Effect of chiral enhancers on the permeability of optically active and racemic metoprolol across hairless mouse skin

The stratum corneum, the rate-limiting barrier in transdermal drug delivery, is chiral in nature and enantiomers behave differently with respect to their transport across the skin, resulting in enantioselective permeation. The permeation characteristics of individual enantiomers of metoprolol free base (MB) were investigated using hairless mouse skin. The influence of chiral permeation enhancers, l-menthol and (+/-)-linalool, on the permeation of MB was also investigated. In the absence of enhancers, the permeation profiles of R- and S-MB from donor solutions containing either RS-MB or pure enantiomers are comparable (p < 0. 05). In presence of enhancers, l-menthol and (+/-)-linalool, the flux values were increased 2.4- to 3.0-fold, respectively, and the permeation profiles of R- and S-MB from donor solutions containing RS-MB are comparable (p < 0.05). However, when donor vehicle contains pure enantiomers, the permeation enhancing effect of l-menthol on S-MB was significantly higher (by 25%) than on R-MB (p < 0.05). Further, in presence of l-menthol, the flux of S-MB from donor solution containing pure S-MB was 35% higher than the flux of RS-MB from racemate. No such effect was seen with (+/-)-linalool. In all the investigations, no enantiomeric inversion was observed during the permeation process. The lag times were shorter in the case of l-menthol compared with (+/-)-linalool.

Enthesitis in spondyloarthropathy

Inflammation at the insertions of ligaments, tendons, or joint capsules to bone, which is termed enthesitis, is a characteristic feature of spondyloarthropathy. Because of the relative inaccessibility of the enthesis, the inflammatory, microbiologic, and immunologic events at that site have been poorly defined. Recent magnetic resonance imaging studies have drawn attention to the ubiquitous nature of enthesitis in spondyloarthropathies, especially adjacent to synovial joints. This may have implications for the mechanisms of synovitis in spondyloarthropathies. Magnetic resonance imaging studies also suggest that enthesitis lesions may be extensive, which could explain the diffuse nature of bone changes seen in some patients with spondyloarthropathies. The importance of enthesitis as a skeletal phenomenon in spondyloarthropathies has gained further support from transgenic models in which either tumor necrosis factor-alpha or bone morphogenetic protein-6 overexpression result in entheseal-associated polyarthropathy.

Diagnosis of Pneumocystis carinii pneumonia: immunofluorescence staining, simple PCR or nPCR

OBJECTIVES

to compare immunofluorescence (IF) test, routinely used in the department for the detection of Pnemocystis carinni with simple polymerase chain reaction (PCR) and nested PCR (nPCR) METHODS: Bronchoalveolar lavage (BAL) and induced sputum (IS) specimens from HIV-positive (39), lung transplant ssart transplant (2), and one each from non-Hodgkin's lymphoma, drug addict and a premature baby were screened by IF test, simple PCR and nPCR for the presence of P.carinii.

RESULTS

of the 46 specimens tested, two (4.3%) were positive by IF, 11 (23.9%) by simple PCR and 21 (45.6%) by nPCR. Both simple and nPCR amplified those found positive by IF test. Analysis of the clinical data revealed both IF positive, 10 of the simple PCR and 15 of the nPCR group were strongly suspected of P. carinii pneumonia (PCP). Two specimens, one from a patient where chest X-ray was suggestive of PCP and the other where post-mortem histology revealed the presence of PCP, were negative by IF test.

CONCLUSION

simple PCR detection may be considered for patients where PCP is suggestive clinically and the specimen is negative by IF test.

Stability and bioequivalence studies of two marketed formulations of coenzyme Q10 in beagle dogs

