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Biomedical subjects

David C Miller

Publications and source records attributed to David C Miller.

46 records · Page 3Linked to original sources
PubMed2003

Temporary perineal urethrostomy for external sphincter dilation in a male patient with high risk myelomeningocele.

PURPOSE: We describe our use of perineal urethrostomy to facilitate serial external sphincter dilations in a male child with high risk myelomeningocele. MATERIALS AND METHODS: A 5-month-old boy with lumbar myelomeningocele presented with poor bladder compliance, increased detrusor leak point pressure and high grade vesicoureteral reflux. Urodynamic parameters failed to improve with clean intermittent catheterization and anticholinergic therapy. Given the persistent risk to the upper urinary tract, perineal urethrostomy was performed to facilitate external sphincter dilation in a serial fashion. RESULTS: The patient underwent 2 aggressive external sphincter dilations (30Fr) under direct vision. The second dilation was performed in the outpatient clinic without anesthesia. Subsequent cystometrographic evaluation revealed dramatic improvement in bladder storage properties with improved compliance and a safe detrusor leak point pressure. Moreover, followup imaging demonstrated complete resolution of vesicoureteral reflux. CONCLUSIONS: Creation and maintenance of perineal urethrostomy is a valuable innovation in the treatment of some boys with high risk myelomeningocele. This easily reversible diversion allows aggressive, sequential external sphincter dilation and produces substantial improvements in bladder storage properties.

Dilatation↗
PubMed2003

Evaluating the Accreditation Council on Graduate Medical Education core clinical competencies: techniques and feasibility in a urology training program.

PURPOSE: We describe several traditional and novel techniques for teaching and evaluating the Accreditation Council on Graduate Medical Education (ACGME) core clinical competencies in a urology residency training program. MATERIALS AND METHODS: The evolution and underpinnings of the ACGME Outcome Project were reviewed. Several publications related to the evaluation of clinical competencies as well as current assessment techniques at our institution were also analyzed. RESULTS: Several tools for the assessment of clinical competencies have been developed and refined in response to the ACGME Outcome project. Standardized patient encounters and expanded patient satisfaction surveys may prove useful with regard to assessing resident professionalism, patient care and communication skills. A feasible and possibly undervalued technique for evaluating a number of core competencies is the implementation of formal written appraisals of the nature and quality of resident performance at departmental conferences. The assessment of competency in practice based learning and systems based practice may be achieved through innovative exercises, such as practice guideline development, that assess the evidence for various urologic interventions as well as the financial and administrative aspects of such care. CONCLUSIONS: We describe several contemporary methods for teaching and evaluating the core clinical competencies in a urology training program. While the techniques described are neither comprehensive nor feasible for every program, they nevertheless provide an important starting point for a meaningful exchange of ideas in the urological graduate medical education community.

Accreditation↗
PubMed2003

Mutational analysis of the carboxy-terminal (YGX)4 repeat domain of CpsD, an autophosphorylating tyrosine kinase required for capsule biosynthesis in Streptococcus pneumoniae.

In Streptococcus pneumoniae, CpsB, CpsC, and CpsD are essential for encapsulation, and mutants containing deletions of cpsB, cpsC, or cpsD exhibit rough colony morphologies. CpsD is an autophosphorylating protein-tyrosine kinase, CpsC is required for CpsD tyrosine phosphorylation, and CpsB is a phosphotyrosine-protein phosphatase. We have previously shown that autophosphorylation of CpsD at tyrosine attenuates its activity and consequently reduces the level of encapsulation and negatively regulates CPS production. In this study, we further investigated the role of the carboxy-terminal (YGX)(4) repeat domain of CpsD in encapsulation. A CpsD truncation mutant in which the entire (YGX)(4) repeat domain was removed was indistinguishable from a strain in which the entire cpsD gene had been deleted, indicating that the carboxy-terminal (YGX)(4) tail is required for CpsD activity in capsular polysaccharide production. Double mutants having a single tyrosine residue at position 2, 3, or 4 in the (YGX)(4) repeat domain and lacking CpsB exhibited a rough colony morphology, indicating that in the absence of an active protein-tyrosine phosphatase, phosphorylation of just one of the tyrosine residues in the (YGX)(4) repeat was sufficient to inactivate CpsD. When various mutants in which CpsD had either one or combinations of two or three tyrosine residues in the (YGX)(4) repeat domain were examined, only those with three tyrosine residues in the (YGX)(4) repeat domain were indistinguishable from the wild-type strain. The mutants with either one or two tyrosine residues exhibited mucoid colony morphologies. Further analysis of the mucoid strains indicated that the mucoid phenotype was not due to overproduction of capsular polysaccharide, as these strains actually produced less capsular polysaccharide than the wild-type strain. Thus, the tyrosine residues in the (YGX)(4) repeat domain are essential for normal functioning of CpsD.

