Biomedical subjects
S Lancaster
Publications and source records attributed to S Lancaster.
Beneficial effects of androgen-primed chemotherapy in the Dunning R3327 G model of prostatic cancer.
The objective of this study was to test the hypothesis that androgen administration prior to chemotherapy (androgen priming) may potentiate tumor cytotoxicity in hormone-responsive prostate cancer. Accordingly, six groups of Copenhagen rats bearing small (i.e., 40-mm3 median volume) Dunning R3327 G tumors were left untreated or received castration, chemotherapy, or a combination of the two, with or without androgen priming. Groups without priming included: intact untreated, castrate alone, intact plus chemotherapy, and castrate plus chemotherapy (cyclophosphamide, 30 mg/kg/day, for 2 days, with repeat cycle in 24 days) (Cx). To specifically evaluate the effect of androgen priming on Cx cytotoxicity, two additional castrate groups were studied. One received testosterone propionate (4 mg/kg/day) for 2 days prior to Cx and the other after Cx. Treatment effect was evaluated by quantitating tumor volume as well as animal survival to an ethically allowable, maximal tumor burden. As expected, castration and Cx produced a retardation of tumor growth and prolongation of survival when compared to untreated animals. The addition of androgen priming prior to but not after Cx enhanced the degree of tumor suppression. Specifically, 26 days after the second Cx cycle, all androgen-primed tumors had regressed; 70% of tumors had disappeared and those remaining were barely palpable. At this same time point, tumors in all the other groups were actively growing and had volumes greater than initial values (P less than 0.01). Although tumor regrowth occurred, median survival for the androgen-primed group was significantly prolonged, to 186 days versus 39 days (P less than 0.01) for untreated animals and 153 days for the non-primed castrate plus Cx animals (P less than 0.01). These data suggested that androgen priming potentiates the effects of Cx in castrate animals bearing R3327 G tumors.
A surface polysaccharide forms when gonococci are converted to serum resistance by cytidine 5'-monophospho-N-acetyl neuraminic acid.
A serum-susceptible, guinea-pig chamber-passaged, laboratory strain (BS4 (agar)) of Neisseria gonorrhoeae was converted to serum resistance by incubation with cytidine 5-monophospho-N-acetyl neuraminic acid (CMP-NANA) and examined by electron microscopy after staining with ruthenium-red. In contrast to serum susceptible gonococci incubated without CMP-NANA, the majority (60-70%) of the serum resistant organisms showed a surface accumulation of polysaccharide. This surface polysaccharide was enhanced on all the resistant gonococci after incubation with fresh human serum. Control susceptible gonococci were devoid of the polysaccharide after incubation with heated human serum. Identical results were obtained with a fresh gonococcal isolate which had lost serum resistance on subculture but which, in common with 3 other isolates, was restored to serum resistance by incubation with CMP-NANA.
Child behavior ratings: the influence of maternal characteristics and child temperament.
This study investigated the extent to which maternal characteristics, such as psychological health problems, marital adjustment and confidence in mother/wife roles, influenced how mothers rated the behavior of their first-born children (n = 100) on the Pre-school Behavior Questionnaire. Results showed that these characteristics were powerful predictors of behavior ratings. In contrast, the independent contribution of child temperament ratings was relatively small. It was concluded that child behavior problem and temperament measures may be confounded. Maternal ratings constitute a valuable source of information concerning parent-child interaction which deserve further investigation, especially of their influence on generally accepted measures of child behavioral adjustment.
Kinetic and morphometric responses of heterogeneous populations of experimental breast cancer cells in vivo.
Although the hormone responsiveness of some breast cancers is well known, the differential sensitivity of tumor cell subpopulations to hormonal effects is not well established. These experiments were designed to address this issue using the hormone-responsive N-nitrosomethylurea-induced rat mammary tumor. Rats bearing these tumors were randomly assigned to no treatment, 7-day castration, and 7-day castration followed by 1-, 3-, 7-, and 10-day treatment with estradiol benzoate (5 micrograms) and perphenazine (1 mg) to stimulate prolactin release. Under these conditions, the proportion of different cell populations was estimated with morphometric analysis, while their replicative activity was assessed using [3H]thymidine autoradiography. In tumors of intact rats the fractions of glandular epithelial, myoepithelial, and nonepithelial cells were 88.2%, 3.8%, and 8.0%, respectively. All cell types manifested a similar kinetic response to our hormonal treatments characterized by a drastic decline in the labeling index after castration followed by a progressive increase with hormone repletion which peaked on Day 7 of treatment. The magnitude of the response was, however, greater in the epithelial components of the tumor (glandular and myoepithelial cells), where the peak labeling indices significantly exceeded those observed in the tumors of control intact rats. Castration reduced the proportion of glandular cells while increasing the fractions of myoepithelial and nonepithelial cells. Furthermore, castration reduced the volume of the glandular-epithelial cells by 35%, which accounted for approximately half of the overall tumor volume reduction induced by ovariectomy. These alterations in tumor morphology were partially reversed by hormone repletion. These results underscore the exquisite hormonal sensitivity of different cellular counterparts of this experimental breast cancer with regard to both kinetic and morphological characteristics. They also provide support for stromal-epithelial interaction in the hormonal modulation of breast cancer growth.
