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Biomedical subjects

R Mathews

Publications and source records attributed to R Mathews.

At least 37 records · Page 2Linked to original sources
PubMed1997

Immunohistochemical and ultrastructural study of rhabdosphincter component of the prostatic capsule.

PURPOSE: There has been no complete agreement on functional anatomy of muscular components of the urethral sphincteric mechanism, particularly in the male patient. The prostatic capsule was studied to define its histological structure and to determine whether its rhabdosphincter component (prostatocapsular rhabdosphincter) consists only of slow twitch or slow and fast twitch striated myofibers. MATERIALS AND METHODS: We studied 11 whole prostates, including 1 obtained at autopsy and 10 by radical prostatectomy. Samples of prostatic capsule from 4 operative specimens were studied by electron microscopy. Whole mount paraffin sections from transverse slices of the remaining 7 prostates were double labeled with avidin biotin conjugate immunostaining using the primary monoclonal antibodies anti-alpha smooth muscle actin plus anti-alpha sarcomeric actin (all striated myofibers) or antiskeletal myosin fast (fast myofibers only). Tissue components of the prostatic capsule, including smooth muscle and slow versus fast twitch striated myofibers, were quantified by computerized image analysis. RESULTS: The prostatic capsule consisted of collagen, smooth muscle and striated myofibers. It varied in thickness and proportion of the 3 components among specimens, and in each in relation to transverse circumferential aspect and craniocaudal (horizontal) level of the prostate. Collagen and smooth muscle were equally important components. Striated muscle elements within the capsule consisted of fast twitch and dominant slow twitch myofibers, and were much more abundant in the caudal (distal, lower) than the cranial (proximal, upper) half of the capsule, where they were deficient ventrally (anteriorly) and dorsally (posteriorly). The prostatocapsular rhabdosphincter thus had a butterfly-like appearance, with a thick posteriorly open ring at the apex and 2 thinner, divergent leaflets tapering toward the base at the bladder neck. The fast myofiber population decreased progressively from apex to base of prostate. CONCLUSIONS: Proof is provided for mixed slow and fast twitch myofiber structure of the prostatocapsular component of human male rhabdosphincter. Sustained (tonic) contraction of slow myofibers probably reinforces the role of urethral smooth muscle in maintaining continence during bladder filling. Swift contraction of fast myofibers that abound caudally in the capsule probably supplements urethral closure by the bulkier membranous urethral part of the rhabdosphincter in preventing leakage of urine under stress when voiding is imminent or willfully withheld.

Aged↗
PubMed1997

Versatility of the adult psoas hitch ureteral reimplantation.

PURPOSE: The psoas hitch ureteral reimplant has been described in the literature as an excellent method to restore ureterovesical continuity in patients with ureteral defects of various etiologies. However, long-term data on the durability of this procedure are lacking. We retrospectively reviewed patients who underwent ureteral reconstruction using the psoas hitch reimplantation to determine long-term efficacy. MATERIALS AND METHODS: Ureteral reimplantation in the adult is frequently performed in the setting of ureteral tissue loss secondary to resection or injury. The psoas hitch reimplantation is a simple, versatile technique that avoids the inclusion of intestinal segments and can be used in most patients requiring reimplantation. Indications for surgery and the long-term followup were examined in 20 patients undergoing reimplantation using the psoas hitch. RESULTS: The indications for ureteral reconstruction included surgical injury in 13 cases, recurrent pyelonephritis with reflux in 1, obstruction secondary to cancer in 2, trauma in 1, retroperitoneal fibrosis in 1 and ureteral stricture in 2. At followup of 1 to 14 years (mean 6) 17 patients have not required further intervention for urological problems and have retained normal renal function. In the 2 patients with cancer ileal conduit was performed later and in 1 flank pain persisted despite negative urological evaluation. CONCLUSIONS: Psoas hitch ureteral reimplantation can be used successfully for bridging various ureteral defects in difficult clinical situations. Adequate renal and bladder mobilization will allow reconstruction despite long ureteral defects.

Adolescent↗
PubMed1997

Sigmoid "tail" modification for bladder augmentation.