Coenzyme Q10 (CoQ10), a highly lipophilic compound present in the inner mitochondrial membrane, is essential for production of cellular energy in the form of ATP. CoQ10 is used as an antioxidant and also in the treatment of various cardiovascular disorders. The relative bioavailabilities of powder filled capsule (I) and oil-based formulation (II) of CoQ10 were compared in beagle dogs in an open, randomized, multiple dose, cross-over design. Poor and slow absorption characteristics were observed for both the formulations. The AUC, Cmax, and Tmax for formulation I and II are comparable (p < 0.05) where the values for formulation I are 22.84 +/- 6.3 micrograms ml-1 h, 0.51 +/- 0.11 microgram/ml, and 6.1 +/- 2.0 h whereas the values for formulation II are 24.32 +/- 5.6 micrograms ml-1 h, 0.55 +/- 0.16 microgram/ml, and 6.6 +/- 2.3 h, respectively. Stability of CoQ10 at various temperature and humidity conditions and its photostability were studied. Various antioxidants were evaluated to determine the type and amount of antioxidant(s) required to improve the stability of CoQ10. Large extent of degradation was observed at 45 degrees C and 55 degrees C. The effect of humidity conditions on degradation was insignificant. Among the various antioxidants studied, mixture of ascorbic acid (5%) and EDTA (0.1%) offered better protection than phenolic antioxidants such as butylated hydroxy anisole (BHA), butylated hydroxy toluene (BHT), or propyl gallate (PG). Further, increasing concentrations of phenolic antioxidants (from 0.1 to 0.3%) accelerated the degradation.

Mutational analysis of p73 and p53 in human cancer cell lines

p73 is a candidate tumor suppressor gene with substantial DNA and protein homology to the p53 tumor suppressor gene. We have investigated two hypotheses: (a) p73 is mutated in diverse types of human cancer, and (b) p73 is functionally redundant with p53 in carcinogenesis so that mutations would be exclusive in these two genes. The entire coding region and intronic splice junctions of p73 were examined in 54 cancer cell lines. Three lung cancer cell lines contained mutations that affected the amino acid sequence. One amino acid substitution was in a region with homology to the specific DNA binding region of p53 and two microdeletions were outside the region of homology. Two of the cell lines with p73 mutations also carried p53 mutations. Although our results are inconsistent with the two hypotheses tested, p73 mutations may contribute infrequently to the molecular pathogenesis of human lung cancer.

Cataplasm-based controlled drug delivery: development and optimization of a novel formulation

The objective of the present study was to study the formulation variables involved in the development of a novel plasterlike preparation (cataplasm) and to optimize important formulation variables with an aim to maximize the in vitro release of the drug with minimum lag time. Cataplasm was prepared by dispersing a model drug (ibuprofen), humectant (glycerol), adhesive (Indopol H100), polymer (Carbopol C934P) with other formulation ingredients in a beaker with an open-blade impeller. The paste was cast on a nonocclusive backing membrane and dried overnight. The diffusion of the model drug was studied across a cellulosic membrane using Franz's diffusion cells. The amounts of three formulation variables, carbopol (X1), glycerol (X2), and indopol (X3) were studied at three levels, and a face-centered cubic design was used to maximize the flux. An optimization procedure for maximum flux and minimum lag time predicted a flux of 97.22 mcg/cm2/hr at X1 (2% w/w), X2 (11.75% w/w), and X3 (6%, w/w). An experimental patch prepared with the above concentrations yielded a flux of 90.7 mcg/cm2/hr.

Imaging guided biopsy of renal masses: indications, accuracy and impact on clinical management

PURPOSE

We evaluated the indications, accuracy and impact of image guided biopsy of focal renal masses.

MATERIALS AND METHODS

We retrospectively reviewed 79 image guided renal biopsies in 73 patients. Indications, imaging, and histological and clinical features were analyzed. We assumed that nephrectomy, partial nephrectomy or surgical biopsy of suspicious masses would be done when no percutaneous biopsy had been performed. A change in management was defined as surgical to nonsurgical.

RESULTS

Clinical management was altered due to results in 32 of the 79 biopsies (41%) in cases managed nonoperatively, including positive and negative biopsies in those followed clinically and with imaging. Of 79 biopsies 49 (62%) were diagnosed positive for malignancy, including 15 (31%) that were not and 34 (69%) that were renal cell carcinoma. The histological diagnosis was negative on 25 biopsies (32%) and positive or negative on 74 (94%). All 5 of the 79 false-negative biopsies (6%) were due to insufficient tissue and involved highly suspicious imaging findings that required further evaluation, such as repeat biopsy or surgery. Renal cell carcinoma was identified in 4 of the 5 cases. In 12 of the 24 patients (50%) with a pre-biopsy history of nonrenal cancer biopsies were diagnostic of nonrenal cancer. No patient had major complications and in 4 small hematomas were treated with observation only.

