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Neeraj Kohli

Publications and source records attributed to Neeraj Kohli.

12 recordsLinked to original sources
PubMed2006

Arrays of lipid bilayers and liposomes on patterned polyelectrolyte templates.

This paper presents novel methods to produce arrays of lipid bilayers and liposomes on patterned polyelectrolyte multilayers. We created the arrays by exposing patterns of poly(dimethyldiallylammonium chloride) (PDAC), polyethylene glycol (m-dPEG) acid, and poly(allylamine hydrochloride) (PAH) on polyelectrolyte multilayers (PEMs) to liposomes of various compositions. The resulting interfaces were characterized by total internal reflection fluorescence microscopy (TIRFM), fluorescence recovery after pattern photobleaching (FRAPP), quartz crystal microbalance (QCM), and fluorescence microscopy. Liposomes composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dioleoyl-sn-glycero-3-phosphate (monosodium salt) (DOPA) were found to preferentially adsorb on PDAC and PAH surfaces. On the other hand, liposome adsorption on sulfonated poly(styrene) (SPS) surfaces was minimal, due to electrostatic repulsion between the negatively charged liposomes and the SPS-coated surface. Surfaces coated with m-dPEG acid were also found to resist liposome adsorption. We exploited these results to create arrays of lipid bilayers by exposing PDAC, PAH and m-dPEG patterned substrates to DOPA/DOPC vesicles of various compositions. The patterned substrates were created by stamping PDAC (or PAH) on SPS-topped multilayers, and m-dPEG acid on PDAC-topped multilayers, respectively. This technique can be used to produce functional biomimetic interfaces for potential applications in biosensors and biocatalysis, for creating arrays that could be used for high-throughput screening of compounds that interact with cell membranes, and for probing, and possibly controlling, interactions between living cells and synthetic membranes.

Adsorption↗
PubMed2006

Striae and pelvic relaxation: two disorders of connective tissue with a strong association.

Pelvic relaxation, a weakening of pelvic support structures, is an under-reported condition that affects a multitude of women. In the United States alone, more than 338,000 procedures for prolapse are performed annually. Decreased collagen content has been noted in the tissues of women affected by this condition. Interestingly, biopsy specimens of women with striae also show a diminution of collagen. Using self-reported anonymous data, we compared the prevalence of striae in women with and without pelvic relaxation to see if an association between these two disorders of connective tissue existed. More than half the women with prolapse (54.7%) (n = 41) reported striae, whereas only 25.0% of women in the non-prolapse group (n = 8) reported striae (P < 0.01). Multivariate logistic regression analysis confirmed striae as a significant risk factor for the development of clinical prolapse (odds ratio 3.12, P < 0.05). There appears to be a strong association between the presence of striae and the development of pelvic relaxation, which is unrelated to conventionally cited risk factors, such as age, weight, number of pregnancies, or postmenopausal status.

Adult↗
PubMed2006

Tethered lipid bilayers on electrolessly deposited gold for bioelectronic applications.

This paper presents the formation of a novel biomimetic interface consisting of an electrolessly deposited gold film overlaid with a tethered bilayer lipid membrane (tBLM). Self-assembly of colloidal gold particles was used to create an electrolessly deposited gold film on a glass slide. The properties of the film were characterized using field-effect scanning electron microscopy, energy dispersive spectroscopy, and atomic force microscopy. Bilayer lipid membranes were then tethered to the gold film by first depositing an inner molecular leaflet using a mixture of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[3-(2-pyridyldithio)propionate], 1,2-di-O-phytanyl-sn-glycero-3-phosphoethanolamine (DPGP), and cystamine in ethanol onto a freshly prepared electrolessly deposited gold surface. The outer leaflet was then formed by the fusion of liposomes made from DPGP or 1,2-dioleoyl-sn-glycero-3-phosphocholine on the inner leaflet. To provide functionality, two membrane biomolecules were also incorporated into the tBLMs: the ionophore valinomycin and a segment of neuropathy target esterase containing the esterase domain. Electrochemical impedance spectroscopy, UV/visible spectroscopy, and fluorescence recovery after pattern photobleaching were used to characterize the resulting biomimetic interfaces and confirm the biomolecule activity of the membrane. Microcontact printing was used to form arrays of electrolessly deposited gold patterns on glass slides. Subsequent deposition of lipids yielded arrays of tBLMs. This approach can be extended to form functional biomimetic interfaces on a wide range of inexpensive materials, including plastics. Potential applications include high-throughput screening of drugs and chemicals that interact with cell membranes and for probing, and possibly controlling, interactions between living cells and synthetic membranes. In addition, the gold electrode provides the possibility of electrochemical applications, including biocatalysis, bio-fuel cells, and biosensors.

Colloids↗
PubMed2006

Incidence of concomitant surgery for pelvic organ prolapse in patients surgically treated for stress urinary incontinence.

