Integration of spatial and single-cell transcriptomic data elucidates mouse organogenesis.

Molecular profiling of single cells has advanced our knowledge of the molecular basis of development. However, current approaches mostly rely on dissociating cells from tissues, thereby losing the crucial spatial context of regulatory processes. Here, we apply an image-based single-cell transcriptomics method, sequential fluorescence in situ hybridization (seqFISH), to detect mRNAs for 387 target genes in tissue sections of mouse embryos at the 8-12 somite stage. By integrating spatial context and multiplexed transcriptional measurements with two single-cell transcriptome atlases, we characterize cell types across the embryo and demonstrate that spatially resolved expression of genes not profiled by seqFISH can be imputed. We use this high-resolution spatial map to characterize fundamental steps in the patterning of the midbrain-hindbrain boundary (MHB) and the developing gut tube. We uncover axes of cell differentiation that are not apparent from single-cell RNA-sequencing (scRNA-seq) data, such as early dorsal-ventral separation of esophageal and tracheal progenitor populations in the gut tube. Our method provides an approach for studying cell fate decisions in complex tissues and development.

Critical Assessment of Myelography Practices: A Call for Rational Guideline Revision.

BACKGROUND AND PURPOSE: Patient preparation for myelography and postprocedural monitoring varies widely between practices, despite published guidelines. Our aim was to examine the current practice variations in discontinuing reportedly seizure threshold-lowering medications before myelography and to assess the reported incidence of postmyelographic seizures. MATERIALS AND METHODS: An e-mail survey was sent to American Society of Neuroradiology members concerning the number of postmyelographic seizures experienced in the past 5 years, the presence of an institutional policy for discontinuing seizure threshold-lowering medications, and the type of myelographic contrast used. We compared the postmyelographic seizure frequency in the responses. RESULTS: Of 700 survey responses, 57% reported that they do not discontinue seizure threshold-lowering medications before myelography. Most (97%) indicated never having a patient experience a seizure following myelography. The number of postmyelographic seizures between those who discontinue seizure threshold-lowering medications and those who do not was not statistically significant (OR = 2.13; 95% CI, 0.91-4.98; P = .08). Most (95%) reported using nonionic hypo-osmolar agents. CONCLUSIONS: Survey results revealed widely variable practices for patient myelography preparation and postprocedural monitoring. We found no difference in reported seizures between those who discontinued seizure threshold-lowering medications and those who did not. In light of our findings, we propose that discontinuing reportedly seizure threshold-lowering medications is not warranted with the current nonionic water-soluble contrast agents and may be potentially harmful in some instances. This work supports revision of existing recommendations to withhold such medications before myelography.

Comparison of the efficacy of a phenothiazine and a bisquinaldinium calmodulin antagonist against multidrug-resistant P388 cell lines.

Dequalinium belongs to a group of cationic lipophilic drugs believed to be selectively cytotoxic to malignant cells of epithelial origin by virtue of their accumulation in mitochondria. In addition, they are potent inhibitors of calmodulin and, therefore, might sensitize multidrug-resistant cells to chemotherapeutic agents. We compared the responsiveness of multidrug-resistant cells to the effect of dequalinium with that to trifluoperazine, a potent phenothiazine inhibitor of calmodulin. In addition, we studied the effect of these drugs on the responsiveness of multidrug-resistant cell lines to doxorubicin. The effect of drugs on P388 murine leukemic cells was determined by cell counting, [3H]thymidine incorporation into DNA, or soft agar cloning. Drug accumulation was measured by fluorescence spectrophotometry. We found that multidrug-resistant lines were less sensitive than parental cell lines to the intrinsic growth inhibitory effects of dequalinium (IC50, 4.4 versus 0.3 microM in multidrug-resistant and sensitive P388 cells, respectively), whereas they were equally sensitive as the parental line to the effects of trifluoperazine. Following a 3-h exposure of P388/doxorubicin-resistant cells to 0-100 microM doxorubicin with or without either 10 microM dequalinium or 10 microM trifluoperazine, the latter increased the sensitivity to doxorubicin whereas the former had little effect (IC50 values were doxorubicin, 30 microM; doxorubicin plus dequalinium, 25 microM; doxorubicin plus trifluoperazine, 4 microM). Calmodulin prepared from resistant cells were equally sensitive to inhibition by dequalinium and trifluoperazine. P388/doxorubicin-resistant cells accumulated 4.5-fold less dequalinium than P388 cells whereas trifluoperazine was accumulated equally in both. The addition of 4 microM trifluoperazine to resistant cells exposed to 0-100 microM dequalinium completely reversed the alteration in accumulation and resistance to the dequalinium. These studies demonstrate that certain multidrug-resistant lines are cross-resistant to dequalinium and that sensitivity can be completely restored by nontoxic concentrations of trifluoperazine. The resistance appears to be due to changes in drug accumulation and not to be related to an altered sensitivity of calmodulin.

