Nucleotide metabolism and nucleic acid synthesis in mouse thymocytes.

Nucleotide pool sizes, DNA polymerizing enzymes, and DNA synthesis were studied in mouse thymocytes over a 24-hr period of culture in Marbrook chambers. The initial rate of cell division was high with an average mitotic index of 1.6%/hr for 12 hr, followed by a decline to 0.14%/hr at 24 hr. The decline in DNA synthesis was not closely correlated with the activities of DNA-dependent DNA polymerases-α or -β or with the activity of terminal deoxynucleotidyl transferase. The amounts of several ribo- and deoxyribonucleotides per thymocyte were measured using high performance liquid chromatography and DNA polymerase. Pool sizes of ATP, GTP, dATP, and dTTP were less than 10% of pool sizes commonly observed in mammalian cells. The rates of DNA and RNA synthesis in thymocytes may be critically affected by minor changes in the availability of nucleotides. Cultures of thymocytes serve as useful experimental systems for investigation of nucleotide and nucleic acid metabolism during lymphoid differentiation.     

Frequency of genetic polymorphisms of ADAM33 and their association with allergic rhinitis among Jordanians

Allergic rhinitis is a chronic inflammatory disease that is assumed to be due to an interaction between different genetic and/or environmental factors. A disintegrin and metalloprotease domain 33 (ADAM33) has been extensively studied as a susceptibility gene in asthma and has been linked to bronchial hyper-responsiveness. In this study, we investigated the association between ADAM33 single nucleotide polymorphisms and the incidence of allergic rhinitis among the Jordanian population. We conducted a case–control association study on 120 adult individuals diagnosed with allergic rhinitis and 128 normal healthy controls. 8 single-nucleotide polymorphisms in ADAM33 were genotyped using PCR-RFLP method. No significant differences in the allelic frequencies of all SNPs tested between AR patients and the control volunteers were found, although S2 C/G SNP showed a tendency toward significance with P = 0.06. On the genotype level significant association were found in the following genotypes: T1 AA, T1 AG, T2 GG, T2 AG, T + 1 GG, T + 1 AG, V4 CG, S2 CC, S2 CG, Q-1AA. Seven haplotypes were present only within AR patients and eight haplotypes were completely absent from the AR patients. Three haplotypes exhibited significant association with AR P ≤ 0.05, two of them were present only in AR patients. In conclusion, the polymorphisms in the ADAM33 gene are associated with susceptibility to AR in the Jordanian population. Furthermore, the haplotype of the tested SNPs were also associated with the risk of AR.     

The regulation of immune responses to multiple non-H-2 antigens on tumor cells: I. Differential responses of BALB/c F1 hybrids to the P815 mastocytoma in vivo

Factors influencing host resistance to the growth of a tumor bearing many mismatched minor histocompatibility antigens (MiHA) were studied. BALB/c (H-2^d) and several of its F₁ hybrids were injected intraperitoneally with DBA/2 (H-2^d) P815 tumor cells. Compared to BALB/c, which was moderately susceptible, F₁ hybrids of BALB/c with CBA, AKR, C3H.OH, and BIO H-2-congenic strains were highly susceptible, whereas hybrids of BALB/ c with A, A.SW, and BALB.B strains were quite resistant. Susceptibility was observed only with the intraperitoneally injected tumor, since both BALB/c and (CBA x BALB/c)F₁ were resistant to the same tumor injected subcutaneously, and survival times of DBA/2 skin grafts did not differ between susceptible and resistant strains. Susceptibility was in part a function of the number of MiHA incompatibilities between tumor and host although the specific loci involved could not be identified. For example, susceptible (CBA x BALB/c)F₁ hybrids probably shared certain MiHA with DBA/2 which BALB/c lacked, and which therefore subtracted from the net antigenic strength of the tumor in the hybrid, compared to its strength in BALB/ c. This interpretation was supported by in vitro studies which confirmed that the susceptible hybrids shared more MiHA with DBA/2, than did the resistant hybrids. Resistance was at least partially regulated by the host H-2 genotype, as shown by the observation that (BALB/ c x BALB.B)F₁ (H-2^d/b) mice were significantly more resistant than BALB/c. Segregation studies of the resistant (BALB/c x A)F₁ hybrids, indicated that in addition to H-2, a nonH-2 gene in the A background was operating to confer resistance. Thus the factors influencing susceptibility to the MiHA-incompatible tumor were: (i) site of injection; (ii) the combined strength of the disparate MiHA; (iii) the host H-2 genotype; and (iv) at least one host nonH-2 gene conferring increased responsiveness.     

Creatine kinase of heart mitochondria: Changes in its kinetic properties induced by coupling to oxidative phosphorylation

A complete kinetic analysis of the forward mitochondrial creatine kinase reaction was conducted to define the mechanism for its rate enhancement when coupled to oxidative phosphorylation. Two experimental systems were employed. In the first, ATP was produced by oxidative phosphorylation. In the second, heart mitochondria were pretreated with rotenone and oligomycin, and ATP was regenerated by a phosphoenolpyruvate-pyruvate kinase system. Product inhibition studies showed that oxidative phosphorylation did not effect the binding of creatine phosphate to the enzyme. Creatine phosphate interacted competitively with both ATP and creatine, and the E · MgATP · CrP dead-end complex was not readily detected. In a similar manner, the dissociation constants for creatine were not influenced by the source of ATP: K_ib = 29 mm; K_b = 5.3 mM, and the maximum velocity of the reaction was unchanged: V₁ = 1 μmol/ min/mg. Slight differences were noted for the dissociation constant (K_ia) of MgATP from the binary enzyme complex, E · MgATP. The values were 0.75 and 0.29 mm in the absence and presence of respiration. However, a 10-fold decrease in the steady-state dissociation constant (K_a) of MgATP from the ternary complex, E · MgATP · creatine, was documented: 0.15 mm with exogenous ATP and 0.014 mm with oxidative phosphorylation. Since K_ia × K_b does not equal K_a × K_ib under respiring conditions, the enzyme appears to be altered from its normal rapid-equilibrium random binding kinetics to some other mechanism by its coupling to oxidative phosphorylation.     

