Biomedical subjects

G Wong

Publications and source records attributed to G Wong.

At least 91 records · Page 5Linked to original sources

PubMed1995

Stereospecific transduction of behavioral effects via diazepam-insensitive GABAA receptors.

Previous studies reported a positive correlation between ligand affinities at diazepam-insensitive GABAA receptors and substitution for the discriminative stimulus effects of the benzodiazepine receptor antagonist, flumazenil, in pigeons. In the present experiments, bretazenil and Ro 14-5974 (ethyl-(S)-11,12,13,13 a-tetrahydro-9-oxo-9H-imidazo[1,5-a]-pyrrolo-[2,1-c] [1,4]benzodiazepine-1-carboxylate) partially substituted for, and blocked the discriminative stimulus effects of midazolam, congruent with their actions at diazepam-sensitive GABAA receptors in vitro. In addition, bretazenil and Ro 14-5974, but not their R-enantiomers, had high affinity for diazepam-insensitive receptors and fully substituted for the discriminative stimulus effects of flumazenil. The R-enantiomers of these compounds had low affinity (Ki > 1 microM) for diazepam-sensitive and diazepam-insensitive receptors, and did not share discriminative stimulus effects with flumazenil or midazolam. Ro 19-0528 (7-chloro-3-(3-cyclopropyl-1,2,4-oxadiazol-5-yl)-4,5-dihydro-5-met hyl-6H- imidazo[1,5-a][1,4]benzodiazepin-6-one), a structurally related compound with full agonist actions at diazepam-sensitive GABAA receptors, had high diazepam-insensitive receptor affinity (Ki = 96 nM) and partially substituted for the discriminative stimulus effects of flumazenil. These results are consistent with stereospecific mediation of the discriminative stimulus effects of flumazenil through high affinity binding to diazepam-insensitive receptors in pigeons.

Animals↗

PubMed1995

Characterization of novel ligands for wild-type and natural mutant diazepam-insensitive benzodiazepine receptors.

A series of benzodiazepine receptor ligands with different chemical structures were evaluated for their affinities at diazepam-sensitive and diazepam-insensitive binding sites for [3H]Ro 15-4513 (ethyl-8-azido-5,6-dihydro-5-methyl-6-oxo-4H-imidazo-[1,5a][1,4] benzodiazepine-3-carboxylate) in cerebellar GABAA receptors. Rats of Wistar strain and of alcohol-sensitive (ANT) and alcohol-insensitive (AT) lines were used. The ANT rats possess a single point mutation in their GABAA receptor alpha 6 subunit, which makes their diazepam-insensitive sites sensitive to benzodiazepine agonists, unlike those of AT and Wistar rats. All compounds evaluated displayed high-affinity binding to diazepam-sensitive sites (Ki < 50 nM). In contrast, a wider range of affinities were observed at diazepam-insensitive sites which depended upon the basic structure and substitutions. The 7- and 8-halogen substituted imidazobenzodiazepines and 12-halogen substituted diimidazoquinazolines displayed the highest affinities (Ki < 15 nM), while intermediate to low affinities (100 < Ki < 4000 nM) were displayed by imidazoquinazolines, thienopyrimidines, one oxoimidazoquinoxaline, and some cyclopyrrolones. The imidazoquinoxalines evaluated displayed the lowest affinity (Ki > 10000 nM). The oxoimidazoquinoxaline, 6-chloro-3-(5-cyclopropyl-1,2,4-oxadiazol-3-yl)-4,5-dihydro-5-isop ropyl-4-oxo-imidazo[1,5-a]quinoxaline (NNC 14-0578) and suriclone represent the first benzodiazepine receptor full agonists to bind with relatively high affinity (Ki approximately 100 nM) to diazepam-insensitive sites. The 5 position substituted methoxybenzyl, dimethylallyl, and 4-fluorobenzyl oxoimidazoquinoxaline analogs demonstrated a 58-336-fold higher affinity for ANT than AT diazepam-insensitive sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Quality of life of women with ovarian cancer.

