Myelopreservation with the CDK4/6 inhibitor trilaciclib in patients with small-cell lung cancer receiving first-line chemotherapy: a phase Ib/randomized phase II trial.

BACKGROUND: Chemotherapy-induced damage of hematopoietic stem and progenitor cells (HSPC) causes multi-lineage myelosuppression. Trilaciclib is an intravenous CDK4/6 inhibitor in development to proactively preserve HSPC and immune system function during chemotherapy (myelopreservation). Preclinically, trilaciclib transiently maintains HSPC in G1 arrest and protects them from chemotherapy damage, leading to faster hematopoietic recovery and enhanced antitumor immunity. PATIENTS AND METHODS: This was a phase Ib (open-label, dose-finding) and phase II (randomized, double-blind placebo-controlled) study of the safety, efficacy and PK of trilaciclib in combination with etoposide/carboplatin (E/P) therapy for treatment-naive extensive-stage small-cell lung cancer patients. Patients received trilaciclib or placebo before E/P on days 1-3 of each cycle. Select end points were prespecified to assess the effect of trilaciclib on myelosuppression and antitumor efficacy. RESULTS: A total of 122 patients were enrolled, with 19 patients in part 1 and 75 patients in part 2 receiving study drug. Improvements were seen with trilaciclib in neutrophil, RBC (red blood cell) and lymphocyte measures. Safety on trilaciclib+E/P was improved with fewer ≥G3 adverse events (AEs) in trilaciclib (50%) versus placebo (83.8%), primarily due to less hematological toxicity. No trilaciclib-related ≥G3 AEs occurred. Antitumor efficacy assessment for trilaciclib versus placebo, respectively, showed: ORR (66.7% versus 56.8%, P = 0.3831); median PFS [6.2 versus 5.0 m; hazard ratio (HR) 0.71; P = 0.1695]; and OS (10.9 versus 10.6 m; HR 0.87; P = 0.6107). CONCLUSION: Trilaciclib demonstrated an improvement in the patient's tolerability of chemotherapy as shown by myelopreservation across multiple hematopoietic lineages resulting in fewer supportive care interventions and dose reductions, improved safety profile, and no detriment to antitumor efficacy. These data demonstrate strong proof-of-concept for trilaciclib's myelopreservation benefits. CLINICAL TRAIL NUMBER: NCT02499770.

Relative efficiency of chlamydia screening in non-clinical settings in two California counties.

We examined the relative efficiency of non-clinical sites to screen for chlamydia in youth and young adults. Chlamydia screening targeting youth (under 30 years of age) was performed at non-clinical sites in high-morbidity neighbourhoods of two California counties. Venues were subdivided into community outreach, schools, parenting centres and drug treatment/correctional facilities. Relative efficiency was estimated with multivariate Poisson regression using incidence of chlamydia per person-hours labour adjusting for strategy and county. Among the 1514 youths screened, the overall prevalence of chlamydia was 5.5%. By venue, the highest prevalence was in drug treatment/correction facilities at 11.1% followed by parenting centres at 6.3%, community outreach at 4.9% and schools at 4.6%. Drug treatment/correctional facilities were the most labour time efficient at 9.9 person-hours per chlamydia case. Schools and parenting centres had the lowest cost per screen at 0.9 person-hours per screen. Adjusted relative labour time efficiency (chlamydia cases per paid person-hour) was significantly higher in schools, 2.0 (95% confidence interval [CI] 1.0-4.2), parenting centres, 3.2 (95% CI 1.6-6.6) and drug treatment/correctional facilities, 2.9 (95% CI 1.0-7.8), compared with community outreach. In conclusion, parenting centres and drug treatment centres and correctional facilities are the most efficient venues for chlamydia screening.

Using strain typing to characterise a fluoroquinolone-resistant Neisseria gonorrhoeae transmission network in southern California.

