Predictors of firearm purchasing during the coronavirus pandemic in the United States: a cross-sectional study

OBJECTIVES

This study aimed to compare determinants of firearm purchasing related to the pandemic.

STUDY DESIGN

This was a cross-sectional survey.

METHODS

A total of 3853 online panel participants completed a survey between December 22, 2020, and January 2, 2021, to approximate a nationally representative sample of US adults (aged ≥18 years). Four firearm ownership groups were created: non-owners, a proxy for first-time COVID-19 owners, prepandemic owners with COVID-19 purchase, and prepandemic owners without COVID-19 purchase. Explanatory variables were in four domains: demographics, concern about the pandemic, actions taken in response to COVID-19, and emotional response to COVID-19. Multivariate analysis estimated the adjusted odds of the outcomes.

RESULTS

Respondents were categorized as non-owners (n = 2440), pandemic-related purchasers with no other firearms (n = 257), pandemic-related purchasers with other firearms (n = 350), and those who did not purchase in response to the pandemic but have other firearms (n = 806). Multivariable logistic regression found that compared with non-owners, those who had firearms at home with no pandemic-related purchases are more likely to be male, live in rural settings, have higher income, and be Republican.

CONCLUSIONS

The results highlight the changing profile of American firearm owners and identify that those who purchased firearms for the first time (in response to the pandemic) should be the focus of tailored public health interventions, including provision of education about recommended firearm storage to reduce firearm violence, particularly because they are more likely to have children at home, and belong to demographic groups that may have less experience with firearm safety.

Population pharmacokinetics modeling and analysis of foretinib in adult patients with advanced solid tumors

Foretinib is a multikinase inhibitor that inhibits multiple receptor tyrosine kinases, including MET and VEGFR, with the potential for treatment of solid tumors. Hepatocellular carcinoma (HCC) pathogenesis is associated with overexpression of MET, and physiologic changes in the livers of HCC patients may decrease CYP3A isozyme-mediated metabolism of foretinib. A population pharmacokinetic model of foretinib was developed to explore the effect of tumor type, formulation, and other covariates. Data from 1 HCC study in Asia and 3 non-HCC studies in the United States with varying foretinib regimens and formulations were used for analysis. A 2-compartment model with a linear first-order absorption and elimination and lag time in absorption adequately described foretinib pharmacokinetics in 132 advanced non-HCC and HCC patients and identified an effect of formulations on bioavailability. The bisphosphate salt capsules and freebase tablets had a relative bioavailability 37% and 20% higher, respectively, than the solution formulation. HCC patients had ≈19.6% lower mean clearance (70.14 L/h), ≈16% lower mean volume of distribution (1725.6 L), and higher dose-normalized exposure compared with non-HCC patients. This could be a result of differences in metabolism in HCC patients, body weight, or activity of CYP3A isozymes between Asian and Western cancer patients.

A pharmacokinetic, pharmacodynamic, and safety study of intravenous cyclophosphamide with an oral casopitant antiemetic regimen in cancer patients

Casopitant is a potent and selective neurokinin-1 receptor antagonist formerly under development for a number of indications, including the treatment of chemotherapy-induced nausea and vomiting. This study was an open-label, randomized, multi-center, two-period crossover casopitant-cyclophosphamide interaction study. Subjects were cancer patients receiving cyclophosphamide based chemotherapy. The objectives of the study were to assess the effect of 3-day, repeat-dose, 150 mg oral casopitant on the pharmacokinetics (PK), safety, tolerability, and pharmacodynamics (white blood cell count) of single-dose IV cyclophosphamide. PK data from 14 evaluable subjects showed the geometric least-squares mean ratios (90% CI) for cyclophosphamide and the metabolite 4-hydroxycyclophosphamide AUC (with:without casopitant) were 1.03 (0.975, 1.09) and 0.948 (0.835, 1.08), respectively. Administration of casopitant was well tolerated and did not impact the safety profile of the treatment regimen. Casopitant did not affect the expected bone marrow toxicity of cyclophosphamide. Co-administration of 150 mg oral casopitant with single-dose IV cyclophosphamide did not appear to result in a clinically relevant change in cyclophosphamide or 4-hydroxycyclophosphamide exposure or safety.

Phase II and biomarker study of the dual MET/VEGFR2 inhibitor foretinib in patients with papillary renal cell carcinoma

PURPOSE

Foretinib is an oral multikinase inhibitor targeting MET, VEGF, RON, AXL, and TIE-2 receptors. Activating mutations or amplifications in MET have been described in patients with papillary renal cell carcinoma (PRCC). We aimed to evaluate the efficacy and safety of foretinib in patients with PRCC.

PATIENTS AND METHODS

Patients were enrolled onto the study in two cohorts with different dosing schedules of foretinib: cohort A, 240 mg once per day on days 1 through 5 every 14 days (intermittent arm); cohort B, 80 mg daily (daily dosing arm). Patients were stratified on the basis of MET pathway activation (germline or somatic MET mutation, MET [7q31] amplification, or gain of chromosome 7). The primary end point was overall response rate (ORR).

RESULTS

Overall, 74 patients were enrolled, with 37 in each dosing cohort. ORR by Response Evaluation Criteria in Solid Tumors (RECIST) 1.0 was 13.5%, median progression-free survival was 9.3 months, and median overall survival was not reached. The presence of a germline MET mutation was highly predictive of a response (five of 10 v five of 57 patients with and without germline MET mutations, respectively). The most frequent adverse events of any grade associated with foretinib were fatigue, hypertension, gastrointestinal toxicities, and nonfatal pulmonary emboli.

CONCLUSION

Foretinib demonstrated activity in patients with advanced PRCC with a manageable toxicity profile and a high response rate in patients with germline MET mutations.

A phase II and biomarker study (MET111644) of the dual Met/VEGFR-2 inhibitor foretinib in patients with sporadic and hereditary papillary renal cell carcinoma: Final efficacy, safety, and PD results

355

Background: Foretinib is an oral multi-kinase inhibitor targeting MET, VEGF, RON, AXL, and TIE-2 receptors. Activating mutations and/or amplifications in MET have been described in patients (pts) with papillary renal cell carcinoma (PRC). The aim of this study was to evaluate the efficacy and safety of 2 dosing regimens of single agent foretinib bisphosphate (foretinib) in pts with PRC and to explore modulation of plasma proteins indicative of target inhibition.

Methods: Pts were enrolled in 2 cohorts with different dosing schedules of foretinib: 240 mg/day on days 1–5 of every 14 days (intermittent arm) or 80 mg/day (daily dosing arm). The primary endpoint was overall response rate (ORR) targeting an ORR of at least 25%. Pts were stratified based on status of MET pathway activation (germline or somatic MET mutation, MET [7q31] amplification, chromosome 7 gain or none of these). Plasma markers reflecting potential target effects of MET and VEGFR inhibition were also analyzed.

Results: Overall, 74 pts were enrolled with 37 in each dosing cohort. ORR was 13.5%, progression-free survival 9.3 months, 1 year overall survival (OS) was 70% and median OS was not reached. The median duration of response was 18.5 months. Of 68 pts with adequate tumor assessment data available, 50 experienced some reduction in the sum of the longest tumor diameters (SLD) ranging from −2% to −75%. The most frequent grade 3/4 adverse events related to foretinib were fatigue (6.8%), hypertension (50%), and diarrhea (6.8%). A high rate of non-fatal pulmonary embolism was observed (11%). There were no significant differences in efficacy or safety between the two cohorts. In both arms, plasma sMET and VEGF increased and sVEGFR2 decreased after 2 cycles indicating target inhibition, but these changes were not associated with response or PFS. Outcomes based on molecular characterization are presented separately at this meeting.

Conclusions: In the largest clinical trial devoted to papillary RCC, foretinib demonstrated anti-tumor activity in patients with PRC, modulation of several target indicator plasma proteins, and a manageable toxicity profile.

Correlation of germline MET mutation with response to the dual Met/VEGFR-2 inhibitor foretinib in patients with sporadic and hereditary papillary renal cell carcinoma: Results from a multicenter phase II study (MET111644)

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Background: Activating mutations and/or amplifications in MET have been described in patients (pts) with papillary renal cell carcinoma (PRC). Foretinib, an oral multi-kinase inhibitor targeting MET, VEGF, RON, AXL, and TIE-2 receptors, was evaluated in a phase 2 study in pts with PRC. An important objective of this study was to evaluate whether activation of the MET receptor pathway by mutation, amplification, or gain of chromosome 7 was predictive for or correlated with clinical outcomes.

