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Biomedical subjects

D Mitchell

Publications and source records attributed to D Mitchell.

At least 271 records · Page 15Linked to original sources
PubMed1984

Immunocytochemistry in the identification of vascular invasion in breast cancer.

Immunocytochemical stains were used to find out whether they would increase the accuracy of detecting lymphatic and vascular invasion by primary breast cancer cells over conventional histological methods. Immune probes for type IV collagen were of value in confirming the conventional diagnosis of vascular invasion while stains for factor VIII assisted in differentiating small blood vessels from lymphatic channels. Antibodies to type IV collagen also increased the accuracy and rate of detection achieved by conventional histology.

Basement Membrane↗
PubMed1984

The relationship of exercise to anovulatory cycles in female athletes: hormonal and physical characteristics.

The objective of this study was to examine the mechanisms by which physical activity affects the menstrual cycle. Women with high, medium, and low levels of physical activity were compared for menstrual function, physical characteristics, and urinary and serum levels of luteinizing hormone, follicle-stimulating hormone, prolactin, estradiol-17 beta, and 2-hydroxyestrone. None of the physical characteristics other than age and muscle area were significantly different in the three groups. The percentage of body fat did not appear to be a factor in the amenorrhea induced by strenuous exercise, as the percent of body fat in all three groups was less than 22%. The group of athletes under strenuous exercise which correlated with oligomenorrhea had decreased serum levels of luteinizing hormone, prolactin, and estradiol-17 beta but elevated levels of 2-hydroxyestrone. These data suggest that anovulatory cycles are correlated with the amount of exercise and increased levels of catechol estrogens. Catecholamines and beta-endorphin elevated by exercise may interact to suppress luteinizing hormone release at the hypothalamic pituitary axis.

Adolescent↗
PubMed1984

The use of immunohistochemical probes in the study of benign and malignant breast disease.

A review is presented of the use of immunohistochemical probes in the study of the cellular pathology of the breast. Using a combination of monoclonal and polyclonal antisera it has been possible to investigate the relationship between myoepithelial cells and basement membrane components in benign breast disease and the disturbance of this relationship in early invasive and infiltrating ductal carcinomas. The use of immunohistochemical techniques at the ultrastructural level provides the methodology for future detailed analyses. The heterogeneous expression of antigenic determinants characteristic of epithelial cells in the normal breast is considered in conjunction with its relevance to the heterogeneity seen in the invasive tumours.

Animals↗
PubMed1984

Invading squamous cell carcinoma can retain a basal lamina. An immunohistochemical study using a monoclonal antibody to type IV collagen.

A monoclonal antibody to human glomerular type IV collagen has been characterized and used in an immunohistochemical study of the distribution of this basement membrane protein in dysplasias, intraepithelial carcinomas, and infiltrating squamous cell carcinomas. Four squamous carcinoma cell lines established as xenografts in nude mice were also examined. In normal epidermis and mucosae, the basement membrane was clearly defined and intact. In areas of intraepidermal carcinoma, the basal lamina as defined by the antibody was usually continuous, and defects were only present in areas associated with an inflammatory infiltrate. Invasive squamous cell carcinomas, regardless of the degree of differentiation had a clearly delineated basement membrane at the epithelial stromal interphase. In areas of invasion, far removed from the in situ component, there were protrusions of tumor cells through the basement membrane into the stroma. Other abnormalities of basement membrane production such as aggregation of basement membrane and reduplication of the basal lamina were also associated with the carcinomas. There was a similar distribution of basal lamina material in involved lymph nodes and in squamous cell carcinomas that were growing as xenografts in nude mice. Our studies suggest that the loss of basement membrane type IV collagen is not generally associated with invasive squamous cell carcinomas and is not likely to be useful in the assessment of early invasion in this tumor. The similar distribution of type IV collagen in the xenografts and in the infiltrating tumors suggests that this system, in conjunction with the use of the same cell lines in vitro, will provide a model with which to study the control of deposition of type IV collagen.

