EPIDEMIOLOGY AND SEASONAL VARIATION OF APPENDICITIS – A SINGLE CENTER RETROSPECTIVE STUDY FROM NORTH-EAST INDIA

Background. Acute appendicitis is the most common surgical emergency presenting in emergency department, and appendectomy is one of the most common surgeries. There is a wide variation in the incidence of acute appendicitis reported for different countries, different regions, race, sex, age and also seasons. Objective. The aim of this study was to understand the epidemiological trend and the seasonal variation of appendicitis in the northeast region of India. Methods. It was a retrospective hospital-based study conducted in Jan 2016 – Dec 2020 at a Tertiary Care Teaching Hospital in the northeast region of India. The patient data were obtained from the Medical Record Department of the hospital and the data regarding the weather was obtained from the Indian Meteorological Department (IMD) and the website www.worldweather.com. The statistical analysis was done using SPSS software version 24.0, and the seasonal variation was studied using Kruskal Wallis test. Results. Acute appendicitis affected both the sexes equally with a marginal higher incidence in males. It also had higher peak during the second and third decade of life in both the sexes. The incidence of acute appendicitis was high in the pre-monsoon and monsoon season with peak in the monsoon season. Conclusions. Acute appendicitis is more common during the pre-monsoon and monsoon season, a period known for humidity, high incidence of bacterial and viral infections.

MODERN APPROACHES IN MANAGEMENT OF CHILDREN WITH CHRONIC HEPATITIS B IN REMISSION OF ACUTE LYMPHOBLASTIC LEUKEMIA

The aim of the study is to assess the effectivity of the drug «Betargin» in complex management of patients with chronic hepatitis B (CHB) in remission of acute lymphoblastic leukemia (ALL). The research had shown the results of treatment of 41 children with CHB in remission of ALL aged from 3 to 17 years old, who were on dispensary observation in Vinnytsia Regional Children's Clinical Infectious Diseases Hospital during 2013-2017 years. Patients were devided into the following groups: the comparison group (group A), which included 18 children with CHB in remission of ALL, who received basis therapy; the main group (group B) which consisted of 23 patients with CHB in remission of ALL, who got betaine arginine complex («Betargin») in addition to basis therapy. The control group was formed out of 30 healthy children. Determination of effectivity of the proposed treatment regimen was performed by studying the indicators of cholestasis, cytolysis, hepatocellular insufficiency, and lipid metabolism. To assess the liver's fibrosis level and necroinflammatory activity we used the determination of the level of plasma osteopontin in the serum using the enzyme-linked immunosorbent assay (ELISA) method: Human Osteopontin Quantikine (RDD systems, Dos Too, Minneapolis, MS, USA). The verification of the diagnosis of CHB was based on the detection of specific markers of HBV-infection in blood using ELISA and PCR analysis. During our scientific research we established that using betaine arginine complex in management of CHB in remission of ALL led to considerable improvement of children's general condition, namely due to reducing (p<0,05) the incidence of asthenovegetative (8.6% against 33.3% in the comparison group), dyspeptic (13.1% against 38.8%) as well as pain syndromes (4.3% against 11%) and hepatomegaly (13.1% against 38.8%). The activity of ALT in the main group was in 1.6 times less (p<0,05) than in comparison group at the end of the course of treatment. «Betargin» has an antifibrotic effect which is confirmed by a decrease in the level of plasma osteopontin up to 104,92 ng/ml against 178,15 ng/ml in the comparison group (p<0,05).

Comparison of two multifraction radiotherapy schedules in management of painful bone metastases: A single institution prospective study

Background

Metastatic disease of bone is a common complication of most of the advanced malignancies. The majority of patients with bone metastases (BM) experience pain during their disease course and pain control can significantly improve their quality of life. Radiotherapy (RT) is an important modality in the management of BM and different schedules are followed worldwide.

Aim

The aim of this study was to compare two multi-fractionated RT regimens (30Gy in 10 fractions and 20Gy in 5 fractions) with respect to the patient's performance, response and pain score in palliative management of painful BM.

Methods

This prospective observational study was undertaken between October 2015 and September 2017 at a government medical college in central India. Two fractionation regimens (30 Gy/10 fractions and 20 Gy/5 fractions) were used to treat 50 patients with painful BM (n = 25 in each arm). Patients were treated on telecobalt machine and response assessment done in terms of complete/partial/intermediate response and pain progression. Assessment was performed at one, two and three months post treatment. Statistical analysis was done using Fisher's exact test, student t-test and Chi-square test. A value of P < 0.05 was considered significant.

Results

There were 9 males (36%) and 16 females (64%) in arm A, and 15 males (60%) and 10 females (40%) in arm B. The median age was 47.50 years (range 28-81 years) in arm A and 54 years (range 34-85 years) in arm B. There was no statistically significant difference between the two groups in terms of pain palliation at a 1 month (p = 0.73), 2 month (p = 0.75) or 3 month (p = 0.71) follow up. In addition, the mean performance scores at the end of 3^rd month in the 2 arms did not show any statistically significant difference (p = 0.51).

