Gemcitabine/cyclophosphamide/5-fluorouracil/folinic acid triplet combination in anthracycline- and taxane-refractory breast cancer patients: a Southern Italy Cooperative Oncology Group phase I/II study

We sought to define the recommended dose of cyclophosphamide (CTX) for subsequent phase II assessment when combined with fixed doses of gemcitabine (Gemzar; Eli Lilly and Company, Indianapolis, IN) and 5-fluorouracil/folinic acid in metastatic breast cancer patients previously treated with anthracyclines and taxanes. Patients age 70 or less, with an Eastern Cooperative Oncology Group performance status 0 to 2, were enrolled. Patients received gemcitabine 1,000 mg/m(2), 5-fluorouracil 425 mg/m(2), folinic acid 100 mg/m(2), and escalating doses of CTX (in 100-mg/m(2) increments), starting at 500 mg/m(2), on days 1 and 8 every 3 weeks. Since March 1999, 46 patients, with a median age of 51 years (range, 38 to 74 years), entered the trial in seven cohorts. Cyclophosphamide dose escalation was stopped at 600 mg/m(2) when three of six patients experienced dose-limiting toxicity (one each with grade 3 thrombocytopenia, grade 3 neutropenia, and persistent grade 2 neutropenia), and then continued with granulocyte colony-stimulating factor support. The CTX dose of 800 mg/m(2) was proven safe and was chosen for phase II study. Two complete and 15 partial responses provided an overall response rate of 37% (95% confidence interval, 23% to 51%). Gemcitabine/CTX/5-fluorouracil/folinic acid is well tolerated by metastatic breast cancer patients pretreated with anthracyclines/taxanes, up to a CTX dose of 800 mg/m(2). The phase II study is ongoing. Semin Oncol 28 (suppl 10):50-56.

Chondral lesions of the knee: A new localization method and correlation with associated pathology

PURPOSE

We report a new method of describing and recording chondral lesions of the knee at arthroscopy in order to permit a more accurate and meaningful analysis of patterns of articular cartilage damage.

TYPE OF STUDY

Case series study.

METHODS

Data were collected prospectively at 1,000 consecutive arthroscopies by the senior author and chondral lesions were recorded on anatomic articular maps divided into different functional zones. Ten zones on the femur were determined by tibiofemoral weight-bearing and flexion horizons (namely the 0 degrees, 45 degrees, 90 degrees, and 120 degrees horizons as they pass the anterior meniscosynovial junction). Ten zones were determined on the tibia, principally by meniscal relations, and 6 zones on the patella. This allowed the size, Outerbridge grade, and location to be analyzed in relation to mechanism, chronicity, and associated intra-articular pathologies. The recording methods were tested for interobserver reproducibility in 50 subsequent cases at the same arthroscopy by 2 independent observers. The results were analyzed by a third person, and showed a relatively small interobserver error of 7.2% for size for a set of grade 3 and 4 lesions and only a 3% error for site. The Fisher exact test was used. The data sheets were entered onto a computer spreadsheet database using standard software (Excel; Microsoft, Redmond, WA) to permit analysis of the data.

RESULTS

There were 1,553 chondral lesions in 853 patients correlated with associated lesions, including 356 meniscal lesions, 230 ligamentous injuries, 440 synovial lesions, and other pathologies. High degrees of correlation have been found between specific lesions and their opposing surfaces and the progression of these with time.

CONCLUSIONS

The problem of precision of localization of articular lesions in the knee has been recently acknowledged by the International Cartilage Research Society (ICRS). However, such recording ought to take into account both function and contact with other structures. This would appear essential in the assessment of prognosis and comparisons between different treatment regimes.

