Overexpression of METAL TOLERANCE PROTEIN8 reveals new aspects of metal transport in Arabidopsis thaliana seeds

METAL TOLERANCE PROTEIN8 (MTP8) of Arabidopsis thaliana is a member of the CATION DIFFUSION FACILITATOR (CDF) family of proteins that transports primarily manganese (Mn), but also iron (Fe). MTP8 mediates Mn allocation to specific cell types in the developing embryo, and Fe re-allocation as well as Mn tolerance during imbibition. We analysed if an overexpression of MTP8 driven by the CaMV 35S promoter has an effect on Mn tolerance during imbibition and on Mn and Fe storage in seeds, which would render it a biofortification target. Fe, Mn and Zn concentrations in MTP8-overexpressing lines in wild type and vit1-1 backgrounds were analysed by ICP-MS. Distribution of metals in intact seeds was determined by synchrotron µXRF tomography. MTP8 overexpression led to a strongly increased Mn tolerance of seeds during imbibition, supporting its effectiveness in loading excess Mn into the vacuole. In mature seeds, MTP8 overexpression did not cause a consistent increase in Mn and Fe accumulation, and it did not change the allocation pattern of these metals. Zn concentrations were consistently increased in bulk samples. The results demonstrate that Mn and Fe allocation is not determined primarily by the MTP8 expression pattern, suggesting either a cell type-specific provision of metals for vacuolar sequestration by upstream transport processes, or the determination of MTP8 activity by post-translational regulation.

Genetic variation at a pig serum protein locus, Po-2 and its assignment to the Phi, Hal, S, H, Pgd linkage group

Two-dimensional agarose gel (pH 5.4)-polyacrylamide gel (pH 9.0) electrophoresis of pig serum samples revealed a new serum protein (postalbumin-2, PO-2) polymorphism. Family data supported the hypothesis that the three PO-2 phenotypes observed were controlled by two codominant, autosomal alleles (Po-2F and Po-2s) at a single locus. The frequency of Po-2F in Swedish Landrace and in Swedish Yorkshire breeds was estimated at 0.74 and 0.65, respectively. Evidence was presented for close genetic linkage between Po-2 and the red cell phosphohexose isomerase locus (Phi). A recombination frequency of 3.2% was obtained from double backcross material. Data obtained in a Danish Landrace material showing linkage between the Po-2 locus and the H blood group locus, the Pgd locus and Hal (locus for halothane sensitivity) are also given. A total of seven recombinants were observed. They show that Po-2 is a new locus in a previously established linkage group. The likely sequence of the loci is: Phi, Hal, S, H, Po-2, Pgd.

Haemolytic anaemia in Basenji dogs. 2. Partial deficiency of erythrocyte pyruvate kinase (PK; EC 2.7.1.40) in heterozygous carriers

Congenital nonspherocytic haemolytic anaemia (HA) in dogs of the Basenji breed is inherited as a simple, autosomal recessive trait. Previous results of pyruvate kinase (PK) assays suggest a causal relationship between the anaemia and PK deficiency in erythrocytes. In the present investigation assays of this enzyme have been performed on haemolysates from 45 Basenji dogs, comprising 3 anaemic and 42 non-anaemic individuals of which 13 were known heterozygotes. The PK activity in haemolysates from the 42 non-anaemic dogs exhibited a bimodal distribution corresponding to the genotypic classes: heterozygotes and normal homozygotes. The results indicate that heterozygotes have a partial, detectable enzyme deficiency, not reflected in clinical disease, and thus give evidence of a gene dosage effect in agreement with observations in man. The proposed genotypes PK PK, PK pk and pk pk refer to normal homozygotes, heterozygotes, and anaemic individuals, respectively. The findings strengthen the genetic hypothesis of recessiveness of the anaemia by direct detection of heterozygosity of parents of affected individuals. Moreover, the results are of value in comparative studies and they have practical application in connection with eradication programmes.

