Phase Ib Study of Unesbulin (PTC596) Plus Dacarbazine for the Treatment of Locally Recurrent, Unresectable or Metastatic, Relapsed or Refractory Leiomyosarcoma

PURPOSE

This multicenter, single-arm, open-label, phase Ib study was designed to determine the recommended phase II dose (RP2D) and to evaluate the safety and preliminary efficacy of unesbulin plus dacarbazine (DTIC) in patients with advanced leiomyosarcoma (LMS).

PATIENTS AND METHODS

Adult subjects with locally advanced, unresectable or metastatic, relapsed or refractory LMS were treated with escalating doses of unesbulin orally twice per week in combination with DTIC 1,000 mg/m2 intravenously (IV) once every 21 days. The time-to-event continual reassessment method was used to determine the RP2D on the basis of dose-limiting toxicities (DLTs) assessed during the first two 21-day treatment cycles. All explored doses of unesbulin (200 mg up to 400 mg) were in combination with DTIC. An expansion cohort was enrolled to evaluate the safety and efficacy of unesbulin at the RP2D.

RESULTS

Unesbulin 300 mg administered orally twice per week in combination with DTIC 1,000 mg/m2 IV once every 21 days was identified as the RP2D. On the basis of data from 27 subjects who were deemed DLT-evaluable, toxicity was higher in the unesbulin 400 mg group, with three of four subjects (75%) experiencing DLTs versus one of four subjects (25%) in the 200 mg group and three of 19 subjects (15.8%) in the 300 mg group. The most commonly reported DLTs and treatment-related grade 3 and 4 adverse events were thrombocytopenia and neutropenia. At the RP2D, seven subjects who were efficacy evaluable achieved partial response for an objective response rate of 24.1%.

CONCLUSION

Unesbulin 300 mg twice per week plus DTIC 1,000 mg/m2 once every 21 days was identified as the RP2D, demonstrating a favorable benefit-risk profile in a heavily pretreated population of adults with advanced LMS.

Quantitative Systems Toxicology Modeling Informed Safe Dose Selection of Emvododstat in Acute Myeloid Leukemia Patients

Clinical investigation of emvododstat for the treatment of solid tumors was halted after two patients who were heavily treated with other anticancer therapies experienced drug-induced liver failure. However, preclinical investigations supported that emvododstat at lower doses might be effective in treating acute myeloid leukemia (AML) and against severe acute respiratory syndrome-coronavirus 2 as a dihydroorotate dehydrogenase inhibitor. Therefore, a quantitative systems toxicology model, DILIsym, was used to predict liver safety of the proposed dosing of emvododstat in AML clinical trials. In vitro mechanistic toxicity data of emvododstat and its desmethyl metabolite were integrated with in vivo exposure within DILIsym to predict hepatotoxicity responses in a simulated human population. DILIsym simulations predicted alanine aminotransferase elevations observed in prior emvododstat clinical trials in patients with solid tumors, but not in the prospective AML clinical trial with the proposed dosing regimens. Exposure predictions based on physiologically-based pharmacokinetic modeling suggested that reduced doses of emvododstat would produce clinical exposures that would be efficacious to treat AML. In the AML clinical trial, only eight patients experienced aminotransferase elevations, all of which were mild (grade 1), all resolving within a short period of time, and no patient showed symptoms of hepatotoxicity, confirming the prospective prediction of liver safety. Overall, retrospective DILIsym simulations adequately predicted the liver safety liabilities of emvododstat in solid tumor trials and prospective simulations predicted the liver safety of reduced doses in an AML clinical trial. The modeling was critical to enabling regulatory approval to proceed with the AML clinical trial wherein the predicted liver safety was confirmed.

