Accelerating Patterned Vascularization Using Granular Hydrogel Scaffolds and Surgical Micropuncture

Bulk hydrogel scaffolds are common in reconstructive surgery. They allow for the staged repair of soft tissue loss by providing a base for revascularization. Unfortunately, they are limited by both slow and random vascularization, which may manifest as treatment failure or suboptimal repair. Rapidly inducing patterned vascularization within biomaterials has profound translational implications for current clinical treatment paradigms and the scaleup of regenerative engineering platforms. To address this long-standing challenge, a novel microsurgical approach and granular hydrogel scaffold (GHS) technology are co-developed to hasten and pattern microvascular network formation. In surgical micropuncture (MP), targeted recipient blood vessels are perforated using a microneedle to accelerate cell extravasation and angiogenic outgrowth. By combining MP with an adjacent GHS with precisely tailored void space architecture, microvascular pattern formation as assessed by density, diameter, length, and intercapillary distance is rapidly guided. This work opens new translational opportunities for microvascular engineering, advancing reconstructive surgery, and regenerative medicine.

Gelatin Methacryloyl Granular Hydrogel Scaffolds: High-throughput Microgel Fabrication, Lyophilization, Chemical Assembly, and 3D Bioprinting

The emergence of granular hydrogel scaffolds (GHS), fabricated via assembling hydrogel microparticles (HMPs), has enabled microporous scaffold formation in situ. Unlike conventional bulk hydrogels, interconnected microscale pores in GHS facilitate degradation-independent cell infiltration as well as oxygen, nutrient, and cellular byproduct transfer. Methacryloyl-modified gelatin (GelMA), a (photo)chemically crosslinkable, protein-based biopolymer containing cell adhesive and biodegradable moieties, has widely been used as a cell-responsive/instructive biomaterial. Converting bulk GelMA to GHS may open a plethora of opportunities for tissue engineering and regeneration. In this article, we demonstrate the procedures of high-throughput GelMA microgel fabrication, conversion to resuspendable dry microgels (micro-aerogels), GHS formation via the chemical assembly of microgels, and granular bioink fabrication for extrusion bioprinting. We show how a sequential physicochemical treatment via cooling and photocrosslinking enables the formation of mechanically robust GHS. When light is inaccessible (e.g., during deep tissue injection), individually crosslinked GelMA HMPs may be bioorthogonally assembled via enzymatic crosslinking using transglutaminases. Finally, three-dimensional (3D) bioprinting of microporous GHS at low HMP packing density is demonstrated via the interfacial self-assembly of heterogeneously charged nanoparticles.

Detection of mutations in mtrR gene in quinolone resistant strains of N. gonorrhoeae isolated from India

BACKGROUND AND OBJECTIVES

Emergence of multi-drug resistant Neisseria gonorrhoeae resulting from new genetic mutation is a serious threat in controlling gonorrhea. This study was undertaken to identify and characterise mutations in the mtrR genes in N.gonorrhoeae isolates resistant to six different antibiotics in the quinolone group.

MATERIALS AND METHODS

The Minimum inhibitory concentrations (MIC) of five quinolones for 64 N.gonorrhoeae isolates isolated during Jan 2007-Jun 2009 were determined by E-test method. Mutations in MtrR loci were examined by deoxyribonucleic acid (DNA) sequencing.

RESULTS

The proportion of N.gonorrhoeae strains resistant to anti-microbials was 98.4% for norfloxacin and ofloxacin, 96.8% for enoxacin and ciprofloxacin, 95.3% for lomefloxacin. Thirty-one (48.4%) strains showed mutation (single/multiple) in mtrR gene. Ten different mutations were observed and Gly-45 → Asp, Tyr-105 → His being the most common observed mutation.

CONCLUSION

This is the first report from India on quinolone resistance mutations in MtrRCDE efflux system in N.gonorrhoeae. In conclusion, the high level of resistance to quinolone and single or multiple mutations in mtrR gene could limit the drug choices for gonorrhoea.