Methods: Pts were stratified based on status of MET pathway activation. Blood samples were collected at screening for determination of germline MET mutational status. Archival tumor tissue samples were obtained for the analysis of somatic MET mutation, amplification of the MET locus (7q31), and gain of chromosome 7 using standardized assays.

Results: A total of 74 pts were enrolled on the trial (37 each in intermittent and daily dosing arms); overall efficacy and safety data are reported separately at this meeting. Sixty-seven pts were evaluable for both mutation status and response. 5/10 pts (50%) with a germline MET mutation experienced a PR, while 5 pts (50%) had SD as their best response, including 4 pts who demonstrated tumor SLD reductions of > 10%, but did not achieve PR by RECIST 1.0. Responses were also seen in pts without germline MET mutation. However, the presence of a germline MET mutation was highly predictive of a response as only 5/57 pts (9%) without a mutation experienced a PR. Other measures of MET pathway activation did not appear to correlate with activity with only 1/5 pts (20%) with somatic MET mutation having a PR; furthermore, in the absence of a concomitant MET mutation, no responses were seen in patients with MET amplification (n=2) and only 1/18 (5%) pts with a gain of chromosome 7 experienced a PR.

Conclusions: The presence of germline MET mutations correlated strongly with activity of the MET inhibitor foretinib in pts with PRC. These data provide early proof of principle that MET may be a valid therapeutic target in a subset of patients with PRC.

Effect of single and repeat doses of casopitant on the pharmacokinetics of CYP450 3A4 substrates midazolam and nifedipine

AIM

To evaluate the impact of single and repeated doses casopitant on the pharmacokinetics of single dose midazolam and nifedipine (CYP3A substrates) in healthy subjects. The effect on debrisoquine metabolism (CYP2D6 substrate) was also assessed.

METHODS

Three open-label studies were conducted in healthy subjects. In the first study subjects received single dose 50 or 100 mg oral casopitant, single dose 5 mg oral midazolam and single dose 10 mg oral debrisoquine. In the other two studies subjects received repeated doses of 10 mg (study 2), 30, or 120 mg oral casopitant and single doses of 5 mg oral midazolam (study 2) and single doses of 10 mg oral nifedipine (study 3). Plasma concentration-time data were analyzed using standard non-compartmental methods. The effect of casopitant on all probes was assessed using geometric means ratios and corresponding 90% confidence intervals (CIs).

RESULTS

The AUC(0,∞) of midazolam was increased 1.44-fold (90% CI 1.35, 1.54) and 1.52-fold (90% CI 1.41, 1.65) after co-administration with a single dose of 50 or 100 mg casopitant, respectively. Debrisoquine metabolism was unchanged. After 3 days of casopitant administration, midazolam AUC(0,∞) was increased 1.45- (90% CI 1.32, 1.59), 2.02- (90% CI 1.75, 2.32), and 2.67-fold (90% CI 2.18, 3.27) after co-administration with 10, 30 or 120 mg casopitant, respectively. After 14 days of casopitant administration, midazolam AUC(0,∞) was increased 1.51- (90% CI 1.40, 1.63) to 3.49-fold (90% CI 2.98, 4.08). After 3 days of casopitant administration, nifedipine AUC(0,∞) was increased 1.56- (90% CI 1.37, 1.78) and 1.77-fold (90% CI 1.54, 2.04) after co-administration with 30 or 120 mg casopitant, respectively. Similar increases in nifedipine exposure were observed after 14 days of casopitant administration.

CONCLUSIONS

Casopitant is a dose- and duration-dependent weak to moderate inhibitor of CYP3A.

A comparison of the pharmacokinetics of the anticancer MET inhibitor foretinib free base tablet formulation to bisphosphate salt capsule formulation in patients with solid tumors

PURPOSE

This phase I, open-label, randomized, 2-part crossover study assessed the safety, pharmacokinetics and relative bioavailability of single doses of the anticancer MET inhibitor foretinib (formerly known as GSK1363089, EXEL-2880 and XL-880) free base tablet formulation compared to a bisphosphate salt capsule formulation (Part 1), and assessed the safety, efficacy, and pharmacokinetics of the bisphosphate salt capsule administered 3 times a week in cancer patients (Part 2).

PATIENTS AND METHODS

In Part 1, patients were randomized in a crossover manner to receive a single oral dose of foretinib formulated as a bisphosphate salt capsule (240 mg; 183 mg free base equivalent) followed one week later by a single dose of a free base tablet (180 mg), or vice versa where the treatment sequence was reversed. In Part 2, patients self-administered oral doses of bisphosphate salt capsules (200 mg) 3 times a week until disease progression.

RESULTS

Twelve patients with solid tumors were enrolled and completed Part 1, and 10 patients continued into Part 2. Most AEs were mild or moderate in severity. The most common drug-related AEs were fatigue, diarrhea, and nausea. The least-squares (LS) mean total area under the curve was 3144 and 3514 ng*h/mL for the free base tablet and bisphosphate salt capsule, respectively, with a ratio of 0.89 (90% confidence interval, CI: 0.69, 1.16). The LS mean maximal concentration (Cmax) was 81.6 and 98.5 ng/mL for the free base and bisphosphate salt, respectively, with a ratio of 0.83 (90% confidence interval, CI: 0.67, 1.02). The time to reach Cmax was ∼4 h for both formulations. The pharmacokinetics of foretinib were not clinically different between the 2 formulations. Of the 10 patients assessed for efficacy, 3 patients achieved stable disease.

CONCLUSIONS

Foretinib was well tolerated as single doses of both the free base and bisphosphate salt formulations. The pharmacokinetics and relative bioavailability of the 2 formulations were not clinically different. The bisphosphate salt formulation was well tolerated on a 3-times a week dosing schedule, and reached steady-state plasma concentration after 2 weeks.

Abstract C132: Effect of hepatic or renal impairment on the pharmacokinetics of casopitant

Introduction: The pharmacokinetics and safety of casopitant, a neurokinin-1 receptor antagonist being developed for the prevention of chemotherapy-induced and post-operative nausea and vomiting, were evaluated in subjects with mild (Child-Pugh score of 5–6) and moderate (Child-Pugh score of 7–9) hepatic impairment; mild (creatinine clearance 50–80 mL/min) and moderate (creatinine clearance 30–49 mL/min) renal impairment; and subjects with normal hepatic and renal function.

Experimental Design: Twenty-six subjects were enrolled in the hepatic impairment study (9 mild, 9 moderate and 8 normal subjects) and 18 subjects in the renal impairment study (6 mild, 6 moderate and 6 normal subjects). Subjects with severe hepatic or renal impairment were excluded. All subjects received a once-daily dose of 100 mg oral casopitant for 5 days. Pharmacokinetics and plasma protein binding of casopitant and its major metabolite, GSK525060, were determined on Days 1 and 5. Safety was continuously assessed.

Results: Subjects with mild or moderate hepatic impairment had an increase in casopitant AUC of 11% and 24%, respectively, on Day 1 compared with normal subjects; a similar increase was observed on Day 5. Casopitant Cmax was variable, but similar across all subjects. GSK525060 AUC was not significantly different between normal subjects and subjects with mild hepatic impairment; however, AUC was reduced 29% and 19% on Days 1 and 5, respectively, in subjects with moderate hepatic impairment. The percent bound of casopitant and GSK525060 was similar in all subjects. Casopitant AUC increased 34% and 22% in subjects with mild or moderate renal impairment on Day 1, respectively, and 28% and 11% on Day 5, respectively, when compared with normal subjects. GSK525060 AUC increased 17% and 24% on Days 1 and 5, respectively, in subjects with mild renal impairment, but did not significantly change in subjects with moderate impairment. Further age-adjusted analysis showed no meaningful effect of renal impairment on casopitant or GSK525060 AUC. Cmax and half-life in renal impaired subjects were similar to normal subjects. The plasma protein-binding of casopitant and GSK525060 was similar in all subjects. Casopitant was well tolerated, with no significant difference in the type or frequency of adverse events (AEs) noted between subjects with mild, moderate or no hepatic or renal impairment. Somnolence, flatulence and nausea were the most frequently reported AEs in the hepatic impairment study; whereas constipation and dyspepsia were the most frequently reported events in the renal impairment study. No AEs were reported in subjects with mild renal impairment.

Conclusion: The pharmacokinetics of casopitant is not altered to a clinically significant extent in subjects with mild or moderate, hepatic or renal impairment. The impact of severe hepatic or renal impairment on the pharmacokinetics and safety of casopitant was not evaluated.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C132.

