Biomedical subjects

M Wallach

Publications and source records attributed to M Wallach.

At least 19 recordsLinked to original sources

PubMed2004

Infant colic and feeding difficulties.

AIMS: To examine the relation between colic and feeding difficulties and their impact on parental functioning for a primarily clinic referred sample. METHODS: Forty three infants (and their mothers) were enrolled between 6 and 8 weeks of age. Infants were divided into two groups, colic (n = 19) and comparison (n = 24), based on a modified Wessel rule of three criteria for colic. Families were assessed at two visits; one occurred in the laboratory and one occurred in a paediatric radiology office. Outcome measures included the clinical assessment of infant oral motor skills, behavioural observation of mother-infant feeding interactions, maternal questionnaires on infant crying, sleeping and feeding behaviours, and the occurrence of gastro-oesophageal reflux (GOR) in the infants using abdominal ultrasound. RESULTS: Infants in the colic group displayed more difficulties with feeding; including disorganised feeding behaviours, less rhythmic nutritive and non-nutritive sucking, more discomfort following feedings, and lower responsiveness during feeding interactions. Infants in the colic group also had more evidence of GOR based on the number of reflux episodes on abdominal ultrasound as well as maternal report of reflux. Mothers in the colic group reported higher levels of parenting stress. CONCLUSIONS: Results provide the first systematic evidence of feeding problems in a subgroup of infants with colic. Data also illustrate the impact of these difficulties on parental and infant functioning. The association between feeding difficulties and colic suggests the potential for ongoing regulatory problems in infants presenting with clinically significant colic symptoms.

Adult↗

PubMed2001

Effects of continuous positive airway pressure on diaphragm dimensions in preterm infants.

OBJECTIVE: The use of continuous positive airway pressure (CPAP) in the treatment of a variety of neonatal respiratory conditions is associated with improvement in arterial oxygen saturation, decreased long-term morbidity, and an overall improvement in infant survival. We reasoned that CPAP might change diaphragm length by increasing end-expiratory lung volume (EEV), but the extent to which this occurs has not been assessed. This study was designed to evaluate (1) the extent to which CPAP shortens the diaphragm and (2) the relationship of diaphragm thickness and excursion with arterial oxygen saturation in spontaneously breathing preterm infants. STUDY DESIGN: Ultrasonographically (7.5 MHz transducer), diaphragm thickness and diaphragm excursion were measured in 12 stable preterm infants [birth weight 1120+/-225 g (mean+/-SD); study weight 1187+/-400 g; gestational age 29+/-1 week; postnatal age 10+/-8 days, six males and six females] at three levels of CPAP [1-3, 4-6, and 7-9 cm H(2)O (low, medium, and high, respectively)]. Heart rate, respiratory rate, and arterial oxygen saturation were simultaneously recorded. RESULTS: We found that diaphragm thickness and arterial oxygen saturation increased, and diaphragm excursion decreased significantly at higher levels of CPAP (p<0.05). The shortening of the diaphragm at the high levels of CPAP, calculated from the increase in diaphragm thickness, was 36% at EEV and 31% at end-inspiratory volume. CONCLUSION: We conclude that the improvement in arterial oxygen saturation with CPAP occurred despite the presence of a shorter and a less mobile diaphragm, and that other physiological and mechanical alterations accompanying the application of CPAP offset its negative effects on diaphragm function. We speculate that with excessive CPAP, however, diaphragm dysfunction along with the previously described adverse hemodynamic effects may outweigh its benefits on oxygenation.

Diaphragm↗

PubMed2001

Diaphragm dimensions of the healthy preterm infant.