CONCLUSIONS

Image guided renal mass biopsy is safe, reliable and accurate, and it changes clinical management in many cases by avoiding nephrectomy or other surgical options. Radiologists should promote imaging guided biopsy as a potentially useful option for managing suspicious or indeterminate renal masses.

Development of trans-2-[1H-imidazol-4-yl] cyclopropane derivatives as new high-affinity histamine H3 receptor ligands

Previously, a novel series of 1H-4-substituted imidazole compounds were described as potent and selective histamine (HA) H3 receptor ligands (Yates et al., 1999). The present studies extend the structure-activity relationships for optimal HA H3 receptor affinity and central nervous system penetration by incorporation of a conformationally restricted cyclopropane nucleus. Moreover, the current studies extend our understanding of ligand-receptor interactions at the HA H3 receptor with the development of high affinity HA H3 receptor antagonists containing a stereochemical presentation. Structure-activity relationships were established from in vitro HA H3 receptor-binding affinities using [3H]Nalpha-methylhistamine and rat cortical tissue homogenates. Systematic optimization of multiple structural features critical for HA H3 receptor affinity provided some of the most potent HA H3 receptor agents described. For example, GT-2331 was determined to bind to a single population of HA H3 receptors with a Ki of 0.125 nM. In vivo, GT-2331 has a favorable central nervous system penetration profile with an ED50 of 0.08 mg/kg (i.p.) in rats and a long duration of action (T1/2 > 4 h). In addition, GT-2331 was extremely selective for the HA H3 receptor versus other HA receptors and a battery of neurotransmitter, neuropeptide, hormone, or enzyme systems. Several compounds were tested in vitro which suggested HA H3 receptor heterogeneity and are discussed in terms of structure-activity relationships for the HA H3 receptor.

Identification and pharmacological characterization of a series of new 1H-4-substituted-imidazoyl histamine H3 receptor ligands

A new series of 1H-4-substituted imidazole compounds were synthesized and identified as potent and selective histamine (HA) H3 receptor ligands. These ligands establish that HA H3 antagonists exhibit stereoselective and conformational preferences in their binding to the HA H3 receptor. Structure-activity relationships were determined in vitro by HA H3 receptor-binding affinities using [3H]Nalpha-methylhistamine and rat cerebral cortical tissue homogenates. Several derivatives containing olefin, amide, and acetylene functional groups were identified as potent HA H3 receptor ligands. In the olefin series, GT-2227 (4-(6-cyclohexylhex-cis-3-enyl)imidazole) was identified as a potent HA H3 receptor ligand with a Ki of 4.2 +/- 0.6 nM, while the trans isomer (GT-2228) displayed a reduced potency (Ki = 15.2 +/- 2.4 nM). GT-2227 was also found to have excellent central nervous system penetration in an ex vivo binding paradigm (ED50 = 0.7 mg/kg i.p.). In the acetylene series, GT-2260 and GT-2286 both exhibited high affinity (Ki = 2.9 +/- 0.2 and 0.95 +/- 0.3 nM) and excellent central nervous system penetration profiles (ED50 = 0.43 and 0.48 mg/kg i.p., respectively). As a prototype for the series, GT-2227 showed high affinity for the human HA H3 receptor (3.2 nM) and minimal affinity for the human HA H1 (Ki = 13,407 +/- 540 nM) and H2 (Ki = 4,469 +/- 564 nM) receptor subtypes. GT-2227 also showed good selectivity for the HA H3 receptor over a broad spectrum of other neurotransmitter receptors (IC50 >/= 1 microM). Furthermore, GT-2227 improved acquisition in a cognitive paradigm without behavioral excitation or effect on spontaneous locomotor activity. In summary, the present studies demonstrate the development of novel HA H3-selective ligands, and lend support for the use of such agents in the treatment of disorders associated with cognitive or attentional deficits.

