Clinical studies to determine the effectiveness of a whitening toothpaste at reducing stain (using a forced stain model)

AIMS

Two single centre, randomized single-blind, crossover studies were performed, to compare the effect of a test toothpaste with a conventional fluoride paste in the inhibition and removal of extrinsic dental stain promoted by repeated chlorhexidine/tea rinses.

METHODS

These studies used 24 subjects in each of two separate clinical trials. On the Friday before each trial period, the subjects received a prophylaxis to remove all staining, plaque and calculus deposits. On the following Monday, subjects were checked whether they were stain free and then under direct supervision they rinsed with a 0.2% chlorhexidine mouthrinse, immediately followed by a rinse with a warm black tea solution. This cycle was repeated hourly eight times throughout the day and on the following days until the Friday. In addition subjects also received daily a single toothpaste slurry rinse or control water rinse in the morning and lunchtime. No other form of oral hygiene was permitted during this period. On the Friday, both stain area and intensity was assessed using the Lobene Stain Index. For the stain removal study, stain was promoted again using chlorhexidine and tea rinses. After 4 days, stain was measured both prior to and immediately after brushing with the allocated toothpaste for 2 min. Subjects were then instructed to use the toothbrush at home according to their normal oral hygiene practices. On the following Wednesday, the amount of stain present was re-assessed. Each subject subsequently received a thorough prophylaxis to remove all plaque calculus and staining before starting the following periods of the study.

RESULTS

The study showed no difference in the ability of the test whitening toothpaste, control toothpaste and water control at inhibiting stain. There was also only a small difference (3.5% for product of area and intensity) between the ability of the two toothpastes to help remove stain after a single brushing. The difference was however in favour of the test product which approached a conventional level of significance (P = 0.089). There was no evidence of superiority for either of the pastes after normal home usage.

CONCLUSIONS

This study has suggested that the test product may have some advantage over the conventional paste at removing stain but the magnitude of difference would appear to be small and of little clinical relevance.

Clinical study to compare the effectiveness of a test whitening toothpaste with a commercial whitening toothpaste at inhibiting dental stain

AIMS

A single centre, randomised single-blind, three-way crossover study was performed, to compare the effect of an experimental test toothpaste with a commercially available whitening toothpaste and water control at inhibiting extrinsic stain promoted by repeated chlorhexidine/tea rinses.

METHODS

This study used 23 subjects. During the week before the study the subjects received a prophylaxis to remove all staining, plaque and calculus deposits. On the Monday of the following week subjects returned to the clinic to receive their rinses and to check their dentition was stain free. Under direct supervision at both 09:00 and 13:00 hours they rinsed with either a toothpaste slurry or water control that was repeated daily up to and including the following Thursday. Additionally from the Monday to the Thursday each subject rinsed with a 0.2% chlorhexidine mouthrinse, immediately followed by a rinse with a warm black tea solution. This cycle was repeated hourly eight times throughout the day and on the following days until the Friday. Throughout this period volunteers omitted all other forms of oral hygiene except rinsing with the chlorhexidine mouthwash. On the Friday the level of stain on the teeth and dorsum of tongue was assessed using the Lobene stain index for both stain area and intensity. At the end of each trial period each subject received a thorough prophylaxis to remove all plaque, calculus and staining before starting the second and third period of the study.

RESULTS

As expected appreciable amounts of extrinsic stain accumulated on the teeth over each study period. The amount of stain following use of the toothpastes and water control was least with the experimental toothpaste, followed by water control and lastly the commercial whitening paste. For all sites combined there was evidence that the experimental paste was significantly superior to both the commercial paste and water control at reducing stain area (p<0.001), a product of stain area and intensity (p<0.001 and 0.05, respectively) but not stain intensity (p>0.05).

CONCLUSIONS

In this stain-prevention model the use of an experimental paste showed a significant reduction in stain accumulation on the teeth compared with a (placebo) negative water control and a commercially available whitening paste. As such the experimental paste would be expected to be of benefit in controlling extrinsic dental staining.

