Annual patterns in bacterioplankton community variability in a humic lake

Bacterioplankton community composition (BCC) was monitored in a shallow humic lake in northern Wisconsin, USA, over 3 years using automated ribosomal intergenic spacer analysis (ARISA). Comparison of ARISA profiles of bacterial communities over time indicated that BCC was highly variable on a seasonal and annual scale. Nonmetric multidimensional scaling (MDS) analysis indicated little similarity in BCC from year to year. Nevertheless, annual patterns in bacterioplankton community diversity were observed. Trends in bacterioplankton community diversity were correlated to annual patterns in community succession observed for phytoplankton and zooplankton populations, consistent with the notion that food web interactions affect bacterioplankton community structure in this humic lake. Bacterioplankton communities experience a dramatic drop in richness and abundance each year in early summer, concurrent with an increase in the abundance of both mixotrophic and heterotrophic flagellates. A second drop in richness, but not abundance, is observed each year in late summer, coinciding with an intense bloom of the nonphagotrophic dinoflagellate Peridinium limbatum. A relationship between bacterial community composition, size, and abundance and the population dynamics of Daphnia was also observed. The noted synchrony between these major population and species shifts suggests that linkages across trophic levels play a role in determining the annual time course of events for the microbial and metazoan components of the plankton.

Tranilast reduces mesenteric vascular collagen deposition and chymase-positive mast cells in experimental diabetes

The mast cell has a central role in the pathogenesis of fibrosis a common feature of diabetic microvascular complications. Increased mast cell numbers have been demonstrated in diabetic nephropathy in association with renal fibrosis, and diabetes acutely increases mast cell infiltration in the mesentery. Antimast cell agents such as tranilast may ameliorate the acute vascular changes in diabetes due to stabilisation of mast cells and/or reduction in mast cell numbers. After 3 weeks of streptozotocin diabetes, light microscopy techniques were used to estimate mesenteric vessel fibrosis and mast cell infiltration. Mast cells were identified by toluidine blue staining and tryptase, chymase and TGF-beta immunohistochemistry in three study groups of rats: control, diabetic and plus tranilast. Diabetes was associated with an increase in both mesenteric vessel fibrosis and mast cell numbers. Administration of tranilast to diabetic rats reduced mesenteric vessel fibrosis and this was associated with a reduction in chymase-positive mast cells. These changes were independent of mast cell TGF-beta and were not associated with a reduction in tryptase-positive mast cells. The amelioration of diabetes-induced vessel fibrosis may be due to a reduction in the liberation of angiotensin II by inhibiting mast cell chymase.

Discriminating between the effect of shunt and reduced VA/Q on arterial oxygen saturation is particularly useful in clinical practice

There is an extensive literature on methods for discriminating between an increased shunt and a reduced ratio of ventilation to perfusion. In this review we prefer the terms "VA/Q" and "reduced or low VA/Q" rather than "V/Q inequality" to refer to the effects on arterial oxygenation of reducing V/Q below 0.8 to about 0.1. Almost without exception the conventional methods for measuring shunt and reduced VA/Q are invasive as well as technically complex. For most clinicians who are dealing with a hypoxemic patient the relevance of these entities is not so obvious as to justify the time and difficulty in either understanding or measuring them. However this review shows that, while an increased shunt and a decreased VA/Q both reduce arterial oxygen saturation (SaO2) at a particular inspired oxygen concentration (PIO2), the effect of shunt and reduced VA/Q have important clinical differences on the relationship between PIO2 and SaO2. The review also outlines a simple non-invasive method for measuring shunt and reduced VA/Q which illustrates the value of discriminating between them in clinical practice.

Double-blind, randomized trial comparing the efficacy and tolerability of fulvestrant versus anastrozole in postmenopausal women with advanced breast cancer progressing on prior endocrine therapy: results of a North American trial

PURPOSE

To compare the efficacy and tolerability of fulvestrant (formerly ICI 182,780) with anastrozole in the treatment of advanced breast cancer in patients whose disease progresses on prior endocrine treatment.

PATIENTS AND METHODS

In this double-blind, double-dummy, parallel-group study, postmenopausal patients were randomized to receive either an intramuscular injection of fulvestrant 250 mg once monthly or a daily oral dose of anastrozole 1 mg. The primary end point was time to progression (TTP). Secondary end points included objective response (OR) rate, duration of response (DOR), and tolerability.

RESULTS

Patients (n = 400) were followed for a median period of 16.8 months. Fulvestrant was as effective as anastrozole in terms of TTP (hazard ratio, 0.92; 95.14% confidence interval [CI], 0.74 to 1.14; P =.43); median TTP was 5.4 months with fulvestrant and 3.4 months with anastrozole. OR rates were 17.5% with both treatments. Clinical benefit rates (complete response + partial response + stable disease > or = 24 weeks) were 42.2% for fulvestrant and 36.1% for anastrozole (95% CI, -4.00% to 16.41%; P =.26). In responding patients, median DOR (from randomization to progression) was 19.0 months for fulvestrant and 10.8 months for anastrozole. Using all patients, DOR was significantly greater for fulvestrant compared with anastrozole; the ratio of average response durations was 1.35 (95% CI, 1.10 to 1.67; P < 0.01). Both treatments were well tolerated.

CONCLUSION

Fulvestrant was at least as effective as anastrozole, with efficacy end points slightly favoring fulvestrant. Fulvestrant represents an additional treatment option for postmenopausal women with advanced breast cancer whose disease progresses on tamoxifen therapy.

Comparable efficacy and safety profiles of once-per-cycle pegfilgrastim and daily injection filgrastim in chemotherapy-induced neutropenia: a multicenter dose-finding study in women with breast cancer

BACKGROUND

Neutropenia is common in patients receiving myelotoxic chemotherapy. Pegfilgrastim, a sustained-duration filgrastim is a once-per-cycle therapy for prophylactic neutrophil support.

PATIENTS AND METHODS

Women, treated with four cycles of doxorubicin/docetaxel chemotherapy every 21 days, received pegfilgrastim or filgrastim 24 h after chemotherapy as a single subcutaneous injection per chemotherapy cycle (pegfilgrastim 30, 60 or 100 microg/kg) or daily subcutaneous injections (filgrastim 5 microg/kg/day). Safety, efficacy and pharmacokinetics were analyzed.

RESULTS

The incidence of grade 4 neutropenia in cycle 1 was 95, 90 and 74%, in patients who received pegfilgrastim 30, 60 and 100 microg/kg, respectively, and 76% in patients who received filgrastim. Mean duration of grade 4 neutropenia in cycle 1 was 2.7,2 and 1.3 days for doses of pegfilgrastim, and 1.6 days for filgrastim. The pharmacokinetics of pegfilgrastim were non-linear and dependent on both dose and neutrophil count. Pegfilgrastim serum concentration was sustained until the neutrophil nadir occurred then declined rapidly as neutrophils started to recover, consistent with a self-regulating neutrophil-mediated clearance mechanism. The safety profiles of pegfilgrastim and filgrastim were similar.

CONCLUSIONS

A single subcutaneous injection of pegfilgrastim 100 microg/kg provided neutrophil support and a safety profile comparable to daily subcutaneous injections of filgrastim during multiple chemotherapy cycles.

Blinded, randomized, multicenter study to evaluate single administration pegfilgrastim once per cycle versus daily filgrastim as an adjunct to chemotherapy in patients with high-risk stage II or stage III/IV breast cancer

PURPOSE

This multicenter, randomized, double-blind, active-control study was designed to determine whether a single subcutaneous injection of pegfilgrastim (SD/01, sustained-duration filgrastim; 100 microg/kg) is as safe and effective as daily filgrastim (5 microg/kg/d) for reducing neutropenia in patients who received four cycles of myelosuppressive chemotherapy.