Conclusion

A shorter treatment schedule (5 fractions) was equally efficacious as the standard schedule (10 fractions) in our setting. With the advantage of shorter overall treatment time and avoidance of re-irradiation, this schedule may be favourable for high volume centres.

Role of Isotocin in the Regulation of the Hypophysiotropic Dopamine Neurones in the Preoptic Area of the Catfish, Clarias batrachus

Dopamine (DA) has emerged as a potent inhibitory neuromodulator of luteinsing hormone (LH) secretion and reproduction in teleosts. The DA neurones located in the anterior subdivision of nucleus preopticus periventricularis (NPPa) in the preoptic area (POA) innervate the pituitary gland and regulate LH cells. Although a reduction in the inhibitory DAergic tone is crucial for stimulatory action of gonadotrophin-releasing hormone (GnRH) on LH cells, the role of other hypothalamic factors is suggested but not fully understood. Nonapeptide, isotocin (IST) has emerged as a likely candidate that may also influence the LH cell function. IST neurones reside in the nucleus preopticus and innervate LH cells. While IST treatment dramatically elevated LH secretion, the IST levels in brain peaked during spawning. In a pilot study on the catfish, Clarias batrachus, we observed a dense network of IST-immunoreactive (IST-IR) fibres in the NPPa, the region known to harbour hypophysiotropic DA neurones. Application of the double immunofluorescence method showed a dense IST-IR fibre network around the tyrosine hydroxylase-immunoreactive (TH-IR) neurones in the NPPa region. A great majority of the TH-IR neurones in the NPPa were contacted by IST-IR fibres during the spawning phase. The NPPa therefore appears to be a site for the intense interaction of DA and IST. IST-IR fibre innervation in NPPa showed reproduction phase-dependent changes. The percent fluorescent area of IST-IR fibres showed a gradual increase from the resting through prespawning phases (resting: 7.5 ± 1.04; preparatory: 8.6 ± 0.8; prespawning: 15.5 ± 1.4), reaching a peak in the spawning phase (28 ± 2.3; P < 0.001). Compared to the spawning phase, a drastic reduction in IST-IR fibres in the NPPa was observed during the postspawning phase (8.4 ± 0.9; P < 0.001). Superfused slices of the POA of C. batrachus treated with IST peptide resulted in a significant reduction in TH immunoreactivity in the NPPa (Control: 45.3 ± 4.2; IST peptide, 5 μm: 29.4 ± 4.7; P < 0.05). We suggest that the intense interaction between IST and DA in the NPPa, most probably of an inhibitory nature, may be critical for the regulation of LH cells and reproduction in teleosts.

Drought yield index to select high yielding rice lines under different drought stress severities

BACKGROUND

Drought is the most severe abiotic stress reducing rice yield in rainfed drought prone ecosystems. Variation in intensity and severity of drought from season to season and place to place requires cultivation of rice varieties with different level of drought tolerance in different areas. Multi environment evaluation of breeding lines helps breeder to identify appropriate genotypes for areas prone to similar level of drought stress. From a set of 129 advanced rice (Oryza sativa L.) breeding lines evaluated under rainfed drought-prone situations at three locations in eastern India from 2005 to 2007, a subset of 39 genotypes that were tested for two or more years was selected to develop a drought yield index (DYI) and mean yield index (MYI) based on yield under irrigated, moderate and severe reproductive-stage drought stress to help breeders select appropriate genotypes for different environments.

RESULTS

ARB 8 and IR55419-04 recorded the highest drought yield index (DYI) and are identified as the best drought-tolerant lines. The proposed DYI provides a more effective assessment as it is calculated after accounting for a significant genotype x stress-level interaction across environments. For rainfed areas with variable frequency of drought occurrence, Mean yield index (MYI) along with deviation in performance of genotypes from currently cultivated popular varieties in all situations helps to select genotypes with a superior performance across irrigated, moderate and severe reproductive-stage drought situations. IR74371-70-1-1 and DGI 75 are the two genotypes identified to have shown a superior performance over IR64 and MTU1010 under all situations.

CONCLUSION

For highly drought-prone areas, a combination of DYI with deviation in performance of genotypes under irrigated situations can enable breeders to select genotypes with no reduction in yield under favorable environments compared with currently cultivated varieties. For rainfed areas with variable frequency of drought stress, use of MYI together with deviation in performance of genotypes under different situations as compared to presently cultivated varieties will help breeders to select genotypes with superior performance under all situations.

Tube sigmoidostomy: a valuable alternative to sigmoidopexy for sigmoid volvulus

OBJECTIVE

To compare the effectiveness of tube sigmoidostomy and sigmoidopexy as effective treatment options for patients with acute uncomplicated sigmoid volvulus.

METHODS

The records of 72 patients with acute uncomplicated sigmoid volvulus with obstruction who were treated by tube sigmoidostomy (Group I: n=32) and sigmoidopexy (Group II: n=40) were reviewed retrospectively. Follow-up period was 22 months (range: 6-51 months).

