory tract infections were 12.5%. Both upper and lower respiratory tract infections declined with increasing age; while the former was similar among boys and girls, the incidence of latter was significantly greater in boys (0.4 episodes per year) as compared to girls (0.2 episodes per year). A total of 87.5% episodes were mild, 10.4% moderate and only 2.1% were severe. The results suggest that acute respiratory infections are a major community health problem and an acute respiratory infection control programme needs to be implemented urgently.

Radioiodination of a monoclonal antibody using N-succinimidyl 5-iodo-3-pyridinecarboxylate

The potential utility of N-succinimidyl 5-iodo-3-pyridinecarboxylate (SIPC) for the radioiodination of monoclonal antibodies was investigated. Paired-label studies were performed using the anti-tenascin antibody 81C6 in athymic mice bearing subcutaneous D-54 MG human glioma xenografts. Radiolabeling was also done using N-succinimidyl 3-iodobenzoate (SIB). Radioiodination of SIPC and SIB both proceeded in 60-80% yield, but protein coupling efficiencies with SIB were higher (76 +/- 16 vs 60 +/- 7%). Immunoreactivity and affinity of both preparations were similar. Using SIPC, thyroid uptake was quite low, decreasing from 0.3% at day 1 to 0.05% at day 8. Tumor uptake reached 46 +/- 11% injected dose/g at day 1 but declined gradually thereafter. This apparent decline reflected the rapid growth of these xenografts since tumor accumulation expressed as percentage of injected dose remained nearly constant up to day 9. These results suggest that SIPC, like SIB, offers significant advantages for labeling antibodies when compared with conventional protein iodination methods.

Topical phenytoin in the treatment of split-thickness skin autograft donor sites: a comparative study with polyurethane membrane drape and conventional dressing

The effectiveness of topical phenytoin as a wound healing agent was compared with that of OpSite (Smith & Nephew) and a conventional topical antibiotic dressing (Soframycin, Roussel) in a controlled study of 60 patients with partial-thickness skin autograft donor sites on the lower extremities. Mean time to complete healing (complete epithelialization) was 6.2 +/- 1.6 days in the phenytoin-treated group (30 patients), compared to 8.6 +/- 2.2 days with OpSite (15 patients), and 12.6 +/- 3.4 days in the 15 Soframycin-treated patients. The differences between the treatment groups were significant at P < 0.001. Mean pain scores were also lower in the phenytoin-treated group, 0.40 +/- 0.55 vs. 0.66 +/- 0.60 with OpSite (P < 0.05) and 1.4 +/- 0.50 with the conventional dressing (P < 0.001). Both phenytoin and OpSite were superior to the Soframycin dressing with respect to bacterial contamination and wound infection as measured by Gram stains of wound smears, swab and aspirate (OpSite) cultures, and clinical assessments (P < 0.001) carried out on the fifth day of treatment. No local or systemic adverse effects of the three agents used were noted. Phenytoin appears to be an effective, low-cost and safe method for the treatment of partial-thickness skin graft donor sites, comparing very favourably with, and in some aspects superior to, occlusive dressings. Further clinical use and evaluation of topical phenytoin are merited.