Clinical development and evolution in plaque removal performance of a battery powered toothbrush

BACKGROUND AND AIM

There is growing evidence that the new generation of electric toothbrushes are more effective than manual toothbrushes. The primary aim of these studies was to compare, as an indication of the stage of development, the plaque removal properties of a prototype battery powered toothbrush with an established product. A secondary aim was to utilise the data to appraise plaque accumulation together with the patterns of removal.

METHOD

The three studies presented used the same, single-examiner, randomised, single-blind cross-over design involving up to 24 healthy volunteers. The prototype brushes, E6500 versions s1, s2 and s3 and E8000 with head speeds of 6500 and 8000 oscillations/min were compared with a similar design marketed product (MP) with a head speed of 8800 oscillations/min. All brushes had circular brush heads with oscillating rotating actions. Subjects accumulated plaque over a 4-day period during which no oral hygiene measures were performed. On day 4, the plaque accumulation was scored by index. Subjects then used the allocated toothbrush for 2 min. This was followed by a re-scoring of the remaining plaque.

RESULTS

Studies 1 and 2 showed significantly less plaque removed by prototype E6500 (s1) and prototype E6500 (s2), respectively, than by MP. In study 3, prototype E8000 removed similar quantities of plaque to MP (approximately 65%). In contrast prototype E6500 (s3) only removed 60% of accrued plaque. Differences, however, did not reach statistical significance.

CONCLUSIONS

The study methodology was appropriate to distinguish between the study toothbrushes and was furthermore able to establish a level of comparability for one of the prototype modifications with a similar MP.

A clinical study to assess the ability of a powered toothbrush to remove chlorhexidine/tea dental stain

AIM

A single-center, single-blind, two-way crossover study was performed to compare the effects of an electric powered toothbrush with a conventional manual toothbrush at removing chlorhexidine/tea tooth staining.

METHODS

This study used 24 subjects. During the week before the study, the subjects received a prophylaxis to remove all staining, plaque and calculus deposits. On the Monday of the following week, subjects returned to the clinic to receive a further prophylaxis. Under direct supervision, they then rinsed with a 0.2% chlorhexidine mouthrinse, immediately followed by a rinse with a warm black tea solution. This cycle was repeated hourly eight times throughout the day and on the following days until the Friday. Throughout this period, volunteers omitted all other forms of oral hygiene except rinsing with the chlorhexidine mouthwash. On the Friday, the level of stain was assessed both prior to and immediately after brushing with the allocated brush with toothpaste for 1 min. This was done in an adjoining room (out of sight of the clinical scorer). Subjects were then instructed to use the toothbrush at home according to their normal oral hygiene practices. On the following Friday, subjects returned to the clinic when the stain present was re-assessed. Each subject received a thorough prophylaxis to remove all plaque calculus and staining before starting the second period of the study and again on completion of the study.

RESULTS

The study showed relatively little difference between the ability of the two brushes to remove stain at a single test brushing. However, there was some evidence that the powered brush was more effective than the manual brush in minimising stain level during the home use period, overall and in particular for gingival crescent sites.

CONCLUSIONS

This study has suggested that the powered brush may become more effective at reducing dental stain, the longer the brush is used under normal home conditions.

Potyviruses, novel and known, in cultivated and wild species of the family Apiaceae in Australia

Three potyviruses were identified by gene sequencing and found to be widespread in species of Apiaceae in Australia. Only celery mosaic virus was found in celery crops and in one of 180 specimens of feral carrot ( Daucus carota). Another related but distinct novel potyvirus, carrot virus Y, was the only virus found in carrot crops and all except one feral carrot. A more distantly related novel potyvirus, apium virus Y, was found in plants of sea celery ( Apium prostratum), cultivated parsley ( Petroselinum crispum) and the immigrant weed species poison hemlock ( Conium maculatum). These three potyviruses, together with celery yellow mosaic virus of South America and the closely related carrot thin leaf virus and carrot virus B of North America, form a distinct subgenus of the Potyviridae most closely related to turnip mosaic virus and two potyviruses of yam; yam mosaic virus from the Ivory Coast and Japanese yam mosaic virus. Celery mosaic and carrot virus Y are probably recent migrants to Australia, but apium virus Y may have been endemic longer. In ELISA tests using polyclonal antibodies against virions of celery mosaic virus, some isolates of carrot virus Y were indistinguishable from celery mosaic virus, whereas others gave smaller absorbancy values, and those of apium virus Y did not react. This study shows the value of virus identification based on gene sequencing for planning control measures.

