An Ensemble Approach for Robust Automated Crack Detection and Segmentation in Concrete Structures

To prevent potential instability the early detection of cracks is imperative due to the prevalent use of concrete in critical infrastructure. Automated techniques leveraging artificial intelligence, machine learning, and deep learning as the traditional manual inspection methods are time-consuming. The existing automated concrete crack detection algorithms, despite recent advancements, face challenges in robustness, particularly in precise crack detection amidst complex backgrounds and visual distractions, while also maintaining low inference times. Therefore, this paper introduces a novel ensemble mechanism based on multiple quantized You Only Look Once version 8 (YOLOv8) models for the detection and segmentation of cracks in concrete structures. The proposed model is tested on different concrete crack datasets yielding enhanced segmentation results with at least 89.62% precision and intersection over a union score of 0.88. Moreover, the inference time per image is reduced to 27 milliseconds which is at least a 5% improvement over other models in the comparison. This is achieved by amalgamating the predictions of the trained models to calculate the final segmentation mask. The noteworthy contributions of this work encompass the creation of a model with low inference time, an ensemble mechanism for robust crack segmentation, and the enhancement of the learning capabilities of crack detection models. The fast inference time of the model renders it appropriate for real-time applications, effectively tackling challenges in infrastructure maintenance and safety.

Knowledge, attitude and practices regarding dengue and its vector among medical practitioners in Malakand region, Pakistan

Abstract Dengue fever (DF) is increasingly recognized as one of the world’s major mosquito borne diseases and causes significant morbidity and mortality in tropical and subtropical countries. Dengue fever is endemic in most part of Pakistan and continues to be a public health concern. Knowledge, attitude and practices can play an important role in management of the disease. Current study was aimed to determine the level of knowledge, attitude and practices regarding dengue fever among health practitioners, to study the level of knowledge and attitude with preventive practices for dengue fever. A cross sectional study was carried out in medical practitioners of the four districts of Malakand region during October to November 2019. A pre-structured questionnaire was used to collect data from medical practitioners. Data was analyzed using Graph Pad version 5. Significant value was considered when less than 0.05 (at 95% confidence of interval). The results revealed that most of participants have seen dengue vector (62%), the media being the most quoted source of information. Nearly 81.2% participants were aware from transmission of dengue fever is by mosquito bite. Practices based upon preventive measures were found to be predominantly focused towards prevention of mosquito bites rather than elimination of breeding places. Although the knowledge regarding DF and mosquito control measure was quite high among the medical practitioners but this knowledge was not put into practice. Further studies are required to aware the people about dengue and its vector in order to get prevention and control.

In Vitro Comparison of Various High-Speed Vitrectomy Machines Using Dual Blade Cutters

Objectives

The objective of this study is to compare various dual blade vitrectomy cutters for their efficiency in an in vitro setting.

Methods

In this in vitro experimental study, we compared various vitrectomy systems including EVA (Dutch Ophthalmic Research Center, Zuidland, The Netherlands), REVOLUTION (Optikon 2000, Inc., Rome, Italy), and OS4 (Oertli Instrumente AG, Berneck, Switzerland) in terms of efficiency in vitreous cutting and aspiration for various vitreous substitutes. These substitutes included water, chicken egg albumin, and goat vitreous. We only used 23-gauge dual blade cutters across all platforms to maintain uniformity. The cutting and aspiration efficiency was measured across various cut and vacuum settings of vitrectomy machines and measured as mass aspirated in a given time. Data analysis included comparing the amount of mass aspirated by these machines at preset cut and vacuum settings.

Results

Scatter plots showed a comparable mass of water aspirated by the EVA and REVOLUTION at 1000 to 5000 cuts per minute at a constant vacuum of 500 mm Hg whereas OS4 aspirated lesser mass at similar settings. Same trends were noted for goat vitreous for EVA and REVOLUTION but aspirated mass of albumin fluctuated widely across various platforms. At peak machine settings, REVOLUTION showed superiority across all three vitreous models due to its higher peak settings. The area under curve (AUC) analysis showed no significant differences among machines for water and goat vitreous at comparable settings but results were fluctuating for egg albumin.