Abstract C133: Effect of casopitant, a novel neurokinin-1 receptor antagonist, on the pharmacokinetics (PK) of the oral contraceptive pill (OCP)

Background: Clinical studies suggest that casopitant, a novel neurokinin-1 receptor antagonist in development for prevention of postoperative and chemotherapy-induced nausea and vomiting (PONV and CINV, respectively), is a mild to moderate inhibitor of CYP3A4. However, in cultured human hepatocytes, induction of CYP3A4 and UGT enzymes also has been observed. Since casopitant is intended for use in women receiving moderately emetogenic chemotherapy for breast cancer, the current studies evaluated the pharmacokinetics (PK) of a combined monophasic oral contraceptive pill (OCP) coadministered with repeat-dose casopitant.

Methods: Healthy female subjects of non-childbearing or of childbearing potential taking OCP were enrolled. Study 1 (N=11) was a randomized, double-blind, placebo-controlled, repeat-dose, crossover study. OCP containing 30 µg ethinylestradiol (ETE) and 150 µg levonorgestrel (LEV) was administered for 2 complete menstrual cycles (21 days + 7-day washout), plus oral placebo or 60 mg casopitant on days 1–14 of each cycle. Study 2 (N=61) was a single-blind, placebo-controlled, repeat-dose, single-sequence study. OCP was administered for 2 complete cycles as above with oral casopitant (30 mg or 120 mg) or placebo administered for cycles 1 and 2, respectively. Casopitant or placebo was administered for 28 consecutive days, beginning 7 days before OCP administration. The geometric least squares mean ratios and 90% confidence intervals (CI) for ETE and LEV AUC and Cmax were calculated to compare OCP + casopitant vs OCP + placebo.

Results: In study 1, ETE AUC(0−) and Cmax were decreased on average by 16% and 17%, respectively, when the OCP was coadministered with 60 mg casopitant vs placebo. Geometric mean LEV AUC(0−) increased 4%, and Cmax decreased 17%. In study 2, for ETE, OCP + casopitant decreased AUC(0−) on average by 15% and 40%, and Cmax by 24% and 32% with 30 mg and 120 mg, respectively. For LEV, the largest mean change in exposure was a 13% decrease in Cmax with 120 mg casopitant given daily for 14 days. Coadministration of casopitant with the combined OCP was well tolerated in both studies.

Conclusions: Continuous coadministration of casopitant for 14 or 28 days with a combined monophasic OCP resulted in only a small change in LEV exposure, but a dose-dependent reduction in ETE exposure that may reduce the efficacy of hormonal contraceptives. The effect of a single oral dose of casopitant on hormonal contraceptives has not been studied.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C133.

Effect of casopitant, a novel NK-1 antagonist, on the pharmacokinetics of dolasetron and granisetron

OBJECTIVE

The objective of this study was to characterize the impact of casopitant, a novel neurokinin-1 receptor antagonist under investigation for the prevention of postoperative and chemotherapy-induced nausea and vomiting, on the pharmacokinetics of the commonly prescribed 5-hydroxytryptamine receptor 3 receptor antagonists, dolasetron or granisetron.

MATERIALS AND METHODS

In a phase I, open-label, two-part, two-period, single-sequence study, two cohorts of healthy subjects received either oral dolasetron (100 mg once daily for 3 days) or oral granisetron (2 mg once daily for 3 days) alone (period 1) and combined with oral casopitant, 150 mg day 1, 50 mg days 2 and 3 (period 2). Pharmacokinetics of hydrodolasetron and granisetron were assessed on days 1 and 3 of each period. Log-transformed area under the curve (AUC) and Cmax were statistically analyzed by performing an analysis of variance. Eighteen subjects were enrolled in the dolasetron cohort; nine subjects were CYP2D6 extensive metabolizers (EMs) and nine subjects were CYP2D6 poor metabolizers. Nineteen subjects were enrolled in the granisetron cohort.

RESULTS

The largest changes in hydrodolasetron exposure after coadministration with casopitant were seen in CYP2D6 EMs, with a 24% increase in hydrodolasetron AUC on day 1 and 30% increase in Cmax on days 1 and 3. All other changes in hydrodolasetron exposure were <20%, and granisetron exposure was not altered to any relevant extent (<11%).

CONCLUSION

None of the changes observed are considered clinically meaningful, and coadministration of casopitant with dolasetron or granisetron was well tolerated.

A Phase I Study of a New Nucleoside Analogue, OSI-7836, Using Two Administration Schedules in Patients with Advanced Solid Malignancies

PURPOSE

To investigate the safety, tolerability, and pharmacokinetic profile of the novel nucleoside analogue OSI-7836 in patients with advanced solid malignancies.

EXPERIMENTAL DESIGN

OSI-7836 was initially given as a 60-minute i.v. infusion on day 1 every 21 days. In view of its dose-limiting toxicities, the administration time was amended to a 5-minute bolus, and subsequently, the schedule was amended to weekly for 4 weeks followed by a 2-week rest. Blood and urine samples were collected for pharmacokinetic studies. Analyses of cytokines and lymphocyte subsets were added later in the study to elucidate a mechanism for the severe fatigue and lymphocyte depletion observed in earlier patients.

RESULTS

Thirty patients received a total of 61 treatment cycles. Fatigue was the main dose-limiting toxicity. Maximum-tolerated dose was defined as 300 mg/m2 in the 60-minute infusion, (three times per week) schedule; 400 mg/m2 in the 5-minute bolus infusion, (three times per week) schedule; and 100 mg/m2 in the weekly schedule. Other common toxicities were nausea, vomiting, rash, fever, and a flu-like syndrome. There were no clinically significant hematologic toxicities. Following the initial dose, OSI-7836 was eliminated from plasma with a median (range) elimination half-life of 48.3 minutes (22.6-64.8 minutes). Lymphocyte subset analysis showed a significant drop in B cell counts, which persisted to day 14 and beyond. Cytokine analysis showed significant elevations of interleukin-6 and interleukin-10 in all patients who received > or = 200 mg/m2 OSI-7836. Best response was disease stabilization in seven patients.

CONCLUSION

OSI-7836 was associated with excessive fatigue, and despite changes in its schedule and duration of administration, we did not observe an improvement in its tolerability. Its potentially selective effect on B lymphocytes could be exploited in further studies in specific hematologic malignancies.

Acute scrotum in Nigeria: an 18-year review

One hundred and seventy-eight patients presenting with an acute scrotum during a period of 18 years (1978-1997) were reviewed retrospectively. Fifty per cent had testicular torsion, with a mean age of 23 years (range 3 weeks-55 years). Torsion was significantly more common in the cold harmattan season (October-early March). The salvage rate of torted testes was 52%. Inguinoscrotal hernia was the cause of testicular infarction in 10% and is an important contributor to male infertility. Twelve per cent of cases of suspected torsion were found to have epididymo-orchitis, at exploration. Twenty-three (13%) patients presented with scrotal gangrene (Fournier's gangrene) which did not result in testicular loss. There was significant morbidity following intervention by non-doctors, and misdiagnosis from unsuspecting physicians. The acute scrotum affecting young patients is a significant cause of male infertility and morbidity in Zaria. Early recognition, prompt treatment and re-education of those who may provide the first line care for such patients will reduce the morbidity and pathologic consequences following neglect.

Reference ranges for thyroid function tests in premature infants beyond the first week of life

OBJECTIVES

To establish reference ranges for the more sensitive assays of thyrotropin and the best available assays of free thyroxine in premature infants after the first week of life.

STUDY DESIGN

Free thyroxine measurements by direct equilibrium dialysis and thyrotropin measurements by third generation immunometric assay were measured in 120 healthy premature infants 25 to 36 weeks' gestation at birth and every 3 weeks until hospital discharge. Infants were stratified by postconceptional age. Differences in free thyroxine and thyrotropin levels among groups were determined by ANOVA. Correlations between hormone measurements and gestational and postnatal ages were sought by linear regression analysis. Reference ranges were determined as arithmetic (free thyroxine) and geometric (thyrotropin) mean+/-2 SD ranges.

RESULTS

From 120 infants, 164 samples were obtained and grouped by postconceptional age at sampling. Free thyroxine was not different among postconceptional age groups and did not correlate with gestational or postnatal age. The free thyroxine reference range based on these data was 10 to 33 pmol/l (0.8 to 2.6 ng/dl). Thyrotropin did not correlate with gestational age. There was a clinically trivial but statistically significant (r(2)=0.03, p<0.05) correlation of thyrotropin with postnatal age. The thyrotropin reference based on these data was 0.8 to 12 mU/l.

CONCLUSIONS

Free thyroxine was closely regulated in these premature infants and levels were similar to those in older children and adults, once the natal surge in thyrotropin has subsided. After the first week of life a single range for each hormone appeared appropriate for all premature infants until 40 weeks postconceptional age.

