Epidemiology, production losses, and control measures associated with an outbreak of avian influenza subtype H7N2 in Pennsylvania (1996-98).

An outbreak of H7N2 low-pathogenicity (LP) avian influenza (AI) occurred in a two-county area in Pennsylvania from December of 1996 through April of 1998. The outbreak resulted in infection of 2,623,116 commercial birds on 25 premises encompassing 47 flocks. Twenty-one (one premise with infection twice) of the twenty-five infected premises housed egg-laying chickens and one premise each had turkeys, layer pullets, quail, and a mixed backyard dealer flock. Despite dose proximity of infected flocks to commercial broiler flocks, no infected broilers were identified. Experimentally, when market age broilers were placed on an influenza-infected premise they seroconverted and developed oviduct lesions. The outbreak was believed to have originated from two separate introductions into commercial layer flocks from premises and by individuals dealing in sales of live fowl in the metropolitan New York and New Jersey live-bird markets. Source flocks for these markets are primarily in the northeast and mid-Atlantic areas, including Pennsylvania. Mixed fowl sold include ducks, geese, guinea hens, quail, chukar partridges, and a variety of chickens grown on perhaps hundreds of small farms. Infections with the H7N2 AI virus were associated with variable morbidity and temporary decreases in egg production ranging from 1.6% to 29.1% in commercial egg-laying chickens. Egg production losses averaged 4.0 weeks duration. Mortality ranged from 1.5 to 18.3 times normal (mean of 4.3 times normal). Duration of mortality ranged from 2 to 13 weeks (average of 3.9 weeks) in flocks not depopulated. Lesions observed were primarily oviducts filled with a mucous and white gelatinous exudates and atypical egg yolk peritonitis. Quarantine of premises and complete depopulation were the early measures employed in control of this outbreak. Epidemiological studies suggested that depopulation furthered the spread of influenza to nearby flocks. Thereafter, later control measures included quarantine, strict biosecurity, and controlled marketing of products.

Treatment of hypertension in pregnancy: effect of atenolol on maternal disease, preterm delivery, and fetal growth.

OBJECTIVE: To assess the impact of antihypertensive therapy initiated early in pregnancy on maternal and fetal outcomes. METHODS: A retrospective review of patients treated in early pregnancy with atenolol was conducted. Therapy was directed by measurements of cardiac output. Fetal growth was analyzed with reference to prior pregnancy outcome, treatment inconsistent with standards present at the end of the study period, and year of treatment. Data were analyzed by paired and unpaired t-test, analysis of variance for multiple comparisons, and linear regression. RESULTS: Two hundred thirty-five pregnancies at risk for preeclampsia were studied. Ten percent (n = 22) received additional therapy with furosemide; 20% (n = 48) with hydralazine. Six and one half percent had treatment inconsistencies. Fifty-five percent had greater than 100 mg of proteinuria at baseline. One patient developed severe preeclampsia. Only 2.1% delivered before 32 weeks; 4.7% delivered before 34 weeks. Low percentile birth weight was strongly associated with a prior pregnancy with intrauterine growth restriction (P = 0.001), treatment inconsistency (P <.001), and a pregnancy earlier in our treatment experience (P <.001). Percentile birth weight increased from the 20th at the beginning of the study period to the 40th by the end (P = 0.002). CONCLUSION: Early intervention with antihypertensive therapy was associated with a low rate of severe maternal hypertension and preterm delivery. The failure to adjust therapy in response to an excessive fall in cardiac output or increase in vascular resistance was associated with reduced fetal growth.

Low-dose, short-acting, angiotensin-converting enzyme inhibitors as rescue therapy in pregnancy.