The primary objectives of this study were to determine the nature and extent of physical problems and psychological distress experienced by women with ovarian cancer and to identify medical and sociodemographic factors that were predictive of distress. Quality of life was assessed at 3-month intervals, for a maximum of 12 months in 151 ovarian cancer patients, most with advanced-stage disease (86%). Patients' pain, other physical symptoms, level of physical functioning, psychological state, and social functioning were evaluated using the following measures: a detailed pain questionnaire, Memorial Pain Assessment Card, Memorial Symptom Assessment Scale, Mental Health Inventory (MHI), Functional Living Index--Cancer (FLIC), and the Karnofsky Performance Status. Upon entry, 33% of patients reported significant psychological distress, as indicated by MHI Psychological Distress scores (MHI-PD) equal or greater to 1.5 standard deviations above the mean of a nationwide community sample. Impaired physical functioning (FLIC subscale) was the most important predictor of heightened psychological distress (MHI-PD) at baseline (1.5 SD or greater above the norm) (P = 0.0004) in a stepwise logistic regression involving medical/physical and sociodemographic variables as predictors. Further, significant differences were found in all quality of life scales between patients with Karnofsky Performance Status scores of < or = 80, and those with ratings of 90 or greater (P = 0.036 to P < 0.0001). These data suggest the need for an improved and more frequent assessment of ovarian cancer patients' psychological status, particularly as physical functioning declines, to improve early detection and referral to treatment of those suffering from psychiatric sequelae of cancer.

Adult↗

PubMed1995

Cytoreductive surgery in ovarian carcinoma patients with a documented previously complete surgical response.

Recurrent ovarian cancer after negative findings at second-look laparotomy is common. A retrospective review of 57 patients who developed recurrent tumor after a negative second-look laparotomy was undertaken to evaluate treatment efficacy and prognostic factors. All patients received primary platinum-based chemotherapy. Recurrences occurred in the abdomen or pelvis (40 patients), lymph nodes (7), liver (4), lungs (3), and vagina (3). Recurrent disease was diagnosed at a mean interval of 20 months after second-look surgery. Of the 38 patients who underwent laparotomy for recurrence, 36 (95%) had > 0.5 cm disease. After cytoreductive surgery 14 patients (37%) were left with minimal (< 0.5 cm) residual disease. Intestinal resection or bypass was performed on 10/38 patients (26%) with one requiring a colostomy. There was no operative mortality and one complication (small bowel obstruction). Treatment after recurrence consisted of platinum-based chemotherapy (88%), with the remaining patients receiving irradiation or hormonal therapy. At a mean follow-up from recurrence for the entire group of 20 months, 18/38 (47%) explored patients are alive. All 19 patients who were not explored died with a median survival time from recurrence of 9 months. Patients who underwent a laparotomy and patients with < 0.5 cm residual disease had a significant survival advantage (P < 0.0001). Initial stage, grade, disease-free interval, and disease found at laparotomy did not influence survival. Recurrent ovarian carcinoma after platinum-based chemotherapy is associated with a grave prognosis when the patient is deemed inoperable or when distant metastasis are found. Patients with disease reduced to < 0.5 cm showed a significant survival advantage.

Abdominal Neoplasms↗

PubMed1995

Subtype specificity of gamma-aminobutyric acid type A receptor antagonism by clozapine.