Antibodies, Monoclonal↗
PubMed1983

Intraventricular injections of drugs which inhibit phospholipase A2 suppress fever in rabbits.

Injection of two chemically dissimilar inhibitors of phospholipase A2 (mepacrine and parabromophenacylbromide) into the cerebral ventricles of rabbits inhibited the febrile response to endogenous pyrogen given by the same route. 2. The same doses of the inhibitors given intravenously did not affect the febrile response to endogenous pyrogen given into the ventricles, indicating that their action was central. 3. When given intraventricularly the inhibitors did not affect the maintenance of core temperature in a cold environment, indicating that they did not impair thermoregulatory ability. 4. The inhibitors had no effect on the temperature rise following intraventricular injection of arachidonic acid. 5. These observations are compatible with the proposition that one or more metabolic products of arachidonic acid other than prostaglandin are involved in pyrogenesis.

Acetophenones↗
PubMed1983

Facial sensitivity to rates of temperature change: neurophysiological and psychophysical evidence from cats and humans.

The dynamic responses in a thermal afferent pathway to rates of temperature change have been studied in anaesthetized cats. Recordings were made in the caudal trigeminal nucleus from neurones with a synaptic input from facial cold receptors. Five rates of cooling and warming ranging from 0.05 degrees C/sec to 1 degree C/sec were applied to the receptive fields of the neurones. Several measures of the dynamic response were computed but the most representative was the maximum rate during cooling or the minimum rate during warming. During cooling the maximum rate increased with increasing cooling rates between 0.05 degrees C/sec and 0.25 degrees C/sec, but did not increase at faster rates. Minimum activity during warming reached near zero at rates of 0.25 degrees C/sec and faster. The total number of impulses generated during cooling or absent during warming was unrelated to rate of temperature change. The same thermal stimuli were applied to the cheeks of human subjects. They were able to sense cooling or warming changes at 0.05 degrees C/sec. They could also distinguish the faster of two cooling changes when these were slow, but not when they were fast. Warming rates could not be distinguished, except from an adapting temperature of 35 degrees C, when warm receptors would have been activated. There was good agreement between the responses of the cat neurones and the human sensations. Slow rates of cooling could be detected or distinguished. Fast rates appeared to saturate the neuronal and sensory mechanisms.

Adult↗
PubMed1983

A proposed method of dissection of the anterolateral abdominal wall -- applied features.

The dissection described allows the segmental nerve supply of the rectus abdominis to be seen in its continuity, namely: intercostal nerves seven to eleven, the subcostal and occasionally the iliohypogastric nerve as shown in Fig. 1. The advantages of transverse or interneural incisions are obvious. The medial retraction of the lower rectus after incision of the anterior part of the rectus sheath, exposing the femoral ring and pectineal ligament is a suitable approach of femoral hernia repair. The posterior part of the dissection shows the relation of subcostal nerve and the ventral ramus of the first lumbar nerve and/or its iliohypogastric and ilioinguinal branches to the superior lumbar triangle, which is of consequence in posterior approaches to the kidney. A lateral cutaneous branch, which normally comes off the iliohypogastric nerve also crosses the field. Brief mention is made concerning the anatomy of local anesthesia for inguinal hernia repair.

Abdominal Muscles↗
PubMed1983

The relationship of serology and nasal microbiology to pulmonary lesions in feedlot cattle.

A group of 62 beef calves, born and raised in an institutional herd, were transferred at nine months of age to a commercial feedlot where they remained until slaughter seven months later. Clinical, immunological and microbiological monitoring was carried out during this period. No serious clinical illness occurred. One hundred percent seroconversion to bovine virus diarrhea virus took place after introduction of the calves into the feedlot as well as almost complete (59/62) seroconversion to bovine herpesvirus 1, a proportion of which could be related to a single vaccination. Significant increases in recoveries of Mycoplasma spp. from nasal swabs also occurred in the feedlot. At slaughter, the lungs of all animals were recovered and examined for pathological lesions: 23 were completely normal and 39 showed minor histological changes chiefly characterized by areas of lobular to sublobular atelectasis. For this group of calves, no relationship was found between the presence of potential pathogens in nasal mucus and the occurrence of lesions in the lung. The serological results are discussed in terms of vaccinations and other known events that occurred during the study period.

