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Biomedical subjects

J Read

Publications and source records attributed to J Read.

At least 73 records · Page 4Linked to original sources
PubMed1988

A model for in vitro studies of epidermal homeostasis: proliferation and involucrin synthesis by cultured human keratinocytes during recovery after stripping off the suprabasal layers.

In normal epidermis there is a balance between the rate of cell division and the rate of terminal differentiation. This can be perturbed by injuries such as wounding or tape-stripping, but is reestablished during recovery. The aim of the studies described in this report was to assess whether cultures of human keratinocytes could be used as an experimental model for investigating the mechanism by which epidermal homeostasis is established and maintained. The suprabasal layers were stripped from confluent keratinocyte cultures by incubation in low-calcium medium (0.1 mM calcium ions). After return to normal medium (2 mM calcium ions), the basal layer regenerated a stratified culture of approximately the same thickness as controls. The kinetics of proliferation and terminal differentiation were monitored by measuring the total number of cells and proportion of involucrin-positive cells at intervals before, during, and after stripping. During recovery the proportion of cells expressing involucrin, assessed by immunofluorescence microscopy and polyacrylamide gel electrophoresis, rapidly returned to control levels, but the total number of cells per dish rose more slowly and often failed to reach control values. Thus, terminal differentiation was initially stimulated at the expense of proliferation. Our in vitro model of epidermal regeneration should provide a useful complement to intact skin and animal models for analyzing epidermal homeostasis.

Cell Differentiation↗
PubMed1987

Superficial bladder cancer treated by intravesical bacillus Calmette-Guerin or adriamycin: multicenter study interim report.

One hundred sixteen patients with superficial bladder cancers (Stages Ta, T1, and TIS) were evaluated and treated with either intravesical bacillus Calmette-Guerin [Tice strain] (BCG) or doxorubicin hydrochloride (Adriamycin [ADR]), in a multicenter study. One hundred nine of these patients currently have follow-up. Of these, 54 were completely resected and 55 incompletely resected. For complete resections, based on recurrence rates per 100 patient months, both BCG (0.22) and ADR (0.91) worked well, although BCG had a slightly lower recurrence rate. However, for incomplete resections, BCG (0.20) had a markedly lower recurrence rate than ADR (2.52). Eighteen patients failed initial treatment, with either BCG or ADR. All have been placed on long-term therapy schedules. Of the 12 failures who currently have follow-up, 11 (92%) have either partially or completely responded with additional intravesical therapy. No patients in this study have yet required cystectomies.

Administration, Intravesical↗
PubMed1987

Dynamic display of the temporomandibular joint meniscus by using "fast-scan" MR imaging.

In order to display temporomandibular joint (TMJ) images as a dynamic or motion study, a protocol was developed to obtain MR images of the TMJ in multiple phases of opening by using the "fast-scanning" capabilities of the GE Signa MR scanner. To facilitate this procedure a prototype device was also developed to passively open the patient's mouth from resting (closed) to fully open in user-defined increments (minimum 1 mm). MR imaging (surface coil) was carried out at each successive station using the GRASS, pulse-sequence data base of the GE Signa system operating at 1.5 T. Image-acquisition parameters were optimized in studies of cadavers and volunteers to obtain the clearest delineation of the TMJ meniscus and to determine any potential tradeoffs between total imaging time per slice (image quality), patient tolerance, and other practical considerations. For viewing, the images were sequentially placed in the video memory of the operating console and displayed in a back-and-forth-closed cine loop or "movie" mode at variable (operator-selectable) speeds. The dynamic sequences in four individuals were compared with static open- and closed-mouth views obtained with routine pulse sequences. Any single image from the dynamic display lacked the high resolution of the routine static images because of technical limitations of the pulse-sequence data base. However, in the movie mode the pertinent joint structures (such as meniscus and condyle) were clearly delineated, as were several of the important muscles of mastication. The anterior motion (translation) of the meniscus during jaw opening is particularly evident and suggests great potential for functional evaluation. These results show the feasibility of dynamic TMJ imaging with MR. The added information of the cine display potentially complements the routine static images and may prove extremely valuable in the assessment of TMJ dysfunction.

Cartilage, Articular↗
PubMed1987

The value of lymphoscintigraphy, lymphangiography and computer tomography scanning in the preoperative assessment of lymph nodes involved by pelvic malignant conditions.

