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Biomedical subjects

M A Jones

Publications and source records attributed to M A Jones.

At least 19 recordsLinked to original sources
PubMed1992

Rabbit blastocysts accumulate platelet-activating factor (PAF) and lyso-PAF in vitro.

Platelet-activating factor (1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine; PAF) is a very potent phospholipid, which has been demonstrated to stimulate smooth muscle and change vascular permeability. PAF has been detected in the rabbit preimplantation uterine endometrium and has been demonstrated to bind specifically to rabbit uterine membranes. To evaluate the possible role of PAF in maternal-embryonic chemical communication, we report here that rabbit blastocysts can accumulate [3H]PAF from their environment. Blastocysts were able to accumulate [3H]PAF as time-, buffer-, age-, and concentration-dependent functions. The accumulation was inhibited by some PAF receptor antagonists, such as U66985, as well as by unlabeled PAF and lyso-PAF, indicating that the accumulation process may be receptor mediated. The data support the current model of PAF as a paracrine factor in preimplantation stages of reproduction.

Animals↗
PubMed1992

Clinical reasoning in manual therapy.

Clinical reasoning refers to the cognitive process or thinking used in the evaluation and management of a patient. In this article, clinical reasoning research and expert-novice studies are examined to provide insight into the growing understanding of clinical reasoning and the nature of expertise. Although hypothetico-deductive methods of reasoning are used by clinicians at all levels of experience, experts appear to possess a superior organization of knowledge. Experts often reach a diagnosis based on pure pattern recognition of clinical patterns. With an atypical problem, however, the expert, like the novice, appears to rely more on hypothetico-deductive clinical reasoning. Five categories of hypotheses are proposed for physical therapists using a hypothetico-deductive method of clinical reasoning. A model of the clinical reasoning process for physical therapists is presented to bring attention to the hypothesis generation, testing, and modification that I feel should take place through all aspects of the patient encounter. Examples of common errors in clinical reasoning are highlighted, and suggestions for facilitating clinical reasoning in our students are made.

Bias↗
PubMed1992

Isolated cerebellar metastasis from ovarian carcinoma. Case report and review of the literature.

Isolated cerebellar metastasis from ovarian cancer is a very rare entity with only one other reported case in the literature. We report an additional case. This patient had a single 3 x 3 cm cerebellar lesion that was removed revealing metastatic papillary carcinoma consistent with a known ovarian primary. We also present a review of the literature concerning central nervous system (CNS) metastases from ovarian cancer and the various methods of treatment currently being used. Current literature suggests that patients with isolated resectable lesions should be managed surgically.

Cerebellar Neoplasms↗
PubMed1991

Calcitonin gene-related peptide and corneal innervation: a developmental study in the rat.

The development of calcitonin gene-related peptide-like immunoreactive (CGRP-LI) nerves was studied in neonatal and adult rat corneas stained immunohistochemically according to an avidin biotin peroxidase procedure. At birth, rat corneas already contained dense plexuses of CGRP-LI nerve fibers. Most of the nerves entered the cornea in 12-15 prominent stromal nerve bundles located at regular intervals around the circumference of the cornea. Fibers in these bundles entered the epithelium approximately midway between the limbus and the center of the cornea and supplied extensive central and pericentral areas of the tissue. In addition, smaller numbers of axons entered the cornea individually and in small fascicles located in between the larger bundles and supplied mainly peripheral territory. In the epithelium, the CGRP-LI nerves formed a complex, highly anastomotic meshwork that ramified uniformly throughout central and peripheral areas of the tissues. Fibers in the plexus gave origin to numerous short, stout terminal axons that extended into the adjacent epithelium in all directions with no preferred orientation. During the first week of neonatal life, several changes in CGRP-LI innervation occurred: 1) the innervation density of the central and pericentral cornea increased relative to the peripheral cornea; 2) intraepithelial axons became progressively longer, increased in branching complexity, and oriented preferentially towards the center of the cornea; and 3) a dense innervation of the corneoscleral limbus and, in particular, the branches of the marginal artery, developed. Midway through the second week of life, immature versions of corneal epithelial "leashes," the dominant feature of the adult corneal innervation, were first observed. Over the next 10 days, the leash formations in the central and pericentral cornea gradually became more complex and gave rise to greater numbers of terminal axons, compared to developing leashes in the peripheral cornea. The mature pattern of corneal CGRP-LI innervation was reached on day 21 and remained constant (except for compensatory growth-related elongation of axons) for at least the first 6 months of life. Transection of the ophthalmomaxillary nerve or neonatal administration of the sensory neurotoxin capsaicin resulted in the total loss of CGRP-LI staining from the cornea. In contrast, removal of the superior cervical ganglion had no effect on corneal CGRP-LI staining. The extraordinary density and complexity of the CGRP-LI innervation of the rat cornea demonstrated at all stages of development in this study suggests that these nerves may play important roles in corneal sensory, reflex, and trophic functions.

Aging↗
PubMed1991

DNA histogram debris theory and compensation.

In this paper we describe a theory of DNA histogram debris generation and compensation that can be applied to paraffin-embedded frozen tissue preparations. The theory predicts the distribution of fragments generated from single and multiple random sectioning of three-dimensional ellipsoids representing nuclei. The fragment distribution is assumed to be a major component of the underlying debris in DNA histograms. A comparison of S-phase fractions (SPF) from matched tissue prepared by frozen and formalin-fixed paraffin-embedded DNA methods demonstrates the usefulness of the theory.

Cell Cycle↗
PubMed1991

A discrete-time model with vaccination for a measles epidemic.