Pharmacokinetics of Dacarbazine and Unesbulin and CYP1A2-Mediated Drug Interactions in Patients With Leiomyosarcoma

Unesbulin is being investigated in combination with dacarbazine (DTIC) as a potential therapeutic agent in patients with advanced leiomyosarcoma (LMS). This paper reports the pharmacokinetics (PK) of unesbulin, DTIC, and its unreactive surrogate metabolite 5-aminoimidazole-4-carboxamide (AIC) in 29 patients with advanced LMS. Drug interactions between DTIC (and AIC) and unesbulin were evaluated. DTIC (1000 mg/m2 ) was administered to patients with LMS via 1-hour intravenous (IV) infusion on Day 1 of every 21-day (q21d) cycle. Unesbulin dispersible tablets were administered orally twice weekly (BIW), starting on Day 2 of every cycle, except for Cycle 2 (C2), where unesbulin was dosed either on Day 1 together with DTIC or on Day 2, 1 day after DTIC administration. The PK of DTIC, AIC, and unesbulin in Cycle 1 (C1) and C2 were estimated using noncompartmental analysis. DTIC and AIC were measurable immediately after the start of infusion and reached Cmax immediately or shortly after end of infusion at 1.0 and 1.4 hours (Tmax ), respectively. Coadministration of unesbulin orally at 200 mg or above with DTIC inhibited cytochrome P450 (CYP)1A2-mediated DTIC metabolism, resulting in 66.7% reduction of AIC exposures. Such inhibition could be mitigated when unesbulin was dosed the day following DTIC infusion. Repeated unesbulin dosing demonstrated evidence of clinical CYP1A2 induction and increased AIC Cmax by 69.4% and AUCinf by 57.9%. No meaningful difference in unesbulin PK was observed between C2 and C1. The combination therapy of 1000 mg/m2 IV DTIC q21d and 300 mg unesbulin BIW in a staggered regimen is well tolerated in patients with LMS.

A clinical pharmacokinetic drug-drug interaction study between dextromethorphan and emvododstat, a potent anti-SARS-CoV-2 dihydroorotate dehydrogenase inhibitor

PURPOSE

A therapeutic agent that targets both viral replication and the hyper-reactive immune response would offer a highly desirable treatment for severe acute respiratory syndrome corona virus 2 (SARS-CoV-2, coronavirus disease 2019, COVID-19) management. Emvododstat (PTC299; 4-chlorophenyl 6-chloro-1-[4-methoxyphenyl]-1,3, 4,9-tetrahydro-2H-pyrido[3,4-b]indole-2-carboxylate) was found to be a potent inhibitor of immunomodulatory and inflammation-related processes by inhibition of dihydroorotate dehydrogenase to reduce the severity of SARS-CoV-2 infections This drug interaction study was performed to determine if emvododstat was an inhibitor of CYP2D6.

METHODS

Potential drug-drug interactions between emvododstat and a CYP2D6 probe substrate (dextromethorphan) were investigated by measuring plasma dextromethorphan and metabolite (dextrorphan) concentrations before and after emvododstat administration. On day 1, 18 healthy subjects received an oral dose of 30 mg dextromethorphan followed by a 4-day washout period. On day 5, subjects received an oral dose of 250 mg emvododstat with food. Two hours later, 30 mg dextromethorphan was administered.

RESULTS

When given with emvododstat, plasma dextromethorphan concentrations increased substantially, while metabolite levels (dextrorphan) remained essentially the same. Maximum plasma dextromethorphan concentration (Cmax) increased from 2006 to 5847 pg/mL. Dextromethorphan exposure (AUC) increased from 18,829 to 157,400 h·pg/mL for AUC0-last and from 21,585 to 362,107 h·pg/mL for AUC0-inf following administration of emvododstat. When dextromethorphan parameters were compared before and after emvododstat, least squares mean ratios (90% confidence interval) were found to be 2.9 (2.2, 3.8), 8.4 (6.1, 11.5), and 14.9 (10.0, 22.1) for Cmax, AUC0-last, and AUC0-inf, respectively.

CONCLUSION

Emvododstat appears to be a strong CYP2D6 inhibitor. No drug-related treatment emergent adverse effects (TEAEs) were considered to be severe or serious.

TRIAL REGISTRATION

EudraCT 2021-004626-29, 11 May 2021.