OBJECTIVE: To assess the risks and potential benefits of low-dose angiotensin-converting enzyme (ACE) inhibitor treatment in pregnancies complicated by severe hypertension. METHODS: A retrospective review of pregnant women treated with ACE inhibitors was conducted. Hemodynamics before and after treatment were assessed by using Doppler technique to measure cardiac output. Data were analyzed by using the Wilcoxon signed-rank test. Maternal and neonatal outcomes were assessed by chart review and phone interview. RESULTS: Ten pregnancies were identified in which ACE inhibitor therapy was initiated in pregnancy for severe, unresponsive vasoconstricted hypertension; three were complicated by severe chronic hypertension, 4 by renal insufficiency, and 3 by severe preeclampsia. Treatment was limited to a low-dose, short-acting ACE inhibitor (captopril, 12.5 to 25 mg/day). Treatment was associated with an increase in cardiac output from 5.7 +/- 1.5 L/minute to 7.4 +/- 1.4 L/minute (P<.01) and a reduction in total peripheral resistance from 1770 +/- 670 to 1222 +/- 271 dyne. sec. cm(-5) (P =.005). No fetal or neonatal complications were observed. The probability of observing one or more adverse neonatal outcome in this sample, based on an assumed true risk of 5% and 10%, was calculated to be 12% and 50%, respectively. CONCLUSION: Low-dose captopril therapy was associated with improvement in maternal hemodynamics and, in cases complicated by severe hypertension and renal insufficiency, successful continuation of pregnancy. Fetal and neonatal complications were not experienced, but complication rates of 5-10% could have been missed because of the small number of exposed pregnancies.

Maternal hemodynamics and pregnancy outcome in women with prior orthotopic liver transplantation.

The aim of this study is to evaluate the hemodynamics and pregnancy outcome of women with prior orthotopic liver transplantation. Hemodynamic measurements by Doppler technique were performed on pregnant subjects with prior orthotopic liver transplantation. Maternal characteristics, renal function, pregnancy complications, delivery indications, delivery mode, and neonatal outcomes were evaluated. Six pregnancies occurred in 5 women after orthotopic liver transplantation at the University of Washington Medical Center (Seattle, WA) between 1991 and 1999. Four of the 6 pregnancies were complicated by chronic hypertension, fetal growth restriction, and preterm delivery. Two pregnancies had worsening hypertension characterized by vasoconstriction in the second trimester despite antihypertensive therapy. These 2 subjects were administered cyclosporine for maintenance immunosuppression and had greater mean arterial pressures preconception and in the first trimester than the other subjects. One of these pregnancies resulted in fetal demise at 25 weeks' gestation. The other subject was delivered at 28 weeks' gestation for nonreassuring fetal status and superimposed preeclampsia. All pregnancies were complicated by renal insufficiency; however, the 2 subjects with poor obstetric outcome had preconception serum creatinine levels greater than 1.5 mg/dL and creatinine clearances less than 40 mL/min. Pregnancies complicated by second-trimester vasoconstriction and moderate renal insufficiency are at risk for preeclamspia, fetal growth restriction, and fetal demise. Good obstetric outcome can occur in women with mild renal insufficiency and well-controlled chronic hypertension. Improved hypertensive control preconception may decrease the risk for preeclampsia and poor obstetric outcome.

Lobular carcinoma of the breast in an 85-year-old man.

The present study describes a case of the extremely rare histological picture of a lobular carcinoma of the male breast. The 85-year-old patient presented with a tumour in a very advanced stage. The results of genetic studies excluded Klinefelter's syndrome, but a new gene mutation affecting the BRCA1 gene (breast cancer gene 1) was found in the patient.

Novel alternatively spliced isoforms of the neurofibromatosis type 2 tumor suppressor are targeted to the nucleus and cytoplasmic granules.