In a preoperative study to identify accurately metastases to the lymph nodes within the pelvis and retroperitoneum, the three imaging techniques of pelvic interstitial lymphoscintigraphy, bipedal lymphangiography and computer tomography (CT) scanning were compared in 69 patients with carcinoma of the cervix uteri or rectum. Results were correlated with histologic node examination in all patients and each technique was assessed for sensitivity, specificity and over-all accuracy. Lymphoscintigraphy is too unreliable for routine use in the diagnosis or staging of pelvic malignant conditions. Lymphangiography detects involved lateral pelvic and para-aortic nodes but is unable to visualize the internal iliac or other medial pelvic nodes. CT scanning is only accurate if metastatic nodes are enlarged but may reveal other pathways of spread which will alter the surgical approach.

Adult↗
PubMed1982

Use of automobile seat restraints by children in two Canadian cities.

A telephone survey was conducted in Montreal and Calgary to determine the extent to which parents use safety restraints for their children in cars, the types of restraints used and the factors associated with such use. Of the combined sample 39% reported that their child regularly used a restraint, and 47% of the children in Montreal and 55% of those in Calgary wore an age-appropriate safety device. Birth order and the child's and the respondent's ages were significantly related to the use of restraints. However, the respondent's use of seatbelts was the factor most likely to affect the rate of use of restraints for children. Although a large proportion of the parents with younger children owned a carseat, one in four did not use it regularly. Parents who did not use carseats believed they were useless or dangerous; many preferred to hold the child in their laps or arms. The seatbelt law in Quebec and the existence of a carseat rental program in Calgary appear to have had some influence on the rate of the use of restraints for children.

Accidents, Traffic↗
PubMed1981

Use of glycopyrrolate in the parturient: effect on the maternal and fetal heart and uterine activity.

The effects of intravenous glycopyrrolate on maternal and fetal heart rate, heart rate variability, and maternal electromechanical intervals and blood pressure were evaluated in 20 term parturients in labor. Direct continuous fetal heart rate and intrauterine pressure were monitored via an intrauterine catheter. Maternal heart rate and R-pulse-wave intervals were measured and maternal blood pressure was recorded at 5-minute intervals. There were no significant changes in fetal heart rate or fetal heart rate variability. The maternal heart rate increased in all cases and the electromechanical interval decreased with the onset of maternal tachycardia. There were no significant changes in maternal blood pressure. Uterine activity increased in all cases; however, this increase does not appear to be greater than that expected in uterine activity as labor progresses.

Blood Pressure↗
PubMed1979

A low cost portable enuresis alarm.

The enuresis alarm described is a portable device designed for 'toilet training' of mentally sub-normal children. It weighs 70 gm with battery, has dimensions of 90 x 60 x 30 mm and conforms to DHSS recommendations. The battery life is over 1000 hours (6 weeks) in continuous use. Total component cost is is pounds 6.20 (in 1978), construction is simple and the circuit may be used as a conventional nocturnal enuresis alarm.

Amplifiers, Electronic↗
PubMed1977

Cytolethal effects of glucocorticoids in human lymphoblastoid cell lines.

Glucocorticoid hormones penetrate rapidly into intact lymphoblastoid cells and are retained with the same high affinity and specificity as with cytoplasmic extracts. Optimal conditions for lethal glucocorticoid responses in vitro were determined for a series of human lymphoblastoid cell lines by using different glucocorticoid preparations, and steroid solvents and by varying the cell density. Kinetic studies revealed that lethal glucocorticoid effects are dose-dependent and that continuous exposure of cells to steroid is necessary for progression of lethal effects to occur. Even under optimal conditions, human lymphoblastoid cells only exhibit a marked cytolethal response to glucocorticoids at concentrations which greatly exceed both physiological and therapeutically attainable steroid levels. They are also greatly in excess of steroid levels required to saturate the cytoplasmic receptors of intact or disrupted lymphoblastoid cells. It is suggested that either lethal steroid mechanisms in vitro differ fundamentally from those in vivo or the pharmacological activity of glucocorticoids in vivo does not involve a direct cytolethal action.

Burkitt Lymphoma↗
PubMed1976

The second oncogenic step.

