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Biomedical subjects

S D Beck

Publications and source records attributed to S D Beck.

At least 19 recordsLinked to original sources
PubMed2001

Laparoscopic transverse hemicystectomy with ileocystoplasty in a porcine model.

BACKGROUND AND PURPOSE: The ideal replacement for bladder tissue is yet to be described, although multiple alternatives have been studied. Currently, enterocystoplasty, despite its limitations, is considered the gold standard for bladder augmentation. This study evaluated the feasibility, safety, and morbidity of laparoscopic ileocystoplasty in a large-animal model. MATERIALS AND METHODS: In eight minipigs, laparoscopy was performed using four ports. A segment of ileum was delivered through a 3-cm umbilical incision and detubularized and refashioned using standard open surgical technique. Laparoscopic hemicystectomy was then performed, followed by laparoscopic suturing of the ileal patch to the bladder. The bladder was drained with a Foley catheter, but no pelvic drain was placed. All animals were followed for for a minimum of 3 months. Preoperative and postoperative evaluation included measurement of bladder capacity, ultrasound imaging of the kidneys, blood counts, and serum electrolyte and creatinine measurements. Two of the animals were sacrificed at 3 months and one at 6 months, and the bladders were harvested. RESULTS: Eight animals underwent ileocystoplasty without intraoperative or postoperative complications. The average operating and anastomosis time was 250 minutes and 96 minutes, respectively. All animals had normal preoperative blood values that remained normal during follow-up. Bladder capacity decreased initially to 71% of the baseline volume and then increased to 83% and 117% at 3 and 6 months. One of three animals sacrificed was noted to have a right midureteral stricture. CONCLUSIONS: We developed a reliable laparoscopic technique for ileocystoplasty that may extend the advantages of laparoscopy, including better cosmesis and reduced risk of postoperative adhesions, to bladder augmentation.

Animals↗
PubMed2001

Aortic replacement during post-chemotherapy retroperitoneal lymph node dissection.

PURPOSE: We reviewed the records of 15 patients with metastatic germ cell cancer who underwent aortic resection and replacement during post-chemotherapy retroperitoneal lymph node dissection to determine the morbidity and the therapeutic benefit. MATERIALS AND METHODS: Between 1970 and 1998, 1,250 patients underwent post-chemotherapy retroperitoneal lymph node dissection. Our retrospective review revealed that 15 patients underwent aortic replacement at that operation. RESULTS: In addition to aortic replacement 11 patients underwent 15 additional procedures, including nephrectomy in 7, vena caval resection in 3, pulmonary resection in 1, small bowel resection in 2, 1 hepatic resection in 1 and L4 vertebrectomy in 1. No patient had necrosis as the only pathological condition. Three patients (20%) had teratoma and 12 (80%) had viable tumor in the retroperitoneal specimen. All 4 patients who underwent post-chemotherapy retroperitoneal lymph node dissection and aortic replacement after induction chemotherapy alone have no evidence of disease. Only 1 of the 11 patients who received salvage chemotherapy with or without previous post-chemotherapy retroperitoneal lymph node dissection have no evidence of disease. Overall 33% of the patients have no evidence of disease. There were no graft related complications. CONCLUSIONS: Aortic resection at post-chemotherapy retroperitoneal lymph node dissection is justified based on therapeutic benefit and morbidity.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Spiral ileal neobladder substitution with orthotopic ureteral reimplantation: early results.

PURPOSE: The aim of this report is to present our experience with the spiral ileal neobladder. MATERIALS AND METHODS: From September 1996 to August 1999, 39 patients (35 men and 4 women) underwent radical cystectomy and spiral ileal orthotopic substitution for muscle invasive bladder cancer. Seventy ureters in 37 patients were reimplanted orthotopically using the nonrefluxing Ghoneim technique. Evaluation of these patients included video urodynamics, intravenous pyelogram, renal ultrasound, and patient history relating to urinary incontinence. RESULTS: There were no perioperative deaths. There were 8 (20.5%) early complications. One patient developed a small bowel anastomotic leak, and another patient presented with a vesicovaginal fistula repaired transabdominally. Of the 70 ureters reimplanted in Ghoneim fashion, 5 (7.1%) developed an anastomotic stricture. Three of these patients had stable hydronephrosis and were managed by observation alone; one stricture was treated successfully transurethrally with balloon dilation; and the last patient was managed with a percutaneous nephrostomy tube and surgical reimplantation. Urodynamics in eight patients revealed a Valsalva leak point pressure >50 in two patients and >100 in the six patients. All women experienced mild daytime and nighttime urinary incontinence. Ninety percent of the men were either dry or complained of mild daytime incontinence. No patient experienced bowel dysfunction from the ileal resection. CONCLUSIONS: The spiral ileal neobladder offers the potential advantages of construction from a relatively short bowel segment, excellent length for ureteral anastomosis, acceptable continence rates, and orthotopically reimplanted ureters, which allow transurethral upper tract access. The nonrefluxing ureteral anastomosis has a high stricture rate, and we currently are reimplanting the ureters orthopically in a nontunneled fashion.