Bacterial contamination and over-dilution of commercial infant formula prepared by HIV-infected mothers in a Prevention of Mother-to-Child Transmission (PMTCT) Programme, South Africa

To examine the safety of formula feeds used by mothers participating in a Prevention of Mother-to-Child Transmission (PMTCT) programme, contents of 94 feeding bottles collected at a PMTCT-clinic were analysed. An additional 17 samples were taken from already prepared feeds during home visits, as well as 21 samples from bottles prepared under observation. Living conditions and educational levels were overall good and mothers had been counselled on safe formula preparation. Samples were analysed for faecal bacteria, using Escherichia coli and Enterococcus sp. as indicators. Protein concentration was used as an indicator of concentration of the formula. Out of 94, 63 (67%) of samples obtained at the clinic and 13/16 (81%) of available home samples were contaminated with faecal bacteria, compared to 8/21 (38%) of those prepared under observation. Out of 94, 58 (62%) of the clinic samples containing E. coli and 23/94 (24%) of those containing Enterococcus sp. were contaminated with more than the US government recommended limit of 10 CFU/ml. Out of 94, 26 (28%) of samples obtained at the clinic, 8/17 (47%) of home samples and 3/21 (14%) of those prepared under observation were over-diluted, compared to standards. Many mothers did not follow recommended practices in preparing and feeding the bottles.

Office prenatal formula advertising and its effect on breast-feeding patterns

OBJECTIVE

To compare the effect of formula company-produced materials about infant feeding to breast-feeding promotion materials without formula advertising on breast-feeding initiation and duration.

METHODS

Five hundred forty-seven pregnant women were randomized to receive either formula company (commercial; n = 277) or specially designed (research; n = 270) educational packs about infant feeding at their first prenatal visit. Feeding method was determined at delivery. Breast-feeding duration of the 294 women who chose to breast-feed was ascertained at 2, 6, 12, and 24 weeks. Survival analyses were used to evaluate continuous outcomes, and chi2 and logistic regression analyses were used to evaluate discrete outcomes.

RESULTS

Breast-feeding initiation (relative risk [RR] 0.93, 95% confidence interval [CI] 0.61, 1.43) and duration after 2 weeks (hazard ratio 1.19, 95% CI 0.86, 1.64) were not affected. Women in the commercial group were more likely to cease breast-feeding before hospital discharge (RR 5.80, 95% CI 1.25, 54.01) and before 2 weeks (adjusted odds ratio [OR] 1.91, 95% CI 1.02, 3.55). In subgroup analyses, women with uncertain goals for breast-feeding or goals of 12 weeks or less experienced shortened exclusive (hazard ratio 1.53, 95% CI 1.06, 2.21), full (hazard ratio 1.70, 95% CI 1.18, 2.48), and overall (hazard ratio 1.75, 95% CI 1.16, 2.64) breast-feeding duration when exposed to the commercial intervention.

CONCLUSION

Although breast-feeding initiation and long-term duration were not affected, exposure to formula promotion materials increased significantly breast-feeding cessation in the first 2 weeks. Additionally, among women with uncertain goals or breast-feeding goals of 12 weeks or less, exclusive, full, and overall breast-feeding duration were shortened. Educational materials about infant feeding should support unequivocally breast-feeding as optimal nutrition for infants; formula promotion products should be eliminated from prenatal settings.

Health counseling in adolescent preventive visits: effectiveness, current practices, and quality measurement

Most morbidity and mortality among adolescents results from their participation in health-compromising behaviors. Recent guidelines for clinical adolescent preventive services recommend that primary care clinicians routinely screen for and counsel adolescents about these behaviors, identify and address related social, psychological, and biologic factors. Office-based counseling can influence adult health behaviors, but little is known about the effectiveness of office-based counseling for adolescents. In this review we: (a) evaluate available information about the effectiveness of office-based health counseling to improve outcomes; (b) report what is known about the health counseling adolescents receive from primary care clinicians; and (c) critically review different approaches that have been, or might be, used to measure the content and quality of health counseling provided during adolescent medical visits. With the emphasis on accountability in the current health care environment, evidence supporting the effectiveness of counseling is needed to justify investment in this aspect of clinical adolescent preventive services. Challenges to studying the effectiveness of health counseling include the lack of well-defined theory-based models for adolescent office-based counseling, the complexity of measuring counseling quality, and the many factors that influence adolescent outcomes. Reliable and valid measures of counseling quality are needed both to study and to ensure the quality of counseling received by adolescents. No single measure can be expected to fully capture counseling quality, although patient self-report deserves further development.