Clozapine, an atypical neuroleptic, functionally antagonizes the gamma-aminobutyric acid-induced chloride uptake via the main central inhibitory receptor, gamma-aminobutyric acid type A (GABAA) receptor, in brain vesicles. GABAA antagonism by micromolar concentrations of clozapine is more efficient in rat cerebrocortical and hippocampal membranes than in cerebellar membranes, as evidenced by clozapine reversal GABA-inhibition of [35S]t-butylbicyclophosphorothionate ([35S]TBPS) binding. A typical neuroleptic, haloperidol, failed to antagonize GABA in any of these brain regions, while the specific GABAA antagonist 2'-(3'-carboxy-2',3'-propyl)-3-amino-6-p -methoxyphenylpyrazinium bromide (SR 95531) was efficient in all three brain regions. Clozapine action on [35S]TBPS binding was unaffected by the benzodiazepine receptor antagonist flumazenil. Clozapine inhibited the binding of [3H]muscimol and [3H]SR 95531 to the GABA recognition site, but this effect only partially correlated with the regional differences in and the potency of clozapine antagonism of GABA-inhibition of [35S]TBPS binding, suggesting that also other than GABA sites may mediate clozapine actions. Autoradiography of [35S]TBPS binding revealed GABA antagonism by clozapine in most brain regions. Main exceptions were cerebellar granule cell and molecular layers, olfactory bulb external plexiform and glomerular layers and primary olfactory cortex, where clozapine antagonized GABA inhibition less than average, and lateral hypothalamic and preoptic areas where its antagonism was greater than average. Recombinant alpha 6 beta 2 gamma 2 receptors, the predominant alpha 6 subunit-containing receptor subtype in cerebellar granule cells, failed to show GABA antagonism by clozapine up to 100 microM. In contrast, recombinant alpha 1 beta 2 gamma 2 receptors, forming the predominant receptor subtype in the brain, were clozapine sensitive. Recombinant alpha 6 beta 2 gamma 2 and alpha 6 beta 3 gamma 2 receptors resulted in clozapine-insensitive receptors, whereas alpha 6 beta 1 gamma 2 receptors were clozapine sensitive. The efficacy of clozapine to antagonize GABA in alpha 1 beta x gamma 2 receptors decreased in the order of alpha 1 beta 1 gamma 2 > alpha 1 beta 2 gamma 2> alpha 1 beta 3 gamma 2. The results indicate that clozapine antagonizes the function of most GABAA receptor subtypes, and that the interaction is determined by the interaction of the alpha and beta subunit variants. GABA antagonism is a unique property of clozapine, not shared by haloperidol, which might be involved in the pharmacological mechanism for the increased seizure susceptibility associated with clozapine treatment.

Animals↗

PubMed1995

The effect on cell phenotype of the mutagenic peptide of herpes simplex virus type-1.

The transforming region of the genome of herpes simplex virus type-1 (HSV-1) encodes a peptide that raises the mutation frequency of cells. To find the effect of this peptide on cell phenotype, three types of cells were transfected with a shuttle vector plasmid that expressed the peptide. When immortalised rat fibroblasts were transfected they rapidly became anchorage-independent with high efficiency, but were not tumorigenic in nude mice. When monkey kidney cells were transfected, five clonal cell lines were isolated, of which one became anchorage-independent but was not tumorigenic in nude mice. When human oral keratinocytes were transfected they did not become immortalised. The peptide therefore induced some of the features of transformation in different cell types, but did not induce a malignant phenotype in any cell. This suggests that interaction with co-factors would be necessary for the peptide to contribute to the development of oral cancer.

Amino Acid Sequence↗

PubMed1995

Phenotypic and genotypic analysis of rats with cerebellar GABAA receptors composed from mutant and wild-type alpha 6 subunits.

The alcohol-sensitive (ANT) rat line, developed for high behavioral sensitivity to ethanol, also exhibits enhanced sensitivity to benzodiazepines, such as diazepam. The rat line carries a point mutation in the cerebellum-specific gamma-aminobutyric acid type A (GABAA) receptor subunit alpha 6, making their diazepam-insensitive (DIS) receptors sensitive to diazepam. We now report that phenotypes of individual ANT and alcohol-insensitive rats, classified on diazepam sensitivity of cerebellar [3H]Ro 15-4513 binding, correlated well with homozygous wild-type, homozygous mutant, and heterozygous genotypes, although some heterozygotes were biased toward the parental phenotypes. GABA down-modulated DIS [3H]Ro 15-4513 binding in mutant homozygotes but tended to up-modulate it in heterozygotes and wild-type homozygotes. Slopes for GABA inhibition of cerebellar t-butyl- bicyclophosphoro[35S]thionate binding were larger in mutant than in wild-type homozygotes, with heterozygotes being intermediate. Diazepam displacement of [3H]Ro 15-4513 binding in heterozygotes revealed three components, with their affinities indistinguishable from those in combined wild-type and mutant homozygotes. This lack of interaction in DIS binding between wild-type and mutant alpha 6 subunits was substantiated by experiments on recombinant receptors. The data suggest that the alpha 6 subunit-containing GABAA receptors in the heterozygotes are formed from individual mutant and wild-type subunits with their relative expression differing from animal to animal.