Differential effect of vinorelbine versus paclitaxel on ERK2 kinase activity during apoptosis in MCF-7 cells

The effects of vinorelbine and paclitaxel on the activity of extracellular signal-regulated protein kinase2 (ERK2), a member of MAP kinase, and its role in the induction of bcl-2 phosphorylation and apoptosis were evaluated in MCF-7 cells. We demonstrated that ERK2 was activated rapidly by vinorelbine, and was inhibited by either paclitaxel or estramustine. A 3-fold increase of ERK2 kinase activity was observed within 30 min when MCF-7 cells were treated with 0.1 microM vinorelbine. In contrast, the same treatment with paclitaxel resulted in a significant decrease of ERK2 kinase activity. We also demonstrated that elevated bcl-2 phosphorylation induced by vinorelbine is paralleled by decrease of a complex formation between bcl-2 and bax, cleavage of poly (ADP) ribose polymerase (PARP) protein, activation of caspase-7, and apoptosis. The levels of bcl-2 phosphorylation, bax, and PARP were not significantly affected by 2'-amino-3'-methoxyflavone (PD 98059), an ERK kinase specific inhibitor. Thus, our data suggest that the apoptosis induced by vinorelbine in MCF-7 cells is mediated through the bcl-2 phosphorylation/bax/caspases pathways, and that activation of ERK2 by vinorelbine does not directly lead to the drug-mediated apoptosis. Since decrease of PARP occurred quickly following the treatment of MCF-7 cells with either 0.1 microM of vinorelbine or paclitaxel, this protein may serve as an early indicator of apoptosis induced not only by DNA damaging agents, but also by antimicrotubule drugs.

SPC-100270, a protein kinase C inhibitor, reduced hypoxic injury due to reperfusion following orthotopic liver transplantation in the rat

Recently, we reported that SPC-100270, a sphingosine derivative and inhibitor of protein kinase C (50-90 microM) in mixed micelle assays, reduced reperfusion injury resulting from hypoxia in a low-flow, reflow model of liver perfusion. Here we report that SPC-100270 has similar beneficial effects following liver transplantation in vivo. Rat liver transplantation was performed using nonarterial and rearterial techniques. Livers from syngenic rats were harvested surgically, prepared with vascular cuffs and a splint, and stored for 24 or 48 h in University of Wisconsin (UW) cold storage solution. Just prior to completion of vascular reconstruction, the organ was rinsed with 3 or 10 ml of Ringer's solution, vehicle, or a solution containing SPC-100270 (up to 500 microM). Following implantation surgery, low doses of SPC-100270 were ineffective at reducing both parenchymal and nonparenchymal cell death, yet significant (P < 0.05) reductions were observed with 500 microM. Further, nonparechnymal cell viability was improved nearly four fold by the drug. SPC-100270 (500 microM) tended to increase survival following 48 h cold storage in UW solution, but the improvement was not statistically significant. SPC-100270 also did not diminish carbon-centered free radical formation in transplanted livers from alcohol-treated rats. Collectively, these data support the hypothesis that pretreatment of donor livers with an inhibitor of protein kinase C is effective in vivo at reducing reperfusion injury, particularly to nonparenchymal cells, following orthotopic liver transplantation in the rat.

Synergism of cytotoxic effects of vinorelbine and paclitaxel in vitro

Empiric combinations of vinca alkaloids with taxanes have been recently used in clinical oncology. To enhance the activity of these two classes of agents, we evaluated the sequence and duration of exposure, looking for synergistic effects. Cell lines DU 145, PC 3, LnCaP, LL 86, MCF7wt, and MCF7/ADR (NCI/ADR-RES) were incubated with varying concentrations of paclitaxel or vinorelbine. Cytotoxicity was evaluated by a semiautomated MTT (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide) method. Synergism or antagonism of these two agents either sequentially or in combination was determined by median effect analysis. Prolonged exposure of cells to either drug enhanced cytotoxic effect. Synergism or antagonism with vinorelbine and paclitaxel were both sequence dependent and cell line specific. In the case of MCF7wt, synergism was seen when a 48-hr exposure to vinorelbine preceded paclitaxel, whereas antagonism was noted when both agents were applied simultaneously or when the sequence was reversed. Concurrent vinorelbine and paclitaxel were synergistic in four of six cell lines when the exposure was extended to 96 hr but not for shorter durations of exposure. Sequential exposure of vinorelbine preceding paclitaxel or prolonged exposure to both agents concurrently needs to be tested clinically to determine whether the antitumor activity of this combination can be enhanced. In addition, these studies suggest concurrent administration of these two agents may lead to a less than optimal cytotoxic result.

Contribution of plasmid-encoded fimbriae and intimin to capacity of rabbit-specific enteropathogenic Escherichia coli to attach to and colonize rabbit intestine

Attachment to the intestinal mucosa is an essential step in the pathogenesis of diarrhea caused by enteropathogenic Escherichia coli (EPEC). Fimbriae and intimin, the outer membrane protein product of the chromosomal eae gene, contribute to this process, but their relative roles and the nature of their interaction are not known. The aim of this study was to determine the relative contribution of plasmid-encoded fimbriae, termed Ral, and intimin to the capacity of rabbit-specific EPEC (REPEC) to attach to the intestinal mucosa of rabbits. To achieve this, we constructed a series of mutants in REPEC strain 83/39 (O15:H-), in which the ralE and eae genes were insertionally inactivated. These strains were then inoculated into ligated loops of rabbit ileum, which were resected 18 h later and examined by light and electron microscopy. The results showed that intimin, but not Ral, is essential for the elicitation of attaching-effacing lesions by REPEC. Nevertheless, a delta eae Ral-bearing mutant adhered to the intestinal epithelium to the same extent as its eae-positive parent and far more extensively than an eae(+) delta ral strain. To examine the contribution of Ral and intimin to colonization of rabbit intestine, we fed these strains to weanling rabbits, which were killed 4 days later, so that the number of bacteria in various regions of the intestine could be determined. The results indicated that strain 83/39 requires both Ral and intimin to colonize the intestine successfully and that a delta eae delta ralE double mutant was incapable of colonizing the intestine. Taken together, these findings indicate that Ral and intimin act independently as adhesion factors of REPEC strain 83/39 and that this strain carries no other significant colonization factor. When both Ral and intimin are present, they appear to act cooperatively, with Ral-mediated adhesion preceding that mediated by intimin.

Infusional vinorelbine in relapsed or refractory lymphomas

Vinorelbine (Navelbine is a semisynthetic vinca alkaloid devoid of serious neurotoxicity. When given weekly vinorelbine has documented activity against many tumors, including lymphomas. Since weekly schedules cannot be easily incorporated in combination regimens, we tested an infusional schedule of vinorelbine given every 21 days in adults with relapsed or refractory lymphoma. Patients with inadequate organ or bone marrow reserve, HIV or other serious infection, central nervous system disease, or prior stem cell or bone marrow transplantation were ineligible. In the phase I part, patients received a constant intravenous bolus of 8 mg/m(2), followed by intravenous continuous infusion over 24 hours daily for four days increasing from 10, 12, to 14 mg/m(2) /d in successive three-patient cohorts. Cycles were repeated every 21 days, and the daily continuous infusion dose was adjusted for toxicity. Dose-limiting mucositis and neutropenia were reached at the continuous dose of 14 mg/m(2) /d. Consequently, for the Phase II trial the starting continuous infusion dose was 12 mg/m(2) /d. After the first 19 patients were entered in the phase II study, the starting infusion dose was reduced to 10 mg/m(2) /d because of frequent grade (3/4) myelosuppression and mucositis. Forty-four patients were entered in the phase II study, of whom 41 are evaluable. Median age was 61 years, 23 were males, with clinically aggressive non-Hodgkin's lymphoma (NHL) in 22, indolent NHL in 18, and Hodgkin's Disease in one patient. The median number of prior regimens was 3 (range 1-11). The lymphoma was refractory to the initial regimen in nine patients, and to the regimen immediately before vinorelbine in 20 patients. Serum LDH was high in 2(1/4)1, and serum beta(2) -microglobulin > 3.0 mg / L in 16/31 patients. Responses were observed in four of 22 patients with aggressive NHL (18%, 95% confidence interval 5%-40%), and in six of 18 with indolent NHL (33%, 95% confidence interval 13%-59%). Median progression-free survival was 6 months for responders. During the Phase II trial 114 vinorelbine courses were administered. Neutrophil nadir was < 1000/microl in 65% and < 100/microl in 35% of courses, respectively. Platelet nadir was < 100,000/microl in 30% and < 20,000/microl in 8% of courses, respectively. Grade (3/4) mucositis was seen in 18% of courses, and neutropenic fever in 13%, and was complicated by death in one patient. We conclude that this dosage and schedule of vinorelbine has modest activity in patients with relapsed or refractory NHL. Myelosuppression is frequent but reversible, but there is no significant neurotoxicity. The role of vinorelbine in combination regimens for patients with relapsed lymphomas, particularly those of indolent histology, should be further investigated.