Characterization of humoral and cellular immune responses elicited by meningococcal carriage

In order to study the immune response elicited by asymptomatic carriage of Neisseria meningitidis, samples of serum, peripheral blood mononuclear cells (PBMCs), and saliva were collected from a cohort of more than 200 undergraduate students in Nottingham, United Kingdom, who were subject to high rates of acquisition and carriage of meningococci. Serum immunoglobulin G levels were elevated following increases in the rate of carriage, and these responses were specific for the colonizing strains. In order to investigate T-cell responses, PBMCs from 15 individuals were stimulated with a whole-cell lysate of the H44/76 meningococcal strain (B:15:P1.7,16), stained to detect cell surface markers and intracellular cytokines, and examined by flow cytometry. The cells were analyzed for expression of CD69 (to indicate activation), gamma interferon (IFN-gamma) (a representative T-helper 1 subset [Th1]-associated cytokine), and interleukin-5 (IL-5) (a Th2-associated cytokine). Following a brief meningococcal stimulation, the numbers of CD69(+) IFN-gamma(+) CD56/16(+) NK cells were much higher than cytokine-positive CD4(+) events. Both IFN-gamma(+) and IL-5(+) events were detected among the CD69(+) CD4(+) population, leading to the conclusion that an unbiased T-helper subset response was elicited by meningococcal carriage.

Early peri-operative glycaemic control and allograft rejection in patients with diabetes mellitus: a pilot study

BACKGROUND

Hyperglycemia alters the inflammatory response to infection and ischemia. We hypothesize that perioperative glycemic control could also influence the risk for allograft rejection.

METHODS

Consecutive patients with established diabetes undergoing their first cadaveric renal transplantation and receiving steroid-sparing immunosuppression were identified (n=50). Records of capillary glucose observations over the first 100 hr following surgery and transplantation variables pertaining to graft function, acute rejection, and postoperative infection were identified and entered into multivariate analysis.

RESULTS

Perioperative glycemic control was associated with an increased incidence of infection and acute rejection. Only 3 of 27 patients (11%) with optimal glycemic control during the 100 hr following surgery (mean<11.2 mmol/L) had rejection episodes compared with 58% of patients with poor control (>11.2 mmol/L). All patients with poor glycemic control experienced postoperative infection.

CONCLUSIONS

This pilot study suggests that hyperglycemia may be associated with an increased risk of both allograft rejection and postoperative infection in patients with diabetes.

Argatroban anticoagulant therapy in patients with heparin-induced thrombocytopenia

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is an immune-mediated syndrome caused by heparin. Complications range from thrombocytopenia to thrombocytopenia with thrombosis. We report a prospective, historical- controlled study evaluating the efficacy and safety of argatroban, a direct thrombin inhibitor, as anticoagulant therapy in patients with HIT or HIT with thrombosis syndrome (HITTS).

