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Dive into the research topics where John S. Kaptein is active.

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Featured researches published by John S. Kaptein.


Urology | 2002

Sacral neuromodulation as an effective treatment for refractory pelvic floor dysfunction

Sherif R. Aboseif; Kirk Tamaddon; Stuart A. Chalfin; Sheldon I. Freedman; John S. Kaptein

OBJECTIVES To determine the long-term efficacy and complications of sacral nerve stimulation as an alternative therapy for pelvic floor dysfunction. Pelvic floor dysfunction is a complex problem that can be refractory to current treatment modalities. Conservative therapy rarely results in a durable cure of patients, and various surgical procedures have significant side effects and less than optimal results. METHODS Sixty-four patients, 54 women and 10 men, with various forms of voiding dysfunction for whom other forms of therapy had failed underwent placement of the Medtronic Implantable Pulse Generator sacral nerve implant. The mean age was 47 years. The presenting complaint was frequency, urgency, and urge incontinence in 44 patients and chronic nonobstructive urinary retention requiring self-catheterization in 20 patients. Forty-one patients also had chronic pelvic and perineal pain associated with their voiding symptoms. The mean duration of symptoms was 69 months. All patients underwent percutaneous nerve evaluation before the permanent implant and demonstrated more than 50% improvement in their symptoms. All patients were evaluated at 1, 3, 6, 12, and 24 months, and yearly thereafter. The assessment of the voiding symptoms was done both subjectively by patient symptoms and objectively using voiding diaries recorded for 3 days. A validated verbal rating pain scale was used to evaluate pain levels. RESULTS Eighty percent of the patients had 50% or greater improvement in their presenting symptoms and quality of life after the procedure, with a mean follow-up of 24 months. Patients with frequency-urgency showed a reduction in the number of voids per day with a significant increase in voided volumes. Patients with urge incontinence showed a reduction in leaking episodes from 6.4 to 2.0/24 hr, with a decrease in the number of pads used from 3.5 to 1.2/day. Sixteen of 20 patients with urinary retention were able to void with a residual volume of less than 100 mL. Patients with chronic pelvic pain showed a decrease in the severity of pain from a score of 5.8 to 3.7. Complications were minimal and encountered in 18.7% of the patients. CONCLUSIONS Sacral nerve stimulation is an effective and durable new approach to pelvic floor dysfunction with minimal complications. Test stimulation provides a valuable tool for patient selection.


Urology | 2003

Use of fibrin glue in percutaneous nephrolithotomy.

Albert Mikhail; John S. Kaptein; Gary C. Bellman

OBJECTIVES To report our experience with the use of fibrin glue during tubeless percutaneous nephrolithotomy. We addressed the safety of this approach and evaluated its use for any clinical benefit with respect to length of hospital stay, bleeding, analgesic usage, and urinary extravasation. METHODS This was a retrospective review of 43 patients who underwent tubeless percutaneous nephrolithotomy. In 20 consecutive patients (one bilateral), percutaneous tracts were injected with 2 to 3 mL of Tissel Vapor Heated sealant at the conclusion of the procedure. The fibrin glue was instilled during simultaneous removal of the percutaneous sheath. These 20 patients were compared with a control group (23 consecutive patients) in which fibrin glue was not used. The length of hospitalization, hematocrit drop, analgesic use, stone burden, operative times, postoperative complications, and any noted computed tomography scan findings were compared. RESULTS Postoperatively, the average length of hospital stay was less in the experimental than in the control group by 0.71 day (P <0.05). Differences in hematocrit drop between the experimental (6.8%) and control (5.6%) groups were not statistically significant. The total analgesic use was less in the experimental group, but the difference was not statistically significant. No statistical difference was found between the operative times for both groups. Postoperative fevers and wound seroma were noted in the experimental group. No abscesses or any significant changes along the percutaneous tracts were seen on postoperative computed tomography scans. In the control group, no procedure-related complications were noted. CONCLUSIONS The use of fibrin glue is safe in percutaneous nephrolithotomy procedures and additional prospective randomized studies are needed to evaluate for any clinical benefit.