OBJECTIVES: The sigmoid colon lends itself well to bladder augmentation particularly in patients requiring reimplantation of ureters or Mitrofanoff valves for continence. We have modified the sigmoid augment to improve ease of catheterization and ureteral reimplantation. METHODS: Seven children underwent sigmoid "tail" bladder augmentation for various indications. Appendix or tapered ileum was used to create the catheterizable stoma. This technique uses a 3 to 5-cm segment of nondetubularized colon, fixed to the abdominal wall to ease catheterization. Durability of the modification and ease of catheterization were assessed. RESULTS: All patients are dry day and night with intermittent catheterization. One patient with mild leakage has been managed with pseudoefedrine. Postoperative bowel obstruction and abscess developed in 1 patient. CONCLUSIONS: The sigmoid "tail" modification does not appear to confer increased morbidity and the short nondetubularized segment fixed to the posterior aspect of the anterior abdominal wall stabilizes the catheterizable stoma improving ease of catheterization.

Child↗
PubMed1997

Metabolic complications secondary to obstruction of a Kock pouch afferent limb.

Metabolic complications are frequently seen following urinary diversion with an intestinal segment. Afferent limb complications are noted in 10% of patients undergoing continent Kock urinary diversion. We present a patient with cloacal exstrophy with developed significant hypocalcemic tetany and metabolic acidosis related to a nondraining afferent limb of a Kock pouch created to achieve continence.

Adolescent↗
PubMed1997

Expression of epidermal growth factor receptor in fetal mouse submandibular gland detected by a biotinyltyramide-based catalyzed signal amplification method.

Branching morphogenesis of the fetal mouse submandibular gland (SMG) can be modulated in vitro by stimulation or inhibition of the epidermal growth factor receptor (EGFR). Because the mRNAs for EGF and EGFR are detectable in RNA of SMG rudiments isolated directly from fetuses, the EGF system probably operates physiologically as a regulator of SMG morphogenesis. However, neither EGFR protein nor its precise cellular localization has been characterized in the fetal SMG. Here we show EGFR protein in fetal mouse SMG by immunoprecipitation, affinity labeling, ligand-induced autophosphorylation, and immunohistochemistry. SMGs from E16 fetuses (day of vaginal plug = E0) were labeled with [35S]-cysteine/methionine and homogenized. After addition of specific antibody to EGFR, the immunoprecipitate was isolated, resolved by polyacrylamide gel electrophoresis, and detected by autoradiography. A single band of 170 kD was detected, corresponding to the EGFR protein. Affinity labeling with [125I]-EGF of the membrane fraction of E18 SMG also revealed a prominent band at 170 kD, showing that this EGFR protein can bind specifically to its ligand. Incubation of SMG membranes from E18 fetuses with EGF in the presence of [gamma-32P]-ATP, followed by immunoprecipitation with anti-phosphotyrosine antibody also showed a single band at 170 kD, demonstrating autophosphorylation of the EGFR in response to binding of its ligand. Immunohistochemical localization of the cellular sites of EGFR in the fetal SMG required use of a catalyzed signal amplification procedure, with biotinyltyramide as the amplifying agent. EGFR was localized predominantly, if not exclusively, in cell membranes of epithelial cells of the rudiment, whereas staining of mesenchymal cells was equivocal. Staining was strongest on duct cells, and weak on cells of the end-pieces. These findings clearly show that a functional EGFR protein is expressed in fetal SMG chiefly, if not exclusively, on epithelial cells.

Affinity Labels↗
PubMed1996

Cyclophosphamide in the treatment of toxic epidermal necrolysis.

A patient with non-small cell lung carcinoma and recent radiotherapy for brain metastases developed toxic epidermal necrolysis (TEN) shortly after therapy with phenytoin was initiated for a seizure. Exfoliation progressed to involve 90% of her body surface despite treatment with high-dose corticosteroids for 5 days, but sloughing and systemic toxicity ceased within 2 days of initiating therapy with intravenous cyclophosphamide (300 mg/day). Reepithelialization rapidly followed. This experience and the reports of others suggest that intravenous cyclophosphamide is helpful in the treatment of TEN.