We cloned novel splice variants Mer150, Mer151 and Mer162 of the neurofibromatosis 2 (NF2) tumor suppressor, which demonstrate a tissue-specific and development-specific expression pattern. Isoform Mer150 is created by cryptic splicing from exon 8 to 14 and represents an N-terminal truncation of 259 residues. Mer151 is characterized by in-frame splicing out of several exons and a modified C-terminus due to a frameshift in exons 13+14 and premature termination. Mer162 represents a head-to-tail isoform resulting from in-frame skipping of exons 5-16. As a common feature, the alpha-helical domain and a variable proportion of the ERM homology domain are spliced out in these isoforms. To investigate differences in subcellular localization, we expressed epitope-tagged cDNA constructs of the wild-type NF2 as well as of the three alternatively spliced transcripts in NIH 3T3 cells by nuclear microinjection or lipid-mediated transfection. Subcellular localization of Mer151 in filopodia and ruffling membranes was similar to the wild-type NF2. Mer151, however, was targeted to the nucleus, which was not observed for wild-type NF2, Mer150 or Mer162. A putative nuclear localization signal created by alternative splicing was identified in Mer151. In contrast to Mer151, Mer150 and Mer162 were not found in regions of the plasma membrane, but localized to a granular intracellular compartment. The results suggest that the recently described actin-binding domain in exon 10, but not the presence or absence of exons 2+3, is relevant for subcellular targeting. Although the NF2 protein is known as a cytoskeletal linker, additional functions in a cytoplasmic compartment and in the nucleus may exist.

Mosaicism for a full mutation and a normal size allele in two fragile X males.

Confirmation of the clinical diagnosis of fragile X syndrome by molecular tests is based on both the presence of a full mutation and methylation of the promotor region of the FMR1 gene. The mechanism leading to mosaic alleles of repeat number and the role of methylation in this process is still under discussion. We report two cases of males who show mosaic patterns for both number of CGG repeats and methylation status. In the first patient, a mosaic pattern of a normal allele of 34+/-1 CGGs, a borderline premutation/full mutation, and a full mutation was observed. The mother exhibited alleles of 30+/-1 and approximately 100 CGGs. The second patient was mosaic for a normal allele of 47+/-1 CGGs and a full mutation. His mother carried alleles of 40+/-1 and approximately 100 CGGs. Chromosomal analysis in the patients showed normal male karyotypes with no evidence that they had inherited both maternal X chromosomes. Furthermore, haplotyping excluded disomy of the repeat flanking region in these patients. So far, it is not clear whether the normal alleles in the patients, leukocytes of 34 and 47 CGGs, respectively, may be caused by the contraction of the maternal premutations of 100 CGGs or be caused by the deletion from the full mutation alleles.

Pulmonary hypertension in pregnancy: treatment with pulmonary vasodilators.

OBJECTIVE: To describe the clinical course of pregnancies complicated by pulmonary hypertension and treated with the pulmonary vasodilators nifedipine and prostacyclin. METHODS: Four pregnant women with pulmonary hypertension were treated with pulmonary vasodilators. Therapy with oral nifedipine and intravenous prostacyclin was guided by right pulmonary artery catheterization and Doppler measurements of cardiac output. RESULTS: Three of four women responded to vasodilator therapy and successfully completed their pregnancies. Two who conceived at least 1 year after successful treatment and normalized right ventricle function carried three uncomplicated pregnancies. The woman who did not respond died. Delay in diagnosis contributed to her outcome. Noninvasive measurement of cardiac output helped diagnosis of right ventricular failure and offered reassurance in women who remained compensated. Postpartum decompensation in one woman was characterized by a negative Starling response as central venous pressure increased from 4 to 11 mmHg. She responded positively to diuresis. CONCLUSION: Early diagnosis of pulmonary hypertension is critical. Volume overload postpartum might significantly contribute to decompensation. We recommend a year of successful therapy after a response to vasodilator therapy and near-normal right ventricular function before pregnancy is considered. In complicated pregnancies, women must balance the best estimate of risk with the value they put on pregnancy.

Prevention of preeclampsia: a randomized trial of atenolol in hyperdynamic patients before onset of hypertension.