OBJECTIVE: We investigated the initial outbreak of fluoroquinolone-resistant Neisseria gonorrhoeae (QRNG) in southern California with analysis of transmission using strain typing. METHODS: Surveillance for QRNG was conducted between 2000 and 2002 in southern California, including epidemiology and strain typing by a combination of antibiogram, auxotype, serovar, Lip type and amino acid alteration patterns in the quinolone-resistance determining region of GyrA and ParC. Combining epidemiological data with strain typing, we describe the emergence of QRNG outbreak strains using risk factor analysis and transmission networks. RESULTS: Two outbreak strains accounted for 82% of isolates. Both strains required proline, were Lip type 17c, had amino acid alterations 91> Phe in GyrA and 87> Arg in ParC, but they differed by their serovar, IB-3C8 versus IB-2H7, 2G2. Outbreak strains were positively associated with men who have sex with men (MSM), adjusted odds ratio (AOR) 23.9 (95% confidence interval (CI) 2.2 to 261) and negatively associated with travel history: AOR 0.05, (95% CI 0.0 to 0.6). Network analysis demonstrated that 17 cases were connected by sexual contacts and/or public venues including bars, bathhouses/sex clubs, and internet sites. CONCLUSIONS: QRNG may have become established among Californian MSM through an identified transmission network of southern Californian bars, bathhouses and internet sites.

Thermoregulatory reflexes and cutaneous active vasodilation during heat stress in hypertensive humans.

During dynamic exercise in the heat, increases in skin blood flow are attenuated in hypertensive subjects when compared with normotensive subjects. We studied responses to passive heat stress (water-perfused suits) in eight hypertensive and eight normotensive subjects. Forearm blood flow was measured by venous-occlusion plethysmography, mean arterial pressure (MAP) was measured by Finapres, and forearm vascular conductance (FVC) was calculated. Bretylium tosylate (BT) iontophoresis was used to block active vasoconstriction in a small area of skin. Skin blood flow was indexed by laser-Doppler flowmetry at BT-treated and untreated sites, and cutaneous vascular conductance was calculated. In normothermia, FVC was lower in hypertensive than in normotensive subjects (P < 0.01). During heat stress, FVC rose to similar levels in both groups (P > 0.80); concurrent cutaneous vascular conductance increases were unaffected by BT treatment (P > 0.60). MAP was greater in hypertensive than in normotensive subjects during normothermia (P < 0.05, hypertensive vs. normotensive subjects). During hyperthermia, MAP fell in hypertensive subjects but showed no statistically significant change in normotensive subjects (P < 0.05, hypertensive vs. normotensive subjects). The internal temperature at which vasodilation began did not differ between groups (P > 0.80). FVC is reduced during normothermia in unmedicated hypertensive subjects; however, they respond to passive heat stress in a fashion no different from normotensive subjects.

Role of bird migration in the long-distance dispersal of Ixodes dammini, the vector of Lyme disease.

To evaluate the role of migratory birds in the long-distance dispersal of Ixodes dammini ticks and in the spread of Lyme disease, a 6-year study of migrating birds to an offshore New England island was conducted during 1989-1994. I. dammini are not endemic on this island, therefore allowing assessment of long-distance tick dispersal rather than local infestation. Of 11,324 spring migrants examined, 1.2% were infested with I. dammini. Of 8607 fall migrants examined, 0.2% were infested. Of nymphal ticks examined, 20% were infected with Borrelia burgdorferi. OspB DNA sequencing of 6 B. burgdorferi isolates was identical to sequences of 2 strains common in coastal Maine. It is evident that bird migration allows for long-distance dispersal of I. dammini from areas where they are endemic to areas where they are not and that a few bird species account for the majority of tick dispersal. The likelihood of establishment of enzootic Lyme disease by this mechanism is discussed.

Characterization of the serine protease and serine protease inhibitor from the tissue-penetrating nematode Anisakis simplex.

