Biomedical subjects
Publications and source records attributed to T R Johnson.
Examination of histopathologic sections taken of tubal ectopic pregnancies and gross dissections of these specimens suggest that, in the majority of cases, the growth of the developing trophoblast takes place in a largely extratubal site and that the common clinical impression that the mass associated with the tubal ectopic pregnancy is a dilated fallopian tube is largely erroneous.
The diagnosis, pathophysiology, and treatment of adult respiratory distress syndrome (ARDS) are discussed and 2 cases are presented. ARDS has varied etiology but common clinical, roentgenographic, and pathologic findings; it has been increasingly recognized as an important cause of morbidity and mortality in seriously ill patients. The obstetrician-gynecologist must be aware of this condition, for survival depends upon prompt diagnosis and meticulous therapy of the condition and its underlying cause.
This study attempts to confirm previous reports of a clinically useful serum unconjugated estriol surge at 36 weeks' gestation. Although an apparently physiologic estriol surge occurred at 36 +/- 2.1 weeks in 25 of 32 patients, clinical reality makes weekly plasma sampling difficult. In individual cases, use of the "surge point" predicted gestational age within a 4-week range with only 66% accuracy, and potentially serious errors in dating occurred. Other biochemical (lecithin:sphingomyelin, phosphatidylglycerol) and sonographic methods are superior in resolving problems with dating gestational age in the third trimester.
Cytosol receptors for progesterone were assayed in human endometrial tissue during the proliferative and secretory phases of the menstrual cycle and in the hyperplastic and carcinomatous endometrium. The assays were performed utilizing a technique involving prior treatment of the cytosol extract with dextran-coated charcoal to remove endogenous progesterone. The results showed that the progesterone receptor activity was higher during the later proliferative and early secretory phases of the menstrual cycle. Hyperplastic and carcinomatous endometrium also contained specific cytosol receptor for progesterone, and the binding activity of the hyperplastic endometria and endometrial polyps was comparable to that found during the later proliferative phase of the menstrual cycle. No apparent correlation between the progesterone receptor level and the morphologic degree of differentiation in Grades 1 and 2 adenocarcinomas of the endometrium was observed.
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A graphic format is presented for the display and storage of data relating to gestational age. The graph permits rapid retrieval and synthesis of often confusion information and is thereby useful in the management of complicated pregnancies.
A unique case of hemothorax caused by proven pleural involvement with benign gestational trophoblastic disease and anticoagulation is presented. The pulmonary manifestations of gestational trophoblastic disease are reviewed. It is stressed that these may be associated with histologically benign as well as frankly malignant disease, and that the clinician must be alert for them in managing all patients with known or suspected gestational trophoblastic disease.
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Two cases of paraneoplastic hypercalcemia secondary to ovarian tumors are presented. Both cases were secondary to ectopic parathormone (PTH) production. Other mediators postulated to cause this syndrome are prostaglandins, vitamin D-like sterols, non-vitamin D sterols, vitamin A, cortisol, and "osteoclast-activating factor.' The key treatment modalities for acute hypercalcemia are hydration and diuresis with furosemide; phosphates, steroids, antiprostaglandins, and hemodialysis may also be of value. Calcitonin is theoretically the most attractive treatment modality, but the rapid development of resistance limits its use to acute management. Mithramycin is most effective for long-term palliation of hypercalcemia if tumor-directed therapy is unsuccessful. Review of the literature confirms the previously made observation that mesonephromas are disproportionaately represented in association with this syndrome.
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Recurrent anterior subluxation of the lateral tibial plateau is a common type of chronic knee instability resulting from trauma. It can be reproduced by the clinical test described and corrected by a surgical procedure called the sling and reef operation, in which a strip of iliotibial tract is used to create a sling and to reef the posterolateral capsule. From 1971 to 1978, eighty-four patients were operated on, of whom fifty had been evaluated at one to six and one-half years after operation. The results were: forty-one good, six fair, and three poor. The lesions found in the thirty-seven knees in which arthrotomy was performed included a tear of the anterior cruciate in every case, a tear of the medial meniscus in fifteen and of the lateral meniscus in eleven, a notch in the articular surface of the lateral femoral condyle in fifteen, and a lateral marginal tibial (Segond) fracture in three. No definite lateral capsular tears were visualized--only stretching comparable to that seen in recurrent dislocation of the shoulder.
Mature ribosomes, their subunits, and their ribonucleoprotein precursors were extracted from HeLa cells and prepared for electron microscopy by a method based on adsorption of nucleic acid to a charged grid. Images so obtained revealed the presence of two types of ribonuclease-sensitive fibrils of consistent morphology. One of these types of fibril is present on the 80S and 55S nucleolar ribonucleoprotein precursors and the mature 60S subunit. The other type is restricted to the 80S precursor. The morphology of the fibrils and their distribution in the various preparations suggest identification with known secondary structural features of isolated pre-rRNA.
DNA fragmented by conventional French press shearing procedures (30,000 lbs/in2) has a number-average fragment size of 230 base pairs. This is considerably smaller than the 450 base pairs typically reported for DNA sheared by this method. Comparison of 5 sizing techniques indicates that sheared DNA fragment size is overestimated by either measurement of velocity sedimentation or Kleinschmidt Electron Microscopic visualization. Both adsorption grid electron microscopic visualization and gel electrophoresis yield the most reliable estimates of the mean size of small DNA fragment populations. In addition, the assessment of fragment size distribution (not possible from sedimentation analysis) potentially allows more critical evaluation of DNA hybridization and reassociation kinetic and measurement parameters.
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