PATIENTS AND METHODS

Sixty-two centers enrolled 310 patients who received chemotherapy with docetaxel 75 mg/m(2) and doxorubicin 60 mg/m(2) on day 1 of each cycle for a maximum of four cycles. Patients were randomized to receive on day 2 either a single subcutaneous injection of pegfilgrastim 100 microg/kg per chemotherapy cycle (154 patients) or daily subcutaneous injections of filgrastim 5 microg/kg/d (156 patients). Absolute neutrophil count (ANC), duration of grade 4 neutropenia, and safety parameters were monitored.

RESULTS

One dose of pegfilgrastim per chemotherapy cycle was comparable to daily subcutaneous injections of filgrastim with regard to all efficacy end points, including the duration of severe neutropenia and the depth of ANC nadir in all cycles. Febrile neutropenia across all cycles occurred less often in patients who received pegfilgrastim. The difference in the mean duration of severe neutropenia between the pegfilgrastim and filgrastim treatment groups was less than 1 day. Pegfilgrastim was safe and well tolerated, and it was similar to filgrastim. Adverse event profiles in the pegfilgrastim and filgrastim groups were similar.

CONCLUSION

A single injection of pegfilgrastim 100 microg/kg per cycle was as safe and effective as daily injections of filgrastim 5 microg/kg/d in reducing neutropenia and its complications in patients who received four cycles of doxorubicin 60 mg/m(2) and docetaxel 75 mg/m(2).

Prevalence and correlates of sunscreen use among US high school students

Sun exposure during childhood and adolescence increases the risk of skin cancer later in life. To determine the prevalence and correlates of sunscreen use among US high school students, researchers assessed data on sunscreen use, demographic characteristics, and health behaviors obtained from the 1999 Youth Risk Behavior Survey (YRBS). This survey used a three-stage cluster sample design to produce a nationally representative sample of students in grades 9-12 (N = 15,349). Overall, 13.3% (95% confidence interval, +/- 1.3) of students used sunscreen always or most of the time (i.e., frequent use). Frequent sunscreen use was lower among males (8.6%, +/- 1.2) than females (18.1%, +/- 1.9) and among Blacks (4.8%, +/- 1.7) and Hispanics (10.8%, +/- 2.8) than Whites (16.5%, +/- 1.9). Frequent sunscreen use decreased with age. Infrequent use of sunscreen was associated with other risky health behaviors, such as driving after drinking or riding in a car with a drinking driver, smoking cigarettes, being sexually active, and being physically inactive. Results indicate a need for health education interventions addressing sunscreen use that target high school students.

Characterization of cell death pathways in murine retinal neurodegeneration implicates cytochrome c release, caspase activation, and bid cleavage

Apoptosis is considered to be the final common pathway of photoreceptor cell death in different inherited retinal diseases. However, apoptosis encompasses diverse pathways of molecular interactions culminating in cellular demise. To begin dissecting these interactions, we have investigated key participants in the rd (retinal degeneration) model of retinal neurodegeneration. By Western blot analysis and immunocytochemistry, we found that cytochrome c release occurs in rd retinas concurrently with the activation of the proapoptotic protein Bid. Active forms of caspase-8 and the mitogen-activated protein kinase p38, both of which are capable of cleaving Bid, were detected in rd retinas at the peak time of photoreceptor death. In addition, the activated form of the cell death effector caspase-3 was detectable particularly at the photoreceptors in parallel with this peak degenerative phase. These data suggest that activation of both major apoptotic pathways occurs during photoreceptor degeneration in the rd mouse model of inherited blindness.

Randomized, open-label, phase II trial of oral capecitabine (Xeloda) vs. a reference arm of intravenous CMF (cyclophosphamide, methotrexate and 5-fluorouracil) as first-line therapy for advanced/metastatic breast cancer

BACKGROUND

Oral capecitabine was evaluated in terms of overall response rate, safety, and tolerability as first-line therapy in women aged > or = 55 years with advanced/metastatic breast cancer.

PATIENTS AND METHODS

Ninety-five patients were randomized (2:1) to either intermittent oral capecitabine 1,255 mg/m2 twice daily (two weeks' treatment followed by a one-week rest period) or intravenous CMF (cyclophosphamide. methotrexate, 5-fluorouracil [5-FU]) administered every three weeks.

RESULTS

The overall response rate in the capecitabine group was 30% (95% confidence interval (95% CI): 19%-43%), including three complete responses (5%). The response rate observed in the CMF group was 16% (95% CI: 5%-33%), with no complete responses. Median time to disease progression was 4.1 months with capecitabine and 3.0 months with CME. Survival was similar in the two treatment groups (median 19.6 months with capecitabine. 17.2 months with CMF). The safety profiles were different for capecitabine and CMF. However, both regimens were generally well tolerated and treatment interruption and/or dose modification was effective in managing toxicities associated with capecitabine. Alopecia and myelosuppression were rare in patients receiving capecitabine while diarrhea and hand-foot syndrome were more common. Treatment interruption and/or individual dose adjustment of capecitabine was required in 34% of patients and was generally effective in managing adverse events. Treatment was stopped owing to toxicity in 16% of patients in the capecitabine arm. The incidence of deaths during or within 28 days of stopping study treatment was 8% and 6% in the capecitabine and CMF arms, respectively.

CONCLUSIONS

An oral, twice-daily regimen of capecitabine is effective and well tolerated when used as first-line chemotherapy in older patients (> or = 55 years) with advanced/metastatic breast cancer, and is suitable for outpatient therapy.

Anaesthesia for insertion of bone-anchored hearing aids in children: a 7-year audit

Forty-three children, aged 23 months to 14 years, received 102 anaesthetics for insertion of bone-anchored hearing aids, each lasting approximately 30-60 min. Forty of the children had a recognised syndrome involving the head and neck, including Goldenhar's and Treacher Collin's syndrome. The incidence of congenital heart disease was 19%. Pre-existing conditions, anaesthetic technique, grade of intubation, complications and discharge were audited. Sixteen of the patients were classified as Grade 3 or 4 intubations. Over the 7 years, laryngeal mask airway usage increased for airway maintenance rather than tracheal intubation, as did the use of propofol for induction rather than inhalational methods. Intra-operative complications (5.9%) were related to the airway, and postoperative ones (17.6%) mainly to nausea and vomiting. Surgery was performed as a day case in 71% of the patients despite some long-distance travel.

Binge drinking among undergraduate college students in the United States: implications for other substance use

The authors examined the relationship between binge drinking and other substance use among US college students, using nationally representative data from the 1995 National College Health Risk Behavior Survey implemented by the Centers for Disease Control and Prevention. Compared with nonbinge drinkers, current binge drinkers were significantly more likely to report "ever" using and current use of cigarettes, marijuana, cocaine, and other illegal drugs. The researchers also found that the more often students binge drank, the more likely they were to have ever used cigarettes, marijuana, cocaine, and other drugs, and the more likely they were to report current use of cigarettes and marijuana. Those who design programs to prevent binge drinking and use of other substances should take into account the reality that many students use more than one substance and that the more frequently students report binge drinking, the more likely they are to be using other substances as well.

Intra-uterine environment influences glomerular number and the acute renal adaptation to experimental diabetes

AIMS/HYPOTHESIS

We sought to test the hypothesis of whether low birth weight rats would have reduced glomerular number, higher systolic blood pressure and an altered acute response to streptozotocin diabetes compared to normal birth weight rats.