Failure of prostatitis treatment secondary to probable ciprofloxacin-sucralfate drug interaction.

Metal cations such as aluminum, magnesium, ferrous sulfate, and zinc are thought to form chelation complexes with fluoroquinolone antibiotics and prevent the drugs from being absorbed. Sucralfate, which has a high aluminum content, reduces the bioavailability of ciprofloxacin to approximately 4%. The concomitant administration of ciprofloxacin and sucralfate resulted in treatment failure for a patient with prostatitis and a subsequent 5-day hospitalization. Fluoroquinolone antibiotics should be administered at least 2 hours before agents containing metal cations to allow for their absorption. In addition, sucralfate should not be administered less than 6 hours before fluoroquinolone antibiotic administration.

Phase III controlled evaluation of glutamine for decreasing stomatitis in patients receiving fluorouracil (5-FU)-based chemotherapy.

Mucositis is a prominent dose-limiting toxicity associated with 5-FU-based chemotherapy. On the basis of preliminary data suggesting that the amino acid glutamine could alleviate this problem, the authors developed this trial. Patients scheduled to receive their first 5-FU-based chemotherapy regimen were selected for study. Following stratification, patients were randomized, in a double-blind manner, to receive oral glutamine or a placebo preparation in a prophylactic manner. Patients in both groups were given oral cryotherapy before chemotherapy and were evaluated for mucositis by standard physicians' evaluation and by a self-report instrument. Sixty-six patients were randomized to receive glutamine and 68 to receive the placebo preparation. There were no significant differences or substantial trends in the mucositis scores between the two study arms as measured by either the physicians or the patients. It was concluded that the dose and schedule of glutamine used in this clinical trial does not alleviate 5-FU-induced mucositis.

Long term use of megestrol acetate by cancer survivors for the treatment of hot flashes.

BACKGROUND: Hot flashes are often a troublesome symptom in breast carcinoma survivors and men with prostate carcinoma who have undergone androgen deprivation therapy. A previous clinical study demonstrated that, on a short term basis, low dose megestrol acetate markedly reduced hot flashes and was well tolerated. Little information has been available regarding the long term use of low dose megestrol acetate for hot flashes. METHODS: Patients previously enrolled on a randomized placebo-controlled trial that evaluated the short term use of megestrol acetate for hot flashes were contacted and interviewed by telephone. RESULTS: A total of 132 persons were contacted. Nine percent of the patients discontinued megestrol acetate after resolution of their hot flashes. Forty-five percent of the patients contacted were continuing to utilize megestrol acetate approximately 3 years beyond the conclusion of the 1992 study. Three-quarters of these patients were utilizing < or =20 mg of megestrol acetate per day. Potential toxicities attributed to megestrol acetate included episodes of chills, appetite stimulation/weight gain, vaginal bleeding, and carpal tunnel syndrome symptoms. CONCLUSIONS: A substantial proportion of patients continue to use megestrol acetate for periods of up to 3 years or longer with continued control of hot flashes. This treatment appears to be relatively well tolerated.