Lung injury leading to respiratory distress syndrome in young Dalmatian dogs

A progressive pulmonary disease resulting in severe respiratory failure and death in an average of 3 weeks was diagnosed in 11 young Dalmatian dogs. The dogs were from 4 litters, all genetically related by a common ancestor. The initial clinical signs were tachypnea and noisy respiration. Respiratory distress developed shortly before death and was characterized by strenuous and rapid respirations, along with cyanosis and vomiting. On blood gas analysis, there were severe arterial hypoxemia, hypercapnia, and marked alveolar-arterial oxygen difference. Radiographically, a diffuse pattern of alveolar, interstitial, and peribronchial densities was observed in the lungs. Most dogs developed pneumomediastinum and gastroesophageal intussusception in the terminal phase of the disease. There was no response to treatment with antibiotics, corticosteroids, diuretics, or oxygen. At necropsy, the lungs were wet, heavy, and relatively airless. Absence of 1 kidney in 2 dogs and severe internal hydrocephalus in 2 dogs were additional necropsy findings. Pulmonary histopathology included metaplasia and atypia of the alveolar and bronchiolar epithelium, a nonpurulent inflammatory reaction characterized mainly by mononuclear cells and macrophages, eosinophilic hyaline membrane formation, and focal pulmonary fibrosis. The histological manifestations were typical of acute lung injury. Clinically, the findings were consistent with adult respiratory distress syndrome (ARDS), except for the relatively long course. No known risk factors for ARDS, such as trauma, toxin exposure, infection, or endotoxemia could be identified. The relationship of the other abnormalities (ie, renal aplasia, hydrocephalus) to the pulmonary disease also remains obscure. An inherited defect is suspected, because segregation analysis of the 4 litters suggests autosomal recessive inheritance.

Thyroid cancer among persons given X-ray treatment in infancy for an enlarged thymus gland

A cohort of 2,657 infants in Rochester, New York, who were given x-ray treatment for a purported enlarged thymus gland, along with 4,833 siblings, have been followed by mail surveys through about 1986, which represents an average of 37 years of follow-up, to determine their incidence of thyroid cancer. Estimated thyroid doses ranged from 0.03 to > 10 Gy, with 62% receiving > 0.5 Gy. There were 37 pathologically diagnosed thyroid cancers in the irradiated group and five in the sibling controls. The dose-response relation was essentially linear, with no evidence of an additional dose-squared component. The estimated relative risk at 1 Gy was 10 (90% confidence interval 5-23). Thyroid cancer rates were elevated even at low doses; i.e., a dose-response analysis over the range of 0-0.3 Gy showed a significant positive slope. The risk ratio was declining over time but was still highly elevated to at least 45 years after irradiation. An examination of potential risk factors showed that older age at first childbirth was significantly associated with thyroid cancer risk. An evaluation of interactions between possible risk factors and radiation suggested that Jewish subjects and women with older ages at menarche or at first childbirth were at greater risk for radiogenic thyroid cancer.

Benign thyroid adenomas among persons X-irradiated in infancy for enlarged thymus glands

Thyroid adenoma incidence in a cohort of 2657 infants given X-ray treatment for a supposedly enlarged thymus gland, along with 4833 unirradiated siblings, has been ascertained for an average of 37 years since irradiation. Estimated thyroid doses ranged from 0.03 to > 8 Gy, with 62% receiving < 0.5 Gy. After excluding 4 adenoma cases with concurrent or previous thyroid cancer, there were 86 cases with pathologically diagnosed thyroid adenomas in the irradiated group and 11 in the sibling controls. The estimated excess relative risk (ERR) was 6.3 per gray (90% CI = 3.7, 11.2). Once the dose group with > or = 6 Gy, which was producing downward curvature in the dose-response function, was removed, the curve was compatible with linearity and the ERR was 7.8 per gray. Thyroid adenoma rates were elevated even at low doses: the lowest dose group (< 0.25 Gy) showed a significant elevation in risk. The relative risk appeared to be constant over time and was comparable for both sexes. Excess adenoma risk was observed in the irradiated group to the maximum follow-up interval of about 50 years. A number of potential risk factors for thyroid adenoma were examined both as risk factors in their own right and as modifiers of the radiogenic risk. Parity and use of hormones in relation to menopause were significantly associated with thyroid adenoma risk in women, while education, Jewish origin, history of hyperthyroidism or hypothyroidism, and family history of cancer were also adenoma risk factors in both sexes. An examination of interactions between possible risk factors and radiation suggested that women with a history of oral contraceptive use or hysterectomy and persons with a family history of cancer may have greater risk (per unit dose) of radiogenic thyroid adenomas than their counterparts.