An integrated cytogenetic, radiation-hybrid, and comparative map of dog chromosome 5

The development of a detailed genome map for the domestic dog (Canis familiaris, CFA) is a prerequisite for the continued use of this species as a model system for the study of inherited traits. We present an integrated cytogenetic, radiation-hybrid, and comparative map of dog Chromosome (Chr) 5 (CFA 5). The map comprises 14 gene markers, selected from loci previously mapped within the corresponding evolutionarily conserved chromosome segments (ECCS) of the human genome. Large-insert clones representing each marker were first isolated and mapped by fluorescence in situ hybridization (FISH) analysis to determine their subchromosomal localization on CFA 5. Thirteen gene markers were subsequently mapped by using a commercially available whole genome radiation hybrid (WG-RH) panel for the dog. Nine anonymous markers were also assigned to CFA 5 by both FISH and WG-RH analysis. The 22 markers formed six RH-linkage groups, spanning each of the four ECCS comprising this 99 megabase chromosome. All cytogenetic, WG-RH, and comparative mapping data were in agreement and were combined to determine both the most likely locus order within each linkage group, and also the gross relative orientation of the corresponding ECCS. This study provides a resource for the transfer of information from the human transcript map to that of the dog, and extends existing data regarding the structural relationships between CFA 5 and its evolutionary counterparts within the human genome.

The effect of standard care, ibuprofen, and music on pain relief and patient satisfaction in adults with musculoskeletal trauma

OBJECTIVE

The purposes of this study were to determine the most effective nursing intervention to decrease pain for patients with minor musculoskeletal trauma and moderate pain at triage and to examine patient satisfaction.

METHODS

Patients were assigned to 1 of 3 intervention groups: (1) standard care (ice, elevation, and immobilization); (2) standard care and ibuprofen; or (3) standard care and music distraction. Patients were monitored for pain ratings for 60 minutes. Patients who sustained minor musculoskeletal trauma within the past 24 hours and presented with pain ratings of 4 or greater were included. Two patient satisfaction questions were asked upon discharge from the emergency department.

RESULTS

Seventy-seven patients met the inclusion criteria. No differences in pain ratings between groups were demonstrated. A statistically significant reduction in pain for all patients occurred at 30 minutes (F = 16.18, P <.01) and was maintained at 60 minutes. However, 70% of patients continued to report pain ratings of 4 or greater (on a scale of 1 to 10) at 60 minutes. The reduction in pain was not found to be clinically significant.Eighty-four percent of patients stated that they were more satisfied with their overall care in the emergency department because of the immediate attention to pain relief they received at triage. No differences in satisfaction existed between treatment groups, although patients who reported higher pain ratings expressed statistically significant lower satisfaction with pain management scores (F = 9.375, P =.003).

CONCLUSION

None of the therapies-standard care (ice, elevation, immobilization), standard care with ibuprofen, or standard care with music distraction-provided clinically significant pain relief to patients who had minor musculoskeletal trauma (ie, sprains and fractures) and moderate pain at triage. Interestingly, satisfaction scores were sometimes positive, even when pain was not relieved.

Clinicopathological correlation in biopsy-proven atherosclerotic nephropathy: implications for renal functional outcome in atherosclerotic renovascular disease

BACKGROUND

Atherosclerotic renovascular disease (ARVD) is commonly associated with renal failure. It is now recognized that intrarenal damage, (ischaemic or atherosclerotic nephropathy) is a major contributor to the renal impairment in these patients. In this study the impact of histological changes upon renal functional outcome was investigated in patients with atherosclerotic nephropathy.

METHODS

The Hope Hospital renal biopsy database (1985-1998) was interrogated for patients with histology compatible with atherosclerotic nephropathy. Case-note review enabled the assessment of several clinical parameters and outcomes, including change in creatinine clearance per year (DeltaCrCl (ml/min/year)), blood pressure control, dialysis need, and death. Renal parenchymal damage was analysed by morphometric analysis (of interstitial fibrosis and glomerulosclerosis) and a semi-quantitative chronic damage score (score 0-3 (normal-severe) for each of glomerulosclerosis, interstitial fibrosis, tubular atrophy, and arteriolar hyalinosis; maximum=12). Patients were stratified into two groups who had either deteriorating (group 1) or stable (group 2) renal function during follow-up.