Lateral idiopathic subluxation of the radial head. Case report.
Idiopathic subluxation of the radial head (ISRH) is a rare entity that is separate from congenital dislocations of the radial head, both symptomatically and radiographically. ISRH causes pain and restriction of rotation. A dome-shaped radial head, a hypertrophied ulna, and a hypoplastic capitellum are not present in ISRH, as they are in a congenital dislocation of the radial head (CDRH). A true lateral ISRH is used as an example to demonstrate these differences. Remodeling of the radial head may preserve motion in the joint surface deformed by growth along abnormal planes of motion.
Complete acromioclavicular separations. A comparison of operative methods.
A retrospective study of the surgical treatment methods for complete acromioclavicular (AC) dislocations was initiated to investigate the efficacy of each. During the years 1972-1985, a total of 95 surgical procedures were performed for complete AC dislocations. The medical records of 90 cases were available for review. The operative methods compared coracoclavicular (CC) with AC fixation methods. Excision of the distal clavicle was performed for chronic dislocations. AC fixation methods included Kirschner wires alone, Kirschner-wire fixation with coracoacromial ligament transfer, and Kirschner-wire fixation with tension wiring. Results were graded using evaluation of pain, range of motion, and residual deformity. AC fixation methods proved to be more successful than CC fixation methods. Excellent results were obtained in more than 89% of both AC and CC methods. AC methods had more minor complications including infections and implant breakage, but no failure or recurrences of the dislocation. CC methods resulted in 9% failure or recurrences. Of the AC fixation methods, the Kirschner wire with tension wiring gave the best results but required a more extensive operation for removal of implants. Excision of the distal end of the clavicle is an adequate form of treatment for the chronic complete painful AC dislocation.
Subtalar dislocations: a prognosticating classification.
A review of the literature and analysis of eight cases of subtalar dislocations was undertaken to correlate our experience with others and to determine a classification for prognostication. Our findings corresponded with those found by others. A 75% incidence of associated injuries was present in our series and these represented a continuum of varying degrees of complication. A new system was devised whereby increasing severity of associated injuries correlated with increasing rate of complications, including loss of motion, arthritis, pain and avascular necrosis. Dislocations were classified according to: no associated injuries, those with soft tissue injuries, extra-articular fractures, intra-articular fractures and those prone to development of avascular necrosis, ie, open dislocations and fractures of the body of the talus. It was found that associated fractures increased the immobilization period as well as the incidence of complications. Intra-articular fractures have demonstrated increased rates of arthroses in the subtalar joint. Avascular necrosis, an infrequent but devastating complication, is primarily associated with open dislocations and dislocations with concomitant fractures of the body of the talus. Our series had two open subtalar dislocations, neither of which developed avascular necrosis.
Kinetic and morphometric responses of heterogeneous populations of NMU-induced rat mammary tumor cells to hormone and antipolyamine therapy in vivo.
The present experiments were designed to evaluate in vivo the differential sensitivity of tumor cell subpopulations to hormone and polyamine manipulations using the hormone-responsive N-nitrosomethyl-urea (NMU)-induced rat mammary tumor. NMU tumor bearing rats were randomly assigned to control, ovariectomy, alpha-difluoromethyl-ornithine (DFMO) administration (an inhibitor of polyamine biosynthesis), or combination treatment, and were sacrificed on day 2, 4, or 7. The proportion of different cells was estimated by morphometric analysis and their replicative activities by [3H]-thymidine autoradiography. In tumors of intact rats, the fractions of glandular, myoepithelial, and non-epithelial cells were 85.3 +/- 2.2%, 4.7 +/- 0.7%, and 9.9 +/- 1.9%, respectively. Ovariectomy induced a similar time-dependent decline in the labelling indices of each cell type (from 5% to 1%). It also decreased the fraction of glandular cells (74.9 +/- 4.5%), while increasing the fraction of myoepithelial (8.6 +/- 1.9%) and non-epithelial (16.3 +/- 3.2%) cells. DFMO exerted similar but more modest effects. DFMO-induced tumor regression was also inferior to that observed with ovariectomy. Combined ovariectomy and DFMO induced a faster and greater suppression of all labelling indices than the individual treatments, even though tumor regression was not superior to that produced by ovariectomy alone. Combination treatment also produced more profound morphologic changes, reducing the fraction of glandular cells to 64.4 +/- 3.9% and increasing that of non-epithelial cells to 26.6 +/- 4.4%. Ovariectomy and DFMO reduced height but not width of glandular cells, resulting in a modest decrease in cell volume. The combination treatment, however, significantly suppressed all three parameters.(ABSTRACT TRUNCATED AT 250 WORDS)