RESULTS

Results show significant improvement in postoperative tachycardia, respiratory distress and urine output in Group I patients as compared to those in Group II. Most of the clinical parameters of Group I patients normalized by day 3, while it took up to 7 days in Group II patients. Intraabdominal hypertension caused by persistent colonic dilatation after sigmoidopexy was found to be an important determinant of postoperative morbidity. As compared to tube sigmoidostomy, the sigmoidopexy group had delayed recovery, more chances of abdominal fascial dehiscence, and longer hospital stay, as well as more prolonged abdominal discomfort, constipation, and recurrent volvulus rates during follow-up.

CONCLUSION

Tube sigmoidostomy provides both fixation and decompression of the redundant sigmoid colon in the postoperative period while allowing time to recover from massive dilatation and edema caused by prolonged volvulus. Compared with sigmoidopexy for the treatment of uncomplicated sigmoid volvulus, tube sigmoidostomy leads to lesser rates of morbidity and recurrence. Thus, it can be considered as a definitive alternative treatment option for uncomplicated sigmoid volvulus.

Vitamin D Status of term exclusively breastfed infants and their mothers from India

OBJECTIVES

(i) To measure 25-OH vitamin D levels in term infants at 10 weeks and 6 months and to correlate with maternal vitamin D levels at 10-week postpartum (ii) To evaluate infants at 6 months for rickets.

PATIENTS AND METHODS

A total of 179 exclusively breastfed infant-mother pairs 96 appropriate-for-gestational age (Group 1) and 83 small- for- gestational age infants (Group 2) recruited at 10 weeks. At 6 months, 52 in group 1 and 45 in group 2 were evaluated. Venous blood sample were collected at 10 weeks and 6 months in infants and at 10 weeks in mothers for calcium, phosphorus, alkaline phosphatase and 25-OH vitamin D estimation.

RESULTS

Mean 25-OH vitamin D levels of infants (n = 97) were 11.55 ± 7.17 ng/mL at 10 weeks and 16.96 ± 13.33 ng/mL at 6 months (p < 0.001). Mean vitamin D levels of infants in group 1 and group 2 did not differ at recruitment and 6 months (p > 0.05)). Maternal vitamin D levels in group 1 and group 2 were 8.89 ± 5.97 and 9.87 ± 6.44 ng/mL, respectively (p = 0.44). Significant correlation was observed between 25-OH vitamin D of infants and mothers (p < 0.05). At 10 weeks, 55.67% infants, 70% mothers and at 6 months, 44.33% infants had vitamin D < 11 ng/mL. At 6 months, 16.49% infants developed rickets.

CONCLUSIONS

Exclusively breastfed infants and their mothers are Vitamin D deficient, hence the need to improve vitamin D status.

Ofloxacin-associated retinopathy in rabbits: role of oxidative stress

Ofloxacin, a quinolone, is an extensively used, well-tolerated antibacterial agent but has been reported to induce photosensitivity at low incidences. In the present investigation, the possible role of oxidative stress in ofloxacin-induced retinopathy in rabbits was evaluated. It was observed that ofloxacin at a dose rate of 10 and 20 mg/rabbit, twice daily for 21 consecutive days, resulted in significant elevation in the extent of lipid peroxidation and depletion of the blood glutathione levels. Marked alterations were also observed in various parameters of the glutathione-redox cycle. There was significant increase in the enzymic activity of glutathione peroxidase and glutathione reductase, whereas a significant decrease was observed in the activities of superoxide dismutase, catalase, and glutathione-S-transferase enzymes. Histopathological studies revealed retinal damage especially in the pigmented cell layer. Degenerative changes in liver and kidneys were also observed. Liver showed focal areas of necrosis, dilation of sinusoids, and cellular infiltration, whereas in kidneys, there was glomerular and tubular degeneration, suggesting impaired renal functioning.

New compounds from Commiphora myrrha (Nees) Engl

Phytochemical investigation of Commiphora myrrha (Nees) Engl. has afforded six new compounds identified as cadina-3-en-15-ol (myrracadinol A) (1), 7, 8-seco-2, 5-dihydroxy-12-acetoxycalam-8-ene (myrracalamene A) (2), 7, 8-seco-2, 3, 5-hydroxy-12-acetoxycalame-8-ene (myrracalamene B) (3), 7, 8-seco-cadin-3, 8-dien-2beta, 12-diol (myrracadinol B) (4), 7, 8-seco-12-hydroxycalam-8-ene (myrracalamene C) (6), 7, 8-seco-cadin-3,7(12)-dien-5alpha,10alpha-diol (myrracadinol C) (7) along with a known compound tria-cont-1-ene (5). Their structures were elucidated on the basis of spectral and chemical analyses.

Mother's iron status, breastmilk iron and lactoferrin--are they related?

OBJECTIVE

Exclusive breastfeeding is recommended till 6 months age. Factors regulating the breastmilk iron and lactoferrin levels are incompletely known. Considering high prevalence of nutritional anemia in lactating mothers, we studied the iron status of lactating mothers, their breastmilk iron and lactoferrin levels to determine any relationship between them.