Amino Acid Sequence↗
PubMed2002

Successful angioembolization of renal artery pseudoaneurysms after blunt abdominal trauma.

We report a case of minimally invasive management of renal artery pseudoaneurysms after blunt abdominal trauma. A 44-year-old man developed gross hematuria after a motor vehicle collision. The initial radiographic evaluation revealed only a parenchymal laceration of the right kidney, and the patient was treated conservatively. Persistent gross hematuria necessitated repeat renal angiography that revealed numerous small pseudoaneurysms. Angioembolization was successfully performed with minimal compromise of the renal parenchyma. Transcatheter embolization is safe and effective for controlling hemorrhage from traumatic renal artery pseudoaneurysms and should be the initial treatment of choice in hemodynamically stable patients.

Abdominal Injuries↗
PubMed2002

Processed total motile sperm count correlates with pregnancy outcome after intrauterine insemination.

OBJECTIVES: To determine the impact of processed total motile sperm (PTMS) count on pregnancy after partner intrauterine insemination (IUI). IUI is generally attempted before proceeding to more expensive and invasive assisted-reproductive techniques such as intracytoplasmic sperm injection. Several semen parameters have been shown to correlate with IUI outcome and may be useful when counseling couples. METHODS: Four hundred thirty-eight couples with diverse causes of infertility underwent 1114 cycles of husband IUI during a 39-month period. The clinical and semen parameters were recorded for each couple and each insemination. The parameters were compared between those couples who achieved a pregnancy and those who did not. RESULTS: The total number of pregnancies was 120, resulting in a pregnancy rate per cycle of 10.8% and a couple pregnancy rate of 27.4%. On multivariable logistic regression analysis, the PTMS count was independently associated with fertility after IUI (P = 0.0014). Moreover, the pregnancy rate was significantly lower for couples with less than 10 million PTMS (P <0.05). CONCLUSIONS: The results of this study have demonstrated that the PTMS count independently predicts success with IUI. Cycles with less than 10 million total motile sperm are significantly less likely to result in a pregnancy. If cause-specific therapy has failed, alternatives to IUI should be considered for couples when the PTMS count is less than 10 million.

Adult↗
PubMed2002

The utility of lockout valve reservoirs in preventing autoinflation in penile prostheses.

INTRODUCTION: Autoinflation is a troublesome complication following penile prosthesis placement that may be potentiated by prevesical scarring following radical prostatectomy. We evaluated the frequency of autoinflation and other complications following penile prosthesis placement in radical prostatectomy patients and controls as a surrogate to establishing the utility of lockout reservoirs in preventing autoinflation. METHODS: 139 prostheses (including 14 with lockout reservoirs) were placed in 132 men (including 35 post-prostatectomy patients) over a 5(1/2) year period at our institution. Outcomes assessed include postoperative complications and the need for revision or replacement of the prosthesis. Multivariable regression analysis was used to determine the association of patient, device-specific, and perioperative characteristics with these outcomes. RESULTS: There was no difference in the postoperative complication and re-operation rates between post-prostatectomy patients and controls (both p > 0.77). The incidence of autoinflation in post-prostatectomy patients and controls was 3% and 5%, respectively (p > 0.99). Patients with prior prostheses were 3 times as likely to develop a postoperative complication or require prosthesis revision (p = 0.02). CONCLUSION: Penile prostheses are well tolerated in post-prostatectomy patients with comparable outcomes to those men with organic erectile dysfunction. The frequency of autoinflation does not appear to be increased in post-prostatectomy patients. Initial results with the lockout valve reservoir in preventing autoinflation are encouraging though additional study is warranted to justify their routine use.

