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Biomedical subjects

A G Lewis

Publications and source records attributed to A G Lewis.

At least 37 records · Page 2Linked to original sources
PubMed1995

Epididymitis in older boys: dysfunctional voiding as an etiology.

Although male infants and young boys with epididymitis have a high incidence of anatomical pathology, dysfunctional voiding is not a well established cause of epididymitis. In our series 36 boys with epididymitis underwent noninvasive urodynamic studies to determine whether a physiological defect could be assigned as an etiology. The 2 mechanisms proposed are similar to that in children with vesicoureteral reflux associated with dyssynergia or bladder instability and to a cause of recurrent urinary tract infection in children (the infrequent voider syndrome). Urinalysis and urine culture are recommended in all children with epididymitis and urethral swabs are obtained from those who are sexually active. We recommend renal/bladder ultrasound and voiding cystourethrography in all infants and young children with epididymitis. In the older child we advocate detailed questioning regarding voiding symptoms and the performance of noninvasive urodynamic studies.

Adolescent↗
PubMed1994

A rabbit model of free bladder mucosal grafting in a damaged urethral bed.

Proximal and distal penile-urethral stomas were created in the rabbit and 1 to 3 months later a free bladder mucosal graft was placed in the damaged urethral bed. The graft adhered to a rapidly proliferating submucosa with active regeneration by post-transplantation day 5. All grafts were adherent and viable by days 10 to 14, during which time sham operated animals that had been stented only showed a degree of epithelial regeneration that was of variable quality and without submucosal proliferation. The graft may stimulate the subepithelial layer, and the most viable bladder mucosa may be associated with the most actively proliferating subepithelial layer, which is also the area of greatest neovascularity. Further studies may explain the apparent paradox of how a free bladder mucosal graft survives in a poorly vascularized, scarred urethral bed.

Animals↗
PubMed1994

Vaginal reconstruction: critical technical principles.

Childhood vaginal anomalies are frequently encountered, often in association with significant anorectal or urinary tract abnormalities. As a result, reconstruction poses a number of technical challenges. We maintain that the best results are achieved by single stage perineal reconstruction. The primary goal of achieving a functional and cosmetically adequate vagina must not be at the expense of the optimal repair of associated urinary and anorectal abnormalities. In addition, since these repairs are performed early in childhood, vaginal growth is an issue that further limits the choice of reconstructive technique. We present a series of successful vaginal reconstructions in complex cases and an outline of the principles of surgical care.

Abnormalities, Multiple↗
PubMed1994

Surgical implications of genitourinary tract anomalies in patients with imperforate anus.

Genitourinary anomalies in patients with imperforate anus are a frequent source of significant morbidity. We report a retrospective study of 64 genitourinary procedures performed on 23 patients. Renal, collecting system, bladder and perineal anomalies were encountered in 65%, 83%, 87% and 65% of these complex cases, respectively. A total of 70% of the patients required intermittent catheterization due to bladder dysfunction. Surgical alternatives, complications of management and functional outcomes are reviewed in detail. Genitourinary reconstruction is best undertaken as an integral part of imperforate anus reconstruction. Failure to do so results in the loss of surgical alternatives, unnecessary reoperative procedures and compromised outcomes.

Abnormalities, Multiple↗
PubMed1994

Laparoscopic correction of vesicoureteral reflux in the pig.

Extravesical detrusorrhaphy is a modification of the Lich-Gregoir antireflux procedure that incorporates ureteral advancement into the repair. We report on our use of laparoscopic detrusorrhaphy to correct vesicoureteral reflux in an animal model. Reflux was created by transurethral incision of the roof of each ureteral orifice. In phase 1 of this study, laparoscopic repair was performed 1 week later in 3 pigs and an open technique was done in the remainder. In phase 2 laparoscopic repair was done in 3 pigs 3 weeks after inducing vesicoureteral reflux. All phase 1 repairs successfully corrected reflux but 1 ureter in the laparoscopic group developed obstruction. All phase 2 repairs were successful, which was determined by preoperative and postoperative cystography, and a postoperative excretory urogram. Average time was 2 hours 21 minutes for laparoscopic repair and 1 hour 10 minutes for the open procedure. Complications included bladder perforation and ureteral obstruction in 1 case each with no postoperative deaths. These preliminary results indicate that laparoscopic detrusorrhaphy is a feasible procedure in a porcine model.