The Journal of Urology | 2000

EFFECT OF SILDENAFIL CITRATE ON POST-RADICAL PROSTATECTOMY ERECTILE DYSFUNCTION

Mark I. Feng; Samuel Huang; John S. Kaptein; J. O. N. Kaswick; Sherif R. Aboseif

PURPOSE We assess the effect of sildenafil in a subgroup of patients after prostatectomy with erectile dysfunction and determine whether nerve preservation improves sildenafil response in this subgroup. MATERIALS AND METHODS Between April 1998 and January 1999, 53 patients who had undergone radical retropubic prostatectomy and were prescribed oral sildenafil were surveyed using a confidential mail questionnaire. Of the patients 21 underwent bilateral and 15 unilateral neurovascular bundle sparing procedures, while in 17 a nonnerve sparing procedure was performed. All patients received 25 to 100 mg. sildenafil in a flexible dose escalation manner. Response, satisfaction and side effects were assessed using a modified, self-administered International Index of Erectile Function questionnaire. Response was defined as erection sufficient for intercourse. Preoperative and postoperative/pretreatment erectile functions were assessed for baseline comparison in each patient, and partner overall satisfaction with sildenafil was measured. Statistical data analysis was performed using analysis of variance and Newman-Keuls multiple comparison tests. RESULTS Of the 21 patients who underwent a bilateral nerve sparing procedure 15 had a positive response. Of the 15 patients who had undergone a unilateral nerve sparing procedure 12 had a positive response, and only 1 of the 17 patients who had undergone a nonnerve sparing procedure responded to sildenafil. The most commonly reported adverse events of all causes were headaches (21%), flushing (8.3%), visual disturbance (6.3%) and nasal congestion (6.3%). CONCLUSIONS Sildenafil is an equally effective treatment for erectile dysfunction after bilateral and unilateral nerve sparing procedures, and patient response to sildenafil is confirmed by the partners. However, patients who undergo nonnerve sparing procedures do not respond satisfactorily to sildenafil.


Journal of Biological Chemistry | 1996

Anti-IgM-mediated Regulation of c-myc and Its Possible Relationship to Apoptosis

John S. Kaptein; Ching-Kow E. Lin; C. Linzhi Wang; Tam Thuan Nguyen; Cosmas I. Kalunta; Eunhee Park; Fun-Shan Chen; Pramod M. Lad

Anti-IgM treatment of Burkitts lymphoma cells is followed by either growth arrest or induction of apoptosis. In this study we have explored the role of c-myc in these events. Our results in Ramos cells indicate the following. (a) The decline in c-myc mRNA occurs at about 4 h; inhibition of about 80% being observed. (b) The stability of c-myc message is involved since the half-life of c-myc mRNA is decreased from about 30 min in untreated cells to about 15 min following treatment with anti-IgM. In the presence of cycloheximide, a protein synthesis inhibitor, the half-life is increased to about 50 min and was unaltered by treatment with anti-IgM. (c) By contrast, nuclear run-on experiments indicated no change in transcription rates for c-myc message due to treatment with anti-IgM. (d) A decrease in c-myc causes apoptosis since specific repression of c-myc with antisense oligonucleotides decreases the levels of c-Myc, inhibits growth rate, decreases viability, and induces apoptosis. (e) Anti-CD40 inhibition of apoptosis occurs without alteration in anti-IgM-induced down-regulation of c-myc mRNA, suggesting that it acts distally to c-myc down-regulation. Other cell lines were also investigated. In Epstein-Barr virus (EBV)-positive cell lines (Daudi, Raji, and Namalwa), anti-IgM treatment for 24 h results in growth inhibition without induction of apoptosis. In EBV-negative cell lines (ST486 and CA46, as well as Ramos), a more heterogeneous pattern of responses to anti-IgM are observed. Ramos and ST486 cells both show growth inhibition and apoptosis upon anti-IgM treatment; CA46 cells shown only growth inhibition but not apoptosis. Anti-IgM causes a decline in c-myc mRNA levels in all of these lines, as well as in c-Myc protein level in the two lines investigated, Daudi and Ramos, regardless of apoptosis. Addition of antisense c-myc oligonucleotides to the cells reduced growth in both Daudi and Ramos cells lines, however it resulted in substantial apoptosis only in Ramos cells. These results suggest that anti-IgM destabilizes c-myc mRNA by a process that involves mRNA turnover, rather than transcription rates. However anti-IgM exerts differential effects in EBV-positive and EBV-negative cell lines. EBV-positive cells are uniformly resistant to apoptosis, while EBV-negative cell lines show a tendency to apoptosis but with exceptions. Growth inhibition can be uncoupled from apoptosis in EBV-positive cell lines, but not in those EBV-negative cell lines prone to apoptosis. Furthermore, down-regulation of c-myc message correlates with growth inhibition in these cells, but is an insufficient link to apoptosis. By contrast inhibition of apoptosis by anti-CD40 occurs even though c-myc mRNA is decreased.