RESULTS

Twenty-five patients (age 64.7+/-10.5, range 43-83 years; 17 male, eight female) were identified. Sixteen patients had undergone angiography; two had significant (>50%) renal artery stenosis. Mean follow-up was 25.6+/-14.8 (range 5-50) months. Group 1 patients had DeltaCrCl -7.4+/-6.8 ml/min/year, n=14 and group 2 patients had DeltaCrCl 4.8+/-7.0 ml/min/year, n=11. Four patients in group 1 developed end-stage renal disease and five patients died (three in group 1 and two in group 2). At study entry, group 1 patients had worse renal function (CrCl 27.6+/-17.6 vs 36.0+/-33.9, NS), greater proteinuria (1.2 vs 0.5 g/24 h, NS), and higher systolic blood pressure (167.1+/-30.8 mmHg vs 150.6+/-37.8, NS) compared with group 2 patients. Group 1 patients showed more glomerulosclerosis (51.6 vs 24.9%, P:<0.01), greater proportional interstitial volume (44.9 vs 33.9%, P:<0.02), and higher overall chronic damage score (P:<0.05) than those in group 2. There was a significant correlation between renal functional outcome and chronic damage score, glomerulosclerosis and proportional interstitial volume for the entire patient cohort.

CONCLUSION

In patients with atherosclerotic nephropathy the severity of histopathological damage is an important determinant and predictor of renal functional outcome.

Activation and habituation in olfaction--an fMRI study

This study investigated human BOLD responses in primary and higher order olfactory cortices following presentation of short- and long-duration odorant stimuli using a 3-T MR scanner. The goal was to identify temporal differences in the course of the response that might underlie habituation. A short-duration stimulus (9 s) consistently activated the primary olfactory cortex (POC). After a long stimulus (60 s), the temporal form of the response differed in different parts of the olfactory network: (1) The POC (piriform, entorhinal cortex, amygdala) and, interestingly, the hippocampus and, to a certain degree, the anterior insula show a short, phasic increase in the signal, followed by a prolonged decrease below baseline. (2) In the orbitofrontal cortex a sustained increase in activation was seen. This increase lasted approximately as long as the duration of odorant presentation ( approximately 60 s). (3) The mediodorsal nucleus of the thalamus and the caudate nucleus responded with an increase in signal which returned to baseline after approximately 15 to 30 s. The correlated biphasic hemodynamic response in the POC, hippocampus, and anterior insula during prolonged olfactory stimulation suggests that these three areas may interact closely with each other in the control of habituation. These results extend recent data which showed habituation of the rat piriform cortex and dissociation between the POC and the orbitofrontal cortex.

An algorithm for targeted convergence of Euler or Newton iterations

The concept of multistationarity has become essential for understanding cell differentiation. For this reason theoretical biologists have more and more frequently to determine the steady values, often multiple, of systems of non-linear differential equations. It is well known that iteration processes of current use converge or not towards a fixed point depending on the absolute value of the slope of the iteration function in the vicinity of the considered fixed point. A number of methods have been developed to obtain or accelerate convergence. As biologists, we do not pretend to review these works. Rather, we propose here a simple algorithm which permits to converge at will towards a chosen type of steady state. Others and we have used this procedure extensively for years for the analysis of complex biological systems. A compact program (using Mathematica) is available.

Interruption of coding sequences by heterologous introns can enhance the functional expression of recombinant genes

Sustained expression of recombinant proteins is a critical factor for the effectiveness of numerous applications in the biomedical sciences including the treatment of human disease by gene therapy, the large scale production of therapeutic proteins, as well as the investigation of gene function by transgenesis or cell type specific mutagenesis. Although much attention has been paid to the optimisation of regulatory sequences such as promoters, untranslated regions and polyadenylation signals, effective and sustained expression of recombinant genes in vivo is often difficult to achieve. Here we report that the creation of artificial exons, by insertion of two short heterologous introns into open reading frames, is not only compatible with functional expression, but also leads to a 30-fold enhancement of mRNA production for both green fluorescent protein and the bacteriophage P1-derived Cre recombinase. The levels of green fluorescence were increased five-fold in cell lines and sustained long-term expression at increased levels was observed in rat brain after transduction with a herpes simplex virus-based vector. The data presented identify a means by which the expression of recombinant genes can be enhanced considerably, in addition to and independently from the surrounding regulatory sequences. The method should help obtain sustained and effective expression of recombinant proteins in vivo.