Animals↗

PubMed1995

Improved experimental cancer therapy by radioantibody dose intensification as a result of syngeneic bone marrow transplantation.

Myelosuppressive toxicity is dose-limiting for radioimmunotherapy. We have reported on the use of cytokine intervention (rhIL-1 and rmGM-CSF) to stimulate differentiation of progenitor cells and reduce radioantibody-induced leukopenia and thrombocytopenia (J. Natl. Cancer Inst. 84:399, 1992; Cancer 73:1073, 1994). As an alternative to the use of cytokines, we investigated the effect of syngeneic bone marrow transplantation on the ability to dose-escalate radioantibody. Injection of 10(7) bone marrow cells from a donor mouse 6 to 8 days after a 340- to 360-microCi dose of radioantibody (LD100/28)--a 25 to 30% increase above the maximal tolerated dose--resulted in 100% survival. This observation is associated with a recovery in neutrophil and thrombocyte counts within 21 days of therapy (normal recovery after 275 microCi takes 42 days). None of the mice survived when BMT was done at either 4 or 11 days after radioantibody. Marrow from normal donor mice was more effective than that from cytokine-primed mice whose marrow cells were actively cycling after a 5-day course of IL-1/GM-CSF. The combination of the two myeloprotective approaches, BMT plus a 14-day schedule of IL-1 (2 x 10(3) U/d) and GM-CSF (1 microgram/d) intervention, provided a greater stimulation of peripheral WBC counts than either approach alone; however, further dose escalation under these conditions was not feasible. The 30% intensification in radioantibody dose offers a therapeutic advantage for both bulky disease (GW-39 subcutaneous nude mouse model) and micrometastatic disease (GW-39 intrapulmonary model). In the bulky tumor model, the increase in administered dose resulting from BMT extends the 8-week growth delay observed at 275 microCi 131I-MN-14 IgG by an additional 7 weeks. In the metastatic model, dose intensification increased median animal survival from 15 to 23 weeks. Therefore, by optimizing the use of BMT, a greater therapeutic benefit can be derived from radioantibody therapy in a solid tumor model. This study represents a proof of principle, that BMT can be effective for low-dose-rate therapy as it has been for short-duration intense chemotherapy and radiation therapy. It also highlights several important issues to consider when attempting to apply the method in the clinic.

Animals↗

PubMed1995

Different subunit requirements for volatile and nonvolatile anesthetics at gamma-aminobutyric acid type A receptors.

The ability of volatile (halothane and isoflurane) and nonvolatile (alphaxalone and pentobarbital) general anesthetics to modulate radioligand binding to gamma-aminobutyric acid (GABA)A receptors was examined in an immortalized cell line (WSS-1) expressing rat alpha 1 and gamma 2 subunits. Volatile anesthetics enhance [3H]flunitrazepam binding to WSS-1 cells in a concentration-dependent manner, with potencies and efficacies comparable to those found with native GABAA receptors. Transfection of these cells with cDNAs encoding rat beta 2 or beta 3 subunits had a significant influence on anesthetic efficacy but not potency in this assay. Thus, transfection with the beta 2 subunit reduced the efficacy of both isoflurane and halothane, whereas transfection with the beta 3 subunit increased the efficacy of isoflurane but not halothane, compared with values obtained in WSS-1 cells. In contrast, alpha-xalone (an anesthetic steroid) had no effect, whereas at high concentrations pentobarbital (an anesthetic barbiturate) produced a modest inhibition of [3H]flunitrazepam binding to GABAA receptors in WSS-1 cells. Transfection of WSS-1 cells with cDNAs encoding either beta 2 or beta 3 subunits resulted in a concentration-dependent enhancement of [3H]flunitrazepam binding by these nonvolatile anesthetics. Moreover, pentobarbital was significantly more potent in enhancing [3H]flunitrazepam binding to WSS-1 cells transfected with the beta 2 subunit, compared with the beta 3 subunit. The difference in subunit requirements between volatile and nonvolatile anesthetics for enhancement of [3H]flunitrazepam binding indicates that these classes of agents affect GABAA receptor function at distinct loci. These studies also provide evidence that the beta subunit is required for these nonvolatile anesthetics to positively modulate GABAA receptors.