A pharmacokinetic drug-drug interaction study between rosuvastatin and emvododstat, a potent anti-SARS-CoV-2 (COVID-19) DHODH (dihydroorotate dehydrogenase) inhibitor

A therapeutic agent that targets both viral replication and the hyper-reactive immune response would offer a highly desirable treatment for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; COVID-19) management. Emvododstat (PTC299) was found to be a potent inhibitor of immunomodulatory and inflammation-related processes by the inhibition of dihydroorotate dehydrogenase (DHODH) to reduce SARS-CoV-2 replication. DHODH is the rate-limiting enzyme of the de novo pyrimidine nucleotide biosynthesis pathway. This drug interaction study was performed to determine whether emvododstat was an inhibitor of breast cancer resistance protein (BCRP) transporters in humans. Potential drug-drug interactions (DDIs) between emvododstat and a BCRP transporter substrate (rosuvastatin) were investigated by measuring plasma rosuvastatin concentrations before and after emvododstat administration. There was no apparent difference in rosuvastatin plasma exposure. The geometric means of maximum plasma rosuvastatin concentrations (Cmax ) were 4369 (rosuvastatin) and 5141 pg/mL (rosuvastatin + emvododstat) at 4 h postdose. Geometric mean rosuvastatin area under the concentration-time curve (AUC) from time 0 to the last measurable plasma concentration was 45 616 and 48 975 h·pg/mL when administered alone and after 7 days of b.i.d. emvododstat dosing, respectively. Geometric least squares mean ratios for Cmax and AUC were approximately equal to 1. Overall, administration of multiple doses of 100 mg emvododstat b.i.d. for 7 days in combination with a single dose of rosuvastatin was safe and well tolerated. Emvododstat can be safely administered with other BCRP substrate drugs. Hence, pharmacokinetic DDI mediated via BCRP inhibition is not expected when emvododstat and BCRP substrates are coadministered.

A phase 1b study of unesbulin (PTC596) plus dacarbazine for the treatment of patients with locally recurrent, unresectable, or metastatic relapsed/refractory leiomyosarcoma

11507

Background: Leiomyosarcoma (LMS) is one of the most common subtypes of soft tissue sarcoma and is associated with high risk of relapse and a poor prognosis for advanced disease. In preclinical LMS models, unesbulin, a microtubule polymerization inhibitor, potentiated the activity of dacarbazine (DTIC) (Jernigan F, et al. Mol Cancer Ther. 2021;20:1846–1857). Here, we report preliminary safety and efficacy results from a Phase 1b dose escalation study evaluating the combination of unesbulin with DTIC in patients with advanced LMS (NCT03761095). Methods: In this single-arm, open-label, Phase 1b clinical trial, patients with advanced LMS received unesbulin orally at 200, 300, or 400 mg twice weekly (BIW) in combination with intravenous DTIC at 1,000 mg/m2 once every 21 days. The primary objectives were to determine the maximum tolerated dose (MTD) and recommended Phase 2 dose (RP2D) of unesbulin in combination with DTIC and to characterize the safety profile of the combination. The time-to-event continual reassessment model (TITE-CRM) was used for dose finding. An expansion cohort with up to 12 additional patients is currently being enrolled. Results: As of the data cutoff on January 6, 2022, 29 LMS patients have been treated. Median prior lines of therapy were 3 (range 1–6). Of 27 evaluable patients, 12 had non-uterine and 15 had uterine LMS. The MTD/RP2D of unesbulin was determined to be 300 mg BIW with DTIC 1,000 mg/m2 every 21 days using the TITE-CRM. At the RP2D, the most common treatment-related adverse events included fatigue, diarrhea, neutropenia, and thrombocytopenia. In the intent-to-treat population, the overall response rate (ORR) was 17.2% (5/29) and the disease control rate (DCR) (DCR = complete response + partial response + stable disease at 12 weeks) was 58.6%. At the 300 mg dose level, the ORR was 19% (4/21) and the DCR was 57.1%. Patients received a median of four cycles (range 1–12). The study is ongoing, with patients continuing to receive treatment. Conclusions: Unesbulin 300 mg BIW in combination with DTIC 1,000 mg/m2 every 21 days was well tolerated and demonstrated promising efficacy in a heavily pre-treated patient population with advanced LMS; these results support further investigation. Updated clinical results will be presented as the data mature. A randomized, placebo-controlled, Phase 2/3 trial is planned. Clinical trial information: NCT03761095.