METHODS AND RESULTS

Patients with HIT (isolated thrombocytopenia, n=160) or HITTS (n=144) received 2 microgram. kg(-1). min(-1) IV argatroban, adjusted to maintain the activated partial thromboplastin time 1.5 to 3.0 times baseline value. Treatment was maintained for 6 days, on average. Clinical outcomes over 37 days were compared with those of 193 historical control subjects with HIT (n=147) or HITTS (n=46). The incidence of the primary efficacy end point, a composite of all-cause death, all-cause amputation, or new thrombosis, was reduced significantly in argatroban-treated patients versus control subjects with HIT (25.6% versus 38.8%, P=0.014). In HITTS, the composite incidence in argatroban-treated patients was 43.8% versus 56.5% in control subjects (P=0.13). Significant between-group differences by time-to-event analysis of the composite end point favored argatroban treatment in HIT (P=0.010) and HITTS (P=0.014). Argatroban therapy, relative to control subjects, also significantly reduced new thrombosis and death caused by thrombosis (P<0.05). Argatroban-treated patients achieved therapeutic activated partial thromboplastin times generally within 4 to 5 hours of starting therapy and, compared with control subjects, had a significantly more rapid rise in platelet counts (P=0.0001). Bleeding events were similar between groups.

CONCLUSIONS

Argatroban anticoagulation, compared with historical control subjects, improves clinical outcomes in patients who have heparin-induced thrombocytopenia, without increasing bleeding risk.

The benefits of toothpaste--real or imagined? The effectiveness of toothpaste in the control of plaque, gingivitis, periodontitis, calculus and oral malodour

Toothbrushing with toothpaste is the most widely used method of home dental care for the populations of the Western world. The traditional role of toothpaste is primarily cosmetic, in aiding the cleaning of teeth and producing fresh breath. Today, however, formulations contain ingredients which may also help oral health by way of reducing dental plaque and improving gingival/periodontal health. This article provides a short review on the usefulness of these chemicals when used primarily in toothpastes.

The benefits of toothpaste--real or imagined? Review of its role in tooth whitening

The market for whitening toothpastes in the UK is burgeoning at present, but little has been published about the modes of action or efficacy of such pastes. Much is known about how the individual ingredients work, but toothpaste formulations are complex and there is potential for interaction. Studies have been undertaken to compare the efficacy of various test products, but these have used different types of trial design and consequently direct comparisons are difficult, not least because there are several ways of measuring 'whiteness', and there is no consensus of opinion between workers in this field as to the best way to record it.

A study to assess the plaque inhibitory action of a new zinc citrate toothpaste formulation

BACKGROUND, AIMS

Zinc-citrate-containing toothpastes have previously been suggested to be of value at inhibiting plaque and gingival inflammation. Present formulations have included triclosan which is thought to contribute major antibacterial/antiplaque effects. Alternative antimicrobial agents and other ingredients such as oils could help to produce equally effective formulations. The aim of this study was to determine whether zinc citrate toothpastes containing bromochlorophene and a triglyceride oil (1% and 8%) could inhibit de novo plaque formation.

METHODS

Toothpaste slurry rinses were used over a 96-h period by 24 volunteers, whilst omitting all other oral hygiene procedures. For comparative purposes, a conventional commercial fluoride control toothpaste was also used in this triple cross-over double blind study.

RESULTS

After 24 and 48 h, there were no statistically significant differences in plaque between the 2 test pastes and the control paste, whether assessed using a plaque index or plaque area. After 96 h, however, a significant reduction in plaque score of 10.6% and 24.2%) in plaque area (both p < 0.001) was found for the zinc citrate/1% oil toothpaste compared to the control paste. In addition, at 96 h, the 8% oil toothpaste significantly reduced plaque score compared to the control paste by 4.3% (p = 0.029).

CONCLUSIONS

These findings would appear to warrant further investigation into the potential value of the zinc citrate/bromochlorophene/triglyceride formulation at inhibiting both plaque and gingival inflammation.

A study to assess the plaque inhibitory action of a newly formulated triclosan toothpaste

BACKGROUND/AIMS

Triclosan containing toothpastes have been noted for their potential to inhibit plaque and gingival inflammation. The aim of this study was to determine whether a toothpaste containing triclosan and an enhanced fluoride system would inhibit de novo plaque formation beyond that of a non-triclosan, conventional fluoride toothpaste.

METHODS

This study used a 4-day plaque regrowth model in which 24 volunteers used toothpaste rinses as the only form of oral hygiene. Following a prophylaxis and a single brushing with the toothpastes, 2x daily rinsing with toothpaste slurries was used over the following 96 h.