Conclusion

Employing higher cut rates for dual blade cutters results in better efficiency of vitrectomy machines.

Forward osmosis for the treatment of reverse osmosis concentrate from water reclamation: process performance and fouling control

While high quality water reuse based on dual membrane filtration (membrane filtration or ultrafiltration, followed by reverse osmosis) is expected to be progressively applied, treatment and sustainable management of the produced reverse osmosis concentrate (ROC) are still important issues. Forward osmosis (FO) is a promising technology for maximising water recovery and further dewatering ROC so that zero liquid discharge is produced. Elevated concentrations of organic and inorganic compounds may act as potential foulants of the concentrate desalting system, in that they consist of, for example, FO and a subsequent crystallizer. The present study investigated conditions under which the FO system can serve as concentration phase with the focus on its fouling propensity using model foulants and real ROC. Bulk organics from ROC consisted mainly of humic acids (HA) and building blocks since wastewater-derived biopolymers were retained by membrane filtration or ultrafiltration. Organic fouling of the FO system by ROC-derived bulk organics was low. HA was only adsorbed moderately at about 7% of the initial concentration, causing a minor flux decline of about 2-4%. However, scaling was a major impediment to this process if not properly controlled, for instance by pH adjustment or softening.

Neuroblastoma cells injected into experimental mature teratoma reveal a tropism for embryonic loose mesenchyme

Embryonic neural tumors are responsible for a disproportionate number of cancer deaths in children. Although dramatic improvements in survival for pediatric malignancy has been achieved in previous years advancements seem to be slowing down. For the development of new enhanced therapy and an increased understanding of the disease, pre-clinical models better capturing the neoplastic niche are essential. Tumors of early childhood present in this respect a particular challenge. Here, we explore how components of the embryonic process in stem‑cell induced mature teratoma can function as an experimental in vivo microenvironment instigating the growth of injected childhood neuroblastoma (NB) cell lines. Three human NB cell lines, IMR-32, Kelly and SK-N-BE(2), were injected into mature pluripotent stem cell‑induced teratoma (PSCT) and compared to xenografts of the same cell lines. Proliferative NB cells from all lines were readily detected in both models with a typical histology of a poorly differentiated NB tumor with a variable amount of fibrovascular stroma. Uniquely in the PSCT microenvironment, NB cells were found integrated in a non‑random fashion. Neuroblastoma cells were never observed in areas with well-differentiated somatic tissue i.e. bone, muscle, gut or areas of other easily identifiable tissue types. Instead, the three cell lines all showed initial growth exclusively occurring in the embryonic loose mesenchymal stroma, resulting in a histology recapitulating NB native presentation in vivo. Whether this reflects the 'open' nature of loose mesenchyme more easily giving space to new cells compared to other more dense tissues, the rigidity of matrix providing physical cues modulating NB characteristics, or if embryonic loose mesenchyme may supply developmental cues that attracted or promoted the integration of NB, remains to be tested. We tentatively hypothesize that mature PSCT provide an embryonic niche well suited for in vivo studies on NB.

Detection of bacterial blight resistance genes in basmati rice landraces

Aromatic basmati rice is vulnerable to bacterial blight disease. Genes conferring resistance to bacterial blight have been identified in coarse rice; however, their incorporation into basmati varieties compromises the prized basmati aroma. We identified bacterial blight resistance genes Xa4, xa5, Xa7, and xa13 in 52 basmati landraces and five basmati cultivars using PCR markers. The Xa7 gene was found to be the most prevalent among the cultivars and landraces. The cultivars Basmati-385 and Basmati-2000 also contained the Xa4 gene; however, xa5 and xa13 were confined to landraces only. Ten landraces were found to have multiple resistance genes. Landraces Basmati-106, Basmati-189 and Basmati-208 contained Xa4 and Xa7 genes. Whereas, landraces Basmati-122, Basmati-427, Basmati-433 were observed to have xa5 and Xa7 genes. Landraces Basmati-48, Basmati-51A, Basmati-334, and Basmati-370A possessed Xa7 and xa13 genes. The use of landraces containing recessive genes xa5 and xa13 as donor parents in hybridization with cultivars Basmati-385 and Basmati-2000, which contain the genes Xa4 and Xa7, will expedite efforts to develop bacterial blight-resistant basmati rice cultivars through marker assisted selection, based on a pyramiding approach, without compromising aroma and grain quality.

