Charles A. Linke

Biological effects of ultrasound

When ultrasound is absorbed by tissue, heat is produced which may be destructive or, if controlled, can be therapeutic. In addition, ultrasound produces biological effects which cannot be explained on the basis of heating alone. Under certain exposure conditions production of ultrasonic lesions in brain tissue can be explained on a purely thermal basis. Examples of nonthermal effects of ultrasound include changes in growth, mitotic index and the production of chromosomal aberrations in plant roots.

Thresholds for Focal Ultrasonic Lesions in Rabbit Kidney, Liver, and Testicle

Thresholds are reported for production of focal ultrasonic lesions in rabbit liver, kidney, and testicle for 2 and 6 MHz, singe pulse exposures ranging in length from 1 to 60 s. Intensity-exposure time thresholds are found to be nearly independent of frequency as shown in earlier work for brain tissue. The results compare favorably with a thermal model for prediction of thresholds which considers the activation energy for thermal destruction of the tissues, their thermal diffusivity, absorption coefficients, time and intensity of exposure, and baseline temperature. All thresholds are of the same magnitude as those previously reported for brain. Those differences which are observed can be explained by the thermal model for the action of ultrasound on tissue.

Diagnosis of Nonopaque Calculi by Computed Tomography

Computed tomography can aid in the distinction of calculi from both tumors and clots in the urinary tract. Its availability, simplicity of interpretation, and noninvasiveness establish it as an important diagnostic modality in selected cases when calculus is in the differential diagnosis of upper urinary tract filling defects.

Thermal destruction of the canine prostate by high intensity microwaves

Abstract Following urinary diversion by bilateral cutaneous ureterostomy, canine prostates were exposed to localized intense microwave radiation (2450 MHz), and the tissue left in situ for observation. Structures adjacent to the prostate were shielded using microwave reflectors. Temperatures at or above 60°C for 15 min were maintained throughout the prostate. The temperature of the rectal lumen did not exceed 38°C. The procedure was well tolerated by all (eight) animals. The dogs were sacrificed 1 week (four animals) and 6 months (four animals) after radiation of the prostate. At sacrifice the bladder, prostate, distal urethra, and underlying rectum were removed en bloc , and examined by serial microscopic sections taken from the area of radiation. Prostate tissue showed thermal necrosis at 1 week and was totally reabsorbed at 6 months leaving only a small fibrous scar at the site of the previous prostate location. Shielded adjacent lateral tissues showed minimal scarring, and the rectal wall was normal. Marked localized tissue heating by exposure to microwave radiation, the development of sterile tissue necrosis in tissue thus exposed, and the ability of the body to absorb this tissue has been demonstrated. Microwave-induced localized hyperthermia in the treatment of malignant tissue for experimental and possible clinical use deserves further investigation.

Leydig cell tumor of testis

In adult patients with Leydig cell tumor of the testis, endocrinologic signs occur in 30 per cent of the cases and often precede the onset of a palpable testicular mass. Gynecomastia is the most common endocrinologic manifestation and probably is due to increased estrogen secretion by the Leydig cells. In the patient with adrenogenital syndrome and testicular enlargement it is difficult to distinguish Leydig cell tumor from adrenal rest hypertrophy. Four patients with Leydig cell tumor and endocrinologic manifestations are discussed; three are adults who presented with gynecomastia and the fourth is a patient with congenital adrenogenital syndrome. In the adult patient inguinal orchiectomy is the treatment of choice, while in the patient with adrenogenital syndrome initial management by high-dose steroid suppression should be attempted prior to testicular exploration.

Penile Abscess Involving the Corpus Cavernosum: A Case Report

A patient with a penile abscess containing mixed colonies of bacteria is presented. Ultrasound scan confirmed the physical examination findings of involvement of the corpus cavernosum. After incision and drainage the patient has normal erectile function.

Blunt renal trauma in the pediatric patient

Injury to the kidney from blunt trauma occurs rather frequently in the active, pediatric patient. Early evaluation and treatment of these children is essential in order to preserve maximum renal function. Ninety cases of pediatric renal trauma from blunt injury have been reviewed. The majority of these responded well to careful conservative, non-operative management. Many of those requiring surgical intervention responded well to initial conservative treatment followed by surgical intervention conducted as an elective procedure within the first week after injury. Five case reports with associated radiographic studies are presented.

The use of percutaneous nephrostomy and urinary alkalinization in the dissolution of obstructing uric acid stones.

Two patients are described who presented with complete urinary obstruction secondary to nonopaque uric acid stones. They were treated with percutaneous nephrostomy for urinary diversion and urinary alkalinization by local irrigation and oral sodium bicarbonate therapy with complete dissolution of the stone after 16 and 21 days of therapy. Percutaneous nephrostomy with urinary alkalinization is a reasonable, relatively safe alternative to surgical stone removal for patients with obstructing uric acid stones.

Percutaneous Nephropyelostomy in the Management of Acute Pyohydronephrosis

Percutaneous nephropyelostomy using the posterolateral approach was employed together with antibiotics and other supportive therapy as the initial step in the treatment of acute pyohydronephrosis, with gratifying results. Percutaneous nephropyelostomy is recommended as the procedure of choice for this specific clinical emergency.

Ultrasonic treatment of tumors: I. Absence of metastases following treatment of a hamster fibrosarcoma

Abstract The rate of metastasis has been compared for a hamster fibrosarcoma line treated either with ultrasound or by surgical excision. Continuous wave, 5 MHz ultrasound at 3 W/cm 2 for 6–8 min brought tumor temperatures to 60–70°C. The animals were observed over a period of 12 weeks. The ultrasound treatment effectively eradicated the local tumor. There was no indication of induction of metastasis by the treatment.