Anesthetics↗

PubMed1994

Pain in ovarian cancer patients. Prevalence, characteristics, and associated symptoms.

BACKGROUND: The prevalence, characteristics, and impact of pain and other symptoms have not been studied systematically in women with ovarian cancer. Anecdotally, pain has been associated with the onset of the disease and is a common problem among those with advanced cancer; symptoms other than pain appear to be highly prevalent. Given the profound influence of pain and other symptoms on quality of life, the evaluation of these phenomena could provide data relevant to the clinical management of these patients and advance quality of life research in the area of symptom assessment. METHODS: Questionnaires were completed by 111 inpatients and 40 outpatients with ovarian cancer who were undergoing treatment at a cancer center. Measures included a comprehensive pain questionnaire; the Rand Mental Health Inventory, Functional Living Index--Cancer; and the Memorial Symptom Assessment Scale. RESULTS: The sample (N = 151) represented 74% of the eligible patients. The median age was 55 years (range, 23-86), 82% had Stage III or IV disease at presentation, and 69% had active disease at the time of the survey. Pain, fatigue, and psychologic distress were the most prevalent symptoms. Sixty-two percent (N = 94) described a pain syndrome that preceded the onset or recurrence of the disease, and 42% (N = 63) reported "persistent or frequent pain" during the preceding 2 weeks. The latter pain had a median duration of 2 weeks (range, less than 1 to 756 weeks) and usually was in the abdominopelvic region (80%), frequent or almost constant (66%), and moderate to severe. Most patients reported moderate or greater pain-related interference with various aspects of function, particularly activity (68%), mood (62%), work (62%), and overall enjoyment of life (61%). Performance status, inpatient status, and unmarried status were significant predictors of pain presence or intensity, and both performance status and extent of tumor were significant predictors of pain interference with function. CONCLUSIONS: Among those with ovarian cancer, greater than 40% experienced pain that substantially undetermined function in one half to two thirds of these patients. Impaired performance status is associated most strongly with pain. The onset or recurrence of disease often is heralded by a stereotypic pain syndrome.

Adult↗

PubMed1994

Zinc finger domains and phorbol ester pharmacophore. Analysis of binding to mutated form of protein kinase C zeta and the vav and c-raf proto-oncogene products.

The phorbol ester binding domain consists of a cysteine-rich region with a postulated consensus sequence for binding that includes 15 amino acids (Ahmed, S., Kozma, R., Lee, J., Monfries, C., Harden, N., and Lim, L. (1991) Biochem. J. 280, 233-241). In PKC zeta, the only PKC isoform lacking phorbol ester binding, this region differs in a single residue from the consensus (proline in position 11 of the motif). Restoration of this proline by site-directed mutagenesis of PKC zeta does not restore binding of either [3H]phorbol 12,13-dibutyrate or of the ultrapotent ligand [3H]bryostatin 1, suggesting that even a low affinity ligand interaction is absent. In addition, the vav and c-raf proto-oncogene products, proteins that possess cysteine-rich regions with high homology to PKC isozymes and other phorbol ester receptors, are unable to bind any of these ligands. Instead, all of these cysteine-rich regions bind zinc. Our results suggest that other amino acids besides those postulated for the consensus must be necessary for ligand binding and argue against direct modulation of PKC zeta, Vav, and c-Raf by phorbol esters.

Amino Acid Sequence↗

PubMed1994

Cytokine intervention permits dose escalation of radioantibody. An analysis of myelostimulation by bolus versus continuous infusion of IL-1/GM-CSF.