Cryptosporidium infection in young children with diarrhea in Rawalpindi, Pakistan

Fecal excretion of Cryptosporidium parvum oocysts was determined in 625 children less than five years old who presented at the pediatric clinic of a teaching hospital in Rawalpindi, Pakistan. Single stool specimens were collected from 475 children with acute diarrhea and from 150 children without diarrhea. The Cryptosporidium infection rate was significantly higher in children with diarrhea than in children without diarrhea (10.3% versus 3.3%). The C. parvum infection rate was highest in children 19-24 months of age (21.8%). There was no significant difference in the Cryptosporidium infection rate among male and female children of any age group studied. Sociodemographic information, drinking water supply, and contact with domestic animals had no significant role in the acquisition of C. parvum infection in our study population. The data suggest that C. parvum is relatively endemic in young children in the Rawalpindi area and that C. parvum may be an important pathogen associated with diarrhea.

Identification of a novel GC-rich 113-nucleotide region to complete the circular, single-stranded DNA genome of TT virus, the first human circovirus

The sequence data (H. Okamoto et al., Hepatol. Res. 10:1-16, 1998) of a newly discovered single-stranded DNA virus, TT virus (TTV), showed that it did not have the terminal structure typical of a parvovirus. Elucidation of the complete genome structure was necessary to understand the nature of TTV. We obtained a 1.0-kb amplified product from serum samples of four TTV carriers by an inverted, nested long PCR targeted for nucleotides (nt) 3025 to 3739 and 1 to 216 of TTV. The sequence of a clone obtained from serum sample TA278 was compared with those registered in GenBank. The complete circular TTV genome contained a novel sequence of 113 nt (nt 3740 to 3852 [=0]) in between the known 3'- and 5'-end arms, forming a 117-nt GC-rich stretch (GC content, 90.6% at nt 3736 to 3852). We found a 36-nt stretch (nt 3816 to 3851) with an 80.6% similarity to chicken anemia virus (CAV) (nt 2237 to 2272 of M55918), a vertebrate circovirus. A putative SP-1 site was located at nt 3834 to 3839, followed by a TATA box at nt 85 to 90, the first initiation codon of a putative VP2 at nt 107 to 109, the termination codon of a putative VP1 at nt 2899 to 2901, and a poly(A) signal at nt 3073 to 3078. The arrangement was similar to that of CAV. Furthermore, several AP-2 and ATF/CREB binding sites and an NF-kappaB site were arranged around the GC-rich region in both TTV and CAV. The data suggested that TTV is circular and similar to CAV in its genomic organization, implying that TTV is the first human circovirus.

Chemical delivery systems: evaluation of physicochemical properties and enzymatic stability of phenylephrone derivatives

The physicochemical properties and enzymatic stability of esters of phenylephrone, synthesized on the basis of the chemical delivery system (CDS) concept, were studied as a new class of mydriatic agents. Potentiometrically determined ionization constants (pKa) of the novel compounds were in the range 7.19-7.21. The three esters of phenylephrone (isovaleryl, phenylacetyl, and pivalyl) were more lipophilic than phenylephrone as indicated by n-octanol/pH 7.4 buffer partition coefficients (log Papp) and the chromatographic capacity factors (log k'). The chemical stability of the esters of phenylephrone was evaluated in hydrochloric acid, citrate, and phosphate buffers (with pH ranging between 2.0 and 8.0), and the enzymatic hydrolysis in rat and human plasma. The samples were analyzed using HPLC assay procedures. The phenylephrone esters were found to undergo comparatively slow hydrolytic degradation in buffer with pH 3.0 and 4.0, with half-lives ranging from 1136 to 1980 hr at 37 degrees C. The novel esters were readily hydrolyzed in human plasma with half-lives ranging between 16.2 and 47.8 min. The hydrolytic degradation rates were higher in rat plasma than in human plasma, in which the half-lives were in the range of 9.8-38.3 min. In the present investigations, only phenylephrone, not the active species phenylephrine, was detected. Among the esters studied, isovaleryl ester was the most labile. Pivalyl ester, having a tertiary carbon, showed relatively high resistance to chemical and enzymatic hydrolysis because of the steric hindrance, followed by phenyl and isovaleryl esters. The results suggest that the duration of action of the phenylephrone CDS can be controlled with proper chemical manipulations.