A serine protease and a serine protease inhibitor were purified from infective larvae of the parasitic nematode Anisakis simplex. The serine protease was found to be trypsin-like and preferentially cleaved substrates with the basic amino acid arginine at the P1 position (Z-Gly-Pro-Arg-AMC (where Z is benzyloxycarbonyl), Km = 0.019 mM, and Z-Phe-Pro-Arg-AMC, Km = 0.013 mM) at rates similar to those determined for trypsin (0.002 mM and 0.006 mM, respectively). However, the presence of a bulky hydrophobic residue at the P2 position (Z-Phe-Arg-AMC, Km = 13.3 mM, and Z-Ile-Leu-Val-Arg-AMC, Km = 24.7 mM) greatly decreased the rate of substrate hydrolysis. Internal amino acid sequence information was obtained from three endo Lys-C digestion fragments of the purified enzyme. These sequences were > 89% (33:37) identical with that of porcine trypsin. A second serine protease 85% (11:13) identical with that of a secreted tissue-destructive serine protease from the pathogenic bacterium Dichelobacter nodosus was also identified. The serine protease inhibitor was found to inhibit trypsin, elastase, and the Anisakis serine protease stoichiometrically, but did not inhibit chymotrypsin. The amino acid sequence of the amino terminus as well as two internal endo Lys-C fragments were determined. Approximately 96% (47:49) of the residues were identical with soybean trypsin inhibitor, indicating that this inhibitor belongs to the Kunitz-type family of inhibitors.

Yeast LEU4 encodes mitochondrial and nonmitochondrial forms of alpha-isopropylmalate synthase.

The LEU4 gene of Saccharomyces cerevisiae is the major structural gene involved in the production of alpha-isopropylmalate synthase. It was recently proposed that LEU4 should be capable of encoding two forms of alpha-isopropylmalate synthase, based mainly on the observation that two of four major transcription start sites are located downstream from the ATG at the beginning of the LEU4 open reading frame (Beltzer, J. P., Chang, L. L., Hinkkanen, A. E., and Kohlhaw, G. B. (1986) J. Biol. Chem. 261, 5160-5167). The two forms with molecular weights of 68,000 and 65,000, respectively, would differ only in the N-terminal region, and only the larger of the two forms would be imported into the mitochondria. We have now constructed LEU4'-'lacZ translational fusion plasmids that contain either a normal LEU4' portion (expected to express both the long and the short forms of the fusion protein) or a modified LEU4' portion in which productive translation is possible only from the second in-frame AUG (expected to express only the short form of the fusion protein). beta-Galactosidase measurements and immunoblotting of crude mitochondrial and cytoplasmic fractions of yeast cells transformed with the fusion plasmids indicate that two forms of hybrid protein are produced and that only the larger form is targeted to the mitochondria. The distinguishing feature of the targeting sequence appears to be its ability to form an 18-residue long amphiphilic helix. Expression of the native short form of LEU4-encoded alpha-isopropylmalate synthase behind a strong yeast promoter has enabled us to show that the short form is functional in leucine biosynthesis, is inhibited by leucine with an apparent inhibitor constant of approximately 0.4 mM, and exists as a cytoplasmic dimer.

Rapid analysis of DNA strand breaks in soft tissues.

A technique was developed to measure rapidly DNA strand breaks in soft tissues. This method measured the rate of alkaline unwinding of DNA, which was proportional to strand breakage. Alkaline unwinding of DNA was done by treating tissue homogenates with NaOH. Single-stranded DNA was removed by extraction with aqueous phenol. DNA unwinding was quantitated by measuring the remaining double-stranded DNA. Using the described technique, a dose-effect relationship was observed between N-nitrosodimethylamine (NDMA) and alkaline unwinding of mouse liver DNA.

A comparison of the proteins of the amoebal and plasmodial phases of the slime mould, Physarum polycephalum.

1. The proteins of amoebae and plasmodia of strain CL of Physarum polycephalum have been compared by two-dimensional gel electrophoresis. Both forms of the organism were labelled by growth on formalin-killed bacteria labelled with [35S]sulphate, [3H]lysine or [14C]lysine. Plasmodia were also labelled from radioactive lysine in the medium. 2. Of 306 relatively abundant proteins examined, 26% were phase-specific, that is they were found only in amoebae or in plasmodia. About a quarter of these apparent differences in gene expression may be due to minor changes in charge and/or size. 3. Amongst the 74% of the proteins present in both amoebae and plasmodia, there are substantial differences in differential rates of synthesis and these have been measured for a representative set of proteins by a double-label procedure.