Surveillance of antibiotic resistance in Neisseria gonorrhoeae in the WHO Western Pacific and South East Asian regions, 2007-2008

Long-term surveillance of antimicrobial resistance in Neisseria gonorrhoeae has been conducted in the World Health Organization (WHO) Western Pacific Region (WPR) to optimise antibiotic treatment of gonococcal disease since 1992. In 2007 and 2008, this Gonococcal Antimicrobial Surveillance Programme (GASP) was enhanced by the inclusion of data from the South East Asian Region (SEAR) and recruitment of additional centres within the WPR. Approximately 17,450 N. gonorrhoeae were examined for their susceptibility to one or more antibiotics used for the treatment of gonorrhoea by external quality controlled methods in 24 reporting centres in 20 countries and/or jurisdictions. A high proportion of penicillin and/or quinolone resistance was again detected amongst isolates tested in North Asia and the WHO SEAR, but much lower rates of penicillin resistance and little quinolone resistance was present in most of the Pacific Island countries. The proportion of gonococci reported as 'resistant', 'less susceptible' or 'non-susceptible' gonococci to the third-generation cephalosporin antibiotic ceftriaxone lay in a wide range, but no major changes were evident in cephalosporin minimal inhibitory concentration (MIC) patterns in 2007-2008. Altered cephalosporin susceptibility was associated with treatment failures following therapy with oral third-generation cephalosporins. There is a need for revision and clarification of some of the in vitro criteria that are currently used to categorise the clinical importance of gonococci with different ceftriaxone and oral cephalosporin MIC levels. The number of instances of spectinomycin resistance remained low. A high proportion of strains tested continued to exhibit a form of plasmid mediated high level resistance to tetracyclines. The continuing emergence and spread of antibiotic resistant gonococci in and from the WHO WPR and SEAR supports the need for gonococcal antimicrobial resistance surveillance programs such as GASP to be maintained and potentially expanded.

Prevalence of HIV infection in pregnant women in remote rural areas of Maharastra State, India

In a study of 304 pregnant women, the prevalence of HIV infection in remote rural areas of western India was 0.7% (confidence interval 0.08-2.3%). It is nearly 2(1/2) times higher than the presumed prevalence for this part of the country.

Phase I safety & preliminary acceptability of nonoxynol-9 vaginal pessary as a vaginal microbicide in low risk women in Pune, India

BACKGROUND & OBJECTIVES

Though nonoxynol-9 (N-9) is available in India as a spermicidal pessary, data on its safety as a potential microbicide among Indian women are not available. Nonoxynol-9 containing compounds have shown anti-HIV activity in in vitro studies and protection against cervical infections. Nonoxynol-9 is being extensively evaluated as a vaginal microbicide world-wide. We assessed the safety and preliminary acceptability of nonoxynol-9 pessary as a vaginal microbicide in women at low risk for human immunodeficiency virus (HIV) infection and sexually transmitted diseases (STDs).

METHODS

Twenty three HIV seronegative women enrolled in the study were given Today pessarys containing 5 per cent of nonoxynol-9 for vaginal use at bedtime for 14 days. Colposcopy was done at enrollment and on day 14 and speculum examination on day 7 to assess the local toxicity.

RESULTS

Most of the women (16/23, 69.6%) did not experience any symptoms of genital irritation. The remaining 7 (30.4%, 95% CI 11.6-49.2) women reported 11 episodes of mild irritative symptoms of short duration. On clinical examination, three adverse events were reported of which one could have been product related. Eight (34.8%) women showed willingness to use the product for protection against HIV transmission if it was approved.

INTERPRETATION & CONCLUSION

Nonoxynol-9 vaginal pessary was found to be safe and acceptable in once daily dose in low risk women after consecutive use for 14 days. Willingness for future use, if found safe and effective for HIV prevention was shown by 8 (34.8%) women.

Prevalence and incidence of hepatitis B virus infection in STD clinic attendees in Pune, India

OBJECTIVES

To estimate the prevalence and incidence of hepatitis B virus (HBV) infection among patients attending three STD clinics in Pune, India, and to identify associated risk factors.

METHODS

Of the 2098 patients screened at STD clinics in Pune during 1996, 497, who returned for at least one follow up visit, were screened for various markers of HBV infection (HBsAg, anti-HBs, anti-HBc), HIV antibody, and VDRL.