DESIGN

Prospective study with 6 months follow-up.

SETTING

Tertiary care referral hospital.

SUBJECTS

Hundred nonanemic and 100 anemic mothers with their babies recruited at birth. Fifty-two nonanemic and 50 anemic mothers and their babies completed the 6-month follow-up.

INTERVENTIONS

Hemoglobin (Hb), total iron binding capacity (TIBC), percent transferrin saturation (%TS), serum iron (SI) and serum ferritin measured on day 1 and 6 months postpartum. Breastmilk iron and lactoferrin measured on day 1, 14 weeks and 6 months after delivery.

RESULTS

Breastmilk iron decreased progressively from day 1 to 14 weeks and at 6 months in both groups, but no significant difference was noted between nonanemic and anemic mothers (P>0.05). Significant decline in breastmilk lactoferrin concentration from day 1 to 14 weeks in nonanemic and anemic mothers (P<0.001) noted. Hemoglobin, TIBC, %TS, SI and serum ferritin of both groups had no correlation with breastmilk iron and lactoferrin concentration on day 1, 14 weeks and 6 months after delivery.

CONCLUSIONS

Breastmilk iron and lactoferrin concentration had no relationship with the mother's Hb and iron status.

Absence of corpus luteum rescue by chorionic gonadotropin in women immunized with a contraceptive vaccine

OBJECTIVE

To determine whether antibodies induced by a betahCG vaccine in women are competent to neutralize the luteotropic action of hCG.

DESIGN

Prospective clinical study.

SETTING

Hospitals and a laboratory at an academic center.

PATIENT(S)

Six immunized and three control women of reproductive age, participating in a clinical testing of betahCG contraceptive vaccine.

INTERVENTION(S)

Increasing doses of hCG simulating early pregnancy.

MAIN OUTCOME MEASURE(S)

Anti-hCG antibody titers, serum progesterone and urinary hCG levels, and onset of menses.

RESULT(S)

Administration of hCG to mimic early pregnancy sustained serum progesterone concentrations and extended the luteal phase in control women. In contrast, serum progesterone levels declined and the luteal phase was not extended if prevailing antibody titers were > or =40 ng/mL in women who had been immunized with a betahCG based vaccine. No booster effect was seen in anti-hCG titers after hCG challenge.

CONCLUSION(S)

Antibodies elicited by a betahCG vaccine inactivate hCG and prevent the hormone from rescuing corpus luteum, resulting in progesterone fall and normal menses. Lack of booster in the antibody response confirms the reversibility of the approach.

High expression of human chorionic gonadotrophin beta-subunit using a synthetic vaccinia virus promoter

We have constructed a recombinant vaccinia virus to express the beta-subunit of human chorionic gonadotrophin (betahCG), a secretory glycoprotein that is used as an antigen for a contraceptive vaccine. The cDNA encoding the subunit was cloned under the control of a synthetic promoter that could be recognised by a vaccinia virus RNA polymerase to direct transcription. The peak expression level of betahCG directed by a late synthetic promoter (Psyn) was 11.5 microg/ml, a level that was at least sixfold higher than that directed by the p7.5 early/late promoter. The expressed protein was correctly processed post-translationally such that it attained a conformation with correctly folded discontinuous epitope(s) similar to that seen in native betahCG.

Enhanced immunogenicity of a contraceptive vaccine using diverse synthetic carriers with permissible adjuvant

A vaccine directed against human chorionic gonadotropin (hCG) has previously undergone clinical testing demonstrating the feasibility of the approach in preventing pregnancy in women. Some individuals, however, did not respond adequately despite employing highly immunogenic bacterial toxoids as carriers. We investigated the potential of three promiscuous pathogen-derived Th peptides as carriers, employing alum as the adjuvant. While conjugation with each peptide improved the antibody response against hCG in mice of different haplotypes, immunisation with a combination of these peptide-conjugates generated anti-hCG responses higher than those achieved with the individual peptides or tetanus toxoid (TT). Antibodies were of high affinity and capable of neutralising the bioactivity of hCG but were devoid of anti-peptide reactivity. These results have implication for the design of hCG vaccine with improved immunogenicity for diverse population.

Formulation and characterization of immunoreactive tetanus toxoid biodegradable polymer particles

Poly lactide-co-glycolide and polylactide polymer particles entrapping immunoreactive tetanus toxoid (TT) were prepared with a view to developing a single shot controlled release vaccine formulation. Denaturation of TT by dichloromethane (DCM) during primary emulsification stage of particle formulation was minimized by incorporation of an optimal amount of rat serum albumin (RSA) in the internal aqueous phase. Incorporation of RSA as a stabilizer during the primary emulsification stage of polymer particle formulation protected the immunoreactivity of TT, enhanced its encapsulation efficiency and also led to uniform polymer particle formation. Use of sonication, both during primary and secondary emulsification processes, resulted in formation of nanoparticles whereas microparticles were formed when the secondary emulsion was carried out by homogenization. Immunoreactive TT particles made from different polymers incorporating stabilizers released antigen continuously for more than four months in vitro. Single injection of both type of particles encapsulating stabilized TT elicited anti-TT antibody titers in rats for more than five months, which was higher than that obtained with TT injected in saline. Anti-TT antibody titers in vivo were in accordance with the in vitro release characteristics of immunoreactive TT from the particles. Immune responses with hydrophobic polymer particles were better than those made using hydrophilic polymers. These results indicate the importance of protecting the immunoreactivity of TT during formation of polymer particles for sustained and improved antibody response.