Adult↗
PubMed1999

Concealed penis in childhood: a spectrum of etiology and treatment.

PURPOSE: Concealed penis is an uncommon condition due to poor skin fixation at the base of the penis, cicatricial scarring after penile surgery and excessive obesity. The condition varies in severity and several surgical options are available, such as excision of previous scarring, degloving the penile shaft, reconstructing the penile shaft skin with flaps, fixing the penile skin at the penopubic and penoscrotal angles, and removing excess suprapubic fat. MATERIALS AND METHODS: We reviewed the records of 43 patients treated for concealed penis from 1993 to 1998. We categorized the cases as type 1-congenital concealed penis, type 2-concealed penis due to scarring from previous surgery and type 3-complex cases involving excessive obesity. Cases were reviewed in regard to surgical techniques and outcomes. We identified 18 type 1, 18 type 2 and 7 type 3 cases. Mean age of type 1 patients at surgery was 12.4 months with 1 patient presented at age 7 years. None had previously undergone penile surgery. All patients underwent complete penile degloving. To reconstruct the penile shaft flaps or Z-plasties with penile skin were used in 12 patients and scrotal skin flaps were used in 2. In 12 patients the penile skin was fixed at the penoscrotal and penopubic angles to maintain penile length and in 2 excess fat was excised. Mean age of type 2 patients at surgery was 19.8 months. All had previously undergone surgery, including hypospadias in 1 and circumcision in 17. All patients underwent complete penile degloving and the cicatricial scar that trapped the penis was excised. Penile skin flaps and Z-plasties were used in 12 cases, scrotal skin flaps were used for reconstruction in 2 and skin grafting was done in 1. In 10 patients the penile skin was fixed with sutures to maintain penile length. Mean age of type 3 patients at surgery was 15.8 years. Of the 7 boys 6 had previously undergone penile surgery. All required extensive scar excision and complex reconstruction involving penile skin flaps in 3, scrotal flaps in 5 and penile skin fixation in 6. Excessive suprapubic fat was removed in 5 patients, of whom 3 underwent liposuction. RESULTS: Surgical results were uniformly good in type 1 patients except in 1 who was believed to have excessive suprapubic fat. Results were good in 14 of the 18 type 2 patients, although 2 retained excessive suprapubic fat and 2 had some unsightly scarring. No type 1 or 2 patient required additional surgery. Of the 7 type 3 patients 6 had a good result and required no additional surgery. One patient has recurrent concealed penis after 2 procedures and awaits additional surgery. CONCLUSIONS: Concealed penis has a varied etiology and requires a flexible surgical approach. The common surgical options in all cases include complete penile degloving, excising the scarring due to previous surgery, removing excess suprapubic fat, reconstructing the penile skin with local flaps, and fixing the penile skin at the penopubic and penoscrotal angles.

Child↗
PubMed1998

Long-term results after inferior vena caval resection during retroperitoneal lymphadenectomy for metastatic germ cell cancer.

PURPOSE: The long-term sequelae of inferior vena caval (IVC) resection during retroperitoneal lymph node dissection for metastatic nonseminomatous germ cell testis tumor (NSGCT) were assessed. METHODS: Between December 1973 and September 1996, 2126 of our patients underwent RPLND for retroperitoneal nodal metastases from NSGCT; 955 had bulky disease (stages B2, B3, or C) after cytoreduction chemotherapy. Of this latter group, 65 patients (6.8%) required infrarenal IVC resection during tumor excision for cure. Our protocol does not include IVC reconstruction in such cases. Indications for IVC resection included tumor encasement or encroachment, postchemotherapy desmoplastic compression, or thrombus with tumor or clot in which cavotomy and thrombectomy cannot be performed. RESULTS: Twenty-four of the 65 patients (postoperative follow-up period range, 11 months to 16 years; median, 89 months) were alive and able to be examined or interviewed by written and/or phone survey to assess the long-term morbidity of their IVC resection. Based on the 1994 American Venous Forum International Consensus Committee reporting standards, the clinical classifications of these 24 patients were C0A (4), C3S (4), C4A (2), C4S (13), and C6A (1). Long-term disability was mild or absent in 75% of these patients. CONCLUSION: Only 1 (4.2%) of the patients surveyed had chronic venous sequelae that would fulfill the accepted criteria for subsequent elective IVC reconstruction. Despite recent reports of IVC reconstruction demonstrating relatively good patency rates and low morbidity, the addition of such a complex, time-consuming procedure to extensive retroperitoneal lymph node dissection for metastatic NSGCT involving IVC resection is generally not necessary.