BACKGROUND: The authors recently reported that a 12-day schedule (beginning 3 days before radioantibody treatment) of twice-daily dosing of rH-IL-1 (1 x 10(3) U/dose) and rM-GM-CSF (0.5 micrograms/dose) can reduce the magnitude and duration of radioantibody-induced myelosuppression, thereby permitting a 25-30% increase in the dose of radioantibody that can be administered without the dose proving lethal. In an effort to further reduce toxicity and escalate the tolerated dose, the authors altered the method of administration of cytokines from daily bolus dosing to continuous infusion by implantable osmotic pumps. METHODS: A control group of mice was compared to five groups of mice that either did or did not receive a 340 microCi dose of radioantibody, and received no cytokines, cytokines by bolus dosing, or cytokines by continuous infusion. For 4 weeks, peripheral white blood cell and thrombocyte counts and thymus and spleen weights were taken, marrow cell number was monitored, and marrow colony-forming unit activity was evaluated weekly in the untreated control mice and the treated mice. RESULTS: These studies demonstrated that after a dose of radioantibody, continuous dosing of cytokines resulted in higher white blood cell (WBC) and platelet values than if bolus delivery was used (day 7, WBC: 110% vs. 59%; day 14, WBC: 85% vs. 62%; day 21, WBC: 98% vs. 42%; day 7, platelets: 122% vs. 51%; day 14, platelets: 159% vs. 72%; day 21, platelets: 239% vs. 171%). A comparison of bolus versus continuous dosing in the absence of radioantibody indicated that spleen weight increased by 40-60% after continuous infusion of cytokines and by 20-25% after bolus dosing. The 20-30% decrease in thymus weight was similar with both dosing regimens. Colony-forming units (CFUs) in marrow increased from 30-35 in untreated mice to 50-55 in mice given cytokines by bolus injection, and to 150-180 in mice given continuous infusion of cytokines. Spleen CFUs exhibited an insignificant increase after bolus dosing of cytokines but increased almost fourfold after continuous dosing. Peak stimulation of marrow and spleen CFUs occurred 28 days after initiation of cytokine administration (2 weeks after cytokines administration was stopped). The probability of survival for 6 weeks after further dose escalation to 360 microCi I-131-MN-14 immunoglobulin G was 16.4% +/- 8.6% after bolus dosing and 58.1% +/- 11.3% after continuous infusion of cytokines. CONCLUSIONS: Although continuous infusion of cytokines proved to be a better method of reducing hematopoietic toxicity, further dose escalation of radioimmunotherapy using the "pump" method of cytokine delivery was not possible. Cytokine intervention by either mode of delivery permits a 25% dose intensification without the dose becoming lethal. Further escalation is not feasible, possibly because of other end organ toxicity.

Animals↗

PubMed1994

Comparison of equitoxic radioimmunotherapy and chemotherapy in the treatment of human colonic cancer xenografts.

The therapeutic efficacy of 5-fluorouracil (5-FUra; 0.6 mg/day x 5 days) + leucovorin (LV; 1.8 mg/day x 5 days) and of 131I-labeled MN-14 anticarcinoembryonic antigen IgG (275 microCi single dose) was evaluated in size-matched (0.3-0.7 cm3) s.c. LoVo, HT-29, DLD-1, HCT-15, LS174T, and MOSER, GW-39, and WidR human colonic tumors. These lines express varying amounts of carcinoembryonic antigen and exhibit varying degrees of in vitro responsiveness to 5-FUra. Unlike radioimmunotherapy (RAIT), multiple cycles of chemotherapy were feasible over a 3-week period. However, no therapeutic advantage to a second cycle of 5-FUra/LV administration was found. Therefore, it is reasonable to compare single cycles of both treatment modalities. RAIT was statistically more effective in 5 of 8 tumor lines (LoVo, LS174T, MOSER, WidR, and GW-39). In 1 other line (DLD-1), RAIT was marginally more efficacious, but tumors responded well to both therapies. The lack of a statistical difference between the 2 modalities of treatment may indicate that the efficacy of the 2 treatments is equivalent, or the relatively large variability within the treatment groups may have prevented significance given the number of animals evaluated. RAIT and 5-FUra/LV were equally efficacious in the HT-29 and the HCT-15 tumor lines. Of the 5 xenografts that responded better to RAIT, 3 lines (LS174T, GW-39, and WidR) demonstrated a greater percentage of tumors responding over a 5- to 6-week period. The other 3 lines (LoVo, MOSER, and DLD-1) exhibited a similar percent of tumors responding to both therapies, but a greater growth inhibition in those RAIT-treated tumors that responded. In vitro responsiveness to 5-FUra/LV did not directly correlate with in vivo responsiveness (r2 = -0.664), since LS174T and LoVo tumors, with rapid growth rates (0.05-0.36 cm3/day), were not highly responsive to therapy. Growth inhibition from RAIT also did not correlate with total tumor carcinoembryonic antigen content (r2 = 0.003), an observation that may be due to additional variables, such as accessibility of antigen and innate radiosensitivity of the tumor. RAIT was most effective in the fastest growing tumor lines (LS174T, GW-39, MOSER, WidR, and LoVo). These preclinical results suggest an advantage to radioantibody therapy over one of the most commonly used forms of chemotherapy to treat colorectal cancer. These studies also highlight the need to establish criteria that will enable the selection of therapeutic modalities in patients.