METHODS

Female offspring of Wistar rats fed an isocaloric diet containing either 6% casein (LPD) or 18% casein (NPD) in utero were studied. Birth weight, body weight, systolic blood pressure and urine albumin excretion were measured before and after streptozotocin diabetes. Glomerular number and volume were estimated after one week of diabetes.

RESULTS

The LPD rats were of low birth weight (5.4 +/- 0.5 g vs 6.4 +/- 0.8 g, p < 0.0001) with higher systolic blood pressure (137 +/- 9mmHg vs 120 +/- 7 mmHg, p < 0.0001) and reduced glomerular number (17,435 +/- 2,074 vs 24,846 +/- 1,864, p < 0.0001). The LPD rats had smaller kidneys (0.925 +/- 0.009 g vs 1.200 +/- 0.173 g, p = 0.041) but similar glomerular volume to NPD control rats (1.11 +/- 0.15 x 10(6) microm3 vs 1.08 +/- 0.17 x 10(6) microm3). After 1 week of diabetes LPD rats had a greater proportional increase in renal size (diabetes 50 +/- 12 % vs control 20 +/- 4%, p = 0.003). Insulin suppressed renal hypertrophy in both LPD and NPD rats but failed to suppress glomerular hypertrophy in LPD rats (1.48 +/- 0.21 x 10(6) microm3 vs 1.03 +/- 0.23 x 10(6) microm3 p = 0.015).

CONCLUSION/INTERPRETATION

Abnormal intra-uterine environment reduces both renal size and glomerular number and influences the acute renal adaptation to experimental diabetes.

A phase I and pharmacologic study of capecitabine and paclitaxel in breast cancer patients

BACKGROUND

Based on preclinical studies demonstrating that treatment with paclitaxel upregulates intratumoral thymidine phosphorylase (dTHdPase), which catalyzes the final step in the conversion of the oral fluoropyrimidine capecitabine to 5-fluorouracil (5-FU), as well as the overlapping spectra of activity for these agents, particularly in metastatic breast cancer, this phase I study evaluated the feasibility of administering capecitabine on an intermittent schedule in combination with paclitaxel in previously-treated patients with locally advanced or metastatic breast cancer. The study also sought to recommend doses for subsequent disease-specific studies, identify clinically significant pharmacokinetic interactions, and detect preliminary antitumor activity.

PATIENTS AND METHODS

Nineteen previously treated women with metastatic breast cancer whose prior treatment included neither paclitaxel or capecitabine received one hundred one courses of capecitabine and paclitaxel. Paclitaxel was administered as a three-hour intravenous (i.v.) infusion at a fixed dose of 175 mg/m2 and capecitabine was administered as 2 divided daily doses for 14 days followed by a seven-day rest period every 3 weeks. The dose of capecitabine was increased from a starting dose of 1650 mg/m2/d. The plasma sampling scheme in the first course permitted characterization of the pharmacokinetics of each agent given alone and concurrently to detect major pharmacokinetic interactions.

RESULTS

Palmar plantar erythrodysesthesia (hand foot syndrome) and neutropenia were the principal dose-limiting toxicities (DLT). Other toxicities included diarrhea and transient hyperbilirubinemia. Three of eight new patients treated with capecitabine 2000 mg/m2/d and paclitaxel 175 mg/m2 experienced DLT in the first course, whereas none of eleven new patients treated with capecitabine 1650 mg/m2/d and paclitaxel 175 mg/m2 developed DLT. Pharmacokinetic studies indicated that capecitabine did not grossly affect the pharmacokinetics of paclitaxel, and there were no major effects of paclitaxel on the pharmacokinetics of capecitabine and capecitabine metabolites. However, AUC values for the major 5-FU catabolite, fluorobeta-alanine (FBAL), were significantly lower in the presence of paclitaxel. Two complete and seven partial responses (56% response rate) were observed in sixteen patients with measurable disease; four of six patients whose disease was previously treated with high-dose chemotherapy and hematopoietic stem-cell support had major responses. Seven of nineteen patients had stable disease as their best response.

CONCLUSIONS

Recommended combination doses of capecitabine on an intermittent schedule and paclitaxel are capecitabine 1650 mg/m2/d orally for 14 days and paclitaxel 175 mg/m2 i.v. every 3 weeks. The favorable preclinical interactions between capecitabine and paclitaxel, as well as the acceptable toxicity profile and antitumor activity in patients with metastatic breast cancer, support further clinical evaluations to determine an optimal role for the combination of capecitabine and paclitaxel in breast cancer and other relevant malignancies.

Outcome of outpatient micro-hysteroscopy performed for abnormal bleeding while on hormone replacement therapy

This retrospective observational study was carried out in a large district general hospital to review the outcome of outpatient micro-hysteroscopy performed on women with abnormal bleeding while on hormone replacement therapy. All women referred to the outpatient hysteroscopy unit with abnormal bleeding while on hormone replacement therapy between November 1994 and August 1998 had hysteroscopy performed using a 1.2 mm semi-rigid hysteroscope with a 2.5 mm sheath. Hysteroscopy was performed on 190 women. Ninety-two women (48.4%) had a normal uterine cavity, 38 (20%) had an atrophic endometrium, 52 (27.4%) were found to have endometrial polyps, seven (3.7%) had suspicious endometrium (histology showed two adenocarcinomas and three hyperplasias) and one patient (0.5%) had a submucous fibroid. Histological evaluation showed 145 (76.32%) specimens were benign, 37 (19.47%) specimens either contained no tissue or insufficient tissue for diagnosis, five (2.63%) showed hyperplasia and three (1.58%) were adenocarcinoma. Two hyperplasias and one focal adenocarcinoma were diagnosed in endometrial polyps. Nearly half of the women who had a hysteroscopy for abnormal bleeding while on hormone replacement therapy had a normal endometrial cavity. Almost one-third had endometrial pathology, of which the majority were endometrial polyps. The incidence of endometrial carcinoma was low. No abnormality was missed on hysteroscopy, but histology was normal in two patients with hysteroscopically suspicious endometrium.

Birth weight has no influence on glomerular number and volume

It has been proposed that low birth weight (LBW) results in a reduction in glomerular number that may, in turn, predispose an individual to develop hypertension in adulthood. Glomerular number is reduced in animal models of intra-uterine malnutrition using a variety of techniques. However, the relevance of such extreme models to man is uncertain. The purpose of this study was to evaluate whether animals with naturally occurring LBW, which have not received any manipulation in utero, have a reduction in glomerular number, altered glomerular volume and abnormal urine albumin excretion. Litters from female rats delivering at term on the same day were weighed and sexed at birth. From each litter 2 males with the lowest birth weight (LBW n = 18) and 2 males with a birth weight closest to the litter mean [normal birth weight (NBW) n = 18] were selected and cross-fostered onto periparturient lactating dams. LBW rats weighted 6.7 +/- 0.6 g compared with 7.2 +/- 0.6 g for NBW rats (P = 0.03). After weaning all rats were weighed weekly and underwent metabolic studies at 4, 8, 12 and 16 weeks. Following perfusion fixation, glomerular number and mean glomerular volume were estimated using standard stereological techniques. There was no significant difference between LBW and NBW rats with respect to glomerular number (24,499 +/- 2,078 vs. 24,825 +/- 1,818), mean glomerular volume and urine albumin excretion, and no rats had a glomerular number outside the normal range. This study suggests that naturally occurring LBW has little influence on renal development, glomerular number and volume.