Colonization of the respiratory tract by a virulent strain of avian Escherichia coli requires carriage of a conjugative plasmid

The E3 strain of E. coli was isolated in an outbreak of respiratory disease in broiler chickens, and experimental aerosol exposure of chickens to this strain induced disease similar to that seen in the field. In order to establish whether the virulent phenotype of this strain was associated with carriage of particular plasmids, four plasmid-cured derivatives, each lacking two or more of the plasmids carried by the wild-type strain, were assessed for virulence. Virulence was found to be associated with one large plasmid, pVM01. Plasmid pVM01 was marked by introduction of the transposon TnphoA, carrying kanamycin resistance, and was then cloned by transformation of E. coli strain DH5alpha. The cloned plasmid was then reintroduced by conjugation into an avirulent plasmid-cured derivative of strain E3 which lacked pVM01. The conjugant was shown to be as virulent as the wild-type strain E3, establishing that this plasmid is required for virulence following aerosol exposure. This virulence plasmid conferred expression of a hydroxamate siderophore, but not colicins, on both strain E3 and strain DH5alpha. Carriage of this plasmid was required for strain E3 to colonize the respiratory tracts of chickens but was not necessary for colonization of the gastrointestinal tract. However, the virulence plasmid did not confer virulence, or the capacity to colonize the respiratory tract, on strain DH5alpha. Thus, these studies have established that infection of chickens with E. coli strain E3 by the respiratory route is dependent on carriage of a conjugative virulence plasmid, which confers the capacity to colonize specifically the respiratory tract and which also carries genes for expression of a hydroxymate siderophore. These findings will facilitate identification of the specific genes required for virulence in these pathogens.

A phase I study of sequential vinorelbine followed by paclitaxel

BACKGROUND

In vitro experiments suggest that administration of vinorelbine preceding paclitaxel results in synergistic cytotoxic effects. A phase I dose escalation trial of vinorelbine daily x 3 with paclitaxel on day 3 repeated every 28 days in metastatic breast cancer patients was completed.

PATIENTS AND METHODS

Female patients, PS 0-2, without evidence of CNS disease or prior neuropathies were treated with vinorelbine at dose levels 7, 10, 13 mg/m2 per day and paclitaxel over three hours at dose levels of 135, 175, and 200 mg/m2.

RESULTS

Twenty-eight patients with six dose levels were studied. At dose level 1, patients developed intolerable but reversible neutropenia. Subsequent dose levels required filgrastim. Dose limiting toxicities were myalgia and fatigue at vinorelbine 13 mg/m2/day and paclitaxel 200 mg/m2. Neuropathy was minor. Twelve of twenty-five patients with measurable disease had a rapid response which did not correlate with dose level.

CONCLUSIONS

Sequential administration of these two agents demonstrates activity in breast cancer patients. Phase II dosing on this schedule should be vinorelbine 13 mg/m2/day x 3 and paclitaxel 175 mg/m2. With proper selection of patients, concern about neurologic toxicity should not impede future trials of vinorelbine with paclitaxel.

Selective early elimination of luteal support in assisted reproduction cycles using a gonadotropin-releasing hormone agonist during ovarian stimulation

OBJECTIVE

To determine if women undergoing GnRH agonist-hMG stimulated IVF cycles can undergo successful discontinuation of luteal phase support.

DESIGN

A protocol for selective discontinuation of luteal phase support was evaluated prospectively in women undergoing assisted reproduction cycles.

SETTING

A tertiary care institutional-based assisted reproduction program.

PATIENT(S)

One hundred eighty-eight women who conceived after an IVF or zygote intrafallopian transfer cycle including a GnRH agonist between January 1994 and June 1997.

INTERVENTION(S)

Women with serum progesterone levels of > or = 60 ng/mL at 4 weeks' gestation were selected for discontinuation of their luteal phase support.

MAIN OUTCOME MEASURE(S)

Delivery rate.

RESULT(S)

Sixty-three women (62.4%) met the criteria for discontinuation of luteal phase support. There were no differences in the mean age, peak E2 levels, number of follicles, number of embryos transferred, or delivery rates (85.7% versus 78.9%) between the women who did and those who did not have discontinuation of their progesterone supplementation.

CONCLUSION(S)

These data reveal that luteal phase support can be discontinued successfully for selective women undergoing IVF who are receiving a GnRH agonist.

Apoptosis in a neonatal rat model of cerebral hypoxia-ischemia

BACKGROUND AND PURPOSE

The mechanisms of excitotoxic cell death in cerebral ischemia are poorly understood. In addition to necrosis, apoptotic cell death may occur. The purpose of this study was to determine whether an established model of cerebral hypoxia-ischemia in the neonatal rat demonstrates any features of apoptosis.

METHODS

Seven-day-old neonatal rats underwent bilateral, permanent carotid ligation followed by 1 hour of hypoxia, and their brains were examined 1, 3, and 4 days after hypoxia-ischemia. The severity of ischemic damage was assessed in the dentate gyrus and frontotemporal cortex by light microscopy. Immunocytochemistry was performed to detect the cleavage of actin by caspases, a family of enzymes activated in apoptosis. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) reactivity was examined in the cortical infarction bed and dentate gyrus. Neonatal rat brain DNA was run on agarose gel electrophoresis to detect DNA fragmentation. Ethidium bromide-staining and electron microscopy were used to determine whether apoptotic bodies, 1 of the hallmarks of apoptosis, were present.

RESULTS

The frontotemporal cortex displayed evidence of infarction, and in most rats the dentate gyrus showed selective, delayed neuronal death. Immunocytochemistry demonstrated caspase-related cleavage of actin. TUNEL and DNA electrophoresis provided evidence of DNA fragmentation. Ethidium bromide-staining and electron microscopy confirmed the presence of chromatin condensation and apoptotic bodies.

CONCLUSIONS

Features of apoptosis are present in the described model of cerebral hypoxia-ischemia. Apoptosis may represent a mode of ischemic cell death that could be the target of novel treatments that could potentially expand the therapeutic window for stroke.

Refractive versus Corneal Changes After Photorefracive Keratectomy for Astigmatism

PURPOSE

To define measures of assessing success and subsequent ways to improve excimer laser treatment of astigmatism.

METHODS

We studied 97 eyes of 79 patients, followed for 12 months, that underwent photorefractive keratectomy (PRK) for myopia and astigmatism with a VISX 20/20 excimer laser. Preoperative spherical equivalent refraction at the corneal plane was between -1.00 and -15.00 D. Mean preoperative refractive astigmatism at the spectacle plan was -2.17 +/- 1.05 D (range, -1.25 to -6.00 D), which is -1.81 +/- 0.86 D (range -1.04 to -4.97 D) when calculated at the corneal plane. All patients were examined before and after surgery; examination included refraction, keratometry, and topography measurement.

RESULTS

The success in treatment of astigmatism appeared measurably less than the treatment of sphere when analogous indices were used for assessment. Success in astigmatism surgery improved, as measured by all parameters, after an additional 20% was applied to astigmatism treatment magnitude indicated by the VISX computer algorithm. The sequential modes of treatment undercorrected astigmatism magnitude to a greater extent than elliptical, but equivalent success rates were present in view of the greater astigmatic changes attempted using the sequential mode. The elliptical mode tended to produce a greater undercorrection of associated sphere (p = 0.313). Results measured by refraction showed a larger change than those measured by topography and keratometry.

CONCLUSION

During PRK with the VISX 20/20 laser, adjustment for undercorrection of astigmatism treatment achieves a fuller correction of astigmatism. When measuring astigmatic changes, results are different when comparing refractive astigmatism changes with corneal astigmatism changes measured by keratometry and topography.