Genetic diversity analysis of Bt cotton genotypes in Pakistan using simple sequence repeat markers

The popularity of genetically modified insect resistant (Bt) cotton has promoted large scale monocultures, which is thought to worsen the problem of crop genetic homogeneity. Information on genetic diversity among Bt cotton varieties is lacking. We evaluated genetic divergence among 19 Bt cotton genotypes using simple sequence repeat (SSR) markers. Thirty-seven of 104 surveyed primers were found informative. Fifty-two primers selected on the basis of reported intra-hirsutum polymorphism in a cotton marker database showed a high degree of polymorphism, 56% compared to 13% for randomly selected primers. A total of 177 loci were amplified, with an average of 1.57 loci per primer, generating 38 markers. The amplicons ranged in size from 98 to 256 bp. The genetic similarities among the 19 genotypes ranged from 0.902 to 0.982, with an average of 0.947, revealing a lack of diversity. Similarities among genotypes from public sector organizations were higher than genotypes developed by private companies. Hybrids were found to be more distant compared to commercial cultivars and advanced breeding lines. Cluster analysis grouped the 19 Bt cotton genotypes into three major clusters and two independent entries. Cultivars IR-3701, Ali Akbar-802 and advanced breeding line VH-259 grouped in subcluster B2, with very narrow genetic distances despite dissimilar parentage. We found a very high level of similarity among Pakistani-bred Bt cotton varieties, which means that genetically diverse recurrent parents should be included to enhance genetic diversity. The intra-hirsutum polymorphic SSRs were found to be highly informative for molecular genetic diversity studies in these cotton varieties.

Effect of black seed on dextromethorphan O- and N-demethylation in human liver microsomes and healthy human subjects

OBJECTIVE

To investigate the effects of black seed on the metabolic activities of CYP3A4 and CYP2D6 in human liver microsomes and in human subjects using dextromethorphan as a probe drug.

METHODS

CYP2D6-mediated O-demethylation and CYP3A4-mediated N-demethylation of dextromethorphan (DEX) to dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively, were utilized to assess the metabolic activities of the two enzymatic pathways. In the in vitro experiments, DEX was incubated with microsomes and NADPH in absence or presence of black seed extract (10-100 microg/ml) and the formation of the metabolites were measured by HPLC. In the clinical study, four healthy volunteers received a single oral dose of DEX 30 mg alone in phase I, and along with last dose of black seed (2.5 g twice daily for seven days) in phase II. Activities of the two enzymes were evaluated based on the urinary metabolic ratios (MRs), which were calculated from eight-hour urine collections. DEX and its metabolites were assayed in urine samples by HPLC following a liquid-liquid extraction.

RESULTS

Black seed extracts significantly inhibited the formation of both metabolites in microsomes. The maximum inhibition was observed at the highest extract concentration (i.e., 100 microg/ml), which was about 80% and 60% for DOR and 3-MM, respectively. In the clinical study, the urinary MRs of DEX/DOR and DEX/3-MM increased by factors of 127 and 1.6-fold, respectively, after consumption of black seed.

CONCLUSION

Black seed significantly inhibited CYP2D6 and CYP3A4 mediated metabolism of DEX in human liver microsomes and healthy human volunteers indicating that it has the potential to interact with CYP2D6 and CYP3A4 substrates.

Medical mortality in Pakistan: experience at a tertiary care hospital

AIM

To acquire systematic data on the causes of hospital mortality in Pakistan, a developing country with scant mortality records.

STUDY DESIGN

Retrospective review of death certificates and hospital charts of patients dying on general and specialty medical services at our hospital during one calendar year.