Adenoma in the middle ear: a report of two cases

Middle-ear adenoma has been reported only in small numbers by surgeons. The few large series reported have been presented by histopathologists. We add two cases of middle-ear adenoma to the published literature, together with pre-, per- and post-operative imaging of one case, as a demonstration of this rare clinical entity. We discuss the pathology of middle-ear adenoma, its diagnosis and treatment, and suggest ways of improving its management.

Frontal recess surgery for diving-related frontal pain: case report

We report the case of a professional scuba diver who was unable to dive because he began experiencing severe frontal pain on descent. Following endoscopic surgery to open the frontal recess, the man was able to resume diving unrestricted by pain. We discuss the causes and treatment of this complaint, and we suggest that this might be considered a new indication for surgery in a limited number of cases.

Epitope-tagged recombinant AAV vectors for expressing neurturin and its receptor in retinal cells

PURPOSE

Neurturin (NTN) is a potent neuronal survival factor in the central and peripheral nervous systems. We previously described altered expression of mRNAs for NTN and one of its receptor components, GFRa-2 in degenerative retinas of rd/rd mice. Towards assessing the potential for transfer of these genes to counteract retinal degeneration, we examined recombinant adeno-associated virus (rAAV) constructs for expression of NTN and GFRa-2 transgenes in retinal cells in vitro and for the effect of transgene expression on retinal function following intraocular delivery in rd/rd mice.

METHODS

The rAAV constructs incorporated epitope tags to facilitate discrimination between transgenic and endogenous expression. Expression of murine NTN was driven by a CMV promoter and a partial murine opsin promoter was used to drive expression of human GFRa-2. rAAV preparations were used to infect mouse retinal cell cultures and for intraocular injection of predegenerative rd/rd mice. Endogenous and transgene expression was analyzed by immunofluorescence. Photoreceptor function in treated mice was assessed by electroretinography.

RESULTS

Both vectors delivered and expressed their transgenes in vitro and in vivo. Differential targeting was achieved in vivo through the use of alternative promoters. Under the conditions examined, no functional rescue of rd photoreceptors was observed.

CONCLUSIONS

Therapeutic treatment of the rd model of retinal degeneration does not appear to be effected by simple modulation of the expression of NTN or GFRa-2, and may therefore depend on additional synergistic factors. Our AAV constructs will facilitate the development of combinatorial approaches to the treatment of central and peripheral neurodegenerations.

Enteric neuroblasts require the phosphatidylinositol 3-kinase pathway for GDNF-stimulated proliferation

The enteric nervous system (ENS) develops from neural crest cells that enter the gut, migrate, proliferate, and differentiate into neurons and glia. The growth factor glial-derived neurotrophic factor (GDNF) stimulates the proliferation and survival of enteric crest-derived cells. We investigated the intracellular signaling pathways activated by GDNF and their involvement in proliferation. We found that GDNF stimulates the phosphorylation of both the PI 3-kinase downstream substrate Akt and the MAP kinase substrate ERK in cultures of immunoaffinity-purified embryonic avian enteric crest-derived cells. The selective PI 3-kinase inhibitor LY-294002 blocked GDNF-stimulated Akt phosphorylation in purified crest cells, and reduced proliferation in cultures of dissociated quail gut. The ERK kinase (MEK) inhibitors PD 98059 and UO126 did not reduce GDNF-stimulated proliferation, although PD 98059 blocked GDNF-stimulated phosphorylation of ERK. We conclude that the PI 3-kinase pathway is necessary for the GDNF-stimulated proliferation of enteric neuroblasts.

Modulated expression of secreted frizzled-related proteins in human retinal degeneration

Inherited retinal degenerations such as retinitis pigmentosa (RP) are characterized by progressive loss of photoreceptors, apparently by apoptosis, and our recent report of increased secreted Frizzled-related protein-2 (SFRP2) in RP retinas suggests altered Wnt signalling may be a component of the degenerative process. The present study shows that levels of SFRPI, SFRP3 and SFRP5 mRNAs are also abnormal in RP, giving rise to idiosyncratic expression patterns. In highly degenerative retinas, the SFRP proteins localize mainly to the inner limiting membrane, but in a well-preserved retina SFRPI and SFRP5 are notably localized to the surviving photoreceptors. Together with increased c-jun mRNA expression in all cases examined, these results support the notion that disruptions of Wnt network signalling are involved retinal neurodegeneration.

Use of small fluorescent molecules to monitor channel activity

The Mechanosensitive channel of Large conductance (MscL) allows bacteria to rapidly adapt to changing environmental conditions such as osmolarity. The MscL channel opens in response to increases in membrane tension, which allows for the efflux of cytoplasmic constituents. Here we describe the cloning and expression of Salmonella typhimurium MscL (St-MscL). The amino acid sequence encoding for this MscL exhibits a high degree of similarity to Escherichia coli MscL (Eco-MscL). Using a fluorescence efflux assay, we demonstrate that efflux through the MscL channel during hypoosmotic shock can be monitored using endogenously produced fluorophores. These fluorophores are synthesized by a cotransformed gene, cobA. In addition, we observe that thermal stimulation, i.e., heat shock, can induce efflux through MscL.

Optic chiasmal herniation--an under recognized complication of dopamine agonist therapy for macroprolactinoma

The initial presentation of macroprolactinoma with visual field impairment, especially in males, is well recognized. Successful treatment with dopamine agonist therapy is characterized by a reduction in hyperprolactinaemia and often rapid and progressive resolution of the visual impairment. A small proportion of patients may subsequently develop a secondary deterioration in both their visual fields and visual acuities despite normalization of prolactin levels and tumour shrinkage. When pituitary apoplexy can be excluded this may result from traction on the optic chiasm which is pulled down into the now partially empty sella. We report a series of seven patients in whom chiasmal traction is believed to be the cause of their secondary deterioration in visual acuity occurring after dopamine agonist therapy for macroprolactinoma. The clinical history of two patients both of whom had rapid resolution of field defect with bromocriptine therapy but subsequently developed a recurrence of their bitemporal hemianopia is detailed. In both patients MRI scanning showed not only tumour involution but also marked optic chiasm herniation into the pituitary fossa. Surgical treatment was considered too risky; but on reduction of bromocriptine dosage the field defect improved in both cases; there was a modest elevation of prolactin and a degree of tumour re-expansion. The latter is believed to have released tethering of the optic chiasm and/or its vascular supply and thus obviated the need for surgery. Regular monitoring of visual fields in patients with macroprolactinoma receiving medical treatment is therefore important. Early recognition of secondary field loss due to chiasmal herniation enables correction of the visual field loss by manipulation of the medical therapy.

Exemestane: a novel aromatase inactivator for breast cancer

Exemestane is a unique inactivator of the aromatase enzyme and differs from the two approved aromatase inhibitors. It is well absorbed at a daily oral dose of 25 mg and produces significant suppression of aromatase and plasma estrogen levels without androgenic side effects. Toxicity is mild with menopausal symptoms predominating. Exemestane is approved for the treatment of postmenopausal women with recurrent breast cancer. In reported clinical trials, exemestane was effective in patients failing tamoxifen, megestrol acetate, or even other aromatase inhibitors in phase II trials and was superior to megestrol acetate in a phase III randomized trial in which an early survival advantage for exemestane was observed. Studies evaluating first-line exemestane for adjuvant use and as a chemopreventive agent are underway.