Metastatic lesions in the joint associated with acute inflammatory arthritis after dendritic cell immunotherapy for metastatic melanoma

A 47 year old man undergoing immunotherapy for metastatic melanoma with autologous dendritic cells pulsed with autologous tumour peptide and hepatitis B surface antigen developed acute left ankle arthritis. Gout and acute infection were excluded, and an autoimmune aetiology or occult metastasis were considered. The arthritis initially subsided with indomethacin, but the symptoms recurred 2 months later, and magnetic resonance imaging demonstrated metastatic melanoma of the left talus. Immunohistochemical staining of a cerebral metastatic deposit biopsied 1 week after the onset of arthritis demonstrated T-cell and macrophage infiltration of the tumour. In addition, the patient developed melanoma-specific delayed type hypersensitivity and cytotoxic T-cell responses after vaccination. Thus, the monoarthritis represented an 'appropriate' inflammatory response directed against metastatic melanoma.

Multistationarity, the basis of cell differentiation and memory. II. Logical analysis of regulatory networks in terms of feedback circuits

Circuits and their involvement in complex dynamics are described in differential terms in Part I of this work. Here, we first explain why it may be appropriate to use a logical description, either by itself or in symbiosis with the differential description. The major problem of a logical description is to find an adequate way to involve time. The procedure we adopted differs radically from the classical one by its fully asynchronous character. In Sec. II we describe our "naive" logical approach, and use it to illustrate the major laws of circuitry (namely, the involvement of positive circuits in multistationarity and of negative circuits in periodicity) and in a biological example. Already in the naive description, the major steps of the logical description are to: (i) describe a model as a set of logical equations, (ii) derive the state table from the equations, (iii) derive the graph of the sequences of states from the state table, and (iv) determine which of the possible pathways will be actually followed in terms of time delays. In the following sections we consider multivalued variables where required, the introduction of logical parameters and of logical values ascribed to the thresholds, and the concept of characteristic state of a circuit. This generalized logical description provides an image whose qualitative fit with the differential description is quite remarkable. A major interest of the generalized logical description is that it implies a limited and often quite small number of possible combinations of values of the logical parameters. The space of the logical parameters is thus cut into a limited number of boxes, each of which is characterized by a defined qualitative behavior of the system. Our analysis tells which constraints on the logical parameters must be fulfilled in order for any circuit (or combination of circuits) to be functional. Functionality of a circuit will result in multistationarity (in the case of a positive circuit) or in a cycle (in the case of a negative circuit). The last sections deal with "more about time delays" and "reverse logic," an approach that aims to proceed rationally from facts to models. (c) 2001 American Institute of Physics.

Immunohistochemical reactivity of anti-melanoma monoclonal antibody 225.28S in human breast cancer biopsies

The high molecular weight melanoma-associated antigen, defined by murine monoclonal antibody (IgG1) 225.28S is largely expressed by melanoma cells and weakly expressed by other human tumors originating from neural crest. In this study, we analyzed the immunohistochemical reactivity of MoAb 225.28S in human breast cancer biopsies. A total of 92 breast cancer biopsies (66 infiltrating lobular and 26 infiltrating ductal carcinomas) were initially tested along with 26 melanomas (positive controls), 23 gastric/colonic adenocarcinomas and 13 neuroendocrine tumors. Forty-four out of 66 lobular breast carcinomas showed positive immunostaining with 225.28S MoAb as well as only 6 out of 26 infiltrating ductal histotype and 12 out of 26 melanomas. Conversely, gastric and colonic adenocarcinomas and neuroendocrine tumors were completely negative. The pattern of positivity in breast carcinomas was associated with malignant cells, rather than with the stroma or histiocytes infiltrating the lesions. Nonspecific cross-reactivity of 225.28S with breast carcinomas was excluded using a similar murine antithyreoglobulin MoAb, which gave negative staining in all biopsies. These results indicated that HMW-MAA or a similar sequence recognized by 225.28S MoAb is often expressed by lobular breast carcinomas but rarely by ductal adenocarcinomas. This seems to suggest that lobular breast carcinoma has common "ancestor" antigens with melanoma.