Inhibition of leukotriene B4 (LTB4) in human neutrophils by L-threo-dihydrosphingosine

The sphingosine analog L-threo-dihydrosphingosine has been shown to inhibit protein kinase C (PKC) isoenzymes in mixed micelle and vesicle assays. This compound also inhibited the reactive oxygen intermediates (ROI) released from isolated neutrophils (IC50 approximately 2 microM) and phorbol ester-induced edema and neutrophil influx in the mouse ear model (ED50 approximately 11 mg/kg). Based on the anti-inflammatory activity of this compound, studies were done to determine its effect on arachidonate metabolism by the lipoxygenase pathway. Neutrophils were preincubated with test agents or vehicle for one minute and then incubated with 1 microM calcium ionophore A23187 for two minutes. Supernatants were assayed for LTB4 using a radioimmunoassay. The reference lipoxygenase inhibitor nordihydroguaiaretic acid exhibited 98.3% inhibition at 1 microM (n = 2) and prevented ROI production (IC50 approximately 6 microM). In contrast, the potent PKC inhibitor staurosporine was inactive against LTB4 in these studies (< 23% inhibition at 10 microM, n = 2), but inhibited ROI formation (IC50 approximately 3nM). L-threo-dihydrosphingosine inhibited LTB4 production 96.9 +/- 1.3%, at 10 microM (IC50 = 6 microM, n = 2). These data suggest that L-threo-dihydrosphingosine blocks the release of LTB4 from human neutrophils via a mechanism independent of PKC.

Role of a general surgeon in obstetrics and gynaecology in a rural setting

In a rural hospital in northern Nigeria, general surgeons performed 217 obstetric and gynaecologic operations over a five-year period. These operations were responsible for 23% of all operations at the hospital. Emergency operations were most frequent with caesarean section accounting for 90%. Eighty five per cent of the caesarean sections were performed for cephalopelvic dysproportion. The complications encountered were mostly septic complications, predominantly in patients who had caesarean section for obstructed labour. The overall mortality was 5.1% and neonatal mortality from caesarean section was 4.8%. It is concluded that in the abscence of an obstetrician and gynaecologist general surgery experience is required to manage obstetric and gynaecologic problems in rural areas. Such experience should be considered when recruiting doctors for rural hospitals in developing countries.

Identification and characterization of a K88- and CS31A-like operon of a rabbit enteropathogenic Escherichia coli strain which encodes fimbriae involved in the colonization of rabbit intestine

Initiation of attaching-effacing lesions, which characterize infections with rabbit enteropathogenic Escherichia coli (REPEC), requires bacteria to adhere to the intestinal epithelium. This adherence is reflected in vitro by the affinity of these E. coli strains for various types of eukaryotic cells. TnphoA mutants of REPEC 83/39 (O15:H-) which had lost the ability to adhere to HEp-2 epithelial cells, guinea pig ileal brush borders, and mouse erythrocytes were generated. DNA sequencing of the region surrounding the inactivating transposon insertions within a 95-kb plasmid, designated pRAP for REPEC adherence plasmid, revealed extensive homology between that region and the structural genes of enterotoxigenic E. coli operons encoding the K88 and CS31A fimbrial adhesins and the genes for the afr2 adhesin from REPEC B10 (O103:H2). Seven genes of the ral operon (for REPEC adherence locus), including three putative minor fimbrial subunit genes (ralC, ralF, and ralH), a major fimbrial subunit gene (ralG), a gene of unknown function (ralI), and genes for two fimbrial subunit chaperones (ralD and ralE), were sequenced. When inoculated perorally into weanling rabbits, a mutant with a TnphoA insertion in the ralE gene showed a 10-fold reduction in colonizing ability, with only 1 of 10 rabbits excreting bacteria compared to all 5 of those infected with the wild-type parent strain (P = 0.002). The severity of the diarrheal illness caused by the mutant strain was also reduced. Western blotting of surface protein extracts of strain 83/39 with hyperimmune anti-83/39 antiserum, adsorbed with the ralE mutant, revealed a 32-kDa protein which was absent from protein extracts of two nonadherent mutants. The adsorbed antiserum also bound to the surface of strain 83/39 but not to nonadherent mutants, as detected by immunogold labeling. These results indicate that the ral operon of REPEC 83/39 contains genes necessary for the biosynthesis of fine fimbriae which are responsible for in vitro adherence of the bacteria and play a role in their colonization of, and hence virulence for, rabbits. The putative major fimbrial subunit is a protein with an observed molecular size of approximately 32 kDa which, when assembled, appears to form a capsule of fimbriae surrounding the bacterium similar to that described for CS31A.

Morphometry of human lumbar apophyseal joints. A novel technique

STUDY DESIGN

The anatomy of cadaveric lumbar apophyseal joints was examined as part of a study of possible correlations between lumbar apophyseal morphology, arthrosis, and cartilage thickness and stiffness.

OBJECTIVES

To establish the morphometry of human upper lumbar apophyseal joints using an objective technique.

SUMMARY OF BACKGROUND DATA

The apophyseal joints of 30 unfixed lumbar motion segments, all from different cadavers (24 male, five female, and one unknown, mean age 35 years, range 16-78 years) were exposed by dissection and disarticulation. Twenty-five motion segments were L1-L2, three were L2-L3, and two were L3-L4. The extent of fibrillation and linear dimensions of 29 of these specimens were examined, whereas the vertebrae and joints of 22 of them (18 being L1-L2) were cast in araldite resin.

METHODS

The casts of the vertebrae were sectioned cephalocaudally at 1-mm intervals. Image processing of photographic slides of the sections established the orientations and dimensions of the lumbar apophyseal joints and their shapes using Fourier analysis.

RESULTS

Apophyseal joint surface area was 158 +/- 43 mm2, cephalocaudal length 15.2 +/- 2.7 mm, and straight line length between anterior and posterior borders was 13.2 +/- 1.9 mm. The joints were orientated at 62.5 +/- 11.8 degrees to the coronal plane. Average maximum depth of concavity was 1.8 +/- 0.7 mm. The posterior edges of two joint pairs twisted inward toward the midsagittal plane in a cephalocaudal direction; thus, some apophyseal joints bear part of the axial spinal load. The right inferior surfaces were more elongated cephalocaudally (but not longer) than their contralateral partners. Inferior apophyses were significantly more elongated cephalocaudally (but not longer) than their ipsilateral articulating superior surfaces.

CONCLUSIONS

In theory, Fourier analysis of joint surfaces was objective, but it dictated the criterion by which joints were grouped; care must be exercised so that measurement methods do not categorize joints artificially. "Symmetry" is too subjective to be applied to contralateral apophyseal joints; correlation coefficients should be quoted for areas and orientations. The morphology of contralateral lumbar apophyseal joint pairs was significantly correlated in all respects, as was the morphology of articulating lumbar apophyseal surfaces.

Blunt traumatic injury of the gallbladder in childhood

OBJECTIVE

To illustrate blunt traumatic injury of the gallbladder in childhood.

DESIGN

A case report.

SETTING

Hospital.

SUBJECT

An eight year old boy.

MAIN OUTCOME MEASURE

Incidence, history, treatment.

RESULT

The gallbladder was ruptured at the neck necessitating a cholecystectomy. The child has remained well at three months follow up.

CONCLUSIONS

Blunt traumatic injury of the gallbladder, though rare, does occur usually as a consequence of direct abdominal injury especially in children during sporting activities and fights. Minor injuries can be repaired but cholecystectomy is necessary in more extensive injuries or injury to the cystic duct and neck. A comprehensive history taking including direct questioning regarding trauma and a high index of suspicion are important for early diagnosis and prompt treatment.

Felbamate protects CA1 neurons from apoptosis in a gerbil model of global ischemia

BACKGROUND AND PURPOSE

Felbamate, a novel anticonvulsant that binds to the glycine site of the N-methyl-D-aspartate receptor, has been shown to have neuroprotective properties in vitro and in vivo. In a rat pup model of hypoxia-ischemia, felbamate selectively reduced delayed death in hippocampal granule cells. The present study explores its neuroprotective potential in a gerbil model of global ischemia, in which good evidence exists that ischemia triggers apoptosis of CA1.

METHODS

Gerbils were subjected to bilateral carotid occlusion for 5 minutes and then treated with felbamate (100 or 200 mg/kg IV) or vehicle. They were killed 3 days later, and the numbers of live and dead neurons in the CA1 sector of the hippocampus were counted at sterotaxically defined levels.

RESULTS

Felbamate (200 mg/kg IV) administered after the release of carotid clamping did not change brain temperature but reduced neuronal death in CA1 from 332 +/- 60 cells per section of dorsal hippocampus in unmedicated gerbils to 62 +/- 12 cells in felbamate-treated animals (P<.001). A lower dose of felbamate (100 mg/kg post hoc) showed only a nonsignificant reduction of neuronal death. In the 200-mg/kg group, felbamate serum concentrations peaked at 162 microg/mL and were above 100 microg/mL for at least 3 hours, and brain levels reached 150 microg/mL at 1 hour. In the 100-mg/kg group, blood serum levels were well below 100 microg/mL.

