Cloning and expression of the cDNA for the murine interferon gamma receptor

A murine interferon gamma (IFN-gamma) receptor cDNA was isolated by screening a murine T-cell hybridoma library prepared in lambda gt10 with probes prepared from a human IFN-gamma receptor cDNA. The 2.1-kilobase (kb) cDNA encoded a serine-rich polypeptide of 477 amino acids that was 52% identical to the human protein. Southern and Northern (RNA) blot analyses indicated the presence of a single receptor gene and a single predominant 2.3-kb receptor transcript. Human embryonic kidney fibroblasts, stably transfected with the murine IFN-gamma receptor cDNA, expressed murine IFN-gamma receptors as detected by flow cytometry with either ligand or a receptor-specific monoclonal antibody. Nontransfected cells bound neither ligand nor antibody. Radioligand-binding analysis demonstrated that the transfectants expressed 530,000 murine IFN-gamma receptors per cell and bound murine IFN-gamma with a Ka of 1 x 10(9) M-1. However, despite high-level expression of murine IFN-gamma receptors, the transfected human cells responded only to human and not to murine IFN-gamma as detected by enhancement of major histocompatibility class I antigen expression and induction of antiviral activity. These results thus document the isolation and expression of a full-length murine IFN-gamma receptor cDNA and suggest that additional species-specific components may be necessary to form a biologically active IFN-gamma receptor.

Influence of preovulatory estradiol concentration on diurnal and pulsatile prolactin secretion patterns

We evaluated the effect of preovulatory concentrations of estradiol on the 24-hour profile of prolactin secretion in women with regular menstrual cycles. An estradiol preparation was chosen to allow comparison with physiologic events. Estradiol benzoate, 1 mg intramuscularly, was administered for 7 days to achieve estradiol concentrations just above preovulatory levels (424 +/- 54 pg/ml); 24-hour mean prolactin concentrations increased threefold (14.0 +/- 2.1 to 40.6 +/- 7.1 ng/ml). Prolactin pulse frequency increased significantly (p less than 0.001) during waking hours after estradiol benzoate administration. The diurnal pattern of prolactin secretion was maintained with estradiol benzoate, although the sleep acrophase often reached high concentrations (86 +/- 11 ng/ml). These results suggest in women with regular menstrual cycles: (1) that estrogen administration that achieves slightly greater than preovulatory estradiol concentrations can stimulate prolactin release, (2) that estradiol may elevate prolactin by increasing its pulsatile secretion, (3) that estradiol does not alter the diurnal pattern of prolactin secretion, (4) that estradiol concentrations just above preovulatory levels can be associated with markedly elevated prolactin concentrations.

Molecular cloning of genes that specify virulence in Pseudomonas solanacearum

The suicide plasmid pSUP2021 was used to introduce Tn5 into the Pseudomonas solanacearum wild-type strain K60. We isolated eight avirulent mutants after screening 6,000 kanamycin-resistant transconjugants by inoculating eggplant (Solanum melongena L. cv. Black Beauty) and tobacco (Nicotiana tabacum L. cv. Bottom Special) seedlings. The Tn5-containing EcoRI fragments from the eight mutants were unique, suggesting that numerous genes specify virulence in this species. These EcoRI fragments were cloned into pBR322 or pUC12, and one of the clones, pKD810, was transformed into K60. All of the kanamycin-resistant, ampicillin-sensitive transformants were avirulent. Three randomly selected avirulent transformants were shown to carry the Tn5-containing fragment in place of the wild-type fragment and to exhibit the same hybridization pattern as the original KD810 mutant did. With pKD810 as a probe, we identified cosmids carrying the wild-type virulence genes by using a genomic library of K60 prepared in pLAFR3. Two of the homologous cosmids, pL810A and pL810C, when introduced into KD810 by transformation, restored virulence and normal growth of this mutant in tobacco. Altogether, these data indicate that the gene(s) interrupted by Tn5 insertion in KD810 is essential for the virulence of P. solanacearum. Further characterization of this gene is now being completed by subcloning, transposon mutagenesis, and complementation analysis.