RESULTS

Of a total 10,590 admissions, 657 (6.2%) died in hospital. The deceased included 357 (54.4%) males and 299 (45.6%) females, with a collective median age of 63 years and mean length of stay 6.71 days (median 4 days, range 1-56 days). Primary cause of death was categorised as infectious (21.2%), pulmonary (17.2%), cancer related (15.7%), cardiovascular (12.6%), gastrointestinal and hepatic (10.8%), neurological (11.4%) and miscellaneous (11.1%). Within each category, the most common diagnoses were septicaemia (76.9% of infectious cases), pneumonia (55.7% of pulmonary cases), myocardial infarction (40.9% of cardiovascular), intracranial haemorrhage (37.3% of neurological), and cirrhosis (45.0% of gastrointestinal). There were multiple causes among malignant disorders with no single cause dominating. Patients with cardiovascular and pulmonary deaths tended to be older than the median age (p = 0.001), while patients with gastrointestinal and cancer related deaths tended to be younger than the median age (p = 0.001). Length of stay did not differ significantly among the various subgroups. About a quarter (26.4%) deaths occurred within 24 h of admission.

CONCLUSIONS

Infections, including septicaemia and pneumonia, are the leading causes of hospital mortality in our setting, followed by malignancy and cardiovascular causes. The overall mortality rate is comparable to published mortality data from other hospital settings.

Relationship between circulating levels of IFN-gamma, IL-10, CXCL9 and CCL2 in pulmonary and extrapulmonary tuberculosis is dependent on disease severity

Protection against Mycobacterium tuberculosis infection is dependent on T cell and macrophage activation regulated by cytokines. Cytokines and chemokines produced at disease sites may be released into circulation. Data available on circulating cytokines in tuberculosis (TB) is mostly on pulmonary TB (PTB) with limited information on extrapulmonary disease (EPul-TB). We measured interferon-gamma (IFN-gamma), interkeukin-10 (IL-10), CXCL9 and CCL2 in sera of patients (n = 80) including; PTB (n = 42), EPul-TB (n = 38) and BCG vaccinated healthy endemic controls (EC, n = 42). EPul-TB patients comprised those with less severe (LNTB) or severe (SevTB) disease. Serum IFN-gamma, IL-10 and CXCL9 levels were significantly greater while CCL2 was reduced in TB patients as compared with EC. IFN-gamma was significantly greater in PTB as compared with LNTB (P = 0.002) and SevTB (P = 0.029). CXCL9 was greater in PTB as compared with LNTB (P = 0.009). In contrast, CCL2 levels were reduced in PTB as compared with LNTB (P = 0.021) and SevTB (P = 0.024). A Spearman's rank correlation analysis determined a positive association between IFN-gamma and IL-10 (rho = 0.473, P = 0.002) and IFN-gamma and CXCL9 (rho = 0.403, P = 0.008) in the PTB group. However, in SevTB, only IFN-gamma and CXCL9 were positively associated (rho = 0.529, P = 0.016). Systemic levels of cytokines are reflective of local responses at disease sites. Therefore, our data suggests that in PTB increased IFN-gamma and CXCL9 balanced by IL-10 may result in a more effective cell mediated response in the host. However, elevated inflammatory chemokines CXCL9 and CCL2 in severe EPul-TB without concomitant down modulatory cytokines may exacerbate disease related pathology and hamper restriction of M. tuberculosis infection.

Inhibitory effect of compounds from Zingiberaceae species on human platelet aggregation

Twelve compounds isolated from Alpinia mutica Roxb., Kaempferia rotunda Linn., Curcuma xanthorhiza Roxb., Curcuma aromatica Valeton and Zingiber zerumbet Smith (Family: Zingiberaceae) and three synthesized derivatives of xanthorrhizol were evaluated for their ability to inhibit arachidonic acid- (AA), collagen- and ADP-induced platelet aggregation in human whole blood. Antiplatelet activity of the compounds was measured in vitro by the Chrono Log whole blood aggregometer using an electrical impedance method. Among the compounds tested, curcumin from C. aromatica, cardamonin, pinocembrine and 5,6-dehydrokawain from A. mutica and 3-deacetylcrotepoxide from K. rotunda showed strong inhibition on platelet aggregation induced by AA with IC(50) values of less than 84 microM. Curcumin was the most effective antiplatelet compound as it inhibited AA-, collagen- and ADP-induced platelet aggregation with IC(50) values of 37.5, 60.9 and 45.7 microM, respectively.