The corrosion behaviour of Ti-6Al-4V, Ti-6Al-7Nb and Ti-13Nb-13Zr in protein solutions

Ti alloys are used in orthopaedic applications owing to their appropriate mechanical properties and their excellent corrosion resistance. The release of titanium and the other alloying elements into the surrounding tissue has been reported due either to passive corrosion or accelerating processes such as wear. Since the passive layer can be broken down in certain circumstances by wear it is important to study the ability of these alloys to repassivate in biological environments, in particular in the presence of proteins, and evaluate how the repassivated surface may vary from the original surface. In this study we investigated the ability of Ti-6Al-4V, Ti-6Al-7Nb and Ti-13Nb-13Zr to repassivate in phosphate buffered saline (PBS), bovine albumin solutions in PBS and 10% foetal calf serum in PBS at different pH values and at different albumin concentrations. It was found that an increase in pH had a greater effect on the corrosion behaviour of Ti-6Al-4V and Ti-6Al-7Nb than on Ti-13Nb-13Zr in PBS and that the addition of protein to the PBS reduced the influence of pH on the corrosion behaviour of all the alloys. The effect of the corrosion and repassivation was investigated by measuring changes in the surface hardness of the alloys and it was found that corrosion reduced the hardness of the surface oxides of all the alloys. In PBS the reduction was smallest for Ti-6Al-4V and largest for Ti-13Nb- 3Zr and that corrosion in protein solutions further reduced the hardness of the surface oxides. This effect was greater for Ti-6Al-4V and Ti-6Al-7Nb than for Ti-13Nb-13Zr. In conclusion, proteins in the environment appear to interact with the repassivation process at the surface of these alloys and influence the resulting surface properties.

The expression of heat shock protein 60 in patients with dilated cardiomyopathy

OBJECTIVE

Heat shock proteins (hsps) have been shown to be important antigens in a number of autoimmune diseases. We have previously shown the presence of autoantibodies against hsp60 in a high proportion of patients with dilated cardiomyopathy (DCM). This study set out to investigate the expression of hsp60 in the myocardium of 30 patients with DCM and a control group of 30 normal donors.

DESIGN

The expression of hsp60 was quantitated at the protein and mRNA level by Western blotting and RT-PCR, respectively, and its distribution was investigated by immunocytochemistry.

RESULTS

Quantitation of hsp60 showed a 5-fold increase in the DCM hearts over that in the donor hearts. By immunocytochemistry 13 patients with DCM showed increased positive staining localised to the connective tissue. Semi-quantitative RT-PCR analysis of hsp60 showed a significantly increased amount of hsp60 at the mRNA level in the DCM hearts than in the controls.

CONCLUSIONS

These results unequivocally demonstrate a raised level of expression of endogenous hsp60 in the myocardium of patients with DCM. The increased expression of hsp60 in the myocardium of patients with DCM may render such cells susceptible to react with circulating autoantibodies to hsp60 and hsp65 found in a high proportion of patients with this disease.

On the presence and absence of behavioural traits in sport: an example from championship squash match-play

Here we report two experiments that analysed sport (squash) competition as a non-linear system that transits intermittently between different behavioural states. The first experiment involved a perceptual analysis of 60 rallies in which stable behaviour and unstable behaviour, delineated by behavioural transitions (i.e. shot perturbations), were reliably (kappa = 0.930) and validly (kappa = 0.844) identified by independent observers. In addition, experts were better than non-experts at identifying the type of system behaviour (P < 0.01). These results provide for three alternative descriptions: (a) the system is multi-stable and transits between states via the mechanism of instability; (b) the system is bi-stable and abruptly transits between two states, labelled stable and unstable; or (c) the system is mono-stable and displays variability, marked by transient instability, as a result of system perturbations. The second experiment analysed squash behaviour as expressed in the phase relation between the two players from time-motion analysis. The data, from four rallies, yielded evidence of a tight anti-phase coupling with transient phase shifts, or perturbations, that were quickly damped. These data suggest a mono-stable system with a single (anti-phase) attractor onto which system fluctuations are occasionally written. However, these fluctuations failed to correspond with the short perturbations that were identified from perceptual analysis. Together, these results affirm the presence of transient behaviours in squash match-play, although the information that forms these perceptual judgements has yet to be identified.