Focus: Personalized Medicine: The Sociology of the Deceased Harvard Medical Unit at Boston City Hospital

Many graduates of the Harvard Medical Unit (HMU) at Boston City Hospital, in either the clinical training/residency program or the research program at the Thorndike Memorial Laboratory, contributed in major ways to the HMU and constantly relived their HMU experiences. The HMU staff physicians, descending from founder and mentor physicians Francis W. Peabody, Soma Weiss, and George R. Minot, were dedicated to the teaching, development, and leadership of its clinical and research trainees, whose confidence and dedication to patient care as a result of their mentorship led many to lifelong achievements as clinicians, teachers, and mentors. Their experience also led to a lifelong love of the HMU (despite its loss), camaraderie, happiness, and intense friendships with their associates.     

Localization of protein phosphokinase activities in the nucleolus distinct from extra-nucleolar regions in rat ventral prostate nuclei

Rat ventral prostate nucleoli contain protein phosphokinase(s) which have distinctly different characteristics from protein phosphokinase(s) localized in the extra-nucleolar regions of the nucleus. The differences pertain to pH vs activity profiles and activation by divalent cations, utilizing dephospho-phosvitin as substrate. Lysine-rich and arginine-rich F3 histones are also phosphorylated by nucleolar protein phosphokinase(s). Phosphorylation of histones by either nucleolar or extra-nucleolar fractions was not stimulated by cAMP, whereas that of phosvitin was slightly inhibited.     

Distribution of legionellae in a hospital water system: prevalence of immunologically and genetically related Legionella pneumophila serogroup 6 isolates

A hospital warm water system was monitored for the presence and distribution of legionellae. Subtyping of ten selected Legionella pneumophila isolates, originating from four different sites in the system by using serogroup specific antisera in an indirect immunofluorescence test, revealed that nine of the ten isolates belong to serogroup 6, while the remaining one was serogroup 10. Two monoclonal antibodies (mAbs) specific for a subgroup of serogroup 6 strains were further used for characterization. None of the strains reacted with these mAbs. Genome analysis by elaborating NotI profiles using the pulsed field gel electrophoresis (PFGE) technique revealed that nearly all serogroup 6 isolates derived from different sites, including a new building connected by a ring pipe, were identical according to restriction fragment patterns. The patterns were distinguishable from those of the two L. pneumophila serogroup 6 reference strains, and from that of the L. pneumophila serogroup 10 isolate. These data argue for a relatively homogeneous L. pneumophila serogroup 6 population in the entire water system.     

Interinstitutional patient transfers between rapid chemotherapy cycles were feasible to utilize proton beam therapy for pediatric Ewing sarcoma family of tumors

Aim

To assess the feasibility of transferring to the University of Tsukuba Hospital for proton beam therapy (PBT) during intensive chemotherapy in children with Ewing sarcoma family of tumors (ESFT) who had been diagnosed and started their first-line treatment at prefectural or regional centers for pediatric oncology.

Overexpression of miRNA 4451 is Associated With a Poor Survival of Patients With Hypopharyngeal Cancer After Surgery With Postoperative Radiotherapy

Hypopharyngeal cancer (HC) is the most common subset of head and neck cancers. These tumors often have an aggressive clinical outcome characterized by local invasion and regional nodal metastasis. Upregulated miRNAs might be useful as biomarkers for prognosis and molecular targets for these tumors. We determined tumor expression of candidate miRNAs using microarray in 8 HC patients and validated in 372 HC patients. We also used paired tumorous and mucosal tissue to verify the miRNA expression. Log-rank test and Cox model were used to evaluate the survival; and Harrell's C-index was used to compare concordance of Cox models. Our results indicated 7 miRNAs aberrantly expressed in HC. Three of these candidate miRNAs (miRNA-4415, miRNA-200a, and miRNA-30b) were selected for further qRT-PCR validation and all of them were frequently found upregulated in HC tumors; with miR-4451 being the most differentially expressed. Moreover, high expression of miR-4451 was positively correlated with advanced tumor stage and increased mortality risk (HR: 1.6, 95% CI: 1.2–2.3; adjusted HR: 1.5, adjusted 95% CI: 1.1–2.1). Finally, significantly higher expression of miR-4451 in tumors compared to in fresh adjacent normal tissues indicates an oncogenic role of miR-4451 in this tumor. Upregulated miR-4451 in HC samples were frequently found and is significantly associated with advanced stage and poor survival of HC, which may indicate an association of this miRNA with the carcinogenesis process in this tumor site; and they could serve as a prognostic biomarker as well as help develop potential new targets for therapy.