Effect of extracorporeal membrane oxygenation on left ventricular function of swine

BACKGROUND

Previous clinical and experimental investigations have produced inconsistent data describing the effects of veno-arterial extracorporeal membrane oxygenation (VA ECMO) on intrinsic left ventricular (LV) function. We report an animal model that allows investigation of the effects of VA ECMO on the mechanics of the LV using two load-insensitive indices: end-systolic pressure-minor axis dimension relationship (ESPDR) and preload recruitable dimensional stroke work (PRDSW).

METHODS

Eight piglets (5 to 11 kg) were anesthetized, instrumented, and placed on VA ECMO. Throughout the experiment, systemic and left atrial partial pressure of oxygen were maintained between 100 to 200 mm Hg. At ECMO flow rate of 50% of baseline cardiac output, data were collected prior to ECMO, at 4 and 6 hours during ECMO, and after weaning from ECMO. Data measured or calculated for each time point included heart rate, LV pressures and minor axis dimensions at different pre-loads, first derivative of LV pressure with respect to time, velocity of circumferential fiber length shortening (VCF), LV shortening fraction (LVSF), ESPDR, and PRDSW.

RESULTS

A significant (p < 0.05) decrease in LVSF and VCF was seen at 4 and 6 hours during ECMO when compared to baseline, but the ESPDR and PRDSW did not change during ECMO.

CONCLUSIONS

VA ECMO alone changes some of the load-dependent parameters of contractility, but intrinsic function of the heart is not significantly affected as measured by load-insensitive indices of LV performance.

Multistationarity, the basis of cell differentiation and memory. I. Structural conditions of multistationarity and other nontrivial behavior

A biological introduction serves to remind us that differentiation is an epigenetic process, that multistationarity can account for epigenetic differences, including those involved in cell differentiation, and that positive feedback circuits are a necessary condition for multistationarity and, by inference, for differentiation. The core of the paper is comprised of a formal description of feedback circuits and unions of disjoint circuits. We introduce the concepts of full-circuit (a circuit or union of disjoint circuits which involves all the variables of the system), and of ambiguous circuit (a circuit whose sign depends on the location in phase space). We describe the partition of phase space (a) according to the signs of the ambiguous circuits, and (b) according to the signs of the eigenvalues or their real part. We introduce a normalization of the system versus one of the circuits; in two variables, this permits an entirely general description in terms of a common diagram in the "circuit space." The paper ends with general statements concerning the requirements for multistationarity, stable periodicity, and deterministic chaos. (c) 2001 American Institute of Physics.

The clinical development of 9-aminocamptothecin

9-Aminocamptothecin (9-AC) is a topoisomerase I-targeting agent first synthesized by Wani and Wall in 1986. Because of its potent in vitro effects and promising preclinical activity in colorectal cancer animal models, it was designated a high-priority compound for further drug development by the NCI. In 1993, 9-AC first entered clinical trials as a 72-hour intravenous (i.v.) infusion. Predictable myelosuppression was the major dose-limiting toxicity, and pharmacokinetic studies showed a relatively short plasma half-life and unstable lactone ring. Unfortunately, phase II studies using this schedule showed minimal or no activity in tumors such as colorectal and lung cancer. Modest activity was observed in ovarian cancer and in refractory lymphomas. Efforts to improve systemic drug exposure by utilizing alternative schedules of administration of 9-AC such as prolonged, continuous intravenous infusions have also been tested. However, phase II studies of 120-hour weekly infusions of 9-AC have not shown improved activity against solid tumors such as colorectal cancer. More recently, a daily times 5 days i.v. administration schedule has been tested. Currently, further development of intravenously administered 9-AC for the treatment of colorectal cancer is not promising. Thus, topotecan and irinotecan remain the only two successfully developed topoisomerase I-targeting drugs in the United States. This experience with 9-AC raises important questions regarding how to best select new topoisomerase I-targeting drugs for future clinical development.