OBJECTIVE: To examine the concomitant incidence of surgery for pelvic organ prolapse in patients undergoing a surgical procedure to correct stress urinary incontinence in both an academic and private urogynecology practices. STUDY DESIGN: A retrospective chart review was performed on all patients undergoing surgical correction of stress urinary incontinence over a 1-year period at 2 centers. RESULTS: Among 150 surgical procedures for stress urinary incontinence in the academic practice, 116 (77%) patients underwent at least 1 additional procedure for a pelvic support defect, and 72 (48%) patients required 2 or more concomitant reconstructive pelvic procedures. In the private urogynecology practice, 182 surgical procedures for stress urinary incontinence were performed, 153 (84%) patients required at least 1 additional procedure for a pelvic support defect, and 86 (47%) patients required 2 or more concomitant reconstructive pelvic procedures. CONCLUSION: Women who require surgical correction of stress urinary incontinence have a high incidence of concomitant pelvic support defects that require surgical repair. The incidence of concomitant surgery for pelvic organ prolapse between the 2 sites was not significantly different.

Cohort Studies↗
PubMed2005

Laparoscopic uterosacral ligament uterine suspension compared with vaginal hysterectomy with vaginal vault suspension for uterovaginal prolapse.

This study compares the outcomes of laparoscopic uterosacral ligament uterine suspension (LUSUS) to those of vaginal vault suspension with total vaginal hysterectomy (TVH) for the treatment of symptomatic uterovaginal prolapse. We compared the outcomes of 25 LUSUS to those of 25 TVH with vaginal vault suspension among age-matched controls. No significant complications occurred in either group. EBL and hospitalization duration were significantly less in LUSUS patients (72 cc vs. 227 cc, P < .0001 and 1.05 vs. 1.65 days, P = .002). Vault support, as measured by postoperative pelvic organ prolapse quantitation system point D in the LUSUS group and point C in the TVH group, was better for the LUSUS group (D = -9 vs. C = -7.6, P = .002). No LUSUS group patient underwent reoperation for recurrent apical prolapse as compared to three TVH patients. LUSUS is an effective treatment for appropriately selected women with uterovaginal prolapse who desire uterine preservation.

Adult↗
PubMed2005

Retropubic hematoma after transobturator sling procedure.

BACKGROUND: The transobturator tape procedure is one of the newer minimally invasive sling procedures used for the surgical treatment of genuine stress urinary incontinence. CASES: Two cases of retropubic hematomas following transobturator tape procedure are reported. One patient was managed conservatively and did not require reoperation, and the other patient required computed tomography-guided drainage of the hematoma. In both cases the patients' hematomas resolved, and they remained continent 3-6 months after surgery. CONCLUSION: The transobturator tape procedure is a minimally invasive alternative to the tension-free vaginal tape operation for stress urinary incontinence, but it may be associated with vascular complications.

Blood Vessels↗
PubMed2004

Laparoscopic pelvic floor repair.

Articles on laparoscopic approach to pelvic floor reconstruction continue to proliferate throughout the worldwide literature. Although procedures like laparoscopic Burch seem to be fading fast, other procedures like the laparoscopic paravaginal repair and sacral colpopexy seem to be more common and visible in the literature. This article reviews the pertinent anatomy, surgical procedures, and literature concerning the laparoscopic approach to pelvic floor reconstruction.

Female↗
PubMed2004

Rectovaginal fistula repair using a porcine dermal graft.

BACKGROUND: Rectovaginal fistula repair is commonly performed through a vaginal route. In many cases, healthy tissue such as an autologous fat pad may be interposed between the suture lines and the vaginal epithelium to facilitate healing and prevent recurrence. We present a simple alternative to autologous flaps with the use of porcine dermal grafts in the repair of rectovaginal fistulae. CASES: Two patients are presented with rectovaginal fistulae. In both cases the patients were found to have insufficient native tissue to achieve an adequate traditional multilayered closure, and therefore an acellular collagen porcine dermal graft was used as an interposition graft between the rectum and the vaginal epithelium in the repair. CONCLUSION: Porcine dermal grafts may be a viable alternative to traditional autologous flaps or human dermal grafts for the repair of rectovaginal fistula.

Adult↗
PubMed2002

Laparoscopic surgery for pelvic support defects.

Reconstructive pelvic surgery for the treatment of vaginal prolapse continues to evolve as surgeons continue their quest for definitive surgical cure. Though there are three primary routes of access to reconstructive pelvic surgery (abdominal, vaginal and laparoscopic) it is the laparoscopic approach that appears to be the least utilized. This is in part due to the great degree of technical difficulty associated with laparoscopic suturing. This paper reviews the general principles and functional anatomy associated with normal vaginal support as well as the laparoscopic surgical approach to pelvic floor support defects.

Female↗
PubMedDate not supplied

Uterine preservation during surgery for uterovaginal prolapse: a review.

The traditional surgical treatment for uterovaginal prolapse has been vaginal hysterectomy. For many reasons, women may request uterine preservation at the time of prolapse surgery. The purpose of this paper is to review the medical literature pertaining to the role of uterine preservation during reconstructive surgery for uterovaginal prolapse. A MEDLINE search of literature in the English language (1966 to current) was carried out using the keywords 'hysterectomy', 'hysteropexy', 'uterine preservation', 'uterine suspension' and 'uterovaginal prolapse.' Fourteen articles primarily addressing the surgical repair of uterovaginal prolapse with uterine preservation were included in this review. Papers primarily addressing other forms of pelvic organ prolapse, incontinence or obliterative procedures were excluded. Existing procedures and their clinical outcomes were reviewed. The current literature suggests that uterine preservation during surgery for uterovaginal prolapse may be an option in appropriately selected women who desire it; prospective, randomized trials are needed to corroborate this.

Adult↗