Emvododstat, a Potent Dihydroorotate Dehydrogenase Inhibitor, Is Effective in Preclinical Models of Acute Myeloid Leukemia

Blocking the pyrimidine nucleotide de novo synthesis pathway by inhibiting dihydroorotate dehydrogenase (DHODH) results in the cell cycle arrest and/or differentiation of rapidly proliferating cells including activated lymphocytes, cancer cells, or virally infected cells. Emvododstat (PTC299) is an orally bioavailable small molecule that inhibits DHODH. We evaluated the potential for emvododstat to inhibit the progression of acute myeloid leukemia (AML) using several in vitro and in vivo models of the disease. Broad potent activity was demonstrated against multiple AML cell lines, AML blasts cultured ex vivo from patient blood samples, and AML tumor models including patient-derived xenograft models. Emvododstat induced differentiation, cytotoxicity, or both in primary AML patient blasts cultured ex vivo with 8 of 10 samples showing sensitivity. AML cells with diverse driver mutations were sensitive, suggesting the potential of emvododstat for broad therapeutic application. AML cell lines that are not sensitive to emvododstat are likely to be more reliant on the salvage pathway than on de novo synthesis of pyrimidine nucleotides. Pharmacokinetic experiments in rhesus monkeys demonstrated that emvododstat levels rose rapidly after oral administration, peaking about 2 hours post-dosing. This was associated with an increase in the levels of dihydroorotate (DHO), the substrate for DHODH, within 2 hours of dosing indicating that DHODH inhibition is rapid. DHO levels declined as drug levels declined, consistent with the reversibility of DHODH inhibition by emvododstat. These preclinical findings provide a rationale for clinical evaluation of emvododstat in an ongoing Phase 1 study of patients with relapsed/refractory acute leukemias.

In Vitro Metabolism, Pharmacokinetics and Drug Interaction Potentials of Emvododstat, a DHODH Inhibitor

Emvododstat was identified as a potent inhibitor of dihydroorotate dehydrogenase and is now in clinical development for the treatment of acute myeloid leukaemia and COVID-19. The objective of this paper is to evaluate the metabolism, pharmacokinetics, and drug interaction potentials of emvododstat.Emvododstat showed high binding to plasma protein with minimal distribution into blood cells in mouse, rat, dog, monkey, and human whole blood.O-Demethylation followed by glucuronidation appeared to be the major metabolic pathway in rat, dog, monkey, and human hepatocytes. CYP2C8, 2C19, 2D6, and 3A4 were involved in O-desmethyl emvododstat metabolite formation. Both emvododstat and O-desmethyl emvododstat inhibited CYP2D6 activity and induced CYP expression to different extents in vitro.Emvododstat and O-desmethyl emvododstat inhibited BCRP transporter activity but did not inhibit bile salt transporters and other efflux or uptake transporters. Neither emvododstat nor O-desmethyl emvododstat was a substrate for common efflux or uptake transporters investigated.Emvododstat is bioavailable in mice, rats, dogs, and monkeys following a single oral dose. The absorption was generally slow with the mean plasma T_max ranging from 2 to 5 h; plasma exposure of O-desmethyl emvododstat was lower in rodents, but relatively higher in dogs and monkeys.

Preclinical and Early Clinical Development of PTC596, a Novel Small-Molecule Tubulin-Binding Agent

PTC596 is an investigational small-molecule tubulin-binding agent. Unlike other tubulin-binding agents, PTC596 is orally bioavailable and is not a P-glycoprotein substrate. So as to characterize PTC596 to position the molecule for optimal clinical development, the interactions of PTC596 with tubulin using crystallography, its spectrum of preclinical in vitro anticancer activity, and its pharmacokinetic-pharmacodynamic relationship were investigated for efficacy in multiple preclinical mouse models of leiomyosarcomas and glioblastoma. Using X-ray crystallography, it was determined that PTC596 binds to the colchicine site of tubulin with unique key interactions. PTC596 exhibited broad-spectrum anticancer activity. PTC596 showed efficacy as monotherapy and additive or synergistic efficacy in combinations in mouse models of leiomyosarcomas and glioblastoma. PTC596 demonstrated efficacy in an orthotopic model of glioblastoma under conditions where temozolomide was inactive. In a first-in-human phase I clinical trial in patients with cancer, PTC596 monotherapy drug exposures were compared with those predicted to be efficacious based on mouse models. PTC596 is currently being tested in combination with dacarbazine in a clinical trial in adults with leiomyosarcoma and in combination with radiation in a clinical trial in children with diffuse intrinsic pontine glioma.