The Journal of Urology | 2001

HOW WELL DOES CONTRALATERAL TESTIS HYPERTROPHY PREDICT THE ABSENCE OF THE NONPALPABLE TESTIS

Richard S. Hurwitz; John S. Kaptein

PURPOSE We assessed the accuracy of contralateral testis hypertrophy for predicting monorchia in patients with a nonpalpable testis. MATERIALS AND METHODS From May 1993 to September 1998 we evaluated 60 patients 7 months to 11 years old for a unilateral nonpalpable testis. Four patients were excluded from study who had received human chorionic gonadotropin or had signs of puberty. We correlated contralateral testis hypertrophy, defined as testis volume greater than 2 cc or testis length greater than 2 cm., with presence or absence of the nonpalpable testis. We also recorded the degree to which contralateral testis length less than 2.1 cm. correlated with the presence or absence of the nonpalpable testis. Laparoscopy and open exploration were performed in 52 and 4 cases, respectively. RESULTS Contralateral testis hypertrophy greater than 2 cm. was noted in 16 patients, including 14 (87.5%) with monorchia and 2 (12.5%) with an intra-abdominal testis. Of the 15 patients with a contralateral measurement of 1.8 to 2.0 cm. 14 had monorchia (93%) and 1 had a tiny ovotestis. Of the 25 patients with a contralateral measurement of less than 1.8 cm. 13 (52%) had testes that were intra-abdominal in 11 and canalicular in 2. The optimal cutoff value for contralateral enlargement was 1.8 cm. (p = 0.00061). The most common laparoscopic finding in patients with contralateral testis hypertrophy greater than 2 cm. was blind ending vessels proximal to the internal ring in 56%. CONCLUSIONS Contralateral testis hypertrophy is common in patients with a nonpalpable testis. Hypertrophy 1.8 cm. or greater predicts monorchia with an accuracy of about 90%. The finding of contralateral testis hypertrophy provides useful information for preoperative counseling, allowing us to inform parents that the nonpalpable testis is most likely absent. Exploration is still required. Laparoscopy is particularly advantageous in contralateral testis hypertrophy since it was the only procedure required in about half of our cases.


Biochimica et Biophysica Acta | 1995

Regulation of low-density lipoprotein receptors and assessment of their functional role in Burkitt's lymphoma cells

Cindy F. Yen; Cosmas I. Kalunta; Fun-Shan Chen; John S. Kaptein; Ching-Kow E. Lin; Pramod M. Lad

The status of low-density lipoprotein receptors (LDLR) in Daudi Burkitts lymphoma (BL) cells was examined using a flow cytometric assay employing the fluorescent ligand DiI-LDL, and a radioligand-binding assay using [125I]LDL. The binding is concentration-and time-dependent; and is specific, as judged by its competitive displacement in the presence of unlabeled LDL, and inhibition by heparin, EGTA, and 4 degrees C incubation. The regulation of the receptor and its functional role were then explored. Our results suggest the following: (a) In sharp contrast to normal peripheral blood lymphocytes, the LDLR levels in BL cells are basally elevated when cultured in fetal bovine serum (FBS) medium. (b) In accord with normal peripheral blood lymphocytes, incubation in lipoprotein-deficient serum (LPDS) medium further up-regulates the level of the receptor in BL cells, and co-incubation with LDL or 25-hydroxycholesterol down-regulates the receptor level. The magnitude of the up-regulation is significantly smaller than in normal peripheral blood lymphocytes. (c) Northern blots using a plasmid-DNA probe for LDLR mRNA point to a similar pattern for message regulation as is observed in direct binding studies. (d) Although the LDLR level is constitutively high in BL cells, availability of LDL, unlike transferrin, is not a growth requirement since incubation of cells in LPDS medium does not prevent proliferation of these cells. (e) In contrast to anti-transferrin receptor antibody which results in apoptosis upon binding, anti-LDLR antibody does not inhibit growth or induce apoptosis. Our results suggest LDLR is expressed at a significantly higher level in BL cells than in normal peripheral blood lymphocytes. Although up-regulation and down-regulation of LDLR are observed, this applies only to a small population of LDLR. The bulk receptor population is significantly resistant to down-regulation. Furthermore, notable differences in the functional role of the LDLR are found relative to the transferrin receptor which is also up-regulated in the BL cells.