Rhabdomyolysis induced by a single dose of a statin

Statins have been shown to cause myotoxicity and rhabdomyolysis. In most cases rhabdomyolysis occurs following the use of these drugs for at least one week. A case of rhabdomyolysis after just a single dose of simvastatin is reported.

Expression and characterization of the Mycobacterium tuberculosis serine/threonine protein kinase PknB

PknB is a member of the newly discovered eukaryotic-like protein serine/threonine kinase (PSTK) family of proteins. The pknB gene was cloned and expressed in Escherichia coli. The active recombinant protein was purified and shown to be reactive with antiphosphoserine antibodies, as well as with antibodies to the phosphorylated eukaryotic Ser/Thr kinases mitogen-activated protein kinase kinase 3 and 6, P38, and Creb. In vitro kinase assays demonstrated that PknB is a functional kinase that is autophosphorylated on serine/threonine residues and is also able to phosphorylate the peptide substrate myelin basic protein. Analysis of pknB expression in Mycobacterium tuberculosis indicates the presence of pknB mRNA in (i) organisms grown in vitro in bacteriological media, (ii) a murine macrophage in vitro infection model, and (iii) in vivo alveolar macrophages from a patient with tuberculosis.

Abnormal mucous cell phenotype induced by neutrophil elastase in hamster bronchi

Bronchial mucous cell metaplasia (MCM) is a histologic component of chronic mucus hypersecretion. The hamster model of elastase-induced MCM appears to involve an irreversible conversion of Clara cells to mucous cells. The present study questioned whether the mucous cells seen in hamster bronchi exposed to neutrophil elastase produce and maintain a form of glycoconjugate secretory product different from that normally found in mucous cells or Clara cells. Ultrastructural cytochemistry using the gold-labeled lectin HPA revealed a difference in the cell surface and stored secretory granules of elastase-derived mucous cells compared to normal mucous cells and Clara cells at 3 weeks and 4 months following exposure. The results suggest that elastase irreversibly alters the glycoconjugate character of the Clara cells normally present so that they produce an abnormal form of mucus. Because secreted glycoconjugates can affect the rate of mucociliary clearance and receptor-mediated binding of microorganisms, this change in phenotype may be involved in the pathogenesis of diseases associated with chronic mucus hypersecretion in humans.

Phenotypic variation in hamster bronchial mucous cells induced by different airway irritants

Chronic mucus hypersecretion (CMH), a common feature of various obstructive pulmonary diseases, is caused by a variety of airway irritants. Bronchial mucous cell metaplasia (MCM), a histological correlate of CMH, can be induced in hamster airways by a number of different irritants. Previous studies with the hamster model suggest that the secretory cell response to different agents is not stereotyped but can vary in the type of mucus glycoconjugate produced. The present ultrastructural study was conducted therefore to provide quantitative evidence of phenotypic variation in mucous cells induced independently by exposure to the metaplastic agents elastase and acid. HPA-gold lectin cytochemistry revealed an increase in N-acetyl galactosamine at the cell surface and secretory granules of mucous cells in elastase-treated vs. acid-treated animals. Although there was no quantitative difference between the acid-treated and untreated groups, a difference in the pattern of binding within granules indicated variation in the secretory product. Because mucus glycoconjugates serve as attachment sites for specific pathogens, phenotypically distinct mucous cells may promote differential microbial colonization. In humans therefore, variation in the severity and progression of CMH may be due in part to secretory cell susceptibility and response to different pathogenic stimuli.