RESULTS

After 24 h, there was no difference in plaque area between the triclosan paste and its control paste. After 96 h, a reduction in plaque score of 5% was noted for the test toothpaste compared to the control paste which was statistically significant (p=0.028). For plaque area this reduction was increased to 16%, which was also significant (p=0.006).

CONCLUSIONS

These findings would appear to warrant further investigation into the potential value of the paste in inhibiting both plaque and gingivitis.

A study to assess the plaque inhibitory activity of a new triclosan mouthrinse formulation

BACKGROUND/AIMS

Toothpastes and mouthrinses containing triclosan have been shown to be of some value at inhibiting both plaque and gingivitis. However much improved activity can be obtained by the addition of other chemicals which increase substantivity or antimicrobial activity. The present study was designed to determine whether a new mouthwash formulation containing a triglyceride oil was capable of reducing plaque reformation when compared to a control rinse containing neither triclosan or oil.

METHODS

A total of 24 subjects took part in a double-blind, single-centre, cross-over study in which rinses were used as the only form of oral hygiene over a 4-day period. On the 1st day of each period, the subjects were given a prophylaxis to remove all plaque and calculus deposits. A single supervised rinse was taken and subsequent 2x daily rinses over the following 3 days. 24 and 96 h after the prophylaxis, the volunteers returned to the clinic, the plaque disclosed and assessed by plaque index and area. The test procedure and wash-out phase were repeated until all of the subjects had used both rinses.

RESULTS

After 24 h, a 12% reduction in plaque score and a 25% reduction in plaque area was noted for the triclosan/oil rinse compared to the control rinse; however, these reductions were not significant (p>0.05). After 96 h, the triclosan/ oil rinse failed to produce a numerical or statistical reduction in plaque whether measured by plaque score or area.

CONCLUSIONS

These findings would suggest that the triclosan/oil rinse would be of little value at inhibiting dental plaque whether used alone or as an adjunct to conventional oral hygiene measures.

Human chorionic gonadotropin as a predictor of outcome in assisted reproductive technology pregnancies

OBJECTIVE

To determine whether serum hCG and progesterone levels obtained 16 days after ovulation are reliable predictors of pregnancy outcome.

DESIGN

A retrospective study.

SETTING

The data were obtained from two integrated Adelaide-based clinics: the Queen Elizabeth Hospital and Wakefield Clinic.

PATIENT(S)

Women who have achieved a pregnancy through ART treatment.

MAIN OUTCOME MEASURE(S)

Analysis of data using logistic regression (STATA v.5.0) to predict a binary outcome: ongoing pregnancy or miscarriage. Ongoing pregnancy was defined as progression to >20 weeks' gestation. Miscarriage included spontaneous abortion, biochemical and ectopic pregnancies, and blighted ovum.

RESULT(S)

Human chorionic gonadotropin was found to be the main determinant of ongoing pregnancy. Age and progesterone had minor effects, whereas stimulation, luteal support, and treatment types were nonpredictive. Low hCG levels between 25 and 50 IU/L are associated with a low probability of ongoing pregnancy (<35%), whereas levels of >500 IU/L predict a >95% chance of ongoing pregnancy.

CONCLUSION(S)

A single serum hCG level 16 days after ovulation provides a useful predictor of pregnancy outcome.

Comparative effects of quaternary ammonium mouthrinses on 4-day plaque regrowth

BACKGROUND

Quaternary ammonium compounds constitute a large group of antibacterial chemicals with a potential for inhibiting plaque and gingivitis. One compound, benzalkonium chloride (BC), may be of value, although there is a dearth of evidence to support efficacy. The aim of this study was to measure the ability of 2 BC mouthrinses (0.05% and 0.1%) to inhibit de novo plaque reformation.

METHOD

A 4-day plaque regrowth model. For comparative purposes, a commercial mouthrinse containing cetyl pyridinium chloride (CPC) and a positive control chlorhexidine (CX) mouthrinse were also evaluated.