Conjoint corrosion and wear in titanium alloys

When considering titanium alloys for orthopaedic applications it is important to examine the conjoint action of corrosion and wear. In this study we investigate the corrosion and wear behaviour of Ti-6Al-4V, Ti-6Al-7Nb and Ti-13Nb-13Zr in phosphate buffered saline (PBS), bovine albumin solutions in PBS and 10% foetal calf serum solutions in PBS. The tests were performed under four different conditions to evaluate the influence of wear on the corrosion and corrosion on the wear behaviour as follows: corrosion without wear, wear-accelerated corrosion, wear in a non-corrosive environment and wear in a corrosive environment. The corrosion behaviour was investigated using cyclic polarisation studies to measure the ability of the surface to repassivate following breakdown of the passive layer. The properties of the repassivated layer were evaluated by measuring changes in the surface hardness of the alloys. The amount of wear that had occurred was assessed from weight changes and measurement of the depth of the wear scar. It was found that in the presence of wear without corrosion the wear behaviour of Ti-13Nb-13Zr was greater than that of Ti-6Al-7Nb or Ti-6Al-4V and that in the presence of proteins the wear of all three alloys is reduced. In the presence of corrosion without wear Ti-13Nb-13Zr was more corrosion resistant than Ti-6Al-7Nb which was more corrosion resistant than Ti-6Al-4V without proteins whereas in the presence of protein the corrosion resistance of Ti-13Nb-13Zr and Ti-6Al-7Nb was reduced and that of Ti-6Al-4V increased. In the presence of corrosion and wear the corrosion resistance of Ti-13Nb-13Zr is higher than that of Ti-6Al-7Nb or Ti-6Al-4V in PBS but in the presence of proteins the corrosion resistance of Ti-13Nb-13Zr and Ti-6Al-7Nb are very similar but higher than that of Ti-6Al-4V. The wear of Ti-13Nb-13Zr is lower than that of Ti-6Al-7Nb and Ti-6Al-4V with or without the presence of proteins in a corrosive environment. Therefore the overall degradation when both corrosion and wear processes are occurring is lowest for Ti-13Nb-13Zr and highest for Ti-6Al-4V and the presence of proteins reduces the degradation of all three alloys.

Selection of instruments in the core set for DC-ART, SMARD, physical therapy, and clinical record keeping in ankylosing spondylitis. Progress report of the ASAS Working Group. Assessments in Ankylosing Spondylitis

To select specific instruments for each domain of the core set for endpoints in ankylosing spondylitis (AS), we gathered all instruments described in the literature to assess the domains chosen as endpoints in AS and sent them to 43 members of the Assessments in Ankylosing Spondylitis (ASAS) Working Group. The following domains were taken into account: function, pain, spinal mobility, patient global assessment, morning stiffness, peripheral joints and entheses, acute phase reactants, x-ray spine, x-ray hips, fatigue. For each instrument the members were asked to judge if the instrument was feasible and relevant. If an instrument was judged to be not feasible or not relevant by more than 50% of the respondents the instrument was deleted from the list. These data were presented during an ASAS workshop and the final decisions were about which instruments to include in the core set. This process was repeated separately for the settings disease controlling antirheumatic therapy (DC-ART), symptom modifying antirheumatic drugs (SMARD) and physical therapy, and clinical record keeping. The response rate to the questionnaire was 72%. For each domain one or more instruments were selected, except for Entheses and Fatigue. The chosen instruments were similar for the 3 above settings. Core sets of specific instruments were selected for the OMERACT filter test for relevance and feasibility. For all these instruments the remaining aspects of the OMERACT filter (truth and discrimination) should be assessed by literature review and if needed by additional research. It is recommended to use these instruments in all research projects in AS.

Management of reproductive tract infections in rural Bangladesh

This study was undertaken to identify existing reproductive tract infection (RTI) treatment practices of the government family planning (FP) paramedics in rural Bangladesh. It also assessed the knowledge and perceptions of the clients about RTIs as well as the service-seeking behaviour of the clients and their husbands. Data on paramedic treatment practices were collected by observing paramedic-client interactions at the family welfare centres (FWCs) and satellite clinics (SCs). One hundred clients seeking RTI treatment were observed. The same clients were interviewed at departure from the health-care facility to assess their knowledge and perceptions about RTIs as well as service-seeking behaviour of the clients and their husbands. Twenty-four village practitioners were also interviewed to assess their knowledge on the subject. Results of the study showed that in the treatment of RTI, paramedics of government FP services commonly: (i) did not do a physical examination, (ii) used a substandard dosage of drugs, and (iii) made no attempt to notify or treat male partners. Thirty-one of the 97 clients reported that their husbands had some kind of genital problem. It was revealed from the study that as an alternative to the government FP services, the clients and their husbands often seek RTI treatment from the village practitioners though the village practitioners' knowledge concerning RTI is poor. Based on the findings of this study, it is recommended that the knowledge and skills of the paramedics and village practitioners for RTI treatment be strengthened. Prevention of RTI through awareness campaigns is essential for the control of RTIs, and especially of STDs.