Fatal pancreatitis presenting with subcutaneous fat necrosis. Evidence that lipase and amylase alone do not induce lipocyte necrosis

We report a case of fatal pancreatitis heralded by the presence of cutaneous panniculitis without abdominal pain or other stigmata of the disease. Although cutaneous fat necrosis has been associated with pancreatitis, it is unusual as the presenting complaint of this relatively common disease. In vitro evidence suggests that human pancreatic amylase or lipase alone is not responsible for the observed panniculitis.

Molecular hybridization study of plasma hepatitis B virus DNA from different carriers

We have used molecular hybridization techniques to show that hepatitis B virus (HBV) DNA from different individuals may have substantial differences in sequence homology. Seven specimens of HBV DNA were isolated from plasma of different blood donors. Samples were applied as dots to membranes and nick-translated to form probes. Densitometry of the radioautograms showed that hybridization was most extensive with probe prepared from the same specimen. The hybridization bias was statistically significant (P less than .02) and visible to the naked eye. Hybridization to probes that were digested with nuclease S1 before nick translation did not eliminate the bias. Nor was the bias related to the d/y subdeterminants; on the average, 15 other specimens hybridized equally well to probes prepared from HBV with the same or different subdeterminant. Many specimens among 37 other serum samples showed greater or lesser degrees of homology to different probes, as demonstrated by reprobing of samples fixed to nylon membranes.

Enumerating T-cell subsets on blood smears. An evaluation of an indirect immunoalkaline phosphatase method

Peripheral blood T-lymphocyte subsets in 179 Chinese subjects were enumerated by an indirect immunoalkaline staining method done on ordinary blood smears. Absolute counts (X 10(9)/L) were 1.32 +/- 0.53 (T11), 0.73 +/- 0.31 (T4), 0.45 +/- 0.22 (T8) for males (n = 135) and 1.22 +/- 0.39 (T11), 0.69 +/- 0.20 (T4), 0.44 +/- 0.19 (T8) for females (n = 44). T4:T8 ratio for males and females were 1.79 and 1.58, respectively (0.05 less than P less than 0.10). Within-film area-to-area difference was 4.2 +/- 2.1% (n = 537 films). Interobserver discrepancy was 54 per 3,000 cells counted, or 1.8%. Film-to-film difference was 5.4 +/- 2.6% (30 pairs). T-lymphocyte subsets enumeration by immunostaining blood smears is a simple and reliable alternative to the immunofluorescence method. It avoids procedures that could artifactually affect lymphocyte subsets. The lower T4:T8 ratios revealed in this study could result because of technical reasons.

The effects of interferon on murine erythropoiesis

The effects of interferon (IF) on erythropoietin (Ep) action and production were studied in mice. In comparison to control animals, Ep action in exhypoxic, polycythemic mice was significantly decreased (p less than 0.05) following two low dose injections of IF (2.9-3.5 X 10(4) units). In addition, renal Ep production in normal intact mice was also significantly decreased (p less than 0.01) following a single injection of IF (5.4-6.3 X 10(4) units) and hypoxic exposure.

The effect of lithium on renal haemodynamic function

Renal concentrating capacity following 18 hours of fluid deprivation was measured in 75 patients receiving prophylactic lithium therapy, and in 30 affectively ill subjects receiving other drugs. The lithium-treated patients had significantly lower urine osmolality and higher serum osmolality than the control subjects. Older subjects, patients maintained at higher serum lithium levels and those with a history of previous neurotoxicity showed the most impairment. Ten patients with urine osmolalities of less than 700 mOsm/1 following this test were investigated further. Inulin and para-amino hippurate (PAH) clearance rates were determined and the effect of a subpressor challenge of dopamine on these measures was observed. Half of the patients showed some reduction in inulin and PAH clearance, which was greatest in those patients who had been taking lithium for over 10 years. However, all of the patients tested showed the expected increase in renal blood flow and sodium and water excretion in response to dopamine. Six additional patients had clearance estimations made before starting lithium treatment which were repeated after a period of 3-6 months on the drug. No consistent changes in haemodynamics were observed. Lithium clearly reduces renal concentrating capacity, but other measures of renal tubular function were well preserved in patients receiving long-term therapy. Glomerular function may be slightly reduced in patients taking lithium for long periods. The results show that prophylactic lithium treatment does not affect renal cortical function adversely in the majority of patients, but impaired renal concentrating ability is a common accompaniment.