RESULTS

Of the 497 participants 3.6%, 26.5%, and 43.2% were positive for HBsAg, anti-HBs, and anti-HBc respectively. Tattooing (AOR 1.64, 95% CI 1.03 to 2.64) was found to be independently associated with presence of core antibody. Additionally, history of being in commercial sex work and history of a genital ulcer were independently associated with a positive anti-HBc antibody test (AOR 12.45, 95% CI 5.58 to 27.82 and AOR 1.70, 95% CI 1.09 to 2.66, respectively). 72 out of 497 (14.5%) participants were HIV positive at baseline. HIV-1 antibody positive patients were more likely to have a positive anti-HBc test (69.4% v 39.0%, p<0.001). 30 out of 282 participants, negative for anti-HBc antibody at enrolment, seroconverted subsequently, resulting in an incidence of 10.86 per 100 person years (95% CI 7.2%, 14.5%) (mean and accumulated follow up of 11.7 months and 276.17 person years, respectively).

CONCLUSIONS

A high prevalence and incidence of HBV infection, seen in STD clinic attendees underscore the need to provide HBV vaccine to commercial sex workers and their clients in India.

Cervical intraepithelial changes & HIV infection in women attending sexually transmitted disease clinics in Pune, India

BACKGROUND & OBJECTIVES

Cervical cancer is the most important cause of malignancy associated deaths among women in India. Western studies have reported higher risk of abnormal Pap smears in HIV infected women. A large burden of HIV infection and increasing HIV epidemic in India threatens to exacerbate incidence of cervical cancer. The objective of this study was to assess the frequency of Pap smear abnormalities and its association with HIV infection in women attending sexually transmitted disease (STD) clinics and to identify associated risk factors.

METHODS

Between June 1996 and September 1999, women attending two STD clinics in Pune were screened for HIV infection, offered STD laboratory diagnosis and treatment and their Pap smears were evaluated.

RESULTS

Squamous cell abnormality was detected in 10 per cent of HIV sero negative women attending STD clinics. This proportion was nearly double (19.2%) (Odds ratio = 2.14, 95% C.I. 1.03-4.48, P = 0.04) in HIV seropositive women. Having more than one life time partners and presence of STDs were also significantly associated with Pap smear abnormality in univariate analysis. In multivariate analysis, women presenting with STD and HIV infection both, were 2.8 times more likely to have inflammatory Pap smear and 3.5 times more likely to have abnormal Pap smear compared to HIV seronegative women presenting without STDs.

INTERPRETATION & CONCLUSION

Pap smear abnormalities were common in women attending STD clinics in Pune. Presence of HIV infection further increased the risk two-folds. Therefore, women suffering from STDs should undergo periodic Pap smear screening for early detection of cervical abnormalities and should receive appropriate management to reduce morbidity and mortality.

The etiology of genital ulcer disease by multiplex polymerase chain reaction and relationship to HIV infection among patients attending sexually transmitted disease clinics in Pune, India

OBJECTIVES

To determine the etiology of genital ulcer disease (GUD) among patients attending sexually transmitted disease (STD) clinics in Pune, India, and to examine the relationship to HIV infection and compare the clinical diagnosis of GUD with the results of a multiplex polymerase chain reaction (M-PCR) assay for Treponema pallidum, herpes simplex virus (HSV), and Hemophilus ducreyi infection.

METHODS

Between June 20, 1994, and September 26, 1994, 302 patients with a genital ulcer were evaluated. Clinical etiology of GUD was based on physical appearance and microbiologic evaluations which included darkfield microscopy and serology for syphilis. Swabs of each genital ulcer were tested for HSV antigen by enzyme immunoassay (Herpchek; Dupont, Wilmington, DE) and processed in a multiplex PCR assay (M-PCR; Roche, Branchburg, NJ) for simultaneous detection of HSV, Treponema pallidum, and Hemophilus ducreyi.

RESULTS

Two hundred seventy-seven men and 25 women with a median age of 25 were evaluated. The seroprevalence of HIV was 22.2%. The etiology of GUD as determined by M-PCR was HSV (26%), H. ducreyi (23%), T. pallidum (10%), and multiple infections (7%); no etiology was identified in 34%. HIV seroprevalence was higher among those patients positive for HSV compared with other etiologies (OR = 2.1, CI: 1.2-3.7; p = 0.01). When compared with M-PCR, the Herpchek test was 68.5% sensitive and 99.5% specific. Darkfield detection for T. pallidum was 39% sensitive and 82% specific, in contrast to rapid plasma reagin and fluorescent treponemal antibody absorption test, which was 66% sensitive and 90% specific. Clinical diagnosis alone or in combination with basic laboratory tests showed poor agreement with M-PCR.