Exemestane improves survival in metastatic breast cancer: results of a phase III randomized study

We compared the efficacy and safety of the oral aromatase inactivator exemestane (EXE) with megestrol acetate (MA) in women with metastatic breast cancer. This phase III randomized, double-blind, multicenter study was conducted in 769 postmenopausal women who had experienced tamoxifen failure. Treatment arms consisted of EXE 25 mg once daily (n=366) or MA 40 mg four times daily (160 mg daily; n=403). Peer-reviewed, intent-to-treat analyses demonstrated that EXE induced a trend toward higher rates of complete response (CR)+partial response (PR) (15.0% vs. 12.4%) and of CR+PR+stable disease (SD)=24 weeks (37.4% vs. 34.6%), but differences were not statistically significant. Statistically significant differences favoring EXE were seen in median duration of CR+PR+SD=24 weeks (60.1 vs. 49.1 weeks; P=0.025), time to tumor progression (20.3 vs. 16.6 weeks; P=0.037), time to treatment failure (16.3 vs. 15.7 weeks; P=0.042), and overall survival (not reached vs. 123.4 weeks; P=0.039). Both treatments were well tolerated, but MA was associated with more grade 3 or 4 weight gain (8% vs. 17%, P=0.001); the pain score was sim-ilar in both groups. There was a trend toward superiority in treatment-related signs and symptoms (TRSS) with EXE. There was greater improvement in the pain score and TRSS in patients achieving an objective response with EXE vs. MA. Quality of life improved or was similar for EXE in most domains. Exemestane offers an important new treatment option for postmenopausal women with hormone-responsive breast cancer.

Exemestane improves survival compared with megoestrol acetate in postmenopausal patients with advanced breast cancer who have failed on tamoxifen. results Of a double-blind randomised phase III trial

Exemestane is an aromatase inactivator. 769 Postmenopausal women with advanced breast cancer who had failed on tamoxifen were randomised to exemestane or megoestrol acetate in this double-blind trial. Objective response rate was similar between treatments. Median time to progression, time to treatment failure and overall survival was significantly longer with exemestane. Drug-related withdrawals and drug-related deaths were more common with megoestrol acetate.

Three-dimensional mapping of cortical thickness using Laplace's equation

We present a novel, computerized method of examining cerebral cortical thickness. The normal cortex varies in thickness from 2 to 4 mm, reflecting the morphology of neuronal sublayers. Cortical pathologies often manifest abnormal variations in thickness, with examples of Alzheimer's disease and cortical dysplasia as thin and thick cortex, respectively. Radiologically, images are 2-D slices through a highly convoluted 3-D object. Depending on the relative orientation of the slices with respect to the object, it is impossible to deduce abnormal cortical thickness without additional information from neighboring slices. We approach the problem by applying Laplace's Equation (V2psi = 0) from mathematical physics. The volume of the cortex is represented as the domain for the solution of the differential equation, with separate boundary conditions at the gray-white junction and the gray-CSF junction. Normalized gradients of psi form a vector field, representing tangent vectors along field lines connecting both boundaries. We define the cortical thickness at any point in the cortex to be the pathlength along such lines. Key advantages of this method are that it is fully three-dimensional, and the thickness is uniquely defined for any point in the cortex. We present graphical results that map cortical thickness everywhere in a normal brain. Results show global variations in cortical thickness consistent with known neuroanatomy. The application of this technique to visualization of cortical thickness in brains with known pathology has broad clinical implications.

Three-dimensional mapping of cortical thickness using Laplace's equation

We present a novel, computerized method of examining cerebral cortical thickness. The normal cortex varies in thickness from 2 to 4 mm, reflecting the morphology of neuronal sublayers. Cortical pathologies often manifest abnormal variations in thickness, with examples of Alzheimer's disease and cortical dysplasia as thin and thick cortex, respectively. Radiologically, images are 2-D slices through a highly convoluted 3-D object. Depending on the relative orientation of the slices with respect to the object, it is impossible to deduce abnormal cortical thickness without additional information from neighboring slices. We approach the problem by applying Laplace's Equation (V2psi = 0) from mathematical physics. The volume of the cortex is represented as the domain for the solution of the differential equation, with separate boundary conditions at the gray-white junction and the gray-CSF junction. Normalized gradients of psi form a vector field, representing tangent vectors along field lines connecting both boundaries. We define the cortical thickness at any point in the cortex to be the pathlength along such lines. Key advantages of this method are that it is fully three-dimensional, and the thickness is uniquely defined for any point in the cortex. We present graphical results that map cortical thickness everywhere in a normal brain. Results show global variations in cortical thickness consistent with known neuroanatomy. The application of this technique to visualization of cortical thickness in brains with known pathology has broad clinical implications.

Low-affinity block of cardiac K(+) currents by nifedipine

Nifedipine inhibits a variety of K(+) currents with IC(50) between 4 and 40 microM. Among the more sensitive of these are two types (transient outward and ultrarapid hKv1.5) found in the heart. To evaluate the actions of the drug on other prominent cardiac K(+) currents, guinea-pig ventricular myocytes were voltage-clamped for measurement of inwardly rectifying K(+) current (I(K1)), rapidly activating delayed-rectifier K(+) current (I(Kr)), and slowly activating delayed-rectifier K(+) current (I(Ks)). The currents were unaffected by < or =10 microM nifedipine, but inhibited by higher concentrations; IC(50) values were 260 microM for I(K1), 275 microM for I(Kr), and 360 microM for I(Ks). The time- and voltage-dependent properties of I(Ks) were unaffected by the drug, and full block was attained on the first depolarisation after a rest. The results establish that the sensitivity of I(Kr) and I(Ks) to inhibition by nifedipine is approximately 50 times lower than the sensitivity of other cardiac delayed-rectifier K(+) currents.

Identification by array screening of altered nm23-M2/PuF mRNA expression in mouse retinal degeneration

In the rd/rd mouse model of inherited retinal degeneration, the majority of photoreceptors die apoptotically between postnatal age (P)10 and 20 days, during which period the inner retina appears morphologically unaffected. To examine mRNA changes associated with the degeneration, we performed differential screening of 588 arrayed murine cDNAs using probes reverse-transcribed from P8 predegenerative and control mouse retinal RNAs. We detected altered expression of the gene encoding nm23-M2, a member of the family of nucleoside diphosphate kinases implicated in diverse processes including metastasis suppression and transcriptional regulation. Retinal nm23 mRNA levels increased during degeneration while control levels decreased over age-matched time-points. In situ hybridization showed the high level of expression at P20 in rd/rd was concentrated in the retinal ganglion cells. Previous studies have indicated upregulation of the stress-response related gene alphaB-crystallin in the rd/rd inner retina, and increased nm23 levels may be a component of this response to photoreceptor loss and altered retinal architecture.

Altered expression of secreted frizzled-related protein-2 in retinitis pigmentosa retinas

PURPOSE

Inherited retinal degenerations such as retinitis pigmentosa (RP) are characterized by progressive death of the photoreceptors due to apoptosis. To identify changes in gene expression associated with the degenerative state in RP retinas, expression profiling of apoptosis-related genes was performed using a gridded array technique.

METHODS

Total RNAs from RP and control retinas were used to generate radiolabeled cDNA probes to screen gridded membrane arrays of 205 apoptosis-related genes. Reverse transcription-polymerase chain reaction was used to generate probes corresponding to differentially expressed genes for Northern blot analysis and for mRNA in situ hybridization studies of retinal cryosections. Fluorescence immunocytochemistry was performed on retinal sections using available antibodies.