Humoral hyporesponsiveness to a conjugate contraceptive vaccine and its bypass by diverse carriers using permissible adjuvant

A contraceptive vaccine directed against human chorionic gonadotropin (hCG) has previously undergone clinical testing that demonstrated the feasibility of the approach in preventing pregnancy in women. Some immunized volunteers however, did not respond with an adequate anti-hCG antibody response despite employing highly immunogenic bacterial toxoids as carriers. Since there is some evidence that T cell responses to a complex protein typically focus on a few immunodominant epitopes, we investigated the responsiveness to hCG in mice of different haplotypes using the protein carrier diphtheria toxoid (DT). Our data showed a differential carrier effect of DT. With the aim of making a more potent immunogen employing promiscuous pathogen-derived Th peptides as carriers, peptide:antigen stoichiometric ratios were optimized. When tested individually using alum as the adjuvant, three such peptide conjugates improved the anti-hCG response, though not consistently to levels higher than the DT conjugate. Immunization with a combination of these synthetic epitopes generated anti-hCG responses higher than those achieved with DT or with the individual peptides. Antibodies were of high affinity and capable of neutralizing the bioactivity of hCG, but were devoid of anti-peptide reactivity. These results support our view that differential hyporesponsiveness in a diverse population may arise from inadequate carrier effect and that it can be overcome by use of pathogen-derived broadly reactive non-B Th epitopes employing only alum, a permissible adjuvant.

Prior immunity to a carrier enhances antibody responses to hCG in recipients of an hCG-carrier conjugate vaccine

Pre-sensitization with carrier often leads to epitopic suppression of subsequent anti-hapten antibody responses. To ascertain whether epitopic suppression occurs in humans, we examined the effect of pre-existing anti-carrier immunity on antibody responses to hCG in volunteers of a clinical trial of an hCG-based conjugate birth-control vaccine. When we studied the correlation between pre-vaccination anti-carrier immunity and post-vaccination anti-hCG responses, we found that prior immunity to the carriers did not lead to epitopic suppression of anti-hCG responses. On the contrary, it was found that prior immunity to TT, one of the two carriers used in this vaccine, led to enhancement of anti-hCG responses. Our data indicates that prior immunity to the carriers may not be detrimental to the performance of conjugate vaccines, and may actually be beneficial in some cases.

Regain of fertility and normality of progeny born during below protective threshold antibody titers in women immunized with the HSD-hCG vaccine

PROBLEM

Phase II clinical trials with the heterospecies dimer of beta hCG and alpha-subunit of ovine luteinizing hormone (HSD)-human chorionic gonadotrophin (hCG) vaccine showed that pregnancy was prevented at and above 50 ng/ml titers, whereas conceptions occurred below 35 ng/ml of hCG bioneutralization capacity. The effect of below-protective threshold anti-hCG antibodies on the progression of pregnancy and the normality of progeny was studied.

METHOD OF STUDY

Four women enrolled by informed consent in the Phase II trials. The women studied were immunized with the HCG vaccine and did not receive booster injections in consideration of their desire to have another child. They were examined clinically at least once every month until delivery. The babies were followed up from 2 to 3.5 years, and their anthropometric indices were compared with elder siblings.

RESULTS

The pregnancies progressed to 35 to 38 weeks with the usual obstetric problems, and the children developed normally.

CONCLUSIONS

The anti-fertility effect of the HSD-hCG vaccine is reversible and low titers of antibodies below the protective threshold have no apparent side effects on the progression of pregnancy and on the early development of the progeny.

Stabilization of dichloromethane-induced protein denaturation during microencapsulation

This paper describes the denaturation of protein drugs by dichloromethane (DCM) during the primary emulsification step of the microencapsulation process using biodegradable polymer matrix for controlled-release application. It was found that interaction of proteins such as tetanus toxoid (TT), diphtheria toxoid (DT), ovine growth hormone (oGH), and human chorionic gonadotropin-based antifertility vaccine (beta-hCG-TT) with DCM during primary emulsification stages of particle formulation led to the precipitation of the proteins at the aqueous organic interface with concomitant reduction in their immunoreactivity. On the other hand, the B subunit of E. coli enterotoxin (LTB) was found to be comparatively stable toward the denaturing action of DCM. Attempts were made to overcome the DCM-induced denaturation by incorporation of stabilizers during the primary emulsification step of the particle formulation. Of the many additives tested to overcome the DCM-induced denaturation of proteins, serum albumins and polyvinyl alcohol (PVA) showed promising results in terms of retention of the immunoreactivity of the protein. TT stabilized by the incorporation of serum albumin during the primary emulsification step not only showed immunoreactivity in vitro, but also invoked antibody titers in rats comparable to those obtained for the native protein molecules. Incorporation of 2.5% of serum albumins in the internal aqueous phase not only protected the protein from the degradative action of DCM but also led to stabilized primary emulsion, which is necessary for uniform entrapment of protein drugs in the polymer matrix.