Adult↗
PubMed1996

Seven-year follow-up of speech/language impaired and control children: psychiatric outcome.

This study examined the 7-year psychiatric outcome of 202 speech/language (S/L) impaired and control children selected from a community sample at age 5 years. Children with S/L at age 5 years were more likely to be psychiatric cases at age 12.5 years than were normal controls, even if their S/L improved. Controlling for concurrent psychiatric disorder, S/L impairment at age 5 years was still associated with an increased rate of psychiatric disorder at 12.5 years. Psychiatric disorder at age 12.5 years was more likely to co-occur with language disorder than with speech disorder.

Articulation Disorders↗
PubMed1995

Modification of Dornier HM-4 lithotriptor for pediatric extracorporeal shockwave lithotripsy.

Extracorporeal shockwave lithotripsy has enjoyed increasing acceptance and utility in pediatric urology. The Dornier HM-4 lithotriptor has had good results in adults, but the gantry design does not allow smaller children to be treated. We have employed a specially designed yet simple 'spacer' to allow smaller children to be treated safely. The device may also have application in other patients with deformities who could not be treated in the past.

Child, Preschool↗
PubMed1995

Minimal surgery with renal preservation in anomalous complete duplicated systems: is it feasible?

From 1985 to 1993, 33 female and 4 male patients 0 to 3 years old presented with abnormal complete duplex systems of whom 25 had a prenatal diagnosis of hydronephrosis. Diagnosis in 40 ureteral moieties included ureteroceles in 10, ectopic ureteral insertions with reflux and obstruction in 17, and refluxing lower ureters in 13. Of 40 renal units only 6 (15%) required upper pole moiety ablation for pyelonephritis or nonfunction. None of the ablated renal tissue showed evidence of dysplasia. With the advent of prenatal diagnosis and minimal surgical intervention complete duplex anomalous urinary systems can be salvaged with preservation of altered renal units.

Female↗
PubMed1992

Metabolic effects of treadmill exercise training on the diabetic heart.

This study determined whether exercise training in rats would prevent the accumulation of lipids and depressed glucose utilization found in hearts from diabetic rats. Diabetes was induced by intravenous streptozotocin (60 mg/kg). Trained diabetic rats were run on a treadmill for 60 min, 27 m/min, 10% grade, 6 days/wk for 10 wk. Training of diabetic rats had no effect on glycemic control but decreased plasma lipids. In vivo myocardial long-chain acylcarnitine, acyl-CoA, and high-energy phosphate levels were similar in sedentary control, sedentary diabetic, and trained diabetic groups. The levels of myocardial triacylglycerol were similar in sedentary control and diabetic rats but decreased in trained diabetic rats. Hearts were perfused with buffer containing diabetic concentrations of glucose (22 mM) and palmitate (1.2 mM). D-[U-14C] glucose oxidation rates (14CO2 production) were depressed in hearts from sedentary diabetic rats relative to sedentary control rats. Hearts from trained diabetic rats exhibited increased glucose oxidation relative to those of sedentary diabetic rats, but this improvement was below that of the sedentary control rats. [9,10(-3)H]palmitate oxidation rates (3H2O production) were identical in all three groups. These findings suggest that exercise training resulted in a partial normalization of myocardial glucose utilization in diabetic rats.

Animals↗
PubMed1992

Primary lymphoma of the rectum.

Primary lymphoma of the rectum is rare. Its usual grouping with primary lymphoma of the gastrointestinal tract leaves little in the literature that deals specifically with a primary rectal lymphoma. Various treatments have been reported ranging from abdominoperineal resection with adjuvant chemotherapy and radiation therapy to chemotherapy or radiation therapy alone. A case of primary rectal lymphoma is presented and the literature is reviewed. In the few cases reported in the literature, patients treated surgically had a better prognosis than those treated nonsurgically with an overall 5-year survival of 50 per cent. Recommended treatment includes varying forms of surgical therapy ranging from local resection to abdominoperineal resection. Adjuvant chemotherapy, radiation therapy, or both should be considered.

Humans↗
PubMed1990

Peritonitis-related deaths in continuous ambulatory peritoneal dialysis (CAPD) patients.