The DHODH inhibitor PTC299 arrests SARS-CoV-2 replication and suppresses induction of inflammatory cytokines

The coronavirus disease 2019 (COVID-19) pandemic has created an urgent need for therapeutics that inhibit the SARS-COV-2 virus and suppress the fulminant inflammation characteristic of advanced illness. Here, we describe the anti-COVID-19 potential of PTC299, an orally bioavailable compound that is a potent inhibitor of dihydroorotate dehydrogenase (DHODH), the rate-limiting enzyme of the de novo pyrimidine nucleotide biosynthesis pathway. In tissue culture, PTC299 manifests robust, dose-dependent, and DHODH-dependent inhibition of SARS-COV-2 replication (EC50 range, 2.0-31.6 nM) with a selectivity index >3,800. PTC299 also blocked replication of other RNA viruses, including Ebola virus. Consistent with known DHODH requirements for immunomodulatory cytokine production, PTC299 inhibited the production of interleukin (IL)-6, IL-17A (also called IL-17), IL-17 F, and vascular endothelial growth factor (VEGF) in tissue culture models. The combination of anti-SARS-CoV-2 activity, cytokine inhibitory activity, and previously established favorable pharmacokinetic and human safety profiles render PTC299 a promising therapeutic for COVID-19.

Pharmacokinetics and Safety of PTC596, a Novel Tubulin-Binding Agent, in Subjects With Advanced Solid Tumors

PTC596 is a novel, orally bioavailable, small-molecule tubulin-binding agent that reduces B-cell-specific Moloney murine leukemia virus insertion site 1 activity and is being developed for the treatment of solid tumors. A phase 1, open-label, multiple-ascending-dose study was conducted to evaluate the pharmacokinetics and safety of the drug in subjects with advanced solid tumors. PTC596 was administered orally biweekly based on body weight. Dose escalation followed a modified 3 + 3 scheme using doses of 0.65, 1.3, 2.6, 5.2, 7.0, and 10.4 mg/kg. Following oral administration, PTC596 was rapidly absorbed, and between 0.65 and 7.0 mg/kg reached a maximum plasma concentration 2 to 4 hours after dosing. Area under the plasma concentration-time curve increased proportionally with body weight-adjusted doses. Maximum plasma concentration increased with dose, although the increase was less than dose proportional at dose levels >2.6 mg/kg. No accumulation occurred after multiple administrations up to 7.0 mg/kg. PTC596 had a terminal half-life ranging 12 to 15 hours at all doses except for the highest dose of 10.4 mg/kg, where the half-life was approximately 20 hours. Overall, PTC596 was well tolerated. The most frequently reported PTC596-related treatment-emergent adverse events were mild to moderate gastrointestinal symptoms, including diarrhea (54.8%), nausea (45.2%), vomiting (35.5%), and fatigue (35.5%). Only 1 patient treated with 10.4 mg/kg experienced dose-limiting toxicity of neutropenia and thrombocytopenia, both of which were reversible. Stable disease as best overall response was observed among 7 patients, with 2 patients receiving the study drug up to 16 weeks. These results support the further development of PTC596 for the treatment of solid tumors.

The DHODH Inhibitor PTC299 Arrests SARS-CoV-2 Replication and Suppresses Induction of Inflammatory Cytokines

The coronavirus disease 2019 (COVID-19) pandemic has created an urgent need for therapeutics that inhibit the SARS-CoV-2 virus and suppress the fulminant inflammation characteristic of advanced illness. Here, we describe the anti-COVID-19 potential of PTC299, an orally available compound that is a potent inhibitor of dihydroorotate dehydrogenase (DHODH), the rate-limiting enzyme of the de novo pyrimidine biosynthesis pathway. In tissue culture, PTC299 manifests robust, dose-dependent, and DHODH-dependent inhibition of SARS CoV-2 replication (EC ₅₀ range, 2.0 to 31.6 nM) with a selectivity index >3,800. PTC299 also blocked replication of other RNA viruses, including Ebola virus. Consistent with known DHODH requirements for immunomodulatory cytokine production, PTC299 inhibited the production of interleukin (IL)-6, IL-17A (also called IL-17), IL-17F, and vascular endothelial growth factor (VEGF) in tissue culture models. The combination of anti-SARS-CoV-2 activity, cytokine inhibitory activity, and previously established favorable pharmacokinetic and human safety profiles render PTC299 a promising therapeutic for COVID-19.

