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Biomedical subjects

T Ahlering

Publications and source records attributed to T Ahlering.

7 recordsLinked to original sources
PubMed1997

Screening cystoscopy and survival of spinal cord injured patients with squamous cell cancer of the bladder.

PURPOSE: Yearly cystoscopy has been advocated in spinal cord injured patients with chronic or recurrent urinary tract infections secondary to the increased risk of squamous cell cancer of the bladder. We examined the effectiveness of this protocol in our patients. MATERIALS AND METHODS: The medical records of all spinal cord injured patients with squamous cell cancer of the bladder between 1980 and 1996 were reviewed for the method of detection of the lesion. Screened patients (those presenting with chronic or recurrent urinary infections) were considered asymptomatic and were compared to symptomatic patients (those presenting with overt signs or symptoms of the bladder lesion) with respect to age, latency since spinal cord injury, treatment of neurogenic bladder, therapy, pathological stage and survival. RESULTS: Of 14 patients (9 symptomatic at presentation) 13 underwent cystoprostatectomy, while 1 presented with metastatic disease and was treated with supportive care only. Three symptomatic patients received adjuvant radiation therapy for positive lymph nodes or margins. Pathological stage was more advanced in the symptomatic group, including 7 patients (78%) with stage pT3a or pT3b (4 had positive lymph nodes), 1 with stage pT1N0M0 and 1 with stage pT2N0M0 cancer. In the asymptomatic group 3 patients had stage pT2N0M0, 1 had stage pT3aN0M0 and 1 had pT3bN0M0 disease. Overall and cancer specific survival rates for symptomatic patients were 44 and 50%, respectively, with a median of 40 months to death. In the asymptomatic group there was 1 noncancer related death, while the remaining patients were alive at a mean followup of 8.2 years. CONCLUSIONS: Cystoscopy to screen for squamous cell cancer of the bladder in spinal cord injured patients with chronic or recurrent urinary tract infection results in an earlier stage at diagnosis and appears to convey a survival advantage. Such a protocol should be strictly followed and careful prospective studies must be performed to ascertain if this will become significant.

Carcinoma, Squamous Cell↗
PubMed1995

Depth of penetration of the neodymium: yttrium-aluminum-garnet laser in the human prostate and clinical results of high-dose laser energy in 50 patients.

We evaluated the treatment of the human prostate with the Nd:YAG laser using a Cytocare Prolase II fiber. We utilized this first in 12 patients prior to radical prostatectomy and then appropriately serially sectioned the prostate to measure the depth of penetration. The studies clearly revealed that 60 W of power and 60 s of pulse duration gave the most consistent depth of penetration in the human prostate model. This depth of penetration averaged 2 cm in the glands that were removed. At the same time there was absolutely no evidence of damage to the neurovascular bundle or to the capsule of the prostate using the above-mentioned dosimetry regime. This study was then transferred to our initial experience in treating 50 patients with benign prostatic hypertrophy and obstructive voiding symptoms. The first 25 patients were also treated with so-called spot radiation of the prostate, whereas the second 25 patients were treated by total photoirradiation of all visible endoscopic tissue. The results reveal that both groups of patients had a fairly highly satisfactory result as measured objectively with American Urological Association (AUA) symptom scores and uroflow studies. In the latter group (photoirradiation of all visible endoscopic tissue) a significantly higher dose of laser energy was utilized and a smaller failure rate was noted on a long-term basis in patients who subsequently came to transurethral resection of the prostate (TURP) because of failure of the laser procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Xanthogranulomatous pyelonephritis: clinical findings and surgical considerations.

