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Biomedical subjects

W Johnston

Publications and source records attributed to W Johnston.

At least 37 records · Page 2Linked to original sources
PubMed1990

New brush-needle for percutaneous biopsy.

A new 21-gauge coaxial brush biopsy needle system is described. Preliminary tests were performed on 20 surgically resected specimens, and the results were compared with those obtained in biopsies taken with a 22-gauge Chiba needle. The brush needle specimens demonstrated a greater yield of biopsy material and better cellularity than those obtained with the Chiba needle, permitting diagnosis in a larger number of specimens. The results of this preliminary study indicate that the use of a brush-type coaxial device can enhance the yield of materials obtained through a small-gauge biopsy needle.

Biopsy, Needle↗
PubMed1989

Uveitis and arthritis induced by adjuvant: clinical, immunologic and histologic characteristics.

The intradermal administration of complete Freund's adjuvant (CFA) containing Mycobacterium butyricum to Sprague-Dawley (SD) and Lewis strain rats results in polyarthritis and uveitis. Over 90% of the eyes examined from the SD rats given CFA had histologic evidence of anterior uveitis, clinically evident in only 20 to 28%. Many rats developed arthritis without clinical uveitis, but uveitis was rare in the absence of arthritis. Histologically, the ocular inflammation was characterized by a polymorphonuclear, and later, a lymphocytic infiltration of the iris and ciliary body with cells and fibrinous exudate in the anterior chamber and cells in the vitreous. Antibodies and cellular immunity to ocular (S antigen, alpha crystallin), articular (type II collagen, proteoglycan) and bacterial components (MDP), were demonstrated in some rats, but positive tests did not correlate with either articular or ocular disease. Ten percent of rats given type II collagen in incomplete Freund's adjuvant developed uveitis. Thus, the pathogenesis of the arthritis and uveitis in the adjuvant model may be mediated by lymphocytes which exhibit crossreactivity with antigens in these structures, although the specificity of such antigens has not been identified in our studies.

Animals↗
PubMed1986

Aortic and right atrial pressures during standard and simultaneous compression and ventilation CPR in human beings.

Coronary perfusion pressure, as reflected by the diastolic aortic to right atrial (Ao-RA) pressure gradient, has been shown to correlate well with coronary blood flow during standard external CPR (SE-CPR) and is an important determinant of successful cardiac resuscitation. Few studies have documented such Ao-RA gradients in human beings, however. Twenty patients sustaining out-of-hospital cardiopulmonary arrests and basic cardiac life support were instrumented with thoracic aortic and right atrial catheters on arrival in the emergency department. The mean time from arrival in the ED to catheter placement was 16.5 +/- 6.0 minutes. With SE-CPR, peak systolic aortic and right atrial pressures were 73.7 +/- 20.2 mm Hg and 69.6 +/- 18.3 mm Hg, respectively. End diastolic aortic and right atrial pressures were 27.9 +/- 7.3 mm Hg and 20.3 +/- 7.2 mm Hg, respectively, with an end diastolic gradient of 7.9 +/- 9.1 mm Hg. Three patients had systolic Ao-RA gradients of more than 25 mm Hg, which is consistent with some cardiac compression as a mechanism of flow. Five patients also had one-minute trials of simultaneous compression and ventilation CPR (SCV-CPR). Ao-RA end diastolic gradients decreased in four of the five during SCV-CPR. No patient in this study was resuscitated successfully. We conclude that ED SE-CPR provides little coronary perfusion for victims of prehospital cardiac arrest. Although SCV-CPR has been shown to improve carotid blood flow in human beings, it appears to have an adverse effect on the already minimal myocardial perfusion provided by SE-CPR.

Aged↗
PubMed1985

The development of radiologic schemata through training and experience. A preliminary communication.

Research underway in our laboratory suggests that radiologists may develop a visual representation of a prototypical radiograph (a schema) in the course of clinical training. This schema appears to guide radiologists' interpretations of chest radiographs. Cognitive psychologists have demonstrated schematic processing for familiar events or scenes. In our experiments, experienced radiologists (18.5 years average experience), junior staff radiologists (3.5 years), and first-year radiology residents participated in a simple recognition/memory test of chest radiographs. The test phase followed a training phase in which each radiograph was viewed for 500 milliseconds. Both abnormal and normal chest radiographs were used. Correct responses were recorded during the test phase for measuring recognition memory. Residents showed no significant difference in memory between normal and abnormal films. Observers with greater radiologic experience exhibited poorer memory for normal films and better memory for abnormal films compared with less experienced observers. We hypothesize that the development of radiographic schemata as a result of experience accounts for these findings.

Cognition↗
PubMed1984

The significance of peritoneal cytology in patients with carcinoma of the cervix.

Between 1972 and 1977, 141 patients with benign gynecologic disease and 149 patients with carcinoma of the cervix were evaluated with peritoneal fluid cytology at time of celiotomy. There was no positive cytology (malignant cells) in the benign disease group. The overall incidence of positive peritoneal cytology in the cervical group was 8.1%. Positive peritoneal cytology was found four times more frequently in adenocarcinoma and adenosquamous carcinomas than squamous carcinomas. The incidence in patients undergoing surgery for recurrent or persistent carcinoma after radiation therapy was 22.6% compared to 4.5% in those treated primarily with definitive surgery. The prognoses do not seem to be influenced by peritoneal cytology status when other poor prognostic factors were considered.

Ascites↗
PubMed1981

Prognostic significance of peritoneal cytology in patients with endometrial cancer and preliminary data concerning therapy with intraperitoneal radiopharmaceuticals.