A total of 636 episodes of peritonitis occurred in 440 patients who entered our continuous ambulatory peritoneal dialysis (CAPD) program from September 1977 to February 1988. Sixteen patients (8 male and 8 female, aged 37-77 years) died during an episode of peritonitis (fatality rate 2.5%). They had been on CAPD for 3 to 105 (average 39) months. Six of them were diabetics. The peritonitis rate among these 16 patients were 1 episode per 12 patient months, while the corresponding figure for the whole (440) CAPD population was 14 patient months. Risk factors present in the 16 patients were: cardiovascular disease (12), cerebrovascular accident (2) peripheral artery disease (1) and pulmonary fibrosis (1). Fever and leukocytosis were present on admission in 11 patients, while total serum proteins and albumin were significantly lower (p less than 0.001) than the corresponding values before peritonitis (56 +/- 8 vs. 65 +/- 5). Staph. aureus was isolated in 8 patients (50%), multiple organisms in 6, Pseudomonas and Candida albicans in 1 each. An abdominal abscess was found in 4 (25%) patients. The peritoneal catheter was removed between the 5th and 10th day in 6 and after the 10th day in 7 patients. Peritonitis with sepsis was the cause of death in 13 patients. Contributing factors were cardiovascular accident in 9, uremic coma in 2, extensive GI bleeding in 2, GI perforation in 2, intestinal infarction in 1, and pneumonia in 2 patients. We conclude that the risk of peritonitis-related death in CAPD patients is increased with Staph. aureus or multibacterial peritonitis. Contributing factors are concomitant cardiovascular disease and delayed (greater than 5 days) catheter removal.

Cardiovascular Diseases↗
PubMed1989

Splenic abscess and peritonitis in a continuous ambulatory peritoneal dialysis (CAPD) patient.

A 26-year-old female was on continuous ambulatory peritoneal dialysis (CAPD) because of diabetic end-stage renal failure. She developed an acute peritonitis that relapsed repeatedly despite appropriate antibiotic treatment. Investigations showed the presence of a splenic abscess, and splenectomy and peritoneal cannula removal were required. The patient died of myocardial infarction two weeks postoperatively. This is the first recorded case of peritonitis secondary to splenic abscess in a CAPD patient. Autopsy findings suggest that the abscess developed from infection of a splenic infarct.

Abscess↗
PubMed1988

Biopsy of nonpalpable breast lesions.

One hundred-three needle-direct breast biopsies were performed in 99 patients. Nine cancers were detected. All of the patients but one had in situ tumor or stage I disease. After analysis, the mammograms were submitted to radiologists for restudy in a blinded fashion. On restudy, 50 percent of the malignancies were read as low suspicion or benign whereas the other 50 percent were read as malignant. Variation between interpretations was significant, with complete agreement among the radiologists in 16 percent of cases. We concluded that needle-directed biopsy for occult breast lesions is very effective in bringing patients with a more favorable prognosis to early surgery. The false-positive rate will be high and the interpretation of a given mammogram will vary, depending on the radiologist. Mammography for subtle lesions is sensitive but nonspecific; therefore, it is wise to biopsy all lesions that are even slightly suspicious, particularly in patients with a previous history of breast cancer or other risk factors.

Adult↗
PubMed1985

Dietary fiber and cancer: a supplement for intervention studies.

Dietary fiber is one of several variables being considered in the study of the relationship between diet and cancer. Intervention trials in which dietary fiber is increased are the most direct way of assessing the possible role of fiber in this disease. Two dietary snack products have been developed for use in a fiber intervention study: the high-fiber snack (HFS), which supplies 23 g of dietary fiber per day (mostly from wheat bran) and the low-fiber product (LFS), which provides 3.5 g. Over a 12-week period, 28 volunteers consumed the HFS for 6 weeks and the LFS for 6 weeks. Compliance, as assessed by reports, through recovery of a riboflavin marker in the urine and fecal fiber analysis, was good. The only adverse effects reported were mild abdominal discomfort and gas. Serum ferritin and calcium decreased in some subjects, indicating a need to supplement the products with these essential minerals. Consumption of the snacks did not affect total energy intake or the intake of the nutrients monitored.

Adult↗