BACKGROUND: The diaphragm is the major inspiratory muscle in the neonate; however, human neonatal diaphragm development has not been extensively studied. We hypothesized that diaphragm thickness (t(di)) would be positively related to postmenstrual age (PMA), body weight, body length, head circumference, and nutritional intake. OBJECTIVES: To evaluate the evolution of diaphragm growth and motion in the healthy, preterm infant. METHODS: We used ultrasound to measure t(di) at the zone of apposition to the rib cage and diaphragm excursion (e(di)) during inspiration. Thirty-four stable, preterm infants (16 males and 18 females) between 26 and 37 weeks' PMA were studied during quiet sleep at weekly intervals until the time of discharge or transfer from the neonatal intensive care unit. All infants were clinically stable and not receiving ventilatory support. RESULTS: We found that 1) t(di) increased from 1.2 +/- 0.1 to 1.7 +/- 0.05 mm between 26 to 28 and 35 to 37 weeks' PMA; 2) t(di) was positively correlated with PMA (r = 0.40), body weight (r = 0.52), body length (r = 0.53), and head circumference (0.49), but not with postnatal nutritional intake (r = 0.09); and 3) e(di) decreased with increasing PMA. CONCLUSIONS: Our findings suggest that diaphragm development in premature infants scales with body dimensions. We speculate that the increase in t(di) with age is likely attributable to increased diaphragm muscle mass, and the reduced e(di) with age may be resulting from a reduction in chest wall compliance.

Analysis of Variance↗

PubMed1999

Patient classification systems, Part 2: The third generation.

In Part 1 (July/August 1999), the authors reviewed the evolution of patient classification systems over four generations of progress, discussed issues of system credibility, and presented a third-generation patient classification system (3PCS) to address the shortcomings of current systems. In this article, an actual implementation of a 3PCS is presented by the authors in collaboration with system users. The development, implementation, and evaluation of the 3PCS, as well as the overall advantages, are discussed. Finally, the authors share lessons learned and thoughts for the future.

Holistic Health↗

PubMed1997

The importance of transmission-blocking immunity in the control of infections by apicomplexan parasites.

Transmission-blocking immunity may have great potential for use in the control of diseases caused by apicomplexan parasites. In this review I will describe our work on the application of transmission-blocking immunity to the control of the Eimeria parasite and compare our results to those working on transmission-blocking immunity against Cryptosporidium and Plasmodium. Eimeria causes the disease known as coccidiosis in domestic animals. Coccidiosis is particularly problematic in the chicken industry, mainly due to the crowded rearing conditions under which chicks are raised. In our work we identified, isolated and characterized 3 major gametocyte antigens (230 kDa, 82 kDa and 56/54 kDa) of Eimeria maxima. We used these native glycoproteins to immunize laying hens that, via the egg yolk, provide large amounts of transmission-blocking maternal antibodies to offspring chicks. We demonstrated that hatchlings from immunized hens shed 60-80% fewer oocysts (i.e. the infective stage of the life-cycle of Eimeria) than those from control hens. Such a reduction in oocyst output acts to significantly reduce parasite numbers in the litter of chicks raised in floor pens. This reduction in oocyst output is comparable to that seen using the most effective coccidiostat drugs and is probably sufficient to control coccidiosis under field conditions. Based on our results together with those of other groups working on transmission-blocking immunity against Cryptosporidium and Plasmodium, it appears that this immunological approach holds great promise for the control of apicomplexan parasites that cause diseases in both animals and man.

Animals↗

PubMed1996

Characterization of a 14 kDa oocyst wall protein of Eimeria tenella and E. acervulina.

We have extracted a protein of 14 kDa from purified oocyst walls of several Eimeria species. Polyclonal antibodies were raised in rats against the 14 kDa proteins of E. acervulina and E. tenella. On immunoblots these antisera reacted in a highly specific manner with the homologous 14 kDa antigens, but not with heterologous antigens. In addition, specific binding of the two antisera to oocyst wall fragments of E. acervulina and E. tenella was demonstrated by immunofluorescence. Partial amino-terminal sequences comprising 20 amino acid residues were obtained from the 14 kDa oocyst wall proteins of E. acervulina and E. tenella. They are characterized by an abundance of amino acids containing hydroxyl groups in their side chains (serine, tyrosine, threonine). Binding of the oocyst wall protein of E. tenella by peanut agglutinin indicates the presence of O-linked carbohydrates.