One hundred sixty-seven patients with clinical State I carcinoma of the endometrium were treated primarily by operation consisting of total abdominal hysterectomy, bilateral salpingo-oophorectomy, selective pelvic and para-aortic lymphadenectomy, and cytologic testing of peritoneal washings. Twenty-six (15.5%) of the 167 patients had malignant cells identified on cytologic examinations of peritoneal washings. Recurrence developed in 10 of these 26 (34.0%) compared to 14/141 (9.9%) patients with negative cytologic testing. Of the 26 patients, 13 (50%) had disease outside of the uterus at operation and seven have died of disease (54%). Thirteen patients had malignant cells in the peritoneal washings but no disease outside of the uterus and six (46%) of these have died of disseminated intra-abdominal carcinomatosis. On the basis of the poor outcome of those patients who had malignant cells in the peritoneal washings in the 167 patients studied, a plan of treating such patients with intraperitoneal radioactive chromic phosphate suspension (P-32) was instituted. Twenty-three subsequent patients with clinical Stage I carcinoma of the endometrium were found to have malignant cells in the peritoneal fluid. All 23 received intra-abdominal P-32 suspension instillation after operation. There have been three recurrences with two patients dying of disease. All of the three recurrences appeared at sites distant from the abdominal cavity. Peritoneal cytologic examination appears to be an important factor in the prognosis of endometrial cancer and, when the washings are positive for malignant cells, intraperitoneal chronic phosphate therapy appears to be efficacious.

Adenocarcinoma↗
PubMed1978

Cementum-like bone production in solitary bone cysts. (so-called "cementoma" of long bones). Report of three cases. Electron microscopic observations supporting a synovial origin to the simple bone cyst.

Three cases of simple bone cysts (S.B.C) in association with cementum-like bone production are reported. Analysis of our cases and the 2 previously reported in the literature as so-called cementomas has led us to conclude that the "cementoma" of long bone is not a distinct entity, but merely, a form of S.B.C. associated with a peculiar, poorly cellular form of bone which mimics tooth cementum by light microscopy only. Electron microscopic studies of this substance demonstrate collagen fibers and numerous matrix vesicles which form the initial sites of calcification. Matrix vesicles are a product of osteoblastic activity and are never found in the cementum of the tooth or oral cementum producing tumors. We also report the first ultramiscroscopic observations on the wall of the simple bone cyst and its lining. Two cell types constitute the lining, having features identical to those described for type A and type B synovial cells. Because of this new observation, we believe, the most reasonable explanation for the simple bone cyst is that it represents a congenital "rest" of synovial tissue displaced into the thin, cortical metaphyseal region of bones at the synovial-capsularbone reflection. Its benign nature and slow growth would explain its discovery in early childhood and the marked preponderance of its proximal humerofemoral location dependent upon the fact that these 2 bones have the largest area of capsular to metaphyseal bone reflection.

Adolescent↗
PubMedDate not supplied

Non-radioisotopic glucose turnover in children with falciparum malaria and enteric fever.

To determine whether glucose turnover is increased in acute falciparum malaria compared to enteric fever in children, steady-state 6,6-D2-glucose turnover was measured in 9 Malaysian children with uncomplicated malaria (6 males and 3 females; median age 10 years, body weight 22 kg) and in 12 with uncomplicated enteric fever (8 males and 4 females; median age 10 years, body weight 24 kg) in acute illness, after quinine (5 malaria patients) and in convalescence. Baseline plasma glucose concentrations in malaria and enteric fever were similar (all values are medians [ranges in brackets]) 5.6 [3.2-11.3] vs. 5.5 [4.2-8.0] mmol/L), as were serum insulin levels (5.6 [0.4-26.5] vs. 6.8 [1.1-22.5] milliunits/L; P > 0.4). Glucose turnover in the malaria patients was higher than in patients with enteric fever (6.27 [2.71-6.87] vs. 5.20 [4.50-6.08] mg/kg.min; P = 0.02) and in convalescence (4.74 [3.35-6.79] mg/kg.min; P = 0.05 vs. acute malaria study), and fell after quinine together with a rise in serum insulin (P = 0.03). Basal plasma lactate concentrations were higher in enteric fever than in malaria (3.4 [1.8-6.4] vs. 0.8 [0.3-3.8] mmol/L; P < 0.0001) and correlated inversely with glucose turnover in this group (rs = -0.60; n = 12; P = 0.02). These data suggest that glucose turnover is 20% greater in malaria than in enteric fever. This might reflect increased non-insulin-mediated glucose uptake in falciparum malaria and/or impaired gluconeogenesis in enteric fever, and may have implications for metabolic complications and their clinical management in both infections.

Adolescent↗
PubMedDate not supplied

Carcinoma of ovarian and other origins in effusions. Immunocytochemical study with a panel of monoclonal antibodies.

One of the more difficult challenges in cytopathology may be distinguishing malignancy from reactive conditions in effusions. Furthermore, it is frequently impossible to determine the primary site of the tumor on the basis of cellular morphology alone. In the present study we sought to construct a panel of antibodies that might distinguish carcinoma of the ovary from other metastatic tumor types as well as aid in the distinction between benign and malignant effusions. One hundred twenty-four cases of effusions (80 malignant and 44 benign) were examined with seven monoclonal antibodies (MAbs) (Ber-EP4, OV-TL3, OV-TL23, ID-3, SH9, H23 and D-14). Sensitivities for the seven MAbs ranged from 11% to 75%, with specificity of 43-100%. No single antibody could reliably distinguish carcinoma from reactive conditions, but Ber-EP4 combined with H23 detected 87% of malignant effusions, with a false-positive rate of 2%. Although these antibodies did not differentiate ovarian carcinoma from other types of malignancies, when used together they are highly accurate in distinguishing benign from malignant effusions.

Antibodies, Monoclonal↗