Animals↗
PubMed1993

The modified pyramid hypospadias procedure: repair of megameatus and deep glanular groove variants.

We present our experience with the pyramid hypospadias repair in 37 patients with distal or subcoronal hypospadias. We also describe a significant modification (in the 7 most recent patients) of Duckett's original procedure that minimizes the risk of ventral fistula formation. This modification involves the creation of a vascularized second-layer tissue flap. We incorporated the modified pyramid hypospadias repair into the general surgical approach to subcoronal hypospadias. Our operative approach permits the delayed selection of either a perimeatal-based flap, preputial flap or a modified pyramid type repair after release of the shaft skin. In 35 patients the repair achieved excellent results, while only 2 had urethrocutaneous fistulas. No patient who underwent the modified repair suffered fistula formation. Our surgical technique is applicable to a number of variants of subcoronal hypospadias and maximizes repair options.

Humans↗
PubMed1991

CSF pretreatment and the diagnosis of herpes encephalitis using the polymerase chain reaction.

A number of techniques for extraction of DNA prior to polymerase chain reaction (PCR) amplification of herpes simplex virus (HSV) DNA in cerebrospinal fluid (CSF) were compared to the use of "native" CSF in the PCR reaction. The results indicate that extraction of DNA (which allows efficient removal of inhibitors of Taq polymerase) is an essential pre-requisite of the PCR detection of CSF HSV DNA.

DNA, Viral↗
PubMed1990

Diagnosis of herpes encephalitis via Southern blotting of cerebrospinal fluid DNA amplified by polymerase chain reaction.

Herpes simplex virus thymidine kinase gene specific polymerase chain reaction (PCR) amplification of DNA extracted from lumbar cerebrospinal fluid (CSF) and Southern blotting (SB) were evaluated as a method for the diagnosis of herpes simplex encephalitis (HSE). Positive PCR-SB results were obtained with CSF samples from 9 of 10 patients (11 of 12 CSF specimens) with proven herpes encephalitis as early as 2 days after onset of neurological illness. Our data support the suggestion that PCR techniques may provide a clinically relevant "non-invasive" method for the diagnosis of HSE.

Base Sequence↗
PubMed1990

Measurement of renal blood flow by 131I-labelled sodium iodohippurate imaging in a rat model of herpes encephalitis.

Renal blood flow was assessed qualitatively over a 30 min period in a rat model of herpes encephalitis by extra-renal scintigraphic imaging following the injection of 131I-labelled sodium iodohippurate. No significant differences were observed for renal blood flow in either kidney between (or within) infected and control groups. Our data suggest that kidney function is not compromised in this animal model of encephalitis. The results are discussed in the context of the development of a non-invasive protocol for the in vivo diagnosis of herpes encephalitis.

Animals↗
PubMed1989

Common forefoot deformities. How to treat, when to refer.

Initial assessment of common forefoot deformities by the primary care physician is quite feasible. A thorough history, examination of the foot with the patient standing and seated, assessment of the patient's footwear, and radiographic evaluation can often lead to gratifying relief with use of simple office measures. Even in cases that require referral to an orthopedic surgeon, interim relief of symptoms and the patient's increased awareness of the problem and its cause enhance the patient's understanding and the final outcome as well.

Arthritis↗
PubMed1989

Altered in vitro uptake of the radiolabelled antiviral imaging "probe" E-5-(2-125iodovinyl)-2'-deoxyuridine following administration of acyclovir.

Current developments in the use of radiolabelled antiviral drugs as specific "probes" for virus-infected cells in vivo may allow the specific neuroradiological diagnosis of herpes encephalitis. As "blind therapy" with the antiviral drug acyclovir may precede specific neuroradiological diagnosis, the aim of the present study was to investigate whether or not acyclovir interferes with the uptake of the radioprobe E-5-(2-125Iodovinyl)-2'-deoxyuridine (rIVDU) by virus-infected cells in vitro. Acyclovir treatment (0.1 to 10 micrograms/ml) was shown to increase initial radioprobe uptake by virus-infected cells. However, with continued incubation in the presence of acyclovir, intracellular radioactivity decreased to a level not significantly different from that associated with noninfected cells. A mechanism to explain these results is proposed. It was concluded that concurrent acyclovir therapy could interfere with neuroradiological diagnosis using rIVDU, although this may not occur with all the candidate radioprobes currently under investigation.