RESULTS

By expression profiling, we identified upregulated expression of the mRNA for secreted Frizzled-related protein-2 (SFRP2) in RP retina in comparison with control. By Northern blot analysis, SFRP2 mRNA levels were 2- to 20-fold higher in RP samples than in controls. The localization of SFRP2 mRNA by in situ hybridization varied according to the degree of degeneration, from stratified in relatively well-preserved retinas to diffuse in the highly degenerative state. By immunofluorescence, SFRP2 protein in RP retinas was found mainly to colocalize with the cell adhesion and signal transducing protein beta-catenin.

CONCLUSIONS

SFRPs can regulate apoptosis in vitro and appear to interact with the Wnt/Frizzled signaling pathway, which includes routes to apoptotic activation. Increased SFRP2 expression in RP retinas suggests that an altered pattern of Wnt signal transduction may be a step in the degenerative process linking causal mutations with eventual photoreceptor demise.

Exemestane is superior to megestrol acetate after tamoxifen failure in postmenopausal women with advanced breast cancer: results of a phase III randomized double-blind trial. The Exemestane Study Group

PURPOSE

This phase III, double-blind, randomized, multicenter study evaluated the efficacy, pharmacodynamics, and safety of the oral aromatase inactivator exemestane (EXE) versus megestrol acetate (MA) in postmenopausal women with progressive advanced breast cancer who experienced failure of tamoxifen.

PATIENTS AND METHODS

A total of 769 patients were randomized to EXE 25 mg/d (n = 366) or MA (n = 403) 40 mg four times daily. Tumor response, duration of tumor control, tumor-related signs and symptoms (TRSS), quality of life (QOL), survival, and tolerability were evaluated.

RESULTS

Overall objective response (OR) rates were higher in patients treated with EXE than in those treated with MA (15.0% v 12.4%); a similar trend was noted in patients with visceral metastases (13.5% v 10.5%). Median survival time was significantly longer with EXE (median not reached) than with MA (123.4 weeks; P =.039), as were the median duration of overall success (OR or stable disease > or = 24 weeks; 60.1 v 49.1 weeks; P =.025), time to tumor progression (20.3 v 16.6 weeks; P =.037), and time to treatment failure (16.3 v 15.7 weeks; P =.042). Compared with MA, there were similar or greater improvements in pain, TRSS, and QOL with EXE. Both drugs were well tolerated. Grade 3 or 4 weight changes were more common with MA (17.1% v 7.6%; P =.001).

CONCLUSION

EXE prolongs survival time, time to tumor progression, and time to treatment failure compared with MA and offers a well-tolerated treatment option for postmenopausal women with progressive advanced breast cancer who experienced failure of tamoxifen.

Analysis of the electrophysiologic effects of short-term oxybutynin on guinea pig and rabbit ventricular cells

The objective of this study was to investigate the cardioactive properties of oxybutynin, a drug that is widely prescribed for management of voiding dysfunction. Membrane currents were recorded from whole-cell-configured guinea pig ventricular myocytes, and action potentials were recorded from guinea pig and rabbit papillary muscles. L-type Ca2+ current (I(Ca),L), inward-rectifier K+ current (I(K1)), and delayed-rectifier K+ current (I(K)) were unaffected by < or = 1 microM oxybutynin, and inhibited by higher concentrations. The concentrations that reduced the currents to one-half of predrug control amplitude (K0.5) were as follows: 1(Ca),L, 16.1 microM, I(K1), 18.2 microM, rapidly activating I(K)(I(Kr)), 11.4 microM, and slowly activating I(K)(I(Ks)), 28.7 microM. Action-potential durations at 20 and 90% repolarization (APD20, APD90) were unaffected by oxybutynin < or =3 microM in guinea pig papillary muscles driven at 1 Hz; higher concentrations selectively shortened the APD20 by as much as 25% (100 microM), and caused moderate reductions in maximal upstroke velocity. Changes in the action potentials of rabbit papillary muscles were even smaller than in the guinea pig muscles. Because the peak therapeutic plasma concentration of oxybutynin is in the 0.01-0.1 microM range, the results suggest that the drug is highly unlikely to have adverse effects on cardiac electrical activity.

Delphi-panel analysis of appropriateness of high-dose chemotherapy and blood cell or bone marrow autotransplants in women with breast cancer

BACKGROUND

There is controversy whether high-dose chemotherapy and a blood cell or bone marrow autotransplant is a better treatment than conventional-dose chemotherapy for women with local/regional or metastatic breast cancer. Subject selection and time-to-treatment biases make definitive comparison impossible. Recent results of randomized trials are contradictory.

OBJECTIVE

Determine appropriateness of high-dose chemotherapy and a blood cell or bone marrow autotransplant in women with breast cancer. PANELISTS: Nine breast cancer experts from diverse geographic sites and practice settings.

EVIDENCE

Boolean MEDLINE searches of 'breast cancer' and 'chemotherapy' and/or 'blood cell' or 'bone marrow transplants'.

PROCESS

We used a modified Delphi-panel group judgement process. Clinical variables were permuted to define 2058 clinical settings. Each panelist rated appropriateness of high-dose therapy and an autotransplant versus conventional therapy on a 9-point ordinal scale (1: most inappropriate, 9: most appropriate). An appropriateness index was developed based on median rating and amount of disagreement. The relationship of appropriateness indices to the permuted clinical variables was considered by analysis of variance and recursive partitioning.

CONCLUSIONS

In women with local/regional breast cancer autotransplants were rated: 1) appropriate in those with > or = 10 cancer-involved lymph nodes; 2) uncertain in those with 4-9 cancer-involved nodes; and 3) inappropriate in women with < or = 3 cancer-involved lymph nodes. In women with metastatic breast cancer autotransplants were rated: 1) appropriate in those with metastases to 'favorable' sites (skin, lymph node, pleura) and a complete or partial response to chemotherapy; 2) uncertain in women with metastases to 'unfavorable' sites (lung, liver, or central nervous system) and a complete response to chemotherapy or those with bone metastases and a complete or partial response or stable disease after chemotherapy; and 3) inappropriate in other settings.

Retinal expression of gamma-crystallins in the mouse

PURPOSE

High levels of expression of a form of gamma-crystallin mRNA in mouse retina have been identified. Because the six murine gamma-crystallins have generally been regarded as specific to the lens, the expression of these crystallins at the mRNA and protein levels in the retina were evaluated in more detail.

METHODS

Expression of gammaE/F-crystallin mRNA was examined by northern blot analysis and reverse transcription-polymerase chain reaction (RT-PCR) analysis applied to murine retinal and lens total RNAs. For gammaA-D-crystallin mRNAs, a multiplex RT-PCR was used on total cDNAs. The detection of total gamma-crystallin protein in the retina was performed using an antibody to bovine lens gamma-crystallins, applied to protein extracts in immunoblot analysis and to cryostat sections of ocular tissues in immunofluorescence studies.

RESULTS

By RT-PCR, we confirmed expression of both gammaE-and gammaF-crystallin as well as all four (gammaA-gammaD) remaining crystallins at the mRNA level in the mouse retina. Gamma-crystallin proteins were also detectable in murine retina by immunoblot analysis, although at a lower level than in the lens. By immunocytochemistry, gamma-crystallins were localized particularly to the inner retina, outer plexiform layer, and the photoreceptors during postnatal development.

CONCLUSIONS

Our findings of gamma-crystallin mRNA and protein expression in the retina indicate that none of the major crystallin classes is uniquely expressed in the lens. The expression of gamma-crystallins in the developing murine retina suggests a role analogous to the anti-stress properties established for the small heat-shock protein alphaB-crystallin, perhaps in response to varying exposure to light.