RESULTS

Compared to water control, a reduction in plaque scores of 52% was noted for the CX mouthrinse, 22.5% for CPC and 5% and 6% for the 2 BC rinses. For plaque area, reductions of 84%, 47%, 16% and 15% were found for CX, CPC, and the 2 BC rinses, respectively. Significant reductions in plaque area compared to the water rinse were also seen with the 2 BC rinses (p<0.05). However, for both plaque score and plaque area, the CX and CPC rinses significantly reduced plaque compared to the BC rinses (p<0.0001).

CONCLUSIONS

These findings would suggest that the 2 benzalkonium rinses would only have a limited value at inhibiting plaque formation.

Longitudinal study of nutrient and food intakes of white preschool children aged 24 to 60 months

OBJECTIVE

To determine nutrient and food intakes of 72 white preschool children primarily from families of middle and upper socioeconomic status and to compare children's nutrient intakes with current recommendations.

DESIGN

Six in-home interviews were conducted with mothers when children were 24 to 60 months old; at each time mothers provided 3 days of dietary information on the child. Children and mothers independently provided information on the child's favorite and least favorite foods at 42 and 54 months.

SUBJECTS

Preschool children (24 to 60 months old) participating in a longitudinal study.

STATISTICAL ANALYSES

Mean nutrient intakes were compared with the most recent Recommended Dietary Allowances/Adequate Intakes. Differences over time were tested with repeated-measures analysis of variance; gender differences were determined with t tests. Food frequencies (i.e., percentage of children consuming specific foods) were determined from dietary recalls and food records. Dietary variety was assessed with the Variety Index for Toddlers or the Variety Index for Children.

RESULTS

Means were consistently less than the RDA/AI for energy, zinc, folate, and vitamins D and E. Energy, carbohydrate, and fat intakes were highest (P < or = .01) at 60 months. Boys consumed more (P < or = .05) protein (10 g), calcium (197 mg), magnesium (35 mg), and pantothenic acid (0.8 mg) at 60 months than did girls. Foods most commonly eaten were fruit drink, carbonated beverages, 2% milk, and french fries. The vegetable group consistently had the lowest variety scores; vegetables also dominated least favorite foods lists.

APPLICATIONS

Parents need to be encouraged to include more sources of zinc, folate, vitamin E, and vitamin D in children's diets. Parents should also encourage their children to eat more vegetables, zinc- and folate-fortified cereals, lean red meats, seafood, vegetable oils, and low-fat milk.

Providing low-cost sexually transmitted diseases services in two semi-urban health centers in Central African Republic (CAR): characteristics of patients and patterns of health care-seeking behavior

BACKGROUND

While treatment of symptomatic sexually transmitted diseases (STDs) has been shown to reduce the incidence of HIV infection, there are few published reports describing the delivery of high quality STD care in Africa.

GOAL

To test the feasibility of providing comprehensive, affordable STD services through the existing primary care infrastructure.

DESIGN

STD treatment services using a syndromic' approach were established in two semi-urban hospital outpatient departments (OPD) in Central African Republic (CAR). A dedicated paramedical provider took a clinical history, performed an examination, explained the diagnosis and the importance of referring partners, dispensed drugs, and offered partner referral vouchers. A fee-for-service system was used to resupply drugs initially purchased with project funds.

RESULTS

Of 9,552 visits by index patients and partners over a 28-month period starting in October 1993, 60% were made by women; of these women, 90% were symptomatic, 77% had "vaginal discharge," 70% "lower abdominal pain," and 7% "genital ulcer." Among men, 64 % were symptomatic, 38 % had "urethral discharge," and 14% "genital ulcer." Half of all symptomatic patients presented within 1 week of the onset of symptoms; 44% of men compared to 18% of women had sought care elsewhere before the clinic visit. The average cost per STD treated with recommended drugs was $3.90. Etiologic data from subpopulations in both sites suggest that a high proportion of patients was infected with an STD.