Dihydropyrancarboxamides related to zanamivir: a new series of inhibitors of influenza virus sialidases. 2. Crystallographic and molecular modeling study of complexes of 4-amino-4H-pyran-6-carboxamides and sialidase from influenza virus types A and B

The first paper in this series (see previous article) described structure-activity studies of carboxamide analogues of zanamivir binding to influenza virus sialidase types A and B and showed that inhibitory activity of these compounds was much greater against influenza A enzyme. To understand the large differences in affinities, a number of protein-ligand complexes have been investigated using crystallography and molecular dynamics. The crystallographic studies show that the binding of ligands containing tertiary amide groups is accompanied by the formation of an intramolecular planar salt bridge between two amino acid residues in the active site of the enzyme. It is proposed that the unexpected strong binding of these inhibitors is a result of the burial of hydrophobic surface area and salt-bridge formation in an environment of low dielectric. In sialidase from type A virus, binding of the carboxamide moeity and salt-bridge formation have only a minor effect on the positions of the surrounding residues, whereas in type B enzyme, significant distortion of the protein is observed. The results suggest that the decreased affinity in enzyme from influenza B is directly correlated with the small changes that occur in the amino acid residue interactions accompanying ligand binding. Molecular dynamics calculations have shown that the tendency for salt-bridge formation is greater in influenza A sialidase than influenza B sialidase and that this tendency is a useful descriptor for the prediction of inhibitor potency.

Helix-loop-helix motif in GnRH associated peptide is critical for negative regulation of prolactin secretion

The GnRH associated prolactin inhibiting factor (GAP) reveals the signature sequence associated with the helix-loop-helix structural motif. A number of different peptide fragments of GAP were designed, synthesized and analysed by circular dichroism and by an in vivo assay for prolactin secretion inhibiting activity. Peptides corresponding to the two individual alpha-helices and a 44-residue peptide comprising the entire helix-loop-helix motif show significant helical propensity in circular dichroism spectra. However, a peptide corresponding to the loop sequence shows no helical propensity. Albeit, the peptide corresponding to helix-loop-helix motif was found to inhibit prolactin secretion and augment circulating levels of gonadotropins in the in vivo assay; other shorter peptides did not show such activity. The activity profile of the 44-residue peptide was biphasic and very similar to that of the recombinant GAP. Thus, the prolactin inhibiting activity of this factor is defined by its helix-loop-helix motif as in the case of the transcription factors of developmental genes. The structural features of a homology-based model of GAP in complex with E47, a ubiquitous HLH-type developmental gene regulator, are consistent with the structural requirements of the negative regulation of transcription by helix-loop-helix proteins.

Biphasic testosterone delivery profile observed with two different transdermal formulations

PURPOSE

Our long-term goal is to develop formulations for pulsatile testosterone (T) delivery. T has been reported earlier to show biphasic pharmacokinetics in humans by Mazer et al, as well as biphasic permeation across excised rat skin by our group. We examined two kinds of formulations to evaluate their delivery profiles and to assess whether differences in the formulation approach affect pharmacokinetics in animal models.

METHODS

One formulation consisted of T and a polymer blend dissolved in isopropanol; administered by dispensing the solution on the skin to cast a film in situ. The other was an adhesive-dispersion patch. In vitro release from the patch was evaluated using a flow-through cell interfaced with an HPLC pump and UV detector. Single dose pharmacokinetics were evaluated in castrated Wistar rats and bonnet monkeys immunized against gonadotropin-releasing hormone to deplete endogenous T.

RESULTS

Two maximas were observed in the T release profile from the patch and in serum concentration versus time profiles in both animal models on application of either formulation. The relative magnitudes of the two maximas and the time interval separating them were different in the case of each formulation.

CONCLUSIONS

Both formulations result in biphasic pharmacokinetics of T in the animal models studied. Discrete maximas presumably correlate with "burst" and "sustained" phases of drug release.

Recombinant adenovirus synthesizing cell surface-anchored beta hCG induces bioneutralizing antibodies in rats

A recombinant adenovirus (re-Ad) has been constructed that synthesizes a cell surface-anchored form of the beta-subunit of human chorionic gonadotropin (beta hCG). This was achieved by in-frame fusion of beta hCG cDNA at its C terminus with the gene sequences coding for the vesicular stomatitis virus glycoprotein (VSVg) transmembrane domain. The fusion protein gene was placed under the control of human cytomegalovirus (hCMV) immediate early promoter and this expression cassette was inserted into the E1 region of Ad type 5 by homologous recombination. In vitro experiments using re-Ad-infected 293 cells showed that beta hCG fusion protein was made as early as 6 h post infection and the protein was anchored to the cell membrane as seen by immunofluorescence staining. The re-Ad induced bioneutralizing antibodies (Ab) to hCG when inoculated in rats through intraperitoneal or intramuscular routes. The Ab were made in a dose-dependent manner. However, orally delivered re-Ad failed to generate any significant immune response.