Acyclovir↗
PubMed1989

HM-PAO-imaging and herpes encephalitis.

Selective uptake of the cerebral blood-flow imaging agent 99mTc-hexamethylpropyleneamine oxime (HM-PAO) by Human Herpesvirus 1 (HSV-1) infected cells was investigated in vivo and in vitro. No specific uptake of HM-PAO was observed either in encephalitic rats (by brain scintigraphic imaging or by immunoperoxidase staining/autoradiography of brain sections) or in HSV-1 infected Vero cells.

Animals↗
PubMed1988

Specific neuro-radiological diagnosis of herpes encephalitis in an animal model.

The potential of utilizing a radio-labelled derivative of the antiviral drug (E)-5-(2-iodovinyl)-2'-deoxyuridine (IVDU) for the specific, non-invasive, in vivo diagnosis of Herpes simplex virus encephalitis (HSVE) was investigated in a rat model of the disease. Following pharmacological disruption of the blood brain barrier radiolabelled IVDU was administered by intra-carotid injection. Brain radioactivity was compared between control and infected animals via gamma camera scintigraphy. After clearance of non-metabolized drug, markedly higher levels of activity were found in infected brain. Post-mortem studies of cryostat sections of brain examined by autoradiography and immunochemical staining showed the radioactivity selectively accumulated in areas of virus infection. These results indicate that radio-labelled derivatives of antiviral drugs may allow the specific neuro-radiological diagnosis of HSVE.

Animals↗
PubMed1987

Altered renal function in chronically hyperprolactinaemic rats.

1. Standard renal clearance techniques were used to investigate the effects of chronic hyperprolactinaemia on kidney function in male, female and ovariectomized female rats. 2. All hyperprolactinaemic rats showed a significantly increased glomerular filtration rate (G.F.R.) compared to controls. Values were (microliter min-1) 2738 +/- 146 vs. 2299 +/- 99 for males (P less than 0.05), 2236 +/- 79 vs. 1865 +/- 74 for females (P less than 0.01) and 2200 +/- 76 vs. 1941 +/- 62 for ovariectomized females (P less than 0.05). 3. Hyperprolactinaemic rats in all groups also showed a significant increase in absolute tubular reabsorption of water, sodium and chloride compared to their respective controls. Increases here averaged 19%. 4. There was a significantly greater fractional tubular reabsorption of fluid and solutes in hyperprolactinaemic male rats compared to controls. Values were (%) 92.9 +/- 0.6 vs. 90.3 +/- 0.7 for water, 93.0 +/- 0.4 vs. 91.0 +/- 0.6 for sodium and 89.9 +/- 0.7 vs. 86.5 +/- 0.9 for chloride. In each case P less than 0.05. 5. These results imply an osmoregulatory role for prolactin which is not specific to pregnancy or related female reproductive states.

Absorption↗
PubMed1981

Partial fibulectomy for ununited fractures of the tibia.

Despite the improved rate of union reported with early weight-bearing in tibial shaft fractures, there continues to be a small number of patients with delayed union and non-union who present a dilemma to the surgeons. Partial fibular ostectomy (fibulectomy) is one means of promoting union in ununited fractures of the tibia. Fifty-one patients at our hospital underwent that treatment between December 1, 1971 and June 30, 1979, at twenty to fifty-nine weeks after the date of injury. Following the partial fibulectomy, 77 per cent of the tibial fractures healed. Failure of union after fibulectomy was associated with either failure of the patient to bear weight postoperatively, the presence of a true pseudarthrosis at the fracture site, or previous prolonged treatment of the initial fracture with external fixation. Partial fibulectomy proved to be a relatively effective and simple method for the treatment of ununited fractures of the tibial shaft.

Adult↗