Biomedical subjects

M C Adams

Publications and source records attributed to M C Adams.

65 records · Page 4Linked to original sources

PubMed1990

Ureteral stump transitional cell carcinoma in a patient with recurrent superficial bladder cancer: an argument for complete nephroureterectomy in selected patients.

A 62-year-old white man had diffuse transitional cell carcinoma of a right ureteral stump 2 1/2 years after initial transurethral resection of a bladder tumor and right radical nephrectomy for renal cell carcinoma. This case and review of the literature suggest an indication for complete ureterectomy in nephrectomy candidates with prior or concurrent transitional cell carcinoma of the bladder.

Carcinoma, Transitional Cell↗

PubMed1989

Constant pressure perfusion: a method to determine obstruction in the upper urinary tract.

In an effort to define a more physiological method to determine obstruction in the upper urinary tract, the technique of constant pressure perfusion was studied in the canine and porcine models. In contrast to the constant flow technique of Whitaker, constant pressure perfusion is independent of upper tract compliance, uses low fixed pressures (7 to 12 cm. water) in the renal pelvis and measures flow rates from the upper tracts. In the canine and porcine models constant pressure perfusion demonstrated increased sensitivity and better discrimination between normal and partially obstructed systems relative to constant flow. Pressures in nonobstructed canine and porcine renal pelves are normally low (less than 8 cm. water) for flow rates into the bladder of 1 to 5 cc per minute. When using constant pressure perfusion in systems with partial distal ureteral obstruction, low or no flow is appreciated across the obstruction at renal pelvic pressures of 7 to 12 cm. water. By constant flow obstruction is defined in the same systems but only after renal pelvic pressures exceed 15 to 20 cm. water. We believe that there is clear clinical applicability.

Animals↗

PubMed1989

Construction of an antirefluxing urinary conduit using a plicated ileocecal segment.

A plicated ileocecal segment was used to construct an antirefluxing urinary conduit in 3 patients. Each patient had markedly dilated or shortened ureters that prevented conventional Leadbetter ureteral reimplantation into a colon conduit. Ascending colon was brought out as a cutaneous stoma, the ureters were anastomosed to ileum, and an antireflux mechanism was created from plicated terminal ileum and the native ileocecal valve. Significant reflux was prevented in all 3 patients. This technique provides a means to prevent urinary reflux into short or dilated ureters, and increases the versatility of the ileocecal segment for use in diversion and urinary tract reconstruction.

Adult↗

PubMed1989

Creation of a transverse colon--gastric composite reservoir: a new technique.

All existing continent urinary reservoirs utilize cecum and/or varying lengths of ileum. In patients who have received prior pelvic radiation therapy, continent diversion has not been feasible because those segments of bowel lie within the field of irradiation. We describe a new technique of continent diversion utilizing only bowel outside the field of pelvic irradiation. A urinary reservoir is constructed from reconfigured transverse colon. A tubularized segment of stomach is implanted beneath the taenia of the reservoir to provide a continent, catheterizable stoma. We describe this technique in detail and report our results in five dogs followed for a mean of 59 days.

Animals↗

PubMed1988

Chronic renal failure and bladder augmentation: stomach versus sigmoid colon in the canine model.

A canine model for chronic renal failure and bladder augmentation with a segment of stomach or sigmoid colon (or control) was developed to evaluate the possible benefit of net chloride ion excretion noted in an earlier canine model for gastrocystoplasty. Gastrocystoplasty animals behaved similar to control animals relative to the sigmoid cystoplasty animals, tolerated significantly greater acid loading, did not have hyperchloremia with acidosis and had less weight loss with acidosis. Gastrocystoplasty seems to be superior to sigmoid cystoplasty in the azotemic canine.

Acidosis↗

PubMed1988

Gastrocystoplasty: an alternative solution to the problem of urological reconstruction in the severely compromised patient.

An isolated segment of stomach was used for bladder augmentation in 10 patients or construction of a continent urinary reservoir in 3. Diagnosis in these 13 patients included cloacal exstrophy (5), myelodysplasia (4), posterior urethral valves (2), radiation cystitis (1) and neurogenic bladder secondary to a rectal pull-through procedure (1). Indications for the use of stomach in bladder reconstruction were decreased renal function and acidosis (6 patients), insufficient large and small bowel (6) and decreased mucus production (1). Postoperative followup averaged 13 months (range 6 to 23 months). All patients have stable upper tracts radiographically and stable or improved renal function. Of 13 patients 10 require intermittent clean catheterization to empty and 11 are completely continent. Nine patients have remained free of infection, while 4 had asymptomatic bacteriuria. Mucus production is reduced relative to other intestinal segments and 10 patients require no bladder irrigations. Postoperative urodynamic evaluation is similar to that of ileocystoplasty or colocystoplasty. Use of stomach has protected these patients from the development of new or worsened hyperchloremic acidosis. Serum chloride values have decreased and serum total carbon dioxide values have increased after bladder reconstruction, particularly in patients with impaired renal function. Stomach should be considered when lower urinary tract reconstruction is necessary in such compromised patients.

Adolescent↗

PubMed1988

Urethral replacement with ureter.