Targeting vaccinia virus-expressed secretory beta subunit of human chorionic gonadotropin to the cell surface induces antibodies

We carried out experiments designed to study the effect of a protein's localization on its immunogenicity. A novel cell-surface protein was generated from a small, glycosylated secretory protein. The DNA sequence encoding the entire precursor of the human chorionic gonadotropin beta (beta hCG) subunit was fused in the correct reading frame to the DNA sequence encoding the transmembrane and cytoplasmic domains of vesicular stomatitis virus glycoprotein. This chimeric gene was introduced into the vaccinia virus genome to generate a recombinant virus. The recombinant virus, when used to infect animal cells, expressed a 135-amino-acid beta hCG subunit anchored in cellular membranes by the 48 carboxy-terminal amino acids of vesicular stomatitis virus glycoprotein. The immunogenicity of this recombinant virus with respect to its ability to generate anti-hCG antibodies was compared with that of a second recombinant vaccinia virus expressing the native secretory form of beta hCG. All animals immunized with the vaccinia virus expressing beta hCG on the cell surface elicited high titers of anti-hCG antibodies. Even after a single immunization with the recombinant vaccinia virus, the anti-hCG antibody titers persisted for a long period of time (more than 6 months). None of the animals immunized with vaccinia virus expressing the native secretory form of beta hCG showed any hCG-specific antibody response.

Biodegradable delivery system for a birth control vaccine: immunogenicity studies in rats and monkeys

PURPOSE

The purpose of this study was to develop a single administration delivery system for a model birth control vaccine, in order to reduce the need for multiple injections and enhance immunogenicity.

METHODS

The immunogen-loaded microspheres were prepared by solvent evaporation method and characterized for loading levels, size distribution and in vitro release kinetics. The microspheres were immunized intramuscularly in wistar rats and bonnet monkeys, and the antibody response was compared to that obtained with the same total dose of the immunogen on alum given at a monthly interval.

RESULTS

Results indicated that a single injection of the immunogen entrapped in the microspheres generated a response comparable to that obtained by the same immunogen on alum injected at a monthly interval. The antibodies generated by the microspheres in the monkeys also had a good bioneutralization capacity indicating immunogen integrity during the microencapsulation process.

CONCLUSIONS

Biodegradable microspheres served as an effective delivery system for a model immunogen used in this study to reduce the need for frequent immunizations and enhance immunogenicity.

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.

Development of contraceptive vaccines for humans using antigens derived from gametes (spermatozoa and zona pellucida) and hormones (human chorionic gonadotrophin): current status

Contraceptive research has entered a new phase of development with the advent of hybridoma and DNA recombinant technologies. During the past 5 years, significant advances have been made in this area and now it seems that realistic prospects exist for the development of contraceptive vaccines for use in humans and animals (veterinary, wild and domestic), applicable to both the female and male sexes. Contraceptive vaccines will be valuable supplements to the presently available methods of family planning, and, due to high specificity, the occurrence of limited side-effects if any, low cost and infrequent administration, contraceptive vaccines may have greater acceptability than the currently available methods. Mammalian reproduction starts with the unison of gametes contributed by the male and female partners. Both spermatozoon and oocyte have antigens on the cell surface that are unique, tissue-specific, immunogenic and accessible to antibodies, and binding of the antibodies to these antigens can cause inhibition of gamete function, resulting in a failure of fertilization. Fertilization is followed by embryogenesis, with the early embryo producing several proteins, some of which, e.g. human chorionic gonadotrophin (HCG), have a vital role in the establishment and maintenance of early pregnancy. Again, these proteins are accessible to antibodies, and their immunoneutralization can cause anti-fertility effects with loss of early embryo. Thus, the antigens derived from proteins on spermatozoa, oocyte and early embryo, especially HCG, constitute interesting molecules for the development of contraceptive vaccines. The aim of the present article is to review the current status of development of contraceptive vaccines based on antigens derived from sperm cell, oocyte zona pellucida and HCG, and to discuss their relative merits and future development.

A vaccine that prevents pregnancy in women

We report here results of clinical trials on a birth control vaccine, consisting of a heterospecies dimer of the beta subunit of human chorionic gonadotropin (hCG) associated noncovalently with the alpha subunit of ovine luteinizing hormone and conjugated to tetanus and diphtheria toxoids as carriers, that induces antibodies of high avidity (K(a) approximately 10(10) M-1) against hCG. Fertile women exposed to conception over 1224 cycles recorded only one pregnancy at antibody titers of > 50 ng/ml (hCG bioneutralization capacity). The antibody response declines with time; fertility was regained when titers fell to < 35 ng/ml. This study presents evidence of the feasibility of a vaccine for control of human fertility.

