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Biomedical subjects

J M Price

Publications and source records attributed to J M Price.

At least 91 records · Page 5Linked to original sources
PubMed1979

Involution of the female Mullerian duct of the fetal rat in the organ-culture assay for the detection of Mullerian Inhibiting Substance.

The study of Mullerian Inhibiting Substance (MIS) has been made possible because of the organ-culture bioassay devised by Picon ('69) for detecting MIS in vitro. We have studied the degeneration of the female Mullerian duct of the rat fetus, the target tissue of the assay, with electron microscopy. We have observed that the involution of the female Mullerian duct in the organ-culture assay follows a pattern of degeneration similar to the normal involution of the male Mullerian duct under the influence of MIS from the fetal testis (Price et al., '77). This involution involves alterations in the duct epithelium subsequent to a response of the mesenchyme surrounding the duct. The degeneration of a specific organ system under the direct influence of a specific factor, Mullerian Inhibiting Substance, represents an example of "programmed cell death."

Animals↗
PubMed1979

Computed tomography in the evaluation of the suspected carcinomatous prostate.

Twenty-six patients with physical findings suspicious for prostatic cancer were examined by contrast-enhanced computed tomography (CT) of the prostate region prior to prostatic biopsy of resection. Twelve had benign hypertrophy and/or prostatitis and fourteen had adenocarcinoma. Prostatic contour, density, seminal vesicle "angle," extraprostatic soft tissue "mass," and the pelvic fat planes were evaluated. A nodular prostatic contour was found only in patients with adenocarcinoma of the prostate, indicating a role for CT in the diagnosis of this disease. Two patients with benign prostatic disease had extraprostatic soft tissue "masses" identical to those seen in six patients with adenocarcinoma of the prostate, suggesting limited usefulness of CT in staging patients with known tumor.

Adenocarcinoma↗
PubMed1977

Programmed cell death in the Müllerian duct induced by Müllerian inhibiting substance.

The importance of a secretory product of the fetal testis, Müllerian Inhibiting Substance, in determining the fate of the Müllerian duct in the developing male fetus has been well documented. The present investigation has examined the mechanism of action of Müllerian Inhibiting Substance in the male rat fetus during the course of Müllerian duct degeneration. The action of Müllerian Inhibiting Substance mimics the general morphogenetic phenomenon of "programmed cell death," although important diferences were found compared to the majority of other studies of cell death. The initial morphological event in the degenerating Müllerian duct is an increase in lysosomes within the duct cells. Following loss of polarity and orientation, the duct cells are subsequently removed by invading macrophages from the surrounding mesenchyme. Concommitant with the differentiation of these macrophages, the adjacent mesenchyme assumes a characteristic whorled pattern around the degenerating Müllerian duct. Cytochemical localization of acid phosphatase confirmed the presence of newly formed lysosomes within the Müllerian duct cells and subsequently within the cytoplasm of the invading macrophages.

Acid Phosphatase↗
PubMed1977

Mechanical properties of taenia coli smooth muscle in spontaneous contraction.

The following mechanical tests have been performed on spontaneously contracting taenia coli: isometric step stretch, isotonic step loading, and length-tension. Passive stress-strain tests have also been done. Information on spontaneous contraction was more readily obtained in isometric tests. In length-tension tests, each isometric contraction was analyzed on a phase plane which is a representation of muscle stress, sigma(t), versus the rate of change of stress, sigma(t). The curve in the phase plane provided parameters for describing spontaneous contraction as a function of muscle length, L. The maximum active stress in a cycle of spontaneous contraction, S(L)max, and the maximum rate of increasing active stress, [S(L)]max, were shown to depend on L in the same way. Both parameters attain a maximum value (upper bound) at the same muscle length, Lmax. When L less than Lmax, the minimum stress in a spontaneous contraction, sigma(l)min, is negligible. If L greater than Lmax, sigma(L)min increases nonlinearly and is equal to the passive stress, tau(L), in an epinephrine-relaxed muscle. The results show that the ratio of [S(L)]max to S(L)max, eta(L), is constant for a physiological range of muscle length. This suggests that eta(L) may be used as an index of contractility for taenia coli.

Animals↗
PubMed1976

Naturally occurring and braken-fern-induced bovine urinary bladder tumors. Clinical and morphological characteristics.

Clinical and morphological characteristics of 139 naturally occurring and 20 braken-fern-induced urinary bladder tumors of cows were studied. Hematuria was prominent and occurred as early as 60 days after braken fern feeding began. Anemia and changes in leukocytes were late manifestations. Papillomas appeared as early as 1 year, whereas invasive carcinomas did not develop until 2.6 years after initiation of feeding. Twenty of 30 cows fed braken fern developed bladder tumors within 5.3 years. None of eight untreated control cows that lived 4 years or six that lived 10 years developed neoplasms. Naturally occurring and fern-induced bladder tumors were epithelial (35%) or mixed epithelial and stromal (55%). Papillomas occurred in 24% and carcinomas in 61% of naturally occurring cases, whereas there were papillomas (40%) and carcinomas (50%) in fern-fed cows. Naturally occurring tumors were metastatic to regional lymph nodes and lung. No metastases were detected in fern-fed cows.

Adenoma↗
PubMed1975

A device for testing mechanical properties of biological materials--the "Biodyne".

An electromechanical servo-controlled device has been developed. This device can be used to test the mechanical behavior of a wide variety of biological soft tissues. Control and execution of material testing procedures such as stress-strain, vibration, relaxation, creep etc. can be performed by manual operation of the device or by interfacing it with a laboratory type minicomputer. Experiments on excitable tissues such as muscle can also be executed. The design details and system performance are discussed.

Biomechanical Phenomena↗
PubMed1970

Bladder tumors in rats fed cyclohexylamine or high doses of a mixture of cyclamate and saccharin.

Papillary transitional cell tumors were found in the urinary bladders in 8 rats out of 80 that received 2600 milligrams per kilogram of body weight per day of a mixture of sodium cyclamate and sodium saccharin (10:1) for up to 105 weeks. From week 79 on, several of these rats received cyclohexylamine hydrochloride (125 milligrams per kilogram per day, the molecular equivalent of the conversion of about 10 percent of the cyclamate dosage to cyclohexylamine) in addition to the sodium cyclamate and sodium saccharin. In another study in which 50 rats were fed daily 15 milligrams of cyclohexylamine sulfate per kilogram of body weight for 2 years, eight males and nine females survived. One of the eight males had a tumor of the urinary bladder. In neither study were bladder tumors found in the control rats or in rats treated with lower doses of the compounds.

Amines↗