Animals↗

PubMed1994

Tamoxifen use in breast cancer patients who subsequently develop corpus cancer is not associated with a higher incidence of adverse histologic features.

Several reports have noted an association between the use of tamoxifen in breast cancer patients and the subsequent development of endometrial carcinoma. Magriples et al. (J. Clin. Oncol. 11, 485-490, 1993) recently reported that 67% of uterine cancers that developed in 15 breast cancer patients on tamoxifen had high-grade lesions or high-risk histologies, compared to 24% of those developing in 38 breast cancer patients not receiving tamoxifen. To confirm these results, we conducted a retrospective review of 73 patients with a history of breast cancer who subsequently developed uterine cancer and underwent surgery at our institution. Twenty-three (32%) had received tamoxifen for at least 1 year, with a median duration of use of 4.5 years, while 50 (68%) did not receive tamoxifen. The median interval between diagnosis of breast and corpus cancer was less in the group that received tamoxifen than in the group that did not (4.6 vs 6.7 years), but this was not statistically significant. Seventy-four percent of the corpus cancers in the tamoxifen group were adenocarcinomas, while 26% were considered high-risk histologies, which was identical to the findings for the group that did not receive tamoxifen. The distribution by FIGO stage was I, 15 (65%); II, 2 (9%); III, 5 (22%); and IV, 1 (4%) for the tamoxifen group, and I, 37 (74%); II, 1 (2%); III, 8 (16%); IV, 3 (6%); and unstaged, 1 (2%) for the group not receiving tamoxifen (P = NS). For patients with endometrial adenocarcinoma, 23% of the tamoxifen group had grade 3 lesions, compared with 19% of the no tamoxifen group (P = NS). Our review of corpus cancers developing in breast cancer patients demonstrated no significant difference in stage, grade, or histologic subtype based on tamoxifen use.

Adenocarcinoma↗

PubMed1994

Perinatal outcomes of a large cohort of extremely low gestational age infants (twenty-three to twenty-eight completed weeks of gestation).

OBJECTIVES: To determine gestational age (GA)-specific mortality rates; the effects of GA, birth weight, sex, and multiple gestation on mortality rates; short-term morbidity for infants born at 23 to 28 weeks GA; and impairment rates at a corrected chronologic age of 18 months for those born at 23 to 25 weeks GA. METHODS: A data base analysis was performed with a linked obstetric and a neonatal database. GA was determined by obstetric data and confirmed by early ultrasonography (available in 88%) on all births < 30 weeks GA at British Columbia's tertiary perinatal center from 1983 to 1989. RESULTS: Of 1024 births occurring between 23 and 28 weeks GA, 911 were live born. The mortality rate decreased with increasing GA: 84% at 23 weeks; 57% at 24 weeks; 45% at 25 weeks; 37% at 26 weeks; 23% at 27 weeks; and 13% at 28 weeks GA. For each GA, mortality rate versus birth weight plots showed a decreasing mortality rate with increasing birth weight, except for infants who were large for GA. Male infants had a higher mortality rate than female infants (odds ratio, 1.8; confidence interval, 1.4 to 2.5). Twins fared worse than singletons with a decreasing effect from 24 weeks GA (odds ratio, 10.3) to no effect at 28 weeks GA. The median number of days supported by mechanical ventilation and the length of stay in the neonatal intensive care unit decreased markedly with increasing GA. Eighteen-month outcome of survivors between 23 and 25 weeks GA with 93% follow-up rate revealed an overall impairment rate of 36%, but 6 of the 9 surviving 23-week infants had major impairments. CONCLUSIONS: The GA-specific perinatal outcome results of this large cohort provide information to assist in perinatal management decision making and for counseling parents prenatally.