OBJECTIVE: Xanthogranulomatous pyelonephritis (XGP) is an uncommon but well-characterized inflammatory process of the kidney. Few reports, however, have correlated preoperative radiographic features with findings at surgical exploration. We report our experience in the surgical management of XGP with emphasis on the use of computed tomography (CT) in the preoperative evaluation. METHODS: We retrospectively reviewed all medical records including radiographic materials of 27 patients with a pathologic diagnosis of XGP. In particular, preoperative CT features were analyzed to see if they correlated with surgical findings. RESULTS: A CT scan was performed in 23 of the 27 patients. Of these 23 patients 20 (87%) were diagnosed with XGP based on the CT findings. CT accurately defined the extent of the perinephric inflammatory reaction, identifying 8 patients with muscular extension, 3 with splenic involvement, 1 with extension into the colon, and 5 with encasement of the great vessels. In no case did CT underestimate the involvement of adjacent tissues. CONCLUSIONS: Although XGP is a rare disease, a careful preoperative evaluation can suggest its diagnosis. CT is particularly valuable in that it not only demonstrates characteristic renal findings, but also shows the extent of inflammation and extent into adjacent tissues. This will aid in surgical planning in choosing an approach that will provide adequate exposure and facilitate patient care.

Adult↗
PubMed1994

Depth of penetration of the neodymium:yttrium-aluminum-garnet laser in the human prostate at various dosimetry.

OBJECTIVE: To determine depth of thermal penetration by the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser at various dosimetry in the human prostate and to compare results of two techniques of laser application, single spot versus whole tissue photoirradiation. METHODS: Twelve men with Stage T2 (B) cancer of the prostate consented to laser prostatectomy immediately prior to a planned radical prostatectomy. In the first 3 patients (group I) the prostate was treated with the Nd:YAG laser in one spot area of each lobe. The next 9 patients underwent photoirradiation of all endoscopically visible tissues on one side of the prostate at different dosimetries: 60 W at sixty seconds (group II), 50 W at sixty seconds (group III), and 40 W at ninety seconds (group IV). Depth of laser penetration was measured from both histologic and gross evaluations of removed specimens within twenty-four hours. RESULTS: Thermal necrosis in group I showed an inconsistent depth of penetration even with the same amount of laser energy. Groups II, III, and IV all demonstrated clearly demarcated areas of thermal necrosis. Group II showed the greatest depth of laser effect among all groups, with a mean depth of 1.75 cm. No laser effect is detected near the true capsule of the prostate on any specimen. CONCLUSIONS: High dosage laser energy application at 60 W and sixty seconds of pulse duration with the whole tissue treatment provide the greatest depth of penetration in the human prostate while maintaining safety for the capsular area.

Burns↗
PubMed1990

Mechanisms of human bladder tumor invasion: role of protease cathepsin B.

To study the biochemical mechanisms of bladder tumor invasion, we analyzed specimens of invasive transitional cell carcinoma cell line EJ and non-invasive transitional cell carcinoma cell line RT4 which had been implanted into the bladders of nude mice. Using immunoprobes specific to basement membrane laminin, we observed that superficial but not invasive tumors were surrounded by intact laminin. With immunoprobes specific to cathepsin B, a cysteine proteinase which has the ability to degrade laminin, we demonstrated that cathepsin B is localized in discrete cytoplasmic granules in the non-invasive tumors, and in a more diffuse cytoplasmic pattern in the invasive tumors. Subcellular fractionation followed by immunoblot analysis and enzymatic analysis confirmed that the invasive EJ cells had active cathepsin B localized to its plasma membrane, while non-invasive RT4 cells had cathepsin B confined to lysosomes. Furthermore, immunoblot analysis revealed that invasive EJ cells had the mature form of cathepsin B with a molecular weight of 25 kD, while non-invasive RT4 cells had predominantly precursor forms with molecular weights between 30 and 35 kD. In vitro degradation assays with plasma membrane fractions isolated from invasive EJ cells and non-invasive RT4 cells demonstrated that the plasma membrane of EJ cells but not that of the RT4 cells had the ability to degrade purified laminin, and that the degradative products were similar to those obtained with purified cathepsin B. We conclude that invasive tumor cells have enhanced cathepsin B in their plasma membranes which may be used to degrade basement membrane components such as laminin and thereby facilitate tumor invasion.

Animals↗