Alpha-difluoromethylornithine as treatment for metastatic breast cancer patients

DFMO (alpha-difluoromethylornithine) is an oral irreversible inhibitor of ornithine decarboxylase, the first rate-limiting enzyme in polyamine synthesis. DFMO has been shown to have antiproliferative effects against several human cancers, and some studies have suggested that DFMO may have pro-apoptotic and anti-invasive properties as well. DFMO is well tolerated with minimal toxicity but has been associated with ototoxicity with prolonged daily administration. We conducted a Phase I/II tolerability, pharmacokinetic, and efficacy study of high-dose DFMO in metastatic breast cancer patients. Twenty-one patients were treated with 4800 mg of DFMO p.o. three times a day for 14 days, followed by a 2-week drug holiday on a 28-day cycle. Urinary polyamine and blood DFMO levels were measured at multiple time points during therapy. High-dose DFMO was well tolerated, and no clinically significant ototoxicity was noted. No patient achieved an objective antitumor response; however, one patient with heavily pretreated liver metastases has achieved stable disease for 18 months to date on DFMO. Putrescine, spermine, and spermidine urinary levels were suppressed with DFMO treatment and remained low during the 2-week drug holiday. High-dose DFMO on a schedule of 2 weeks on treatment followed by 2 weeks off is well tolerated, is not associated with ototoxicity, and leads to sustained suppression of urinary polyamine levels. Although not an active cytotoxic agent for metastatic breast cancer, the intriguing prolonged growth arrest of liver metastases in one patient highlights the potential clinical growth inhibitory properties of DFMO. We believe that DFMO is worthy of study as adjuvant therapy in primary breast cancer patients and as a chemopreventive agent.

Randomized, double-blind, placebo-controlled trial to evaluate the hematopoietic growth factor PIXY321 after moderate-dose fluorouracil, doxorubicin, and cyclophosphamide in stage II and III breast cancer

PURPOSE

To measure the effect of PIXY321 (granulocyte-macrophage colony-stimulating factor/interleukin-3 S. cerevisiae fusion protein) on the incidence, duration, and complications of neutropenia and thrombocytopenia after moderate-dose fluorouracil 600 mg/m(2), doxorubicin 60 mg/m(2), and cyclophosphamide 750 mg/m(2) (FAC) chemotherapy in patients with stage II and III breast cancer.

PATIENTS AND METHODS

In this multicenter, randomized, double-blind placebo-controlled trial, 71 women were to receive four 21-day cycles of treatment with moderate-dose FAC chemotherapy by short intravenous infusion on day 1, followed by either placebo or PIXY321 (375 microg/m(2) subcutaneously twice a day) on days 3 to 15. All patients were to receive prophylactic oral ciprofloxacin when the absolute neutrophil count was less than 1,000/microL.

RESULTS

PIXY321 significantly reduced the incidence and duration of grade 3 and grade 4 neutropenia in cycles 1 and 2 and the duration of grade 3 neutropenia in cycles 1 through 4. In cycles 3 and 4, grade 3 thrombocytopenia was significantly more common with PIXY321 (P <.05). Two patients, both in the PIXY321 group, required platelet transfusions. Fever and hospitalization for intravenous antibiotics were significantly more common in the PIXY321 group during cycle 1 only. More patients in the PIXY321 group achieved hematologic recovery by day 22 in cycles 1 through 3, and time to recovery was significantly shorter with PIXY321 in all cycles. FAC dose intensity was roughly 2% higher in the PIXY321 group (P = NS). Nonhematologic events of any intensity occurring with significantly greater overall frequency in the PIXY321 group included injection-site reactions, fever, chills, abdominal pain, and arthralgia. No patient died on study or within 30 days of her last dose of study drug.

CONCLUSION

PIXY321 decreased the incidence and duration of FAC-induced grade 3 and 4 neutropenia in cycles 1 and 2 and significantly shortened the time to hematologic recovery in all cycles. However, it produced more systemic toxicity as well as thrombocytopenia in cycles 3 and 4.

Action potentials, contraction, and membrane currents in guinea pig ventricular preparations treated with the antispasmodic agent terodiline

Terodiline was widely prescribed for urinary incontinence before reports of adverse cardiac effects that included bradycardia, QT lengthening, and ventricular tachyarrhythmia. The present study on guinea pig papillary muscles and ventricular myocytes was undertaken to gain insight into the cardioactive properties of the drug. Clinically relevant concentrations (<10 microM) of terodiline lengthened the action potential duration by up to 12%; higher concentrations shortened the duration in a concentration-dependent manner. The drug depressed maximal upstroke velocity in a use-dependent manner; the IC(50) value was near 150 microM in muscles driven at 1 Hz, 60 microM at 3 Hz, 38 microM at 5 Hz, and 3 microM at 1 Hz in muscles depolarized with 14 mM K(+). Submicromolar terodiline frequently had a small positive inotropic effect, whereas micromolar concentrations depressed force in a frequency-dependent manner. Voltage-clamp results on myocytes indicate that terodiline inhibits three membrane currents that govern repolarization: 1) E4031-sensitive, rapidly activating K(+) current with an IC(50) value near 0.7 microM as previously reported; 2) slowly activating, delayed-rectifier K(+) current with an IC(50) value of 26 microM; and 3) L-type Ca(2+) current with an IC(50) value of 12 microM. These findings are correlated with the changes in action potential configuration and developed tension and discussed in relation to the cardiotoxic effects of the drug.

Exaggerated cardiovascular response to anaesthesia--a case for investigation

We present a case of a 40-year-old woman who developed major cardiovascular complications during anaesthesia for an elective clipping of a cerebral arteriovenous malformation. Postoperative investigation confirmed the diagnosis of an adrenal phaeochromocytoma. In retrospect, it became apparent that she had experienced a series of potentially life-threatening events over a 20-year period all of which are known complications of phaeochromocytoma. This case highlights the importance of investigating young patients who have unexpected and unexplained cardiovascular events during anaesthesia and surgery.

The theory and practice of internal 'tunnel' restorations: a review of the literature and observations on clinical performance over eight years in practice

The tunnel or 'internal' restoration to restore an approximal caries lesion was first described in 1984. The technique allows the operator to conserve the important external anatomical features of the tooth, thereby saving considerable clinical time while leaving relatively little of the material externalized. The development of a new generation of glass-ionomer materials with higher flexural and compressive strengths appears to satisfy the main objective of carious dentine replacement facilitated by a 'keyhole' internal preparation. The long-term clinical evaluation of these materials is difficult since new formulations are being continually developed. The literature was reviewed. Clinical cases restoring approximal caries lesions in permanent molars and premolars were observed in a private practice. Over the course of eight years 60 tunnel restorations were placed in 48 regularly attending patients. The materials used in both total and partial tunnel restorations were Ketac Silver, Hi-Dense and Fuji IX. At eight years a failure rate of 15% was seen in the 50 restorations observed at last dental examination. The findings suggest that modern tunnel techniques may offer a restorative technique worthy of consideration in treating primary approximal caries lesions.

Effect of targeted expression of clusterin in photoreceptor cells on retinal development and differentiation

Clusterin expression is increased in tissues undergoing apoptosis, including neurodegenerative retina, but the causal relationships remain to be clarified. To test the hypothesis that overexpression of clusterin could induce apoptosis in neurons, transgenic mice were generated in which rat clusterin transgene was expressed in photoreceptor cells under the transcriptional control of the human interphotoreceptor retinoid-binding protein (IRBP) promoter. Photoreceptor cell death in the resulting transgenic mice was examined by histology and TUNEL techniques. The expression of the clusterin transgene was confirmed by in situ hybridization in the photoreceptor cells, and results in a complex pattern of clusterin protein distribution in the retina. A reduction in apoptotic staining in the transgenic retinas was observed from birth to postnatal day 15. These results suggest that clusterin is not causally involved in apoptotic mechanisms of photoreceptor cell death, but may relate to cytoprotective functions.