Three theories of the development of a malignant change which each involve two successive steps are described. Armitage, Doll (1957) proposed that two homologous chromosomes each contained a region which was critical in the control of cell division. The two steps were mutations in these regions brought about by random exposure to carcinogenic agents. Comings (1973) proposed a similar theory but the two steps were considered to be spontaneous mutatons. This paper points out that if one mutation has occurred this can become dominant in at least six ways which mostly involve chromosome translocations. The synergism between oncogenic agents and ionizing radiation and the ability to breed out high and low cancer incidence stocks of animals from a common stock can be explained on the same lines.

Animals↗
PubMed1976

Measurement of 3,3',5'-Triiodothyroinine (reverse T3), 3,3'-L-diiodothyronine, T3 and T4 in human amniotic fluid and in cord and maternal serum.

In order to assess fetal function at term, we have investigated parameters of thyroid hormone secretion and degradation in human amniotic fluid and in cord and maternal sera at delivery. The parameters measured included 3,3' L-diiodothyronine (3,3'T2), 3,3',5'-triiodothyronine (reverse T3), 3,3',5'-triiodothyronine (T3), thyroxine (T4), dialyzable T3 and T4, thyroxine binding globulin (TBG),and total iodine. The mean (+/- SE) 3,3'T2 concentrations in cord sera, amniotic fluid, and maternal sera were 20 +/- 1 ng/100 ml, 20 +/- 2 ng/100 ml,and 27 +/- 3 ng/100 ml, respectively. The normal range of this metabolite in the sera of non-pregnant adult subjects was 7 to 29 ng/100 ml. The mean (+/- SE) concentration of reverse T3 was higher in cord sera (315 +/- 16 ng/100 ml), amniotic fluid (82 +/- 25 ng/100 ml) and maternal sera (79 +/- 5 ng/100 ml) than in the sera of normal subjects (mean +/- 2 SD; 60 +/- 12 ng/100 ml). In amniotic fluid, T3, T4, and TBG were low, per cent dialyzable T3 and T4 were increased, and iodine concentrations were relatively normal in comparison to their respective serum levels in euthyroid adults. Since T3 and T4 were low in amniotic fluid our data indicate that measurements of 3,3'T2, reverse T3, or per cent dialyzable T3 and T4 in amniotic fluid would be the potentially most useful in establishing the diagnosis of congenital hypothyroidism before birth. In addition, these studies demonstrate that 3,3'T2 is normally present in the peripheral circulation and suggest that reverse T3 is the major source of 3,3'T2 in both amniotic fluid and cord blood.

Amniotic Fluid↗
PubMed1975

The lethal effect on bacteria of dimethylnitrosamine used without an activating agent.

Survival curves have been obtained for various strains of bacteria treated with dimethylnitrosamine (DMN) solutions of different concentrations. The results are compatible with the conclusion that DMN kills the bacteria by an attack on their deoxyribonucleic acid (DNA) and the damage so caused can be repaired by the same systems that repair damage created by ultraviolet light or X radiation. No activating agent was added to the DMN solutions and under these circumstances their activities were in proportion to the squares of their concentrations. It is suggested that this is because two molecules of DMN plus one of oxygen produce two carbonium ions, two hydroxyl ions, two formaldehyde molecules and two nitrogen molecules.

DNA Repair↗
PubMed1975

Traumatic hyphema: surgical vs medical management.

We undertook a prospective study of traumatic hyphema during the years 1970 through 1972 to compare the effects of medical management and surgical evacuation in the more severe hyphemas. A protocol for sutdy of the two regimens enabled us to compare the results of therapy. The findings indicate that medical management is preferable for the initial 4 days in major hyphemas. Surgical intervention does not offer improvement in the poor prognosis of total hyphemas during this early period. The incidence of complications and the incidence of permanent poor visual results are higher in surgically treated patients than in those managed medically. Surgical intervention should be reserved for cases showing: (1) microscopic corneal blood staining; (2)total hyphemas with intraocular pressures of 50 mm Hg or more for 5 days (to prevent optic nerve damage); (3) hyphemas that are initially total and do not resolve below 50% at 6 days with intraocular pressures of 25 mm Hg or more (to prevent corneal blood staining); and (4) hyphemas that remain unresolved for 9 days (to prevent peripheral anterior synechiae). A brief review of problems that may be encountered in the various forms of surgical management is included in an effort to prevent repeating similar pitfalls.

Adult↗