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Biomedical subjects

J Petrek

Publications and source records attributed to J Petrek.

At least 37 records · Page 2Linked to original sources
PubMed1987

Auditory brain stem responses to monoaural stimulation registered in symmetrical areas of cat's brain cortex.

In five anaesthetized cats (Nembutal 35 mg/kg) with 14 chronically implanted recording epidural electrodes the auditory brain stem responses (ABR) to monoaural stimulation (click) in symmetrical areas of the brain cortex were recorded. Each ABR to acoustic stimulus of sufficient intensity is formed by a complex of alternating five positive (P1-P5) and four negative (N1-N4) peaks; two further small peaks often follow on this complex. The amplitude of ABR peaks N3, P4, N4 and P5 to monoaural stimulation in symmetrical areas of cat's cortex was always higher in records from the hemisphere contralateral to the stimulated ear than in records from the ipsilateral one. The amplitude of P3 ABR peak behaved to the contrary--it was higher on ipsilateral hemisphere. On the other hand the amplitude of ABR peaks P1, N1, P2 and N2 to monoaural stimulation in symmetrical areas of the brain cortex showed no degree of lateralization in our experimental animals. The present findings support indirectly the presumption that each peak of the ABR is generated by a particular acoustic brain stem structure.

Acoustic Stimulation↗
PubMed1984

Biliary cystadenoma.

In the differential diagnosis of liver cysts, biliary cystadenoma is one of the rarest causes. We have reported a typical case, our patient having relatively asymptomatic, insidiously progressive, massive hepatic enlargement. Ultrasonography and computed tomography were the most helpful tests. The gross and microscopic pathologic findings are distinctive.

Aged↗
PubMed1983

Interaction of short latency cortical responses to somatosensory and acoustic stimuli in anterior part of middle suprasylvian gyrus of cat's brain.

The work sums up the results of experiments in which interaction was studied between cortical short latency nonprimary responses (SNPR) produced by paired stimuli in the anterior part of the middle suprasylvian gyrus of cat's brain. In paired stimuli (somatosensory + acoustic or acoustic + somatosensory) the second stimulus (test stimulus) followed after the first stimulus (conditioning stimulus) in intervals of 20 to 400 ms. An analysis of the results demonstrates that in an animal anaesthetized with Nembutal (35 mg/kg) an interaction takes place between central systems taking part in the origin of acoustic and somatosensory SNPR in the anterior part of middle suprasylvian gyrus. On the basis of these data the authors conclude that acoustic and somatosensory SNPR in the anterior part of middle suprasylvian gyrus result from the activity of two different and independent systems.

Acoustic Stimulation↗
PubMed1982

Postmenopausal breast abscess.

Eighteen postmenopausal women with breast abscess were treated at Grady Hospital between 1975 and 1978. Breast abscess was remarkable for its characteristic lack of inflammation, as well as its rarity, in this age group (median, 59 years). Only 17% of patients reported fever and/or breast pain. On initial examination, 33% had erythema, warmth, and/or fluctuance. The white blood cell count was greater than 10,000/cu mm in only 14% of patients. (Abscess was not even suspected in 22%, as a breast "mass" was excised for diagnostic frozen section.) The preoperative diagnosis was cancer in 55%. Location was peripheral in 27% and subareolar in 72%, similar to what has been noted in premenopausal women. The rare occurrence of breast abscess in postmenopausal women can be confused with cancer because of the abscess' indolent characteristics. History, physical examination, mammograms, and white blood cell count are equally unhelpful in the diagnosis. Although ideal treatment of abscess is usually incision and drainage, in this age group excision of the total "mass" is sometimes beneficial for diagnosis and prevention of recurrence.

Abscess↗
PubMed1977

Ultrasound in renal transplantation.

Because of important differences in prognosis and treatment, prompt and accurate diagnosis of fever, decreasing function, and pain and tenderness around a renal allograft is crucial for differentiation between acute rejection and other post-operative conditions which may give a similar picture. Ultrasound examinations within 24 hours have been performed on all transplant recipients exhibiting symtoms compatible on all transplant recipients exhibiting symptoms compatible with an episode of acute rejection between September 1973 and June 1976 at the Peter Bent Brigham Hospital. The patients were separated into four groups dependent upon diagnosis by ultrasound; Group I(73 patients); allograft enlargment consistent with acute rejection; Group II (14 patients); dilitation of the collecting system; Group III (14 patients); perinephric fluid collections; Group IV (6 patients); miscellaneous conditions. The accuracy of the ultrasound technique was compared within each group to the results from intravenous pyelography, retrograde pyelography, serial renograms, kidney biopsy and/or surgical exploration. This convenient, non-invasive and reproducible method has been extremely effective in the differential diagnosis of rejection in clinical transplantation.

Adult↗