OBJECTIVE: To determine if assessment of maternal hemodynamics could predict women at risk for the development of preeclampsia, if treatment directed at hemodynamic abnormalities before the onset of hypertension could prevent preeclampsia, and if mothers could be treated in a way that protects fetal growth. METHODS: A double-blinded, randomized controlled trial was conducted. Subjects were considered to be at risk for preeclampsia if their cardiac output was greater than 7.4 L/min before 24 weeks' gestation. Nulliparous and diabetic subjects at risk were treated with 100 mg of atenolol or placebo. Cardiac output was measured by Doppler technique. Inulin and para-aminohippurate clearances were performed. RESULTS: Treatment with atenolol reduced the incidence of preeclampsia from 5 of 28 (18%) to 1 of 28 (3.8%), (P = .04). Nulliparous women determined to be at risk for preeclampsia were similar to diabetic women at risk. Each was significantly heavier and had inulin and para-aminohippurate clearances greater than the control group. Treatment with atenolol was associated with infants weighing 440 g less than infants in the nulliparous placebo group, (P = .02). No effect on birth weight was seen in the diabetic patients. Mothers of the smallest infants who were treated with atenolol could be identified by unexpectedly large reductions in cardiac output. CONCLUSION: Measurement of cardiac output in the second trimester identified women at risk for preeclampsia. Treatment with atenolol decreased the incidence of preeclampsia. Nulliparous and diabetic women at risk for preeclampsia were similar with regard to maternal hemodynamics, maternal weight, and renal function. Treatment with atenolol was associated with reduced infant birth weight.

A randomized controlled trial of the effect of third-trimester calcium supplementation on maternal hemodynamic function.

OBJECTIVE: To determine the effect of third-trimester calcium supplementation on maternal hemodynamic function. METHODS: Pregnant women were randomized to receive either 1.5 g of elemental calcium or placebo for 6 weeks during the third trimester. Using Doppler technique, maternal hemodynamic characteristics were measured at baseline, at 2 hours after the first dose of study drug, and at the completion of 6 weeks. Serum, dietary, and urinary calcium levels were also assessed. Power calculation indicated the need to study ten subjects in each group to detect a 1.2 L (20%) difference in cardiac output between groups, assuming a mean of 6.2 +/- 1.0 L/minute. Data were analyzed by analysis of variance for repeated measures, Student t test, Mann-Whitney U test, and Fisher exact test. RESULTS: Twenty-three women enrolled, and 18 completed the study. There were no statistically significant differences in demographic characteristics or in serum, dietary, or urinary calcium levels between the two groups. There were also no statistically significant differences in hemodynamic function over time within the calcium supplementation or placebo group (P > .05; analysis of variance for repeated measures). After 6 weeks, there were no significant differences between the calcium- and placebo-treated subjects in any hemodynamic measurement. Specifically, there was not a statistically significant difference in cardiac output (7.3 +/- 1.2 L/minute versus 8.0 +/- 0.9 L/minute; P = .09) between the calcium- and placebo-treated groups. CONCLUSION: These findings suggest that third-trimester calcium supplementation does not significantly alter cardiac output. The mechanism by which calcium supplementation lowers blood pressure remains to be elucidated.

Mutational analysis and expression studies of the neurofibromatosis type 2 (NF2) gene in a patient with a ring chromosome 22 and NF2.

The case of a seriously disabled and retarded female patient with neurofibromatosis type 2 (NF2) is reported. She suffered from bilateral vestibular schwannomas, multiple intracranial meningiomas and neurinomas. The constitutional karyotype of the patient was 46, XX, r(22)/45,XX,-22. A constitutional G to A transition in the proximal 3' untranslated region of isoforms 1 and 2 was identified in the patient's NF2 gene and shown not to affect differential splicing or mRNA stability. The instability of the ring chromosome 22 with the associated loss of tumor suppressor genes on chromosome 22, in particular the loss of the NF2 gene, are assumed to have caused multiple tumorigenesis in this patient.

Subcellular localization and expression pattern of the neurofibromatosis type 2 protein merlin/schwannomin.

