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Laparoscopy was performed on 107 patients 8 months to 18.5 years old (mean age 46.9 months) with 119 nonpalpable testes. The procedure accurately determined the location of the gonad in 95.3% of the patients, while 16 were spared formal surgical exploration with the laparoscopic visualization of blind-ending spermatic vessels and vasa deferentia. Additionally, patency of the internal inguinal ring, determined laparoscopically, was an accurate predictor of testicular salvageability. We advocate the use of laparoscopy for all boys with a nonpalpable gonad in conjunction with operative intervention if necessary.

Magnetic shields that use both active and passive components to enable the generation of a tailored lowfield environment are required for many applications in science, engineering, and medical imaging. Until now, accurate field nulling, or field generation, has only been possible over a small fraction of the overall volume of the shield. This is due to the interaction between the active field-generating components and the surrounding high-permeability passive shielding material. In this paper, we formulate the interaction between an arbitrary static current flow on a cylinder and an exterior closed high-permeability cylinder. We modify the Green's function for the magnetic vector potential and match boundary conditions on the shield's interior surface to calculate the total magnetic field generated by the system. We cast this formulation into an inverse optimization problem to design active-passive magnetic field shaping systems that accurately generate any physical static magnetic field in the interior of a closed cylindrical passive shield. We illustrate this method by designing hybrid systems that generate a range of magnetic field profiles to high accuracy over large interior volumes, and simulate them in real-world shields whose passive components have finite permeability, thickness, and axial entry holes. Our optimization procedure can be adapted to design active-passive magnetic field shaping systems that accurately generate any physical user-specified static magnetic field in the interior of a closed cylindrical shield of any length, enabling the development and miniaturization of systems that require accurate magnetic shielding and control.

To understand better the relationship among radionuclide renal scan differential function, renal histology and the outcome of pyeloplasty we performed ipsilateral renal biopsies in a series of patients undergoing primary pyeloplasty. A total of 17 consecutive patients with unilateral ureteropelvic junction obstruction underwent renal biopsy at the time of pyeloplasty. Biopsies were examined systematically after sections were stained with hematoxylin and eosin, periodic acid, Schiff, Jones modified silver or Masson trichrome stains, and they were reviewed by 1 pathologist. Biopsy results were correlated with preoperative and postoperative radionuclide renal scan differential functions. Patient age ranged from 1 month to 7 years (mean 19.8 months). Renal biopsy was abnormal in 6 kidneys, of which 5 had a preoperative differential function of less than 33%. None of these kidneys had evidence of postoperative improvement in renal function on followup scans despite a technically successful result. All remaining 11 kidneys had normal biopsies and a preoperative differential function of greater than 44%. We conclude from these data that patients with ureteropelvic junction obstruction with a differential function of less than 35% have a high probability of significant histological changes on biopsy and a low probability of postoperative improvement in differential function.

We report on 226 male patients with cryptorchidism 6 months to 16 years old who underwent open testis biopsy at orchiopexy or orchiectomy at Children's Hospital and Health Center from 1986 to 1990. A total of 355 specimens was obtained. Tissues were preserved in Bouin's solution and examined on light microscopy for fertility index measurements. Several biopsies prepared using Bouin's preserved paraffinized tissue and glutaraldehyde preserved semi-thin cut tissue were found to have comparable fertility index measurements. Of 184 patients with unilateral undescended testes 87 also underwent biopsy on the contralateral descended testis. A total of 42 patients had bilateral undescended testes. Age matched comparisons were made between fertility index measurements of the undescended testes and those previously reported of normal testes. Additional case matched comparisons of fertility indexes were made in those children who underwent biopsy of the undescended testis and its descended mate. Statistical analysis was performed using the independent Student t-test. When comparing undescended to descended testes, there was no significant difference in the fertility index of patients 1 year old or younger but fertility index differences were statistically significant in all of the other age groups. Fertility index measurements were significantly decreased from normal expected values in all age groups with unilateral cryptorchidism and in all but the 13 to 18-month-old group with bilateral cryptorchidism. The fertility index in the descended testis was similar to previously reported normal testis measurements in boys between 13 months and 6 years old. Our data suggest that potential fertility in the cryptorchid testis may be significantly impaired compared to normal testicular fertility regardless of patient age at the time of discovery of the undescended testis. The fertility index of the descended mates of unilateral undescended testes may also be somewhat impaired in certain age groups. Orchiopexy in the first year of life may be indicate to preserve available fertility potential.

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