CONCLUSIONS

These results suggest that felbamate given post hoc is remarkably effective in preventing delayed apoptosis secondary to global ischemia but that effective neuroprotection requires doses higher than those used for anticonvulsant treatment.

Human lumbar apophyseal joint damage and intervertebral disc degeneration

OBJECTIVES

To record the extent and location of lumbar apophyseal cartilage damage, and to ascertain if the extent of damage is correlated with the grade of disc degeneration, age, or both.

METHODS

The extent and location of fibrillated areas of the apophyseal cartilage of the joint surfaces of 29 lumbar motion segments were examined using computer aided image processing of Indian ink stained areas, and degeneration of the associated intervertebral discs graded using the method of Nachemson.

RESULTS

It was found that these joints showed a greater extent and prevalence of cartilage fibrillation than the knee, hip or ankle, with significant damage in specimens younger than 30 years. Damage was predominantly located peripherally, superiorly, and posteriorly in the concave superior apophyseal surfaces, and was predominantly peripheral and posterior in the inferior surfaces, with a tendency to be located inferiorly. There was a weak correlation between apophyseal joint damage and the intervertebral disc degenerative grade, but this was inconclusive, as both increased with age.

CONCLUSIONS

The pattern of damage exhibited by superior joint surfaces is most probably caused by tension on collagenous joint capsule fibres which insert into the surfaces posteriorly, so producing an area of fibrocartilage unsuited to loadbearing. Tension on such fibres would be greatest during spinal flexion. The pattern of damage of the inferior surfaces lends some support to the hypothesis that their apices impact the laminae of the lumbar vertebra inferior to them, consequent upon the degeneration and narrowing of the associated intervertebral disc. The predominantly peripheral location of fibrillation of both superior and inferior surfaces may be associated with inadequate mechanical conditioning of marginal joint areas. Disc degeneration cannot be the initial cause of apophyseal fibrillation in most specimens. The study indicates a need for regular spinal exercise, starting at a young age.

Naturally occurring protein kinase C inhibitors; II. Isolation of oligomeric stilbenes from Caragana sinica

The oligomeric stilbenes (+)-alpha-viniferin (1), miyabenol C (2), and kobophenol A (3) have been isolated from Caragana sinica (Buchoz) Rehd (Leguminosae). (+)-alpha-Viniferin (1) and miyabenol C (2) exhibited protein kinase C inhibitory activity at low micromolar concentrations. (+)-alpha-Viniferin inhibited keratinocyte proliferation (0.4 microM) and free radical release in whole blood (47 microM), in vitro, and may be useful in treating hyperproliferative or inflammatory skin diseases.

Reference ranges for newer thyroid function tests in premature infants

OBJECTIVE

To establish reference ranges for recently developed assays of thyroid function in premature infants.

METHODS

We measured serum free thyroxine (T4) by direct equilibrium dialysis and serum thyrotropin by a sensitive immunometric method in 104 preterm infants (25 to 36 weeks of gestational age) during the first week of life.

RESULTS

The free T4 level correlated positively with gestational age (p < 0.0001; r2 = 0.09) and differed significantly between adjacent gestational age groups (p < 0.05). Free T4 concentrations (mean +/- SD) for the 25- to 27-, 28-to 30-, 31- to 33-, and 34- to 36-week groups were 18.0 +/- 5.2, 25.7 +/- 9.0, 30.9 +/- 9.0, 36.0 +/- 10.3 pmol/L (1.4 +/- 0.4, 2.0 +/- 0.7, 2.8 +/- 0.8 ng/dl), respectively. Two reference ranges for free T4 were determined, one for 25 to 30 weeks (6.4 to 42.5 pmol/L (0.5 to 3.3 ng/dl) and one for 31 to 36 weeks (16.7 to 60.5 pmol/L (1.3 to 4.7 ng/dl)). The logarithm of the value for thyrotropin correlated positively with gestational age (p < 0.001; r2 = 0.08); one reference range of 0.5 to 29 mU/L was determined for thyrotropin.

CONCLUSION

This study extends information on thyroid function of preterm infants and establishes reference ranges for this population.

Host specificity of enteropathogenic Escherichia coli from rabbits: lack of correlation between adherence in vitro and pathogenicity for laboratory animals

The pathogenicity of four attaching and effacing strains of enteropathogenic Escherichia coli originally isolated from diarrheic rabbits was investigated by inoculating them perorally into rabbits, guinea pigs, and mice. The ability of the four strains to adhere to cultured epithelial cells, erythrocytes, and intestinal brush borders from various animal species, including rabbits, guinea pigs, and mice, varied considerably. Only one strain carried AF/R1 fimbriae, which are believed to determine the host specificity of these bacteria. Despite these differences, the pattern of behavior of the four strains in experimentally infected animals was similar. Each strain caused fatal diarrhea in rabbits (although the virulence of individual strains for rabbits differed significantly), and none was virulent for guinea pigs or mice. None of the strains colonized the intestinal tract of guinea pigs, but all were able to cause attaching-effacing lesions in ligated loops of guinea pig small intestine. By contrast, all four strains colonized mice, in particular the distal intestine, but none induced attaching-effacing lesions in mouse intestinal loops. These findings suggest that there may be previously unrecognized host-restricted adhesins in enteropathogenic E. coli and indicate that adherence to erythrocytes or intestinal brush borders in vitro does not necessarily reflect colonizing ability or pathogenicity in vivo.

Adherence characteristics of attaching and effacing strains of Escherichia coli from rabbits

Twelve strains of Escherichia coli previously reported to cause diarrhea in rabbits were examined for properties associated with virulence. Ten strains met the criteria for classification as enteropathogenic E. coli in that they were diarrheagenic strains that evoked attaching-effacing lesions in the small intestine and did not produce detectable enterotoxins or cytotoxins. These bacteria exhibited a variety of patterns when investigated for adherence to HEp-2 epithelial cells. Although several strains displayed localized and/or diffuse adherence to epithelial cells, they did not hybridize with DNA probes that recognize the genes responsible for these phenotypes in diarrheagenic E. coli from humans. The bacteria also varied in their ability to bind to erythrocytes and intestinal brush borders from various animal species. Six strains adhered to rabbit brush borders; two of these also adhered to brush borders from other animals. Two strains that did not adhere to rabbit brush borders adhered to those from guinea pigs or sheep. Only one of the strains investigated carried AF/R1 fimbriae, which are believed to govern the host specificity of this category of diarrheagenic E. coli. This strain was E. coli RDEC-1, which remains the only E. coli strain to date that is known to carry fimbriae of this type. The results indicate that although diarrheagenic E. coli strains from rabbits may have common properties associated with the ability to produce attaching-effacing lesions, they differ from each other and from enteropathogenic E. coli of humans in terms of some of the adhesins that mediate binding to eukaryotic cells.

The Stiffness of Human Apophyseal Articular Cartilage as an Indicator of Joint Loading

The stiffness and thickness distribution of healthy lumbar apophyseal cartilage was measured in 25 lumbar motion segments (L1–4). The cartilage indentation and needling techniques of Swann and Seedhom (37) were suitably altered to cope with the low modulus and small size of the joint surfaces. A load of 3.12 ± 0.19 N (mean ± s.d.) was applied to the cartilage through a hemispherical indenter of 4.756 mm diameter. The stiffness was calculated using the displacement and instantaneous load 150 ms and 2 s after the indenter first contacted the surface, and using the equations of both Waters (46) and Hayes et al. (47). The mean stiffness of apophyseal joint cartilage was 2.8 M Pa ± 4 per cent (mean ± 95 per cent confidence limit), and thickness 1.02 mm ± 3 per cent. Peripheral apophyseal joint cartilage was softer than central cartilage. The stiffnesses of the centres of the superior and inferior joint surfaces were 3.01 MPa ± 12 per cent and 3.55 MPa ± 11 per cent. Inferior surfaces had a mean thickness of 0.93 mm ± 5 per cent and stiffness of 2.88 MPa ± 7 per cent. Superior surfaces had a mean thickness of 1.10 mm ± 4 per cent and stiffness of 2.74 MPa ± 5 per cent. It was found that the stiffness of cartilage calculated according to the formula of Hayes et al. (47), based on a constitutive analysis of a thin isotropic elastic layer, was directly proportional to both the stiffness calculated using the semi-empirical formula of Waters (46), derived to describe indentation of thin rubber sheets, and the nominal compressive creep modulus calculated by dividing the mean contact stress by the strain at the deepest point of indentation. The creep modulus calculated 2 s after contact was directly proportional to the creep modulus calculated 150 ms after indenter contact, implying that deformation behaviour was uniform between these points despite variation of cartilage stiffness.