To elucidate the physiological function of the neurofibromatosis type 2 (NF2) tumor suppressor protein merlin/schwannomin, we studied the expression pattern and subcellular localization in human fibroblasts by Western blot analyses and immunofluorescence using a polyclonal antibody raised against the C-terminus of merlin. Three of the six merlin isoforms identified in this study (75 kDa, 58 kDa, 45 kDa) have been reported earlier and can be explained by alternative splicing. In addition, we detected higher molecular weight bands of about 110 kDa, 100 kDa and 84 kDa. Although the merlin bands of 100 kDa and 110 kDa may represent homo- or heterodimers, oligomerization due to formation of disulfide bonds was excluded. Furthermore, the isoforms of 84 kDa and 58 kDa were quantitatively extractable in Lubrol WX, indicating a localization in or close to the plasma membrane. The 45 kDa band, however, was not soluble in Lubrol WX compatible with a localization of this NF2 isoform in the endoplasmic reticulum. Applying confocal laser scanning microscopy, merlin was shown to be located in four subcellular compartments: (i) perinuclear in a compartment resembling endoplasmic reticulum, (ii) in ruffling membranes and at the leading edges, (iii) in filopodia, and (iv) at cell/substrate adhesion points. Codistribution of merlin and F-actin filaments was found in filopodia, ruffling membranes and at the insertion points of stress fibers at cell/substrate adhesion junctions as shown by phalloidin-rhodamine staining. Double immunofluorescence analyses of merlin and moesin revealed a colocalization in filopodia and ruffling membranes. The localization of merlin in the actin-rich cortical cytoskeleton corresponds to the ezrin-radixin-moesin family of proteins suggesting the NF2 protein to contribute to the regulation of cell growth by interaction with cytoskeleton-associated proteins.

Mosaicism of a microdeletion of 486 bp involving the CGG repeat of the FMR1 gene due to misalignment of GTT tandem repeats at chi-like elements flanking both breakpoints and a full mutation.

Although the majority of fragile-X patients demonstrate methylation and a much-expanded CGG repeat region in the 5'-untranslated region of exon 1 of the FMR1 gene, exceptional cases have been reported to be due to deletions. However, fine mapping of the deletion breakpoints is still lacking and so far the underlying mechanism is unknown. We identified a fragile-X patient mosaic for a full mutation and a microdeletion. The microdeletion spans 486 bp, involving 168 bp upstream from the CGG repeat region, the entire CGG repeat region, exon 1, and 138 bp of the first intron of the FMR1 gene. In contrast to previous reports, the 5' breakpoint does not fall into the hotspot region. The proximal breakpoint, 5'-GTGGTT/T-3', and the distal breakpoint, 5'-GTTGTT/GG-3', can be characterized as chi-like elements and are flanked by direct tandem repeats. Mosaicism of a full mutation and the microdeletion in the DNA of the patient's leukocytes indicates the mitotic origin of the microdeletion. Since the microdeletion allele is unmethylated, it can be concluded that it is not derived from the methylated full mutation but from an unmethylated premutational allele.

Two brothers with multiple congenital anomalies and mental retardation due to disomy (X)(q12-->q13.3) inherited from the mother.

We present the phenotypic, cytogenetic and molecular findings in two dysmorphic and mentally retarded brothers with disomy Xq12-->q13.3. The mother and the grandmother carry the same rearrangement of the X chromosome, which was interpreted as an inverted insertion of the segment (X)(q12-->q13.3) into Xq21.2. The X-inactivation-specific-transcript (XIST) is expressed in the probands mother but is absent in her son, confirming the hypothesis that X inactivation is realized only if two X inactivation centers reside on different X-chromosomes (trans-configuration). In the phenotypically normal mother the aberrant X chromosome was late replicating in all cells, indicating functional monosomy of the constitutional segment trisomy. The phenotype of the brothers is considered to be the consequence of a functional disomy Xq12-->q13.3. The trait combination observed in the brothers was compared with the spectrum of clinical and anthropological traits for proximal Xq disomy in males, elaborated by phenotype analyses of the available literature cases.

A PCR based X-chromosome inactivation assay for carrier detection in X-linked immunodeficiencies using differential methylation of the androgen receptor gene.