Adolescent↗

PubMed1994

Stereotactic biopsy of 100 intracerebral lesions at Sir Charles Gairdner Hospital.

The pathological findings in a retrospective review of 100 consecutive intracranial stereotactic biopsies are presented. Definite diagnosis could be established in the majority (89) of cases and included 85 neoplasms (69 primary cerebral tumors, 10 non-Hodgkin's lymphomas and 6 metastases) and 4 non-neoplastic processes. In the remaining 11 samples the findings were non-diagnostic; 2 consisted of normal glial tissue, while the remainder variously showed changes of necrosis, hematoma, histiocytic reaction or astrocytic proliferations of uncertain nature. Verification of the stereotactic diagnosis by examination of lesional tissue obtained at subsequent craniotomy or postmortem was possible in 7 of 10 cases. Two broad categories of diagnostic difficulty were identified in interpreting stereotactic biopsies: (1) accurate tumor typing and grading, and (2) the distinction between reactive and neoplastic astrocytic proliferations. Two essential components in the diagnostic process are: (1) careful correlation with the clinical and radiological findings; and (2) use of intraoperative smear and/or frozen section preparations to confirm specimen adequacy. By adhering to these principles accurate intraoperative diagnosis can usually be established, particularly for high grade astrocytoma, lymphoma and metastasis. Tumor typing is aided by the use of immunohistochemistry and ultrastructural examination and the examination of serial sections is of value in grading.

Adolescent↗

PubMed1994

Mammary ductal epithelial cell hyperproliferation and hyperplasia induced by a nutritional stress diet containing four components of a western-style diet.

We have studied effects of several nutrients on the proliferation of mammary ductal epithelial cells in C57BL/6J virgin female mice, using morphometry and [3H]dT in vivo labeling. A nutritional stress diet was given based on the AIN-76A semi-synthetic diet modified to contain four significant risk factors of a Western-style diet: high fat and phosphate and decreased calcium and vitamin D. The numbers of large, intermediate and terminal ducts and proliferating epithelial cells in mammary glands were assayed in control and stress diet groups. An increased number of mammary ducts and increased number of proliferating cells were found at the level of the small terminal ducts, a cancer-prone region in the mammary gland in the stress diet group compared to the control group after 20 weeks of diet administration. Thus, mammary terminal ductal hyperproliferation, expansion in the size of the proliferative epithelial cell compartment and excessive duplication of mammary ductal epithelial cells were found after this Western-style diet containing decreased dietary calcium and vitamin D. These changes are similar to those developing in colonic epithelium of mice maintained on the same diets and during chemically induced colonic carcinogenesis.

Animals↗

PubMed1994

How to choose: nurses' judgements of the effectiveness of a range of currently marketed continence aids.

Continence is a costly health problem, both in terms of financial burden in continence aids, but also in terms of quality-of-life issues for the person who has continence problems. Manufacturers are often perturbed as to why products specially designed to help continence problems are not popular, or do not appear to be applied as intended. This paper reports on a study involving a quantitative evaluation of a range of continence aids presently being marketed, as applied in a large elderly care centre. The evaluation used nursing judgements on a series of comfort and effectiveness criteria: amount of leakage around the pad, comfort to the client when the pad was either wet or dry, skin integrity and snugness of fit, as well as whether the pad concealed well beneath clothing. Five body pads were evaluated--two disposable and three washable--and three bed under-sheets. Effectiveness of pads was found to vary substantially according to sex of client and voiding type, that is whether the client had heavy or moderate incontinent episodes.

Aged↗