Aged↗
PubMed2002

Streptococcus pneumoniae capsule biosynthesis protein CpsB is a novel manganese-dependent phosphotyrosine-protein phosphatase.

The first four genes of the capsule locus (cps) of Streptococcus pneumoniae (cpsA to cpsD) are common to most serotypes. We have previously determined that CpsD is an autophosphorylating protein-tyrosine kinase, demonstrated that CpsC is required for CpsD tyrosine-phosphorylation, and shown that CpsB is required for dephosphorylation of CpsD. In the present study we show that CpsB is a novel manganese-dependent phosphotyrosine-protein phosphatase that belongs to the PHP (polymerase and histidinol phosphatase) family of phosphoesterases. We also show that an S. pneumoniae strain with point mutations in cpsB, affecting one of the conserved motifs of CpsB, is unencapsulated and appears to be morphologically identical to a strain in which the cpsB gene had been deleted.

Amino Acid Sequence↗
PubMed1999

Molecular and genetic characterization of the capsule biosynthesis locus of Streptococcus pneumoniae type 23F.

The authors have previously reported the nucleotide sequence of the 5' and 3' portions of the Streptococcus pneumoniae type 23F capsular polysaccharide biosynthesis locus (cps23f) (from dexB to cps23fB and from cps23fL to aliA). These regions of cps23f were very similar to the sequence reported for cps19f, the capsule locus of S. pneumoniae type 19F. However, Southern hybridization analysis indicated that no other genes closely related to cps19f are present in the cps23f locus. In this study long-range PCR was used to amplify and clone the section of the S. pneumoniae type 23F capsule locus between cps23fB and cps23fL. This region is 13 kb in size and contains 12 new ORFs, designated cps23fC-E, I, J, and T-Z. Functions are proposed for all of the protein products, including functional homologues of Cps19fC-E, Cps19fI and Cps19fJ. A biosynthetic pathway for type 23F capsular polysaccharide is also proposed.

Amino Acid Sequence↗
PubMedDate not supplied

The effects of stage divergence on survival after radical cystectomy for urothelial cancer.

INTRODUCTION: Discrepancies between clinical and pathologic staging, herein referred to as stage divergence, are common after radical cystectomy. The implications of stage divergence on survival are ill defined in the context of those treated by surgery alone and would facilitate patient counseling and enhance prognostication. METHODS: There were 78 consecutive radical cystectomy patients with clinical stage T2 or less urothelial carcinoma who comprised our study population. Kaplan-Meier plots were constructed to determine the effects of stage divergence on survival and the log-rank test employed to assess the significance. Regression models were developed to determine predictors of overall and cancer-specific survival. RESULTS: Stage divergence was common after radical cystectomy with downstaging and upstaging occurring in 27% and 49% of patients, respectively. Downstaged patients had better overall (P = 0.003) and bladder cancer-specific (P = 0.0004) survivals. None of the downstaged patient died from bladder cancer (median follow-up 35.9 months). Upstaged patients were five times as likely to succumb from bladder cancer or other illness compared to downstaged patients. This effect was not isolated to patients with lower clinical stages but also demonstrated in patients with clinical stage T2 bladder cancer. CONCLUSIONS: Stage divergence is common after radical cystectomy occurring in 76% of patients in this study. The implications of stage divergence are equally relevant for those who are upstaged or downstaged in terms of survival, and such data is useful when counseling patients postoperatively. Downstaging at the time of radical cystectomy is associated with better overall and cancer-specific survival.

Aged↗