Abstract 292: PTC596 combination therapy for sarcoma

Sarcomas are rare cancers derived from mesenchymal tissues. Although rare, there are approximately 15,000 new cases of sarcoma diagnosed each year in the United States. Certain soft tissue sarcomas are treated with doxorubicin and olaratumabas first line, gemcitabine as second line, and often dacarbazine (DTIC) as third line. PTC596 is a first-in-class, oral investigational new drug that reduces levels of BMI1, a protein required for cancer stem cell survival. PTC596 acts by binding to tubulin causing a G2M cell cycle arrest. PTC596 lowers levels of BMI1 in preclinical tumor models and is generally well tolerated as a monotherapy at doses that result in preclinical target plasma concentrations. Efficacy of PTC596 was evaluated in a series of preclinical models. PTC596 delayed tumor growth as monotherapy and significantly enhanced, in combination, the activity of standard chemotherapeutics including gemcitabine, doxorubicin/ doxil, dacarbazine (DTIC), and other tubulin binding agents. Based on these results, a Ph1b clinical trial in patients with relapsed refractory leiomyosarcoma is to be initiated. It is a dose escalation study of a combination regimen of dacarbazine and PTC596 with the dose-limiting toxicity (DLT) to be determined using a continuous reassessment methodology. Previously, a Phase I multi-center dose escalation study was conducted in patients with advanced solid tumors. PTC596 was administered as an oral monotherapy in 4-week cycles using bodyweight-adjusted twice-per-week (biw) dosing. A maximum tolerated dose (MTD) was not determined though a well-tolerated recommended Phase 2 dose of 7mg/kg biw was identified. The most relevant toxicities observed were neutropenia, nausea, and vomiting which were generally mild to moderate, manageable and reversible.

Citation Format: Marla Weetall, Art Branstrom, John Baird, Liang Cao, Josephine Sheedy, Kylie O'Keefe, Matthew Ingham, Gary K. Schwartz, Robert Spiegel, Edward O'Mara. PTC596 combination therapy for sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 292.

An assessment of opinion of Indian physicians about emergency medicine in India

BACKGROUND

Emergency medicine (EM) has recently been recognized as a specialty in India and formal training programmes are yet to be developed.

METHODS

A survey was devised to elicit the opinion of recently graduated physicians in Chennai, India about EM as well as about the current state of EM in India. A convenience sample of 130 respondents filled out a 21-question survey.

RESULTS

Ninety-four per cent of respondents stated that EM was essential for providing quality healthcare; 94% of respondents felt there needs to be a change in emergency departments in India, with only 20% stating they were proud of the emergency departments in India. Seventy-six per cent of respondents were more likely to consider EM if the specialty was recognized by the Medical Council of India and 76% were inclined to pursue the specialty if there were more training programmes.

CONCLUSION

Recently graduated physicians found flaws in the current state of emergency care in India; however, overall they remain interested in the field of EM.

What goes down must come up: role of the posteromedial cortices in encoding and retrieval

The hypothesis that the neural network supporting successful episodic memory retrieval overlaps with the regions involved in episodic encoding has garnered much interest; however, the role of the posteromedial regions remains to be fully elucidated. Functional magnetic resonance imaging (fMRI) studies during successful encoding typically demonstrate deactivation of posteromedial cortices, whereas successful retrieval of previously encoded information has been associated with activation of these regions. Here, we performed an event-related fMRI experiment during an associative face-name encoding and retrieval task to investigate the topography and functional relationship of the brain regions involved in successful memory processes. A conjunction analysis of novel encoding and subsequent successful retrieval of names revealed an anatomical overlap in bilateral posteromedial cortices. In this region, a significant negative correlation was found: Greater deactivation during encoding was related to greater activation during successful retrieval. In contrast, the hippocampus and prefrontal cortex demonstrated positive activation during both encoding and retrieval. Our results provide further evidence that posteromedial regions constitute critical nodes in the large-scale cortical network subserving episodic memory. These results are discussed in relation to the default mode hypothesis, the involvement of posteromedial cortices in successful memory formation and retention, as well as potential implications for aging and neurodegenerative disease.