Immunobiology | 1995

Synergy between Signal Transduction Pathways is Obligatory for Expression of c-FOS in B and T Cell Lines: Implication for c-FOS Control via Surface Immunoglobulin and T Cell Antigen Receptors

John S. Kaptein; C. Linzhi Yang; Ching-Kow E. Lin; Tam Thuan Nguyen; Fun-Shan Chen; Pramod M. Lad

Expression of the protooncogene c-fos is controlled by three main regulatory pathways involving kinase C, cAMP, and calcium. Kinase C mediates its effects via phosphorylation of serum response factor (SRF) which interacts with the serum response element (SRE); cAMP and calcium mediate their effects via phosphorylation of CREB (cAMP regulatory element binding protein) presumably by activation of a protein kinase A or calmodulin-regulated kinase. We have examined the function of these elements in Burkitts lymphoma cells (Ramos and Daudi) as well as a T lymphocytic cell line (Jurkat). We have found that stimulation of any one of these pathways alone has little or no effect on c-fos induction. However, kinase C activation (PMA stimulation) combined with either cAMP (forskolin plus MIX) or calcium stimulation (ionophore) leads to greatly enhanced c-fos induction. By contrast, cAMP in the presence of calcium shows no synergy in c-fos induction. Okadaic acid augments PMA- as well as calcium-mediated activation of c-fos, and has little or no effect when combined with cAMP. The main difference between Ramos (B cells) and Jurkat (T cells) in the regulation of c-fos is that cAMP plus calcium is strongly synergistic in Jurkat and is without effect in Ramos. Analysis of AP-1 activity using gel mobility shift assays confirms that the requirements for synergy in c-fos mRNA induction are paralleled by requirements for synergy in induction of AP-1 activity. Signaling in B cells due to anti-Ig stimulation involves both kinase C activation and release of intracellular calcium, and results in c-fos mRNA induction. Our results indicate that synergy between the kinase C activation and calcium is needed for efficient c-fos induction since neither of these two alone induces c-fos well. That synergy of signaling pathways is relevant for the anti-Ig induction of c-fos is supported by the fact that cAMP-inducing agents and okadaic acid further enhance anti-Ig induction of c-fos. These results suggest that cell-specific patterns of synergy are an essential feature for c-fos induction and may be relevant for c-fos control through B and T cell antigen receptors.


Journal of Endourology | 2008

IL-6 Does Not Predict Current Urolithiasis in Stone Formers

Jocelyn M. Rieder; Alan A. Nisbet; Timothy Lesser; Ethan I. Franke; John P. Brusky; Ashish R. Parekh; John S. Kaptein; Gary C. Bellman