Amino Acid Sequence↗

PubMed1995

Eimeria maxima gametocyte antigens: potential use in a subunit maternal vaccine against coccidiosis in chickens.

Affinity-purified gametocyte antigens (APGA) from Eimeria maxima, emulsified in Freund's adjuvant, were injected intramuscularly into breeding hens on two or three occasions. As a result, progeny of the immunized hens were partially immune to infection with E. maxima, Eimeria tenella and Eimeria acervulina (with a reduction in total oocyst output of 45-63% as compared with progeny of untreated hens). Thus, APGA in Freund's adjuvant appears to have great potential as part of a maternally applied vaccine against coccidiosis. The ability of APGA to induce partial cross-species protection is most probably due to the existence of conserved epitopes in the different species as indicated by comparative Western blots of E. maxima and E. tenella. Surprisingly, Freund's adjuvant by itself also induced significant levels of maternal immunity to coccidiosis (with a 12-35% reduction in oocyst output in the progeny). In contrast to the purified antigens or Freund's alone, crude extracts from gametocytes as well as other developmental stages, induced little if any significant maternal immunity despite provoking the production of large amounts of parasite-specific IgG, including antibodies to APGA. This result indicates that a successful maternal vaccine against coccidiosis requires, in addition to good recognition of protective antigens, the exclusion of irrelevant antigens from the vaccine preparation.

Animals↗

PubMed1994

Maternal transfer of antibodies induced by infection with Eimeria maxima partially protects chickens against challenge with Eimeria tenella.

Infection of breeding hens with Eimeria maxima induces production of Eimeria-specific IgG antibodies which are transferred to hatchlings via the egg yolk and confer a high degree of maternal immunity against homologous challenge and partial immunity to infection with another important species, Eimeria tenella. As an example, in an experiment using hatchlings from eggs collected between days 28 and 39 after infection of the hens with 20,000 sporulated E. maxima oocysts, control chicks (challenged with 100 sporulated oocysts) excreted 6.8 +/- 1.2 million (mean +/- S.E., n = 10) or 5.8 +/- 1.2 million (n = 8) oocysts of E. maxima or E. tenella, respectively, compared to 0.9 +/- 0.4 million (n = 5) E. maxima oocysts or 2.2 +/- 0.4 million (n = 9) E. tenella oocysts excreted by hatchlings of infected hens. This represents an 87% reduction in oocyst excretion with regard to E. maxima and a 62% reduction in oocyst excretion with regard to E. tenella in the progeny of the infected hens. In another experiment, eggs were collected from days 28 to 37 and again from days 114 to 123 after infection of the hens with E. maxima and hatchling oocyst excretion rates were 82% and 62%, respectively, reduced for E. maxima and 43% and 41%, respectively, reduced for E. tenella in the progeny of hens infected with E. maxima compared to the progeny of uninfected hens. ELISA and Western blot analyses of maternally-derived IgG revealed a high degree of cross-reactivity to antigens of E. maxima and E. tenella.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Eimeria maxima: ELISA and western blot analyses of protective sera.

Infection of chickens with Eimeria maxima induces the production of parasite-specific antisera which can be used passively to protect naive chickens against infection. Globulin fractions of these antisera can also be used passively to protect chickens. Similarly, intramuscular injection of soybean lectin affinity purified gametocyte antigens of E. maxima in Freund's Complete Adjuvant induces production of antibodies which are maternally transferred and thereby protect hatchlings against E. maxima. ELISA analyses of serum pools having varying protective capacities revealed good correlations between passive protection and levels of anti-unsporulated oocyst, anti-sporulated oocyst, anti-merozoite and anti-gametocyte antibodies. Western blotting demonstrated that the sera mainly recognized a number of high molecular weight antigens in all developmental stages and that the intensity of the reactions reflected the degree of protection induced by the sera. Sera from birds immunized with gametocyte antigens also recognized high molecular weight antigens from all the developmental stages, with banding patterns remarkably similar to those observed for sera from infected birds. Taken together, these results indicate that antibodies can protect against infection with E. maxima and these antibodies may recognize and act against asexual and/or sexual stages of the parasite.