Polymerase chain reaction of nasal swabs from tuberculosis patients and their contacts

Previous studies have found Mycobacterium leprae in nasal swabs from leprosy patients, their contacts, and persons living in endemic areas. It might be expected that M. tuberculosis would be present on nasal mucosa of pulmonary tuberculosis patients, but whether they can be detected in patients or contacts is unknown. We used the polymerase chain reaction (PCR) technique on nasal swabs from tuberculosis patients, contacts of tuberculosis patients, leprosy patients, and London controls to look for both M. tuberculosis and M. leprae. Swabs dipped in sputum specimens from smear-positive patients were used as positive controls. The PCRs were conducted in two independent laboratories. M. tuberculosis was detected in nasal swabs from 6/16 smear-positive tuberculosis patients and from 1/10 household contacts by one of the laboratories. All of the sputum swabs were positive for M. tuberculosis, and all of the London controls were negative. M. leprae were found in nasal swabs from 2/5 leprosy patients, but one laboratory also reported M. leprae in swabs from 4/21 tuberculosis patients and from one sputum specimen. The results show that M. tuberculosis can be found in the noses of some tuberculosis patients, and suggest that the bacilli also may be detected in some household contacts. The comparisons with M. leprae and between the two laboratories give further insights into the sensitivity and specificity of the technique.

Serotype analysis of Indian patients with HIV infection

HIV infection has established itself in India. Besides Bombay, Madras and Manipur it has assumed epidemic proportions in Punjab, where 24% of seropositives acquired infection through blood products. Preliminary observations on genetic analysis in 13 isolates revealed that the principal neutralizing determinant (PND) of the V3 loop was closely related to the South African isolate. Since serotyping can give reliable information about genotypic prevalence in the population, serotyping in the present study used 5 synthetic peptides (NOF, EL1, MN, IIIB, IND) of African, North American, European and Indian origin. The Indian consensus was derived from genotype analysis of 13 cases. Results of serotype analysis indicated that 82% of patients harboured a strain related to the South African type of HIV-1. These observations have a sinister significance for designing vaccine strategies for this region.

Clinical and histological discrepancies in diagnosis of ENL reactions classified by assessment of acute phase proteins SAA and CRP

Sixteen out of 45 (36%) leprosy patients with clinical features of acute erythema nodosum leprosum (ENL) did not show the characteristic presence of neutrophils (polymorphs) in histology of the ENL lesion. The acute-phase reactants, serum amyloid A (SAA) and C-reactive protein (CRP) which are systemic markers of inflammation, and IgM and IgG antibody to Mycobacterium leprae were determined in these patients in order to understand the differences in histological diagnosis. Both SAA and CRP were elevated in ENL patients, irrespective of the presence of polymorph infiltrates, as compared to nonreactional lepromatous patients, patients with histologically confirmed reversal reactions and endemic controls, indicating that all clinically diagnosed ENL patients had ongoing inflammatory reactions. On the other hand, IgM and IgG antibodies were significantly lower (> 70%) in ENL patients as compared to nonreactional lepromatous patients. When the two ENL groups [ENL-PMN+ve (positive for neutrophils) and ENL-PMN-ve (negative for neutrophils)] were compared, there were no significant differences in the mean SAA, IgM or IgG antibody concentrations, but CRP was eightfold lower in ENL-PMN-ve as compared to the ENL-PMN+ve group. This may indicate that the timing or modulation of the reaction was different in the two ENL groups. Thus, measurement of the acute-phase response and the ratio of SAA/CRP in particular are helpful in the clinical diagnosis of ENL reactions in leprosy.

A colorimetric PCR method for the detection of M. leprae in skin biopsies from leprosy patients

A one-tube nested polymerase chain reaction (PCR) method for the diagnosis of paucibacillary leprosy was developed using the repetitive RLEP sequence as a target. Detection of the PCR products was simplified by the adaptation of a colorimetric method. The test was specific for Mycobacterium leprae, and the sensitivity of the assay was 1 fg of purified genomic M. leprae DNA (less than one genome). Complete concordance was seen between the development of color and resolution on agarose gels. The results of frozen skin sections from untreated patients showed that the assay could detect 100% of multibacillary samples [bacterial index (BI) of 2 or more] and 69% and 70% of the samples with BIs of 1 and 0, respectively. The use of one-tube nested PCR in assessing the effectiveness of multidrug therapy (MDT) in leprosy also was determined. The simplified colorimetric assay was found to be sensitive, rapid and specific, and is suitable for use in routing diagnostic laboratories.