Use of the automatic external defibrillator in homes of survivors of out-of-hospital ventricular fibrillation

This 57-month study evaluated the use of automatic external defibrillators (AEDs) in the homes of high risk cardiac patients (survivors of out-of-hospital ventricular fibrillation [VF]). The goal was to determine the utility of these devices by trained lay persons in actual cardiac arrest episodes. Ninety-seven survivors of out-of-hospital VF were enrolled in the study; 59 patients received AEDs, and 38 patients served as a control group. During the study period, 7 deaths occurred in the hospital without preceding out-of-hospital cardiac arrest or from noncardiac causes. There were 14 out-of-hospital cardiac arrests, 10 in the AED group and 4 in the control group. There was 1 long-term survivor in the control group. In the AED group, among the 10 cardiac arrests for which the device was available, it was used in 6. Only 2 patients were in VF; 1 was resuscitated with residual neurologic deficits and survived several months. This study observed a small potential for AEDs to save high risk patients.

Home placement of automatic external defibrillators among survivors of ventricular fibrillation

We performed a study to determine how many patients at highest risk for an episode of ventricular fibrillation (those who have already survived such an event) are potential candidates for automatic external defibrillator placement and accepting of such a device in their homes. All VF survivors in King County, Washington, during 1984 were screened for possible enrollment in the study. Of 95 survivors of out-of-hospital VF, 63 (66%) were eligible and of 47 patients approached, 38 (81%) agreed to participate in the study. These findings suggest that approximately half (product of 66% and 81% acceptance rate equals 53%) of VF survivors potentially could use automatic external defibrillators.

Automatic external defibrillators: clinical, training, psychological, and public health issues

Automatic external defibrillators (AEDs) will be used by spouses, family members, emergency first-responders, and the citizenry at large. Such use, however, raises a number of clinical, training, psychological, and public health issues. Clinical issues: Is cardiac arrest to be verified by the operator or the AED? Second verification systems, such as breath detectors, produce errors of omission, but greatly expand the pool of potential users. The relative merits of high sensitivity and low specificity in arrest verification must be defined by clinicians relative to the setting and the potential users. AEDs require cessation of basic CPR during their assessment periods; clinicians must determine the tradeoff between long interruption of basic life support and much earlier delivery of countershocks. Training issues: Criteria for those to be trained include consideration of who the patient will be and who the AED operator might be. AEDs pose a familiar adult education problem, that is, acquisition of a new psychomotor skill and retention of that skill for long periods before performance. What are the best teaching techniques? Currently available AEDs have different designs for device-operator interaction. Which design is most likely to assure proper performance during an actual arrest? Psychological issues: What are the psychological effects of learning about, living with, and eventually using an AED? The development of the automatic external defibrillator constitutes the most recent attempt to achieve early defibrillation of patients in cardiac arrest. The potential public health effect of such devices is enormous.

Hemophilia in dogs, with special reference to hemophilia A among German shepherd dogs in Denmark. II: Clinical study, therapy and prophylaxis

Clinical data, pedigrees, screening tests (APTT, PT and TT) and specific tests (VIII:C, VIIIC:Ag, VIIIR:Ag and IX:C) were used to diagnose hemophilia A (classical hemophilia) in two colonies of German Shepherd dogs in Denmark. The affected individuals in both colonies were males, and they descended from a common, hemophilic ancestor. All observations were in accordance with X-linked, recessive inheritance. Therapeutic and prophylactic measures are discussed.

Hemophilia in dogs, with special reference to hemophilia A among German shepherd dogs in Denmark. I: Pathophysiology, laboratory tests and genetics

A review is given of the history and distribution of hemophilia in dogs. The current knowledge of Factor VIII relative to hemophilia A and von Willebrand's Disease is presented. The tests required for distinguishing between hemophilia A, hemophilia B, von Willebrand's Disease, and various disorders caused by other factor defects in the coagulation cascade are described. X-linked, recessive inheritance of hemophilia A is illustrated in genealogical diagrams. The precautions required in connection with blood sampling for diagnostic tests are emphasized.

Functional additive effect of H blood group alleles on carcass length in Danish landrace pigs

Previous investigations have revealed statistically significant associations between H blood group genotypes and carcass length in Danish Landrace pigs. The same data were subjected to an analysis aimed at a genetic interpretation of the associations. The regression of the average carcass length (in cm) on the average number of H- alleles for individuals within three genetically characterized classes was 0.725 and the correlation coefficient was 0.995. The results indicate that the associations can be interpreted as being due to an additive effect of the H blood group alleles on carcass length. The additive effect is designated as being functional. A similar effect is expected with respect to any allelic pair exhibiting linkage disequilibrium with alleles at the H locus.