Proximal or total urethral replacement was performed in 8 patients using distal ureter. This was accomplished by basing the ureteral segment solely on a vascular pedicle arising from the internal iliac artery. Diagnoses included classical bladder exstrophy in 4 patients, cloacal exstrophy in 3 and an imperforate anus with hypoplasia of the bladder neck and urethra in 1. Continence was achieved by a tunneled submucosal reimplantation into either the bladder (4 cases), gastric reservoir (2) or colonic reservoir (2). Although an isolated distal segment of ureter was used in each case, all segments have remained viable. With limited followup (5 to 44 months) continence with either normal voiding or intermittent catheterization has been achieved in 7 of the 8 patients. A distal ureteral segment should be considered potentially useful in the construction or reconstruction of the proximal (male) or total (female) urethra in patients with congenital urethral malformations.

Anus, Imperforate↗

PubMed1987

Kinetics of vein graft hyperplasia: association with tangential stress.

Vein grafts become thicker as they adapt to arterial circulation, and in large measure this is the consequence of cellular hyperplasia. The kinetics of smooth muscle cell (SMC) and endothelial cell (EC) replication were evaluated in rabbit jugular vein segments transplanted into the carotid arterial circulation to define the role of cell proliferation in this process, and these data were correlated with dimensional changes in grafts from 1 hour to 24 weeks after implantation. At 1 hour most of the perianastomotic endothelium was denuded, as were occasional cells in the graft away from the anastomosis. EC replication (thymidine labeling index) in the center of the graft increased 400 times during the first week and produced an intact endothelial surface by 2 weeks. The EC thymidine index then fell progressively to quiescent pretransplant levels by the twelfth week. SMC replication was maximal at 1 week after grafting and returned to near quiescent levels at 12 and 24 weeks. Graft wall thickness and cross-sectional area reached a maximum at 12 weeks and then remained constant. Deoxyribonucleic acid content exhibited a thirty-five-fold increase in the first 4 weeks, then did not change. Likewise, SMC mass did not increase after 4 weeks. Further increase in cross-sectional wall area between 4 and 12 weeks was accounted for by accumulation of connective tissue. The final ratio of luminal radius to wall thickness decreased to a level equal to that of normal artery. Since blood pressure did not change over the period of the study, this observation supports a possible regulatory role for wall tangential stress in the modification of vein graft structure after transplantation into the arterial circulation.

Animals↗

PubMed1978

Microbial degradation of diethanolamine and related compounds.

Thirteen diethanolamine compounds were tested for their biodegradability employing (1) a bacterium selectively isolated from an industral cutting fluid, and (2) an acclimatized sewage population obtained from a domestic waste treatment plant. Pure culture growth and biochemical oxygen demand studies with the isolate showed that only diethanolamine, methyl-diethanolamine, triethanolamine, and laurylsulphate-diethanolamine were degradable. Biochemical oxygen demand techniques using the acclimatized sewage micro-organisms as seed yielded similar results with only diethanolamine, methyl-diethanolamine, triethanolamine, and laurylsulphate-diethanolamine being oxidized to any meaningful extent. Cyclohexyldiethanolamine, phenyl-diethanolamine, and m-tolyl-diethanolamine had oxygen demands of less than 1% of their theoretically calculated values, while ethyl-diethanolamine and benzyl-diethanolamine accounted for 3.6 and 2.3% of their theoretical values respectively. In both systems employed substitution of the tertiary hydrogen of the amine group with isopropyl, 3-aminopropyl, n-butyl, or t-butyl resulted in biologically recalcitrant compounds.

Bacteria↗

PubMed1977

The Philadelphia variant of galactokinase.

We have previously reported the existence of a polymorphism that causes black populations to have lower mean RBC galactokinase activity than comparable white populations. We have designated this allele the Philadelphia variant, GALKP, and have suggested that it is common in blacks and rare in whites. GALKP individuals have normal WBC GALK activity, in contrast to the half normal WBC GALK activities of heterozygotes for the allele (GALKG) that causes the galactokinase-deficient form of galactosemia. In one family, we have presented evidence for the existence of two sisters heterozygous for both GALKG and GALKP alleles. These individuals have 50% normal WBC GALK activity and less than 50% normal red cell activity. The latter finding indicates that the two variant GALK alleles additively affect RBC activity. The WBC results suggest that the low activity of GALK in RBC of individuals with the GALKP allele is due to its relative instability. We could obtain no evidence for such instability from studies of high reticulocyte bloods or RBC fractionation. Furthermore, we could not demonstrate that the GALK in WBC from GALKP individuals has altered electrophoretic migration.

Alleles↗

PubMedDate not supplied

Determination of the efficacy of preservation of non-eye area water-miscible cosmetic and toiletry formulations: collaborative study.

A collaborative study was conducted to test a method developed to distinguish between adequately and inadequately preserved cosmetic formulations. Nineteen laboratories participated in the study. Samples tested included shampoos, hair conditioners, oil-in-water emulsions, and water-in-oil-emulsions. Triplicate samples of 4 adequately preserved and 4 inadequately preserved cosmetic products were tested by each collaborative laboratory. Results showed that all inadequately preserved shampoo and conditioner samples failed to meet the acceptance criteria for adequately preserved formulations. Of the 51 preserved samples, 49 shampoos and 48 conditioners met the criteria for adequate preservation. All samples of inadequately preserved water-in-oil emulsions and oil-in-water emulsions failed to meet the acceptance criteria, whereas all adequately preserved emulsion formulations met the acceptance criteria.

Algorithms↗