Carrier detection in X-linked immunodeficiencies (X-SCID, WAS, XLA) relies on the demonstration of non-random X inactivation patterns in blood cell lineages. Only a limited number of cells are available after cell separation methods. PCR-based techniques are therefore necessary to analyze active and inactive X chromosomes. Amplifying a polymorphic CAG repeat in the first exon of the androgen receptor gene after selective digestion of the active X chromosome with a methylation-sensitive restriction enzyme allows to distinguish between the paternal and maternal alleles and to identify their methylation status. DNA from B-, T-lymphocytes and total peripheral leukocytes of normal males, females and obligate carriers of X-linked immunodeficiencies were analyzed. The results of this PCR-based X inactivation assay are concordant with the standard methylation studies at the DXS255 locus using Southern blotting. This PCR assay provides a rapid and informative (heterozygosity > 90%) method in carrier detection of X-linked immunodeficiencies and other X-linked disorders, which show non-random X inactivation in cell lineages from the affected tissues.

The hemodynamic effects of isometric exercise during late normal pregnancy.

OBJECTIVE: Our study was designed to evaluate the hemodynamic effects of isometric exercise in late normal pregnancy. STUDY DESIGN: Study subjects were 10 healthy pregnant volunteers with uncomplicated singleton gestations between 25 and 36 weeks. Doppler methods were used to derive cardiac output, total peripheral resistance, and stroke volume before, during, and after a defined protocol of lower extremity isometric exercise. Hemodynamics and blood pressure were evaluated and compared. RESULTS: Mean arterial blood pressure and total peripheral resistance increased during the performance of isometric effort (mean blood pressure +/- SD was 78.9 +/- 7.3 to 97.5 +/- 8.6 mm Hg; total peripheral resistance +/- SD was 924 +/- 148 to 1153 +/- 18.3 dyne.sec.cm-5; p < 0.002 and p < 0.001, respectively). Cardiac output remained unchanged throughout the study period. CONCLUSION: In advanced normal pregnancy isometric exercise increases the mean arterial blood pressure by raising the total peripheral resistance.

Maternal hemodynamics and aortic diameter in normal and hypertensive pregnancies.

The aortic diameters of 89 normotensive pregnant women were compared with those of nine rigorously defined preeclamptic women and 59 women who required antihypertensive therapy. Over the course of normal pregnancy, the diameter increased significantly; it was larger in preeclamptic than in normotensive women throughout pregnancy. The aortic diameter in women with high-resistance hypertension was smaller than that in normotensive women and in those with high-output, low-resistance hypertension, but it was larger in women with low-resistance hypertension than in normotensive women. The aortic diameter increased after treatment of high-resistance hypertension with hydralazine, but decreased after treatment of high-output, low-resistance hypertension.

The effect of maternal hemodynamics on fetal growth in hypertensive pregnancies.

Seventy-six pregnancies in which hypertension complicated pregnancy before 28 weeks' gestation were studied. In 36, hemodynamics were characterized by increased cardiac output and low vascular resistance; in 32, hemodynamics were characterized by high resistance; in eight hemodynamics crossed over from high output to high resistance during pregnancy. High-resistance hypertension was associated with a mean birth weight 1058 gm less than that in the low-resistance group (p = 0.001). The reduction in birth weight was due to a 4-week difference in gestational age (p = 0.001) and lower percentile weights for gestational age, 19th versus 39th (p = 0.005). Infants in the crossover group had low percentile weights and a high rate of intrauterine fetal death.

Maternal hemodynamics in pregnancies complicated by hyperthyroidism.

The hemodynamics of six pregnant women with hyperthyroidism were studied before and after therapy. Cardiac output was measured by Doppler technique, and blood pressure by automated cuff. When compared with values in euthyroid pregnant women, blood pressure (83.6 mmHg, P less than .001), heart rate (89.2 beats per minute, P less than .001), cardiac output (11.2 L/minute, P less than .001), and stroke volume (123 mL, P less than .001) were significantly elevated. Total peripheral resistance was significantly reduced (609 dyne.second.cm-5, P less than .001). Despite normalization of thyroid indices after therapy, cardiac output remained markedly elevated (9.7 L/minute, P less than .001) and vascular resistance remained reduced (708 dyne.second.cm-5, P = .01). Although the hemodynamics of pregnant thyrotoxic women normalize with therapy, they remain significantly hyperdynamic.