The sequence of the human genome

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

Ischemic colitis during treatment with alosetron

Irritable bowel syndrome (IBS) is one of the most common entities observed by both primary care physicians and gastroenterologists. Alosetron is a potent and selective serotonin antagonist that recently became the first Food and Drug Administration-approved agent for diarrhea-predominant IBS. However, since approval, significant side effects have been noted with the use of alosetron including severe constipation, fecal impaction, and ischemic colitis. We describe a case of ischemic colitis in a male patient with IBS who was briefly treated with alosetron. Clinical, endoscopic, and pathologic features of the focal colitis strongly suggested ischemia. Symptoms correlated temporally with alosetron use, and symptoms abated with discontinuation of the drug. Endoscopic and pathologic resolution of the colitis were documented.

The effects of intracellular pH changes on resting cytosolic calcium in voltage-clamped snail neurones

We have investigated the effects of changing intracellular pH on intracellular free calcium concentration ([Ca2+]i) in voltage-clamped neurones of the snail Helix aspersa. Intracellular pH (pHi) was measured using the fluorescent dye 8-hydroxypyrene-1,3,6-trisulphonic acid (HPTS) and changed using weak acids and weak bases. Changes in [Ca2+]i were recorded using either fura-2 or calcium-sensitive microelectrodes. Acidification of the neurones with 5 mM or 20 mM propionate (approximately 0.2 or 0.3 pH units acidification, respectively) caused a small reduction in resting [Ca2+]i of 5 +/- 2 nM (n = 4) and 7 +/- 16 nM (n = 4), respectively. The removal of the 20 mM propionate after approximately 40 min superfusion resulted in an alkalinization of approximately 0.35 pH units and an accompanying rise in resting [Ca2+]i of 31 +/- 9 nM (n = 4, P < 0.05). The removal of 5 mM propionate did not significantly affect [Ca2+]i. Alkalinizations of approximately 0.2-0.4 pH units of Helix neurones induced by superfusion with 3 mM concentrations of the weak bases trimethylamine (TMA), ammonium chloride (NH4Cl) and procaine were accompanied by significant (P < 0.05) increases in resting [Ca2+]i of 42 +/- 4 nM (n = 26), 30 +/- 7 nM (n = 5) and 36 +/- 4 nM (n = 3), respectively. The effect of TMA (0.5-6 mM) on [Ca2+]i was dose dependent with an increase in [Ca2+]i during pHi increases of less than 0.1 pH units (0.5 mM TMA). Superfusion of neurones with zero calcium (1 mM EGTA) Ringer solution inhibited depolarization-induced calcium increases but not the calcium increase produced by the first exposure to TMA (3 mM). In the prolonged absence of extracellular calcium (approximately 50 min) TMA-induced calcium rises were decreased by 64 +/- 10% compared to those seen in the presence of external calcium (P < 0.05). The calcium rise induced by TMA (3 mM) was reduced by 60 +/- 5% following a 10 min period of superfusion with caffeine (10 mM) to deplete the endoplasmic reticulum (ER) stores of calcium (P < 0.05). Cyclopiazonic acid (10-30 microM CPA), an inhibitor of the ER calcium pump, inhibited the calcium rise produced by TMA (3 mM) and NH4Cl (3 mM) by 61 +/- 4% compared to controls (P < 0.05). These data are consistent with physiological intracellular alkaline shifts stimulating release of calcium, or inhibiting re-uptake of calcium by an intracellular store. The calcium increase was much reduced following application of caffeine, treatment with CPA or prolonged removal of external calcium. Hence the ER was likely to be the source of mobilized calcium.