INTRODUCTION Interleukin-6 (IL-6), an inflammatory marker, has previously been found to be elevated in the urine of patients with urolithiasis. Oxalate and other stone precursors have been shown to increase IL-6 production in proximal tubular epithelial cells in vitro. We examined whether urinary IL-6 could be used as a screening test to determine current urolithiasis in individuals who are known to form urinary stones. METHODS Thirty-five adult patients with current urolithiasis demonstrated on imaging were enrolled in the study. Exclusion criteria included disease known to elevate IL-6. Each patient provided a pre-treatment urine specimen and one month after proven to be stone-free an additional urine specimen was obtained. The urinary IL-6/creatinine ratio was determined for both specimens and compared. RESULTS Ten patients provided both specimens. The mean pre-operative urinary IL-6/creatinine ratio before the procedure was 1.63 pg/mL. The mean post procedure urinary IL-6/creatinine ratio after the patient was confirmed to be stone-free was 1.81 pg/mL. These were not significantly different (p=0.38). Preoperative urinary IL-6/creatinine ratio did not correlate to stone size (r=0.15) and no correlation was seen between time from treatment and stone free IL-6/creatinine ratio (r=0.48). CONCLUSION Urinary IL-6 is not a good screening test for current urolithiasis in stone-forming individuals. It is elevated whether the stone is present or not.


Journal of Endourology | 2008

Usefulness of urinalysis in following patients with distal ureterolithiasis.

Gerald H. Yoon; Ethan I. Franke; John S. Kaptein; Gary C. Bellman

PURPOSE The determine the usefulness of urinalysis in monitoring patients with distal ureterolithiasis. MATERIALS AND METHODS Patients with microhematuria who were found to have a distal ureteral stone and who were candidates for conservative management were enrolled in the study. Patients were typically seen in clinic at 1 to 2 weeks after initial diagnosis and reassessed. A urinalysis, including office dipstick and automated laboratory analysis using the IQ 200 IRIS analyzer, were performed. The absence or presence of microhematuria was determined and compared with results of repeated unenhanced helical CT of the abdomen and pelvis to determine the sensitivity, specificity, and positive and negative predictive values of urinalysis. RESULTS Twenty-nine patients were enrolled in this prospective study. The mean age of the patients was 43.5 years. The sex distribution was predominantly male, with 72% men and 28% women. Ultimately, 18 patients are included in our analysis with the remainder either lost to follow-up or excluded because of protocol violation. Average distal stone size was 4.1 mm (range 2.0-6.5 mm). Stones were evenly distributed between the right and the left ureters, with 50% on either side. Mean time to follow-up was 18 days with a range of 2 to 63 days. The sensitivity of urinalysis was determined to be 40% (8%-72%) while the specificity was 63% (28%-98%). The predictive value of a positive test was 57% (19%-95%) and the predictive value of a negative test was 55 % (25%-85%). The confidence interval for each of these parameters is inclusive of the value of 50%, indicating that urinalysis is no better than randomness in predicting presence or absence of a stone by CT. CONCLUSIONS The absence or presence of microhematuria does not accurately predict whether a distal ureteral stone has passed or is still present. In those patients who need or want to know whether a stone is still present, unless a stone is strained, we suggest repeated CT imaging.


Immunology Letters | 1993

Multiple forms of the G protein-related beta subunit in Daudi lymphoblastoid cells

Ching-Kow E. Lin; John S. Kaptein; David Guoqing Gu; Cosmas I. Kalunta; Pramod M. Lad

We have explored the forms of the G protein-related beta subunit which are present in Daudi lymphoblastoid cells. Northern blotting with labeled beta-1 and beta-2 probes indicates that two messages of 3.3 kb and 1.7 kb are present for both beta-1 and beta-2, implying that multiple forms of the beta subunit are present. Antibodies were raised against two peptides of the beta subunit (residues 1-23 and 127-145). Both antibodies detected subunits at 35 kDa and 31 kDa, of which the 35-kDa form predominates in the membrane fraction and the 31-kDa one in the cell cytosol. Crosslinking of the membrane fraction with the cleavable crosslinker (DTSSP) caused a simultaneous diminution in the 31-kDa form while increasing the amount of the 35-kDa form--a pattern which was reversed upon the reduction of these crosslinks with DTT. Studies of the soluble form indicate that this is truly a soluble protein since centrifugation at 200,000 x g for 2 h did not diminish the levels of the protein in the soluble fraction. Sedimentation analysis indicates that the soluble beta-homologue is found in fractions which overlap with those which contain the mu chain of immunoglobulin at a position clearly distinct from the expected positions of free mu or free beta. Our results suggest that at least two forms of a subunit which is closely related to, or identical with, the beta subunit of G proteins are present in Daudi cells.

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