Lack of causal relationship between clusterin expression and photoreceptor apoptosis in light-induced retinal degeneration

Induction of apoptosis in the retina leads to cellular death by molecular mechanisms that are not well understood. Clusterin expression is increased in tissues undergoing apoptosis, including retinal neurodegenerative states, but the causal relationships remain to be clarified. To gain insight into clusterin's role in photoreceptor apoptosis, the cellular distribution of clusterin mRNA was compared with the pattern of apoptotic nuclear labelling in a rat model of light-induced retinal degeneration. In control retinal sections, clusterin mRNA was localized to the retinal pigment epithelium cells, photoreceptor inner segments, inner nuclear layer, and ganglion cell layer. Clusterin expression decreased in photoreceptors and retinal pigment epithelium cells, which progressively degenerated, and increased in preserved inner nuclear layer, in proportion to the duration of light exposure in both cyclic light- and dark-reared animals. These results suggest that clusterin is not causally involved in apoptotic mechanisms of photoreceptor death, but may relate to cytoprotective functions.

Inhibition of cardiac inward-rectifier K+ current by terodiline

The antispasmodic agent terodiline has cardiotoxic effects that include QT lengthening. To determine whether inhibition of inwardly-rectifying K+ current (I(K1)) might be a factor in the cardiotoxicity, we measured I(K1) in guinea pig ventricular myocytes. Terodiline reduced outward I(K1) with an IC50 of 7 microM; maximal reduction was 60% with 100-300 microM concentration. Inhibition was independent of current direction, and persisted after removal of the drug. Terodiline (3-5 microM) lengthened action potentials in guinea pig papillary muscles by ca. 10%, primarily by slowing phase 3 repolarization; higher concentrations abbreviated the plateau and markedly slowed late repolarization. Terodiline washout provoked an extra lengthening, consistent with persistent inhibition of I(K1) and rapid recovery of net inward plateau current. The results suggest that inhibition of I(K1) is a likely factor in the cardiotoxicity of the drug.

Initial experience of intramammary prostheses in breast conservation surgery

AIMS

We assessed the cosmetic and psychological effects of prosthetic intramammary breast reconstruction on women undergoing complete local excision for breast cancer.

METHODS

Twenty-two women (mean age 54) underwent insertion of a Nagor silicone prosthesis into the breast cavity immediately following complete local excision. Following surgery, patients were assessed (range: 6 weeks to 1 year) by a postal questionnaire and independent photographs.

RESULTS

Eighteen out of twenty-two (81.8%) women completed and returned the questionnaire, and 14 out of 22 (63.6%) women were photographed. Thirteen out of eighteen (72.2%) women were either satisfied or very satisfied with the prosthesis, and 10 had experienced no problems since surgery. From the group of patients who were either satisfied or very satisfied, the total photograph assessment score was 135 out of a possible maximum score of 165. Five patients (27.8%) were very dissatisfied and requested removal of the prosthesis.

CONCLUSIONS

When performing a complete local excision for carcinoma of the breast, insertion of an intracavity prosthesis should be considered when this would significantly improve the cosmetic outcome.

Expression patterns of neurturin and its receptor components in developing and degenerative mouse retina

PURPOSE

Neurturin (NTN) and its receptor components (GFRalpha2 and Ret) play an important role in the survival of different populations of neurons in the central and peripheral nervous systems. To gain insight into their possible functions throughout normal retinal development and during retinal neuronal apoptosis, the retinal distribution of expression of NTN and GFRalpha2 mRNAs and Ret protein were compared in control and retinal degeneration (rd) mice.

METHODS

Eyes from control and rd animals were fixed in paraformaldehyde before sectioning. For in situ hybridization, retinal sections were hybridized with 35S-radiolabeled sense and antisense riboprobes for murine NTN and GFRalpha2 and were autoradiographed. Ret localization was detected by immunofluorescence.

RESULTS

Neurturin mRNA expression was modulated through normal postnatal retinal development and was localized primarily to the inner retina and photoreceptor outer segments. GFRalpha2 mRNA displayed a diffuse developmental pattern of expression, but in the mature normal retina, NTN and GFRalpha2 mRNAs were more closely colocalized. Ret protein was localized particularly at the outer segments of photoreceptors, inner retina, and ganglion cell layers, but there were no prominent differences among genotypes. Increased NTN mRNA expression was detected in the retinal pigment epithelium and neural retina in concert with photoreceptor degeneration in rd mouse. In contrast, the level of GFRalpha2 mRNA was lower in rd compared with that in normal retina.

CONCLUSIONS

These results suggest that NTN and its receptor are involved in retinal postnatal development and maintenance and that alterations in their transcription patterns are associated with inherited retinal degeneration.

Multicenter phase II study of capecitabine in paclitaxel-refractory metastatic breast cancer

PURPOSE

Capecitabine is a novel, oral, selectively tumor-activated fluoropyrimidine carbamate. This large multicenter phase II trial tested the efficacy and safety of twice-daily oral capecitabine at 2,510 mg/m2/d given for 2 weeks followed by a 1-week rest period and repeated in 3-week cycles, in patients with paclitaxel-refractory metastatic breast cancer.

PATIENTS AND METHODS

Patients were to have received at least two but not more than three prior chemotherapeutic regimens, one of which had to have contained paclitaxel given for metastatic disease. One hundred sixty-three patients were entered onto the study at 25 centers, and 162 patients received capecitabine. One hundred thirty-five patients had bidimensionally measurable disease, and 27 patients had assessable disease.

RESULTS

The overall response rate was 20% (95% confidence interval, 14% to 28%). All responding patients were resistant to or had failed paclitaxel, and all had received an anthracycline. Three complete responses were seen, with complete response durations of 106, 109, and 194+ days. Median duration of response was 8.1 months, median survival time was 12.8 months, and the median time to disease progression was 93 days. The most common treatment-related adverse events were hand-foot syndrome, diarrhea, nausea, vomiting, and fatigue. Diarrhea (14%) and hand-foot syndrome (10%) were the only treatment-related adverse events that occurred with grade 3 or 4 intensity in more than 10% of patients.

CONCLUSION

Capecitabine is an active drug in the treatment of paclitaxel-refractory metastatic breast cancer. It has a favorable toxicity profile with the added advantage of being an oral drug administered at home.

Expression of alphaB-crystallin in a mouse model of inherited retinal degeneration

AlphaB-crystallin, which is abundantly expressed in the lens but also in a diversity of other tissues, functions as a stress-inducible molecular chaperone and is increased in brain neurodegenerative diseases. We compared retinal alphaB-crystallin expression in a model of inherited retinal degeneration, the rd mouse, and controls. Northern and in situ hybridization analysis showed alphaB-crystallin mRNA to have an altered spatio-temporal pattern with increased levels localized to glial cells in the degenerative state. Immunocytochemistry confirmed increased expression at Müller cells and astrocytes, together with transiently increased localization to the degenerating photoreceptors. These findings suggest that increased alphaB-crystallin expression is associated with glial cell reaction to neuronal damage in the retina, and may comprise part of the retina's overall defensive response to the stress of apoptotic photoreceptor cell death.