CONCLUSIONS

Comprehensive yet affordable care for STDs in persons (and their partners) who recognize symptoms is feasible and should be widely implemented in primary care systems to prevent the spread and complications of STDs and HIV in Africa.

A humanized anti-CD3 antibody, HuM291, with low mitogenic activity, mediates complete and reversible T-cell depletion in chimpanzees

BACKGROUND

An anti-CD3 antibody that reduces cytokine release syndrome (CRS) while maintaining immunosuppression would be a major advance in the treatment of acute allograft rejection. A humanized (Hu) anti-CD3 IgG2 Ab, HuM291 gamma2 M3 (HuM291; Protein Design Labs, Inc., Mountain View, CA), was engineered with mutations in the upper CH2 region of the Fc domain. The mutations were intended to reduce affinity for Fcgamma receptors, thought to be relevant to CRS.

METHODS

In vitro studies using chimpanzee peripheral blood mononuclear cells (PBMCs) were conducted to characterize HuM291 and to establish an animal model. A multidose study was conducted in chimpanzees to evaluate the safety, pharmacokinetics, immunomodulatory activity, and immunogenicity of HuM291, when administered at doses ranging from 0.1 to 10 mg.

RESULTS

HuM291 bound to and effectively downmodulated CD3 from chimpanzee PBMCs and stimulated substantially less cytokine secretion and proliferation of chimpanzee PBMCs compared with OKT3 (Orthoclone OKT3; Ortho Pharmaceutical Corp., Raritan, NJ). Multiple doses of HuM291 (0.1, 1.0, or 10 mg/dose) were not associated with adverse events, signs of toxicity, or CRS, despite cytokine release. HuM291 exhibited a long elimination t1/2 (81.5 hr) and, after three 10-mg doses, sustained serum concentrations > 1000 ng/ml were maintained for 1 week. Multiple 10-mg doses induced complete depletion of circulating CD2+CD3+ T cells for up to 10 days after the last dose; T cells recovered by Day 28. Anti-HuM291 Abs were observed in only 4 of 12 animals and were transient in 2 of those animals.

CONCLUSIONS

In vitro, HuM291 is substantially less mitogenic than OKT3. In chimpanzees, HuM291 effectively depleted peripheral T cells without eliciting clinical signs of CRS, and recovered T cells were functionally normal.

Caspase-3 expression by cerebellar granule neurons is regulated by calcium and cyclic AMP

Caspase-3 enzyme activity is induced, and cell death follows, when cerebellar granule neurons (CGNs) from 8-day-old rats are transferred from an extracellular concentration of 25 mM K+ (25 mM [K+]e) to 5 mM [K+]e. Death of these neurons is diminished by an inhibitor of caspase-3 but not by an inhibitor of caspase-1. Actinomycin D and cycloheximide inhibit induction of caspase-3 and prevent death. Experiments in which CGN intracellular Ca2+ concentration ([Ca2+]i) was manipulated by either changing [K+]e or adding a voltage-gated Ca2+ channel antagonist or a Ca2+ ionophore to the medium showed that caspase-3 mRNA rises 2.5-fold when [Ca2+]i is diminished from 300 to 150 nM, with a corresponding rise in peak caspase enzyme activity. Whereas the caspase-3 mRNA level does not rise further with a still greater diminution in [Ca2+]i, peak caspase enzyme activity continues to increase, reaching sevenfold induction when [Ca2+]i is reduced to 55 nM. In CGNs in which [Ca2+]i is set at 55 nM by incubation in 5 mM [K+]e, treatment with forskolin or dibutyryl 3',5'-cyclic adenosine-5'-monophosphate delays caspase-3 induction and diminishes death but does not alter [Ca2+]i. We conclude that, in immature CGNs, both caspase-3 transcription and the subsequent processing of caspase-3 are induced by a fall in [Ca2+]i. Elevating cyclic AMP content delays caspase-3 induction by a mechanism that does not require an increase in [Ca2+]i.