Systemic lupus erythematosus in a pediatric patient with congenital acquired immunodeficiency syndrome

The coexistence of congenital HIV infection with primary rheumatologic disease is rare. We have described a child with congenital AIDS and concurrent systemic lupus erythematosus who presented with small vessel vasculitis with no renal involvement. Oral corticosteroid therapy resulted in significant improvement in her clinical state. The child also responded strongly to potent antiretroviral therapy both virologically and immunologically.

Comparative avian phylogeography of Cameroon and equatorial Guinea mountains: implications for conservation

We illustrate the use of Faith's 'Phylogenetic Diversity' measure to compare the phylogeographic structure of two bird species with patterns of avian endemism across six mountains in Cameroon and Equatorial Guinea. The Mountain Greenbul and Cameroon Blue-headed Sunbird showed phylogeographic patterns that together defined three biogeographic regions: Bioko, Mt. Cameroon, and the northern mountains of Cameroon. In contrast, the distributions of endemic species were largely a function of geographical distance, with close mountains sharing more endemic species than distant mountains. Moreover, for both species, populations on Mt. Cameroon were distinctive with respect to the ecologically relevant character bill size. Our results, while preliminary, illustrate the utility of a comparative approach for identifying geographical regions that harbour evolutionarily distinct populations and caution against using only the distributional patterns of endemics to prioritize regions for conservation. Results show that patterns of endemism may not be concordant with patterns of phylogenetic diversity nor morphological variation in a character important in fitness. While incorporation of additional species from unrelated taxa will be necessary to draw definitive conclusions about evolutionarily distinct regions, our preliminary results suggest a conservation approach for the Afromontane region of the Gulf of Guinea that would: (i) emphasize protection of both Bioko and Mt. Cameroon, thereby maximizing preservation of within-species phylogenetic and morphologic diversity; (ii) emphasize protection within the northern mountains to further conserve intraspecific phylogenetic diversity and maximize protection of endemic species.

Human immunodeficiency virus seroprevalence and risk assessment of a homeless population in Denver

OBJECTIVE

TO determine the prevalence of human immunodeficiency virus (HIV) infection among the homeless of Denver and to describe behaviors in the homeless that may be associated with HIV infection.

DESIGN

A cross-sectional cohort study.

METHODS

From July 1990 through June 1994, the authors conducted an unlinked survey collecting demographic and risk exposure data, and from August 1990 through June 1992, a more detailed risk behavior survey was completed on persons who attended the largest homeless clinic in Denver.

RESULTS

For the combined survey years, the overall seroprevalence rate in the unlinked survey was 0.9%. Men were more likely to be seropositive than women (1.3% versus 0.1%) (P < 0.001). Black and Hispanic men had higher seroprevalence rates than white men (3.1% and 2.2% versus 0.5%) (P < 0.001). Gay and bisexual men, men who were injection drug users, and men with partners at risk had a nearly fivefold higher seroprevalence rate compared to other risk groups (3.1% versus 0.7%, P < 0.001). During the 4 study years, 14% of homeless persons tested positive for tuberculosis. In the risk behavior survey, 41% of the clients reported previous injection drug use (since 1978), and 22% reported recent use (past 12 months); of this 22%, 16% reported sharing their works (needles and paraphernalia). Seventy percent of the study participants stated that they changed their sexual behavior, and 39% reported using condoms in the past 12 months.

CONCLUSIONS

In this homeless Denver population, there is a low seroprevalence of HIV but a high rate of HIV risk behavior. Certain groups of homeless persons are at high risk for HIV infection, and targeted interventions are necessary.

Occupational exposure to human immunodeficiency virus (HIV)-infected blood in Denver, Colorado, police officers

The authors undertook a study of Denver, Colorado, police department officers to measure their risk of exposure to blood and human immunodeficiency virus (HIV) by type of work assignment and to document how exposures occurred. From December 1989 through March 1991, 137 officers reported an exposure to either blood or saliva, and 42 exposures to blood were independently documented. The overall rate of exposure to HIV-infected blood for medium and high risk assignments was 0.10 per 10,000 person-days. Thirty-two source persons underwent voluntary testing for HIV antibodies, and five (15.6%) were seropositive. Two thirds of the 42 blood exposures occurred in circumstances in which 1) there was little or no time for the officer to put on protective gloves and clothing because the officer was restraining or being assaulted by a suspect or 2) gloves would have not been protective because of penetration by needles. The authors conclude that Denver police officers rarely have percutaneous or mucosal exposures to blood, but when they do, the risk of exposure to HIV-infected blood is quite high. A health department can provide to police officers a number of services: evaluation of an incident involving contact with blood or body fluids to determine whether there was potential for disease transmission; information about modes of transmission and prevention of bloodborne diseases; serologic testing of source persons; HIV counseling for exposed officers and source persons; documentation for worker's compensation claims; and consultation regarding the use of zidovudine for postexposure prophylaxis.