A discrete-time, age-independent SIR-type epidemic model is formulated and analyzed. The effects of vaccination are also included in the model. Three mathematically important properties are verified for the model: solutions are nonnegative, the population size is time-invariant, and the epidemic concludes with all individuals either remaining susceptible or becoming immune (a property typical of SIR models). The model is applied to a measles epidemic on a university campus. The simulated results are in good agreement with the actual data if it is assumed that the population mixes nonhomogeneously. The results of the simulations indicate that a rate of immunity greater than 98% may be required to prevent an epidemic in a university population. The model has applications to other contagious diseases of SIR type. Furthermore, the simulated results of the model can easily be compared to data, and the effects of a vaccination program can be examined.

Adolescent↗
PubMed1991

Flow cytometric DNA analysis versus cytology in the evaluation of peritoneal fluids.

The use of flow cytometric DNA analysis as an adjunct to cytology in peritoneal fluid evaluation was studied. One hundred ninety-five fluids from 193 gynecologic patients were subjected to both DNA analysis and cytologic examination. It was found that 117/195 (60%) had invasive malignancies (50 ovarian, 48 endometrial, 17 cervical, and 2 miscellaneous); 34/117 (28%) patients with malignancies were positive by cytology, and 10/117 (8.5%) were positive (aneuploid) by DNA analysis. Of 34 cytologically positive cases, 7 (21%) were DNA positive, 25 (74%) were DNA negative, and in 2 (6%) insufficient cells were obtained. Only 3 fluids (3%) from malignancies were positive by flow cytometry and negative by cytology (1 stage I ovarian cancer, 1 stage I endometrial cancer, and 1 stage III ovarian cancer). No false-positive cytology and one probable false-positive flow result was obtained. If only those patients with histologically documented peritoneal involvement are considered, 29/43 (65%) had positive cytology and 8/43 (19%) had a positive flow result. We conclude that: (1) the high false-negative rate of flow cytometry (79%) versus cytology in this study may be related to a high percentage of diploid cancers, specimen preparation, or histogram interpretation, and (2) flow cytometry rarely adds to cytologic evaluation and is probably best reserved for use only in selected cases.

Ascitic Fluid↗
PubMed1991

Extragenital malignant mixed müllerian tumor: review of the literature.

A case of extragenital malignant mixed mullerian tumor (MMMT) of the heterologous type 11 years after treatment of a Stage I ovarian neoplasm in a 65-year-old patient is described. There was no evidence of a histologic relationship between these two neoplasms. This case represents the 10th report of an extragenital MMMT. The medical literature and histogenesis of this rare tumor are discussed.

Aged↗
PubMed1991

Diffuse laminar endocervical glandular hyperplasia. A benign lesion often confused with adenoma malignum (minimal deviation adenocarcinoma).

We report seven examples of a hitherto undescribed pseudoneoplastic glandular lesion of the uterine cervix that we have designated "diffuse laminar endocervical glandular hyperplasia." The patients ranged in age from 22 to 48 (mean 37) years. Only one of them had a history of hormone intake. All the lesions were incidental findings in hysterectomy specimens performed for dysfunctional uterine bleeding (five cases) or symptomatic leiomyomas (two cases). Microscopic examination revealed a proliferation of moderate-sized, evenly spaced, differentiated endocervical glands within the inner one-third of the cervical wall, sharply demarcated from the underlying cervical stroma. Reactive atypia was seen in some cases but significant cytologic atypia was absent. A marked inflammatory response was present in five of the seven cases. The main consideration in differential diagnosis was adenoma malignum (minimal deviation adenocarcinoma). Major features that helped in this distinction were a lack of irregular stromal infiltration and a desmoplastic stromal response, and an absence of focal malignant cytologic features. Follow-up for an average of 6.5 years in five of the seven cases was uneventful.

Adenocarcinoma↗
PubMed1991

FMS (CSF-1 receptor) and CSF-1 transcripts and protein are expressed by human breast carcinomas in vivo and in vitro.

The expression in vivo of FMS transcripts and antigen by neoplastic epithelial cells was demonstrated immunohistochemically or by in situ hybridization in sixteen of seventeen human breast carcinoma specimens and one case of sclerosing adenosis. Expression of CSF-1 receptor (FMS) transcripts and protein was also observed in vitro in two or three breast carcinoma-derived cell lines and was dramatically increased by dexamethasone, a potent glucocorticoid and inducer of mammary epithelial cell differentiation. Immunohistochemical staining with an anti-CSF-1 antibody identified neoplastic epithelial cell co-expression of fms and CSF-1 antigens in more than one-third of the fms-positive invasive carcinoma specimens. These results suggest that autocrine and paracrine interactions of the lymphohematopoietic cytokine CSF-1 and its receptor may participate in the biology of human mammary neoplasms.

Blotting, Northern↗
PubMed1978

Missing pieces.

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Catheterization↗
PubMed1978

Connective tissue proteins of the baboon lung: concentration, content and synthesis of collagen in the normal lung.

Lung connective tissue proteins have been assayed in 12 normal juvenile baboons (Papio cynocephalus). The collagen concentration (26.8 +/- 5.1 microgram hydroxyproline per mg dry weight) is comparable to values reported for adult human lung, while the rate of collagen synthesis (0.242 +/- 0.082 nmoles hydroxyproline per mg DNA per hour) is approximately half that of human lung. Proteins other than collagen are synthesized at approximately equal rates in human and baboon lung. Elastin concentration was estimated to be 33 microgram insoluble elastin protein per mg dry weight, within the range reported for normal human lung. Values have also been calculated for the lobar contents of protein, DNA, and collagen, as well as the rates of synthesis of collagen and other proteins in the entire upper lobe of the right lung of these animals. The collagen concentrations in the lung show wide differences among various animal species. However, the baboon lung is similar to human lung. This similarity may be important in the interpretation of alterations in lung connective tissue metabolism associated with experimental diseases.

Animals↗