Effect of amino acids on inhibition of lactate dehydrogenase-X by gossypol

Gossypol acetic acid (GAA) has been shown to have male antifertility effects, but there are pronounced differences among animal species. In the search of endogenous effector molecules, which interfere with the functions of GAA, we have studied the in vitro effect of various amino acids on the inhibition of the purified LDH-X by GAA. Histidine, cysteine and glycine were shown to block the effect of GAA. The effects of these amino acids were concentration dependent. Histidine and glycine protection was found to be complex type in which both the Km and Vmax were decreased compared to control. Arginine, glutamic acid, phenylalanine and valine were found to be ineffective against the inhibitory action of GAA.

GADD45 induction of a G2/M cell cycle checkpoint

G1/S and G2/M cell cycle checkpoints maintain genomic stability in eukaryotes in response to genotoxic stress. We report here both genetic and functional evidence of a Gadd45-mediated G2/M checkpoint in human and murine cells. Increased expression of Gadd45 via microinjection of an expression vector into primary human fibroblasts arrests the cells at the G2/M boundary with a phenotype of MPM2 immunopositivity, 4n DNA content and, in 15% of the cells, centrosome separation. The Gadd45-mediated G2/M arrest depends on wild-type p53, because no arrest was observed either in p53-null Li-Fraumeni fibroblasts or in normal fibroblasts coexpressed with p53 mutants. Increased expression of cyclin B1 and Cdc25C inhibited the Gadd45-mediated G2/M arrest in human fibroblasts, indicating that the mechanism of Gadd45-mediated G2/M checkpoint is at least in part through modulation of the activity of the G2-specific kinase, cyclin B1/p34(cdc2). Genetic and physiological evidence of a Gadd45-mediated G2/M checkpoint was obtained by using GADD45-deficient human or murine cells. Human cells with endogenous Gadd45 expression reduced by antisense GADD45 expression have an impaired G2/M checkpoint after exposure to either ultraviolet radiation or methyl methanesulfonate but are still able to undergo G2 arrest after ionizing radiation. Lymphocytes from gadd45-knockout mice (gadd45 -/-) also retained a G2/M checkpoint initiated by ionizing radiation and failed to arrest at G2/M after exposure to ultraviolet radiation. Therefore, the mammalian genome is protected by a multiplicity of G2/M checkpoints in response to specific types of DNA damage.

Chemical composition and medicinal properties of Nigella sativa Linn

The black cumin or Nigella sativa L. seeds have many acclaimed medicinal properties such as bronchodilatory, hypotensive, antibacterial, antifungal, analgesic, anti-inflammatory and immunopotentiating and are universally accepted as a panacea. This review article has surveyed the relevant literature on Nigella sativa from 1960-1998 and examines the scientific evidence for these medicinal claims and highlights areas in need of research.

Potentiometric study of vitamin D3 complexes with manganese(II), iron(II), iron(III) and zinc(II) in water-ethanol medium

Vitamin D3 (LH) complexes with manganese(II), iron(II), iron(III) and zinc(II) were identified in water-ethanol medium (30/70). Their stability constants were determined at 298 K and at a constant ionic strength of 0.100 M using potentiometric methods. The computerisation of the experimental data showed the presence of ML (M = metal, L = deprotonated vitamin D3) and ML2 species in all cases; in addition, the ML3 iron(III) complex was detected. The calculated overall stability constants beta for MnIIL, FeIIL, FeIIIL and ZnIIL are, respectively, in logarithms, 12.4, 16.5, 28.5 and 16.5. Under the experimental conditions, the only protonated species MLH detected was with iron(III).