Resolving conflict in a multicultural nursing department

As a result of the turn toward recruitment from overseas in the 1980s, various challenges must be met and obstacles overcome to achieve harmony among multicultural staffs. A program was implemented to address volatile multicultural issues as part of the Nursing Incentive Reimbursement Award project in New Jersey. Nurses who participated in this sensitive program gave positive feedback, generally reporting that awareness was raised and collegial relationships improved. Specific interventions for dealing with a multicultural staff are offered.

Non-organic failure to thrive: implications of placement through analysis of videotaped interactions

This paper presents 6-month follow-up on a group of 16 infants hospitalized during the first months of life for non-organic failure to thrive (N-O FTT) and their mothers. Eight of these infants were placed in foster care and eight were returned home with their parents following hospitalization. The effects of placement on infant outcomes were examined through comparison of developmental scores and weight percentile changes, and the implications of foster care placements for mother-infant interactions were examined through analysis of patterns of interaction in videotaped sessions of feeding and play six months after hospital discharge. This analysis showed that (1) mothers in both groups failed to make significant progress in resolving their own emotional or psychological conflicts through treatment available; (2) weight and developmental status of the infants did not improve as expected in either group, and finally that (3) the patterns of interaction between mother and infant showed little change over time, and, regardless of placement at home or in foster care, remained concerning.

Non-organic failure to thrive: decision for placement and videotaped evaluations

Infants hospitalized for non-organic failure to thrive in the first six months of life are in a life-threatening situation and are already at risk for poor bonding with mother. In light of this, the meaning and use of foster care and how this separation affects the developing mother-child relationship are the issues addressed through examination of 16 cases in which 8 of the infants were placed in foster care and 8 discharged home after the failure to thrive hospitalization. This paper examines (1) maternal histories of pregnancy, labor and delivery and the neonatal status of placed and non-placed infants; (2) the developmental and weight status of placed children; (3) the nature of the decision criteria for after-hospital care; and (4) the mother-infant relationship at initial intake in terms of mother's report of events and observations of feeding and play interactions during a videotaped assessment process. The study found that the interactions between mother and infant in those situations which required foster care were clearly more dysfunctional when compared to those in which the baby was discharged home to mother. Babies in the two groups were comparable in weight status at the time of hospitalization although babies in foster placement had slightly lower scores on the Bayley Scales. Maternal histories of pregnancy, labor, and delivery were similar for the two groups as were the birth and neonatal histories of the infants.

Histochemistry of mouse extraocular muscle

The organization, histochemical and endplate characteristics, and percentage fiber composition are described for mouse extraocular muscle (EOM). Both recti and obliques, but not the retractor bulbi, have two concentric layers, an inner global and superficial orbital. Three histochemical fiber types, coarse, fine and granular, are present in the EOM. The intermediate diameter coarse fibers are focally innervated and occur in both layers in all muscles. The large diameter granular fibers are focally innervated and occur in all EOM in the global layer. The small diameter fine fibers have multiterminal endplates and occur in both layers of the recti. Fine fibers are not seen in the obliques or retractor bulbi. Focal endplates are confined to a broad diagonal band across the middle one third of the muscle, whereas multiterminal endplates are scattered throughout the length of the muscle.

Fundus camera based retinal LDV

A new bidirectional laser Doppler velocimeter (LDV) is described for absolute measurement of the speed of red blood cells flowing in individual retinal vessels. The basic component of the instrument is a standard retinal camera that eliminates the need for a contact lens. The laser beam is delivered to the eye through the fundus illumination optical system of the camera. Target fixation is done with the eye under examination. The measurements are independent from the ocular refraction; only the axial length of the eye need be determined. The instrument markedly simplifies the technique of retinal blood flow measurement.