A birth control vaccine is on the horizon for family planning

Vaccines for control of fertility are likely to have an important impact on family planning methods. They are designed to act by mobilization of an internal physiological process and do not require external medication on a continuous basis. A number of birth control vaccines are at different stages of development, the most advanced being a vaccine inducing antibodies against human chorionic gonadotrophin (hCG). This vaccine consists of a heterospecies dimer (HSD, beta hCG associated with alpha-subunit of ovine luteinizing hormone, beta hCG:alpha oLH) linked to tetanus toxoid (TT) or diphtheria toxoid (DT) as carriers. The vaccine has recently passed an important milestone; it has completed the first leg of phase II efficacy trials. Women of proven fertility leading active sexual life were protected from becoming pregnant at antibody titres > or = 50 ng of hCG bioneutralization capacity per ml. This vaccine has previously been demonstrated to be reversible in its effect. It is free from any notable side-effects on endocrine, cardiovascular and other body functions. Ovulation was not disturbed and menstrual regularity was maintained. A logistic disadvantage of the present vaccine is the requirement for multiple injections. This is expected to be overcome by encapsulation of the requisite doses of the vaccine in biodegradable microspheres, which could be given at a single contact point for sustained antibody titres lasting over a year. A live recombinant vaccine has also been made that elicits high anti-hCG titres in monkeys for nearly 2 years following primary immunization and a booster at 8-9 months.

Genetic analysis of agronomic characters in chickpea. II. Estimates of genetic variances from line × tester mating designs

Thirty line x tester experiments involving diverse chickpea (Cicer arietinum L.) germplasm were conducted over 8 years and three locations to determine the nature of the genetic variance for grain yield and related characters, and the effects of generation and environment on these genetic parameters. Days-to-flowering, 100-seed mass, and seeds per pod were predominantly under the control of additive genetic variance, while both additive and non-additive genetic components of variance were important for days-to-maturity, plant height, primary and secondary branches, pods per plant, and seed yield. The F1 and F2 generations were found equally useful in estimating the genetic variances for different characters because the generation did not significantly interact with genetic parameters in the majority of cases. Sites or seasons, on the other hand, showed significant interaction with genetic components of variances; additive variance showed a larger interaction with environments than non-additive variance. This indicated the importance of more than one site and/ or season for unbiased estimation of the genetic components of variance. The results were compared with previous findings from diallel analyses.

Anti-hCG vaccines are in clinical trials

Two vaccines inducing antibodies against human chorionic gonadotropin (hCG) have completed Phase I clinical trials, indicating the reversibility and safety of these vaccines. One is currently in Phase II efficacy trials in women in three major centres in India. The available data suggest that the vaccine prevents pregnancy above antibody titres of 50 ng/ml hCG bioneutralization capacity.

Genetic analysis of agronomic characters in chickpea : I. Estimates of genetic variances from diallel mating designs

Twenty-eight diallel trials over 8 years and two locations were analysed to estimate genetic variances for agronomic characters of chickpea (Cicer arietinum L.). The data were analysed according to Method 4 and Model I of Griffing (1956). Days to flowering, plant height, and seed size were found to be predominantly under additive inheritance and were highly predictable. Both additive and non-additive genetic components were important for seed yield, number of branches, pods per plant, and seeds per pod. Although both general combining ability (gca) and specific combining ability (sca) varied significantly with generation, components of gca mean squares were invariably much larger than gca x generation interaction components, indicating that either the F1 or the F2 generation can be used to estimate the gca components effectively. Combined diallel analysis of F2s over locations revealed the importance of combining ability x location interactions and emphasized the need for testing over more than one location for the precise estimation of combining ability. The implications of these findings and those reported earlier in the literature on the breeding strategies/methods for the genetic improvement of agronomic characters in chickpea are discussed.

Vaccines for control of fertility and hormone dependent cancers

Two vaccines, namely one inducing antibodies against hCG and the other against GnRH, are now in clinical trials. The hCG vaccine has entered Phase II clinical trials in three centres in India after successfully completing Phase I clinical studies in several centres in India and in four countries abroad. The vaccine was found to be devoid of side-effects; its effect was reversible. The available data on 179 cycles indicate that the vaccine prevents pregnancy at antibody titres above 50 ng/ml. A genetically engineered version of the vaccine has also been approved for trials in human lung cancer patients of the type which make hCG. hCG is observed to be a growth factor for such tumours. The GnRH vaccine is usable in both males and females as the deca-peptide is common to both sexes. Following suitable experimental and toxicology studies, the vaccine is currently in Phase I/Phase II clinical trials in patients of prostate carcinoma. Where antibody GnRH antibodies were induced, the LH, FSH and testosterone levels declined. This was accompanied by a reduction in prostate specific antigen. Clinical improvement was observed in many cases. The vaccine has also entered Phase I clinical studies in postpartum women, with the objective to extend the lactational amenorrhoea and extend inter-child interval.