Retrospective analysis of assisted conception techniques: A three year experience

In this retrospective survey, we present the results of infertility treatment by various assisted conception techniques at the assisted conception unit, New Jeddah Clinic Hospital, Jeddah, Saudi Arabia. During a three year period from January 1990 to December 1992, a total of 249 treatment cycles were started in patients with long-standing infertility. There were 107 ovulation induction cycles carried out in patients with chronic anovulation and patent tubes and normal spermogram using rigorous ovulation induction therapy with intensive ultrasound monitoring. In 34 treatment cycles in patients with long-standing infertility and patent tubes, controlled superovolution (CSO) plus intrauterine insemination was carried out. In 30 treatment cycles, CSO plus sperm intrafallopian transfers (SIFT) were done. In the in vitro fertilization (IVF) and embryo transfer (ET) group, 73 oocyte pickups were carried out. Five gamete intrafallopian transfer (GIFT) procedures were done. A total of 54 pregnancies resulted from these treatments, giving an overall pregnancy rate of 21.6%. The highest pregnancy rate of 32.35% is seen in the CSO and intrauterine insemination (IUI) in the GIFT. The pregnancy rate in the IVF/ET group was 22.2%/oocyte pickup and 30.8%/embryo transfer.

Tropist3: a cosmid vector for simplified mapping of both G+C-rich and A+T-rich genomic DNA

We have constructed a cosmid vector, Tropist3, based on the lambda origin double-cos-site vector Lawrist4, which is designed for efficient cloning and mapping of genomic DNA. Tropist3 contains two cloning sites in addition to the HindIII and BamHI sites present in Lawrist4; a SalI site allows cloning of Sau3AI partial digests following partial filling-in of the ends, and a PmlI site is suitable for blunt-end cloning. Both these strategies reduce the chance of co-cloning two inserts. Tropist3 also contains NotI, PacI, SacII and KpnI sites flanking the cloning region; these allow most inserts to be excised cleanly and mapped by partial digestion followed by hybridization with short vector sequences which lie adjacent to the cloning sites. This will also be useful for recloning inserts into different vectors, or for cosmid sequencing projects.

Antigen-coated latex particles as a model system for probing monocyte responses in leprosy

To study responses to Mycobacterium leprae antigens, we developed an in vitro model system in which latex particles coated with M. leprae sonic extract (MLSON) antigen were presented to monocytes. Uptake and oxidative response as measured by superoxide production to these antigens were investigated. Phagocytosis of MLSON-coated particles was greater than that of control particles in monocytes from both leprosy patients and controls from leprosy-endemic areas; uptake of MLSON-coated particles was higher in monocytes from lepromatous leprosy patients than in cells from tuberculoid leprosy patients and controls. In both patients and controls, uptake of latex particles coated with leprosy antigens triggered very little reduction of nitroblue tetrazolium although the cells were capable of mounting a respiratory burst. Antigen-coated latex particles can therefore be used as a tool to investigate monocyte responses to M. leprae and individual recombinant antigens.

Use of polymerase chain reaction to assess efficacy of leprosy chemotherapy

The assessment of chemotherapy efficacy in leprosy is difficult, since the only reliable method for determining whether the causative organism, Mycobacterium leprae, is viable depends on its growth in mouse foot pads. In an attempt to replace this expensive, time-consuming test, methods based on the polymerase chain reaction (PCR) have been developed. These methods depend on detection of DNA, which is more susceptible to degradation on cell death than are other cell components, so should be a more accurate indicator of viability. We have used a specific PCR assay to detect M leprae DNA in skin biopsy samples from leprosy patients. By use of limiting dilution PCR (LD-PCR), the concentration of M leprae DNA in the original sample could be measured. The DNA concentration was more closely correlated with the morphological index (derived from a staining technique that distinguishes morphologically intact and damaged bacteria) than with the number of bacteria visible (bacterial index, BI, which counts both alive and dead bacteria). In a longitudinal study of multibacillary patients on multi-drug therapy, skin biopsy samples were collected before treatment and 3, 6, 12, and 24 months after the start of therapy. While the BI showed little or no change during treatment, the number of genomes detected by PCR fell sharply, in parallel with the MI. We propose that PCR can be used as a rapid measure of M leprae viability and that this approach can be used for monitoring individual leprosy patients and for assessment of existing and new regimens. The method may be applicable to other infectious diseases in which culture of the causative organism is slow or impossible.