Rapamycin prolongs survival and arrests pathophysiologic changes in murine systemic lupus erythematosus

OBJECTIVE

To evaluate the effects of oral rapamycin (RAPA), a macrolide immunosuppressant that has been shown to interfere with T cell activation events, on the course of spontaneous disease progression in the MRL/MpJ/lpr/lpr (MRL/l) mouse model of lupus.

METHODS

RAPA treatment (6, 12, or 25 mg/kg 3 times per week) was evaluated by monitoring survival rates, autoantibody levels, and urinary albumin levels. Additionally, concanavalin A responsiveness, interleukin-2 (IL-2) production, lymphoid organ size, and histopathology were evaluated ex vivo.

RESULTS

RAPA prevented the typical rise in anti-double-stranded DNA antibody and urinary albumin levels and prolonged survival. Spleen and lymph node sizes were significantly decreased, inflammatory changes in the lung, liver, kidney, spleen, lymph node, and thymus were significantly reduced, and T cell mitogen-stimulated splenocyte proliferation and IL-2 production were restored.

CONCLUSION

Data from 3 independent experiments demonstrated that RAPA significantly reduced or prevented many pathologic features of lupus normally seen in the MRL/l mouse, and suggest that RAPA may be useful as a therapeutic agent in SLE in humans.

Posthypoxic treatment with felbamate is neuroprotective in a rat model of hypoxia-ischemia

Felbamate, a novel dicarbamate anticonvulsant that blocks the glycine site of the N-methyl-D-aspartate receptor and protects the hippocampal slice from hypoxic damage, shows remarkably low toxicity in animals and in humans. Since most treatment of human cerebral ischemia will have to be delivered after the insult, we investigated the neuroprotective potency of post hoc felbamate in rat pups with bilateral carotid ligations exposed to an atmosphere of 6.5% O2 for 1 hour. Brain temperature was unaffected by surgery, hypoxia, or felbamate. Neuroprotection was greatest at 300 mg/kg, less effective at 200 and 400 mg/kg, and ineffective at 100 mg/kg. Post hoc felbamate (300 mg/kg) reduced the volume of infarction from 67% +/- 7% of neocortex in unmedicated rats to 32% +/- 8%, 51% +/- 12%, 38% +/- 19%, and 53% +/- 10% when given 0, 1, 2, and 4 hours after hypoxic exposure, respectively. By 6 hours, post hoc protection was no longer significant. Delayed neuronal necrosis in hippocampal granule cells was reduced from 156 +/- 33 neurons to 12 +/- 7 (0 hours, p < 0.01) and 37 +/- 17 (1 hour, p < 0.05). These effects were obtained at plasma concentrations (60 to 120 mg/ml) that have occasionally been reached without serious toxicity in human anticonvulsant trials. These data suggest that, in this animal model, felbamate given after a hypoxic-ischemic insult is effective in reducing cerebral infarction and extremely effective in preventing delayed neuronal necrosis, but that the window of opportunity for post hoc treatment is only 1 to 4 hours.

A prospective controlled investigation of the cognitive effects of amateur boxing

Eighty six amateur boxers underwent a series of neuropsychological assessments on three occasions--pre bout, immediate post bout and follow up within two years; 31 water polo players and 47 rugby union players acted as controls. The neuropsychological tests were selected as being sensitive to subtle cognitive dysfunction and formed part of a battery of other neurological and ophthalmic assessments. No evidence of neuropsychological dysfunction due to boxing was found, either following a bout or a series of bouts at follow up. None of a range of parameters including number of previous contests, recovery from an earlier bout, number of head blows received during a bout and number of bouts between initial assessment and follow up, were found to be related to changes in cognitive functioning.

A modification of the in vivo mixed lymphocyte reaction and rapamycin's effect in this model

Rapamycin, a novel macrocyclic immunosuppressive agent, suppresses murine T cell activation in vitro by mechanisms distinct from cyclosporin A (CsA). This study was designed to examine rapamycin and CsA in the host vs graft popliteal lymph node (PLN) model, an in vivo system of T cell-dependent lymphocyte activation. The PLN procedure was modified by using irradiated CTLL-2 cells of C57BL/6 origin, instead of primary mouse splenocytes, as the allogeneic stimulus in C3H/HeN recipient mice. PLN cell proliferation was determined by [3H]-thymidine uptake. We found that the host lymphocyte proliferative response to CTLL-2 cells (H-2b) is greater than the response to mouse Balb/c splenocytes (H-2d). Rapamycin (ip or po) produced a dose-related inhibition of the in vivo mixed lymphocyte reaction. By contrast, the effects of CsA and FK-506 were not dose related within the same dose range (0.006-12 mg/kg). These data indicate that rapamycin is an effective immunosuppressive agent and confirm its ability to affect the allogeneic T cell response in vivo. Furthermore, the pharmacological data suggest that this PLN model utilizing irradiated CTLL-2 cells as an allogeneic stimulus provides a reproducible system to examine mixed lymphocyte reactions in vivo.

Rapamycin prevents the onset of insulin-dependent diabetes mellitus (IDDM) in NOD mice

The effect of the immunosuppressive agent rapamycin (RAPA) was assessed in the non-obese diabetic (NOD) mouse which is an autoimmune model of IDDM. RAPA was prepared in a vehicle of 8% cremophor EL/2% ethanol and investigated in two studies. NOD/MrK female mice (six per group, study no. 1; 10 per group, study no. 2) were dosed three times per week p.o. by gavage from 56 to 170 days of age (study no. 1) or from 64 to 176 days of age (study no. 2). Mice treated with RAPA at 0.6 mg/kg, 6 mg/kg, or 12 mg/kg maintained normal plasma glucose through 170 or 176 days of age with 10%, 0%, and 0% incidence of diabetes respectively. In contrast, naive, vehicle-treated, or RAPA 0.06 mg/kg-treated mice exhibited elevated plasma glucose and disease incidence typical for female NOD mice. Mice which became diabetic had elevated levels of beta-hydroxybutyrate, triglycerides and cholesterol. These plasma lipid concentrations were positively correlated with the duration of hyperglycaemia (r = 0.85, 0.87 and 0.84 respectively). Outside of its ability to prevent diabetes, RAPA itself did not affect the lipid profile of the mice. Intervention therapy with RAPA was ineffective at reversing the course of disease after IDDM onset under these experimental conditions. Finally, we report here that prophylactic treatment with RAPA was able to protect against IDDM development in some RAPA-treated mice 41 weeks after cessation of treatment. These data show that orally administered RAPA is effective in preventing onset of disease in the NOD mouse, a relevant model of autoimmune type I diabetes in man.

Felbamate reduces hypoxic-ischemic brain damage in vivo

The neuroprotective effects of felbamate were tested in a model of incomplete cerebral ischemia and hypoxia in 7-day-old rat pups. Felbamate pretreatment (300 mg/kg) reduced the surface of infarcted cortex following bilateral carotid ligation, by 42-49% compared to saline and dimethylsulfoxide (DMSO) controls, respectively. The number of necrotic neurons in the dentate gyrus was reduced by 77% over both DMSO controls and saline controls. These results suggest that felbamate deserves further evaluation for its therapeutic potential in hypoxia-ischemia.

Inhibition of interleukin-1 (IL-1) induced neutral proteases from rabbit articular chondrocytes by WY-46,135 and WY-48,989

The effects of potential anti-osteoarthritic compounds both on the direct inhibition of collagenase and neutral protease activities and on IL-1 induced release of neutral proteases from rabbit articular chondrocytes were investigated. WY-46,135 ((+)-N-[[[(5-chloro-2-benzothiazolyl)thio]phenyl]acetyl]-L- cysteine) directly inhibited collagenase activity (IC50 = 15.4 microM). This inhibition was reversible upon dialysis. WY-46,135 also directly inhibited neutral protease activity (IC50 = 16.8 microM) but did not significantly block bacterial collagenase activity at a concentration of 80 microM. In contrast, WY-48,989 (4-[[2-(7-chloro-2-phenyl-2H-pyrazolo[4,3-c]quinolin-4- yl)ethyl]amino]benzonitrile) did not directly inhibit either collagenase (10 microM) or neutral protease (100 microM) activity. Both WY-48,989 and WY-46,135 inhibited IL-1 stimulated release of neutral proteases (IC50 = 3 microM). The activities of these compounds represents two potential approaches for the treatment of osteoarthritis. WY-46,135 combines direct metalloprotease inhibitory activity with the inhibition of IL-1 stimulated neutral protease release from articular chondrocytes while WY-48,989 selectively inhibits the IL-1 induced release of metalloproteases.