Mitotic index in mouse embryos with 6-aminonicotinamide-induced and inherited cleft lip

Three types of cleft lip were studied histologically before and during lip formation in mouse embryos. C57BL/6 embryos observed near term following treatment with 6-aminonicotinamide (6AN) at gestation D9/12 (vp day = day 0) had 18% median cleft lip. Treated embryos observed at D10 and D11 showed retarded somite and nasal placode development. Sections at lip closure time showed marked reduction of medial and some reduction of lateral nasal processes, and the mitotic index was significantly reduced in the nasal area on D10 and D11 but less consistently in the neural area. 6AN-treatment on D10/8, caused 22% lateral cleft lip. Treated embryos showed initial retardation of somite and nasal placode development that became normal by D11/14. Sections showed reduction of the medial and lateral nasal processes, and less organized denser nasal ectoderm. The mitotic index was significantly reduced in the nasal and neural areas on D10 and D11. In crosses having the major gene mutation dancer (Dc) 20% of embryos had lateral cleft lip and potential cleft lip mutant embryos showed reduced lateral and medial nasal processes. Mitotic index was not reduced in the nasal area but it was in the neural area. The CL/Fr strain, with a predisposing face shape in which 26% of the embryos have cleft lip of multifactorial origin, had a mitotic index similar to that of C57BL/6 (0% cleft lip) at lip closure time, D11/14, and prominent medial nasal processes. It is postulated that 6AN-induced median cleft lip is due to reduced cell proliferation in and size of the medial nasal processes; 6AN-induced lateral cleft lip to reduced cell proliferation and reduced medial and lateral nasal processes and dancer lateral cleft lip to reduction of the medial nasals.

Intrauterine fatty acid accretion rates in human brain: implications for fatty acid requirements

Fatty acid components of infant brain were determined to assess fatty acid requirements for synthesis of structural lipids in brain tissue during the last trimester of development in the fetus. Quantitative fatty acid analysis of cerebellum, frontal and occipital brain lobes indicated rapid accretion of chain elongation and desaturation products during the last trimester of brain growth. Frontal and occipital brain lobes were similar in fatty acid content. Fatty acid accretion rates were determined by regression analysis of tissue fat components at varying gestational ages. Tissue accretion of saturated and omega-9 fatty acids, as well as total fatty acid content, paralleled increases in whole brain weight. Levels of linoleic (C18:2, omega-6) and linolenic (C18:3, omega-3) acids were consistently low in brain during the last trimester of development, while marked substantial accretion of long chain desaturation products, arachidonic (C20:4, omega-6) and docosahexaenoic (C22:6, omega-3) acids occurred. Accretion of individual fatty acids of cerebellum also reflected changes in tissue total fatty acid content, with exception of the levels of C18:3, omega-3 and its chain elongation products present in cerebellum during the last trimester. These developmental changes and estimates of fatty acid incorporation into whole brain and cerebellum are quantitatively relevant to estimation of fatty acid requirements of the low birth weight neonate.

Extrauterine fatty acid accretion in infant brain: implications for fatty acid requirements

Total fatty acid content of infant brain was determined to assess minimal fatty acid requirements for synthesis of structural lipids in brain tissue during the first 13 weeks of life. Fatty acid accretion rates were determined by regression analysis of tissue fat components at varying postnatal ages. Quantitative fatty acid analysis indicated that postnatal accretion of long-chain polyenoic fatty acids in cerebellum, frontal and occipital brain lobes initially appeared to lag behind the rate of increase in brain weight and brain fat content. After a 4-week period total long-chain fatty acids increased at a rate similar to the increase in brain weight. Accretion of individual fatty acids in cerebellum also reflected changes in tissue total fatty acid content. These developmental changes in fatty acid components of whole brain and cerebellum are quantitatively relevant to estimation of the minimal extrauterine fatty acid requirements of the human neonate.