Adult↗
PubMed1977

In vivo sterol biosynthesis by pea aphid symbiotes as determined by digitonin and electron microscopic autoradiography.

Pea aphid primary symbiotes have previously been shown to synthesize cholesterol in vitro. Two electron microscopic techniques were used here to determine whether the symbiotes also synthesize cholesterol in vivo and whether this cholesterol is made available to the aphid. We also inquired into a possible role of secondary symbiotes in chosesterol biosynthesis. Treatment of aphids with digitonin resulted in significant alteration of ultrastructural sites in primary and secondary symbiote membranes. We concluded that these sites are areas of high cholesterol concentration in the symbiotes. Electron microscopic autoradiography with 3H-mevalonate precursor indicated that both primary and secondary symbiotes synthesize cholesterol; in both cases, the majority of grains were associated with the symbiote membranes. While the frequency of grains on the symbiotes remained constant, irrespective of incubation time in labelled media, the frequency of grains over surrounding tissues increased exponentially as the time of incubation was increased from 30 min to 8 h, indicating that symbiote cholesterol is transported to other tissues. High voltage electron microscopic autoradiography permitted thick section autoradiography, reducing the time of emulsion exposure from 54 days (thin section) to 12 days (0.5 mum sections).

Animals↗
PubMed1977

Effect of dietary cholesterol on the pattern of osmium deposition in the symbiote-containing cells of the pea aphid.

Pea aphids left for 48 h in unbuffered osmium tetroxide show heavy staining of many organelles in the symbiote-containing cells (mycetocytes and sheath), embryos and oenocytes very similar to that characteristic of mammalian sterol-synthesizing cells. However, the staining of the per-aphid cells is, to a large extent, dependent on the presence of cholesterol benzoate, or free cholesterol, in the aphid's diet. In aphids cultured in vitro with 3H mevalonate in the presence of added cholesterol, the incorporation of label into the cholesterol and lanosterol fractions is significantly reduced. If the dietary cholesterol effects a similar inhibition in vivo, the cholesterol-dependent osmium staining could be due to precursors(s) of cholesterol accumulating in the intracellular sites described. There is also osmium staining of large (normally electron-transparent) vacuoles in mycetocytes, gut and fat body, irrespective of dietary cholesterol.

Animals↗
PubMed1975

Comparative ultrastructure and blood-brain barrier in diapause and nondiapause larvae of the European corn borer Ostrinia nubilalis (Hübner).

Ultrastructural examination of diapause and nondiapause larval brains of the European corn borer disclosed anatomical differences that may be related to the insect's "blood-barrier". The perineurial type I cells are quite closely appressed in the diapause brain, but thrown into extensive folds with large intercellular spaces in the nondiapause brain. The perineurial type II cells of diapause and nondiapause larvae are basically similar in general ultrastructure, and most likely form the basis for the "blood-brain barrier." Horseradish peroxidase penetration studies indicated that the outer margin of the perineurial type II cells constitute the limits of infiltration into the brain. An enzymatic component of the "blood-brain barrier" is postulated in this insect. The localization of ATPase in the perineurial type II cells indicates that energy-requiring regulatory mechanisms may be localized here. Metabolic studies with isolated brains, coupled with recent evidence from mammalian systems, suggest that glial cells may be of importance in an enzymatic "blood-brain barrier."

Adenosine Triphosphatases↗
PubMed1975

Ultrastructure of pea aphid mycetocytes: evidence for symbiote secretion.

A detailed investigation into the ultrastructure of the pea aphid mycetocytes and their contained symbiotes and organelles was carried out with the transmission electron microscope. The most striking observation was the presence of small vesicles in the space between the primary symbiote cell wall and membrane envelope (outer membrane space). The vesicles appear to form by a budding process at the outer cell wall layer. Subsequently, the vesicles, we suggest, may move out into the mycetocyte cytoplasm via a similar budding of the membrane envelope; The Golgi apparatus was found to be an important structural component of the primary mycetocyte; it is continuous with the rough endoplasmic reticulum and the latter, in turn, appears to be closely connected to the primary symbiote membrane envelope. This may be of functional significance. A number of other organelles not previously described in mycetocytes were found, including transparent vacuoles, granular bodies, multi-vesicular bodies and microfilaments. The chemical composition of the various vesicles and organelles is unknown at present.

Animals↗
PubMed1972

Reversed development and cellular aging in an insect.

Larvae of the beetle Trogoderma glabrum undergo partially reversed development when deprived of food and water. Retrogressive larval ecdyses occur, and the larvae become diminished in size and weight. Given food, the larvae regrow, ecdyze, and regain their previous degree of maturity. Repeated cycles of retrogression and regrowth are possible. Although larval in form and organ differentiation, repeatedly retrogressed insects display a physiological deterioration suggestive of aging. A deterioration of the ability to regrow is accompanied by increasing fat body polyploidy.

Adipose Tissue↗