Animals↗
PubMed1983

Comparison of the glycaemic effect of fructose, sucrose and starch-containing mid-morning snacks in insulin-dependent diabetics.

Capillary blood glucose levels were measured every 30 min for 2 h after four different 20 g carbohydrate mid-morning snacks of foods containing predominantly fructose, sucrose or starch in eight insulin-dependent diabetics and eight normal control subjects. In the diabetic subjects, there was no significant difference in the glycaemic effect of the four different snacks. This study does not support the view that fructose is a useful alternative sweetener for diabetics or the view that sucrose should be excluded from the diet of insulin-dependent diabetics.

Adult↗
PubMed1983

Penetrating ocular injury caused by nylon cord fragment from electric lawn trimmer.

A 58-year-old man sustained a penetrating injury in the left eye from a nylon cord fragment from an electric rotary weed trimmer. Repair of the corneal laceration, foreign body extraction, and anterior vitrectomy were performed. One year post injury the visual acuity was stable at 6/60. The need for protective eyewear when using power tools is emphasized.

Cataract↗
PubMed1982

Transfer of embryos from bovine leukaemia virus-infected cattle to uninfected recipients: preliminary results.

One hundred and fifty-one, day 6 or 7, embryos collected from cattle infected with bovine leukaemia virus (BLV) were transferred to uninfected recipients. Thirty-two pregnancies resulted. Two animals aborted at seven months. Three sets of twins and one single calf were still-born. The remaining 26 pregnancies produced 27 live calves which were raised to six months of age. All of the recipients, pregnant and non-pregnant, and all of the calves remained serologically negative for antibodies to BLV-glycoprotein antigen.

Animals↗
PubMed1982

The control of chondroitin sulphate biosynthesis and its influence on the structure of cartilage proteoglycans.

Chondroitin sulphate synthesis on proteoglycans was decreased in rat chondrosarcoma cell cultures in the presence of cycloheximide (0.1-1.0 muM) or p-nitrophenyl beta-D-xyloside (50 microM). In the presence of cycloheximide the proteoglycan monomer was of larger size, the chondroitin sulphate chains were increased in length, but a similar number of chains was attached to each proteoglycan and the size of the core protein was unaltered. In the presence of p-nitrophenyl beta-D-xyloside (50 microM), chondroitin sulphate synthesis was increased (by 60-80%), but the incorporation into proteoglycans was decreased (by 70%). The chondroitin sulphate chains were of shorter length than in control cultured and the number of chains attached to each proteoglycan was decreased. In cultures with cycloheximide or actinomycin D the synthesis of chondroitin sulphate was less inhibited on beta-xyloside than on endogenous proteoglycan. When the rate of chondroitin sulphate synthesis was decreased by lowering the temperature of cultures, the chains synthesized at 22 and 4 degrees C were much longer than at 37 degrees C, but in the presence of p-nitrophenyl beta-D-xyloside the chains were of the same length at all three temperatures. A model of chain elongation is thus proposed in which the rate of chain synthesis is determined by the concentration of xylosyl acceptor and the length of the chains is determined by the ratio of elongation activity to xylosyl-acceptor concentration.

Animals↗
PubMed1982

Monensin inhibits synthesis of proteoglycan, but not of hyaluronate, in chondrocytes.

Monensin (10nm-1mum) inhibited the incorporation of [(35)S]sulphate and [(3)H]glucosamine into proteoglycans by rat chondrosarcoma cells, but the incorporation of [(3)H]glucosamine into hyaluronate was unaffected. The results suggest that hyaluronate synthesis occurs in a cell compartment separate from chondroitin sulphate synthesis.

Animals↗