Detection of high titres of Toxoplasma gondii antibodies in sera of patients with leprosy in Pakistan

Untreated and treated leprosy patients and their household contacts were screened for antibody to Toxoplasma gondii using antigen-coated latex particles. A significantly high level of seroprevalence (29.6%) was observed in the untreated leprosy patients compared to endemic controls (P < 0.01) with a mean reciprocal antibody titre of 20,007 +/- 3580 (n = 98) in seropositive patients. In treated patients seroprevalence dropped to 13.5%. Seroprevalence in a group of household contacts of leprosy patients was similar to that of control subjects from an endemic area but not exposed to leprosy (7.8% and 6.1% respectively), indicating that the increased seroprevalence in leprosy patients was not merely due to increased exposure related to socioeconomic factors. Antigenic cross-reactivity between T. gondii and Mycobacterium leprae antigens was ruled out by cross inhibition experiments carried out with soluble antigens from each of the organisms. We believe these antibodies may be induced by an increase in T. gondii load in leprosy due to a transient reactivation of latent T. gondii infections, as the antibodies in these leprosy patients were not associated with any sign of eye or lymphatic pathology related to toxoplasmosis.

Quantitation of IgM antibodies to the M. leprae synthetic disaccharide can predict early bacterial multiplication in leprosy

Quantitative enzyme-linked immunosorbent assays detecting IgM to the soluble Mycobacterium leprae crude sonicate (CD75) and the synthetic disaccharide antigen coupled to bovine serum albumin (ND-BSA) were assessed for their ability to determine early infection in families/household contacts of leprosy patients and employees of a leprosy center working in close contact with leprosy patients. Although IgM to both antigens (CD75 and ND-BSA) correlated with the bacterial index (BI) assessed histologically on skin-biopsy samples, the level of IgM antibodies to ND-BSA was a much more sensitive indicator of low bacterial loads. A 4.4-fold difference in antibody levels was observed between the mean group levels of endemic controls (N = 116) and tuberculoid leprosy patients with a BI of 0 (N = 88), increasing to sevenfold in tuberculoid leprosy patients with a BI of 1 (N = 20). Using a statistical cut off with endemic controls (mean + 2 S.D.), household/family contacts showed 30% seropositivity (N = 180) as compared to staff contacts who showed 17% seropositivity (N = 55). Percent seropositivity in family contacts was not related to the type of leprosy of the index case (lepromatous vs. tuberculoid) or the duration of treatment of the index case. Age of the individual in the family contact group had a significant influence on seropositivity. These results support the hypothesis that, in this community, factors other than the viable bacterial load of the index case, such as genetic susceptibility, may be influencing the high rate of seropositivity in family contacts. IgM ND-BSA antibodies seem to provide a good indicator of low antigenic loads and could prove to be useful in detecting subclinical infection before the onset of disease. Follow-up studies of these seropositive individuals are in progress to understand the relationship between seropositivity and the progress of clinical disease.

Study of skin lesions in 221 patients of meningococcal disease

During a meningococcal outbreak, 221 patients were studied. A skin rash was present in 78 (35.3%) patients. Twenty one (11.3%) patients had a frankly purpuric rash, involving mainly the extremities and the remaining had a generalised macular or petechial lesions. Extensive purpuric lesions, involving mainly the extremities were associated with disseminated intravascular coagulation (DIC), shock and a fatal outcome. This peripherally distributed rash may be used as a clinical substitute for the laboratory tests that confirm DIC.