Animals↗

PubMed1994

Maternal transmission of immunity to Eimeria maxima: western blot analysis of protective antibodies induced by infection.

Infection of breeding hens with Eimeria maxima induces production of parasite-specific antibodies which are transferred, via the egg yolk, to hatchling chicks. These antibodies (immunoglobulin G) are highly protective, mediating up to a 97% reduction in oocyst excretion in challenged hatchlings. However, the degree of maternally derived immunity transferred by the hens to their offspring declines with increasing time after infection of the hens. This decline in immunity is directly related to declining immunoglobulin G titers. However, sera from highly protected hatchlings recognize only a very few E. maxima proteins on Western blots (immunoblots). In particular, a 230-kDa protein band is outstanding for its association with maternally derived immunity to E. maxima in hatchlings. This band was excised from a sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) preparative gel of crude merozoite protein extract. The SDS-PAGE cutout was emulsified in Freund's adjuvant and injected, intramuscularly, into six breeding hens on two occasions, 2 weeks apart. Eggs were collected from these hens 28 to 39 days after the second injection, and the hatchlings from these eggs were challenged with 150 sporulated oocysts of E. maxima. Subsequent oocyst excretion in these hatchlings was, on average, 54% lower than oocyst excretion by control chicks but only 37% lower (significant at P < 0.05) than that by chicks from hens sham immunized with Freund's adjuvant. The latter result is apparently due to the ability of the adjuvant to induce production of antibodies which recognize Eimeria spp. and thereby transfer some degree of protection to hatchlings. These experiments indicate that protective, maternally derived immunoglobulin G antibodies may be useful for the identification of putative anticoccidial vaccine candidates.

Animals↗

PubMed1994

Maternal transmission of immunity to Eimeria maxima: enzyme-linked immunosorbent assay analysis of protective antibodies induced by infection.

Vaccination of broiler chickens against Eimeria infection is problematic because of the need to ensure that birds are protected from the time of hatching. We have therefore investigated the feasibility of protecting hatchling broilers via maternal transfer of protective antibodies from hens to their offspring. Oral infection of broiler breeder hens with 20,000 sporulated Eimeria maxima oocysts caused production of antibodies which were passed into the egg yolk and subsequently to hatchlings. The level of specific antibodies in the yolks to unsporulated oocysts, sporulated oocysts, merozoites, and gametocytes was assessed by enzyme-linked immunosorbent assays. The levels in yolks of antibodies to all developmental stages peaked 3 to 4 weeks after infection of the hens. Groups of 10 hatchlings were challenged at 3 days of age by oral infection with 100 sporulated E. maxima oocysts. In the first experiment, the mean 4-day (days 6 to 9 post-infection) total number of oocysts excreted in the feces of chicks from eggs collected 3 weeks after infection of the hens was (0.6 +/- 0.4) x 10(6) (mean +/- standard error) compared with (9.9 +/- 1.4) x 10(6) for the progeny of uninfected hens, which represents a greater than 90% reduction. However, oocyst excretion by chicks from eggs collected 7 or 8 weeks after infection of the hens was only 47 or 68% lower than control values, reflecting declining levels of protective antibodies. In a second experiment, in which the hens were somewhat older and pretreated by intramuscular injection of saline in the emulsifying agent, Arlacel A, the period for which protective antibodies were transferred to hatchlings was prolonged. Thus, oocyst excretion by challenged hatchlings from eggs collected for an 8-week period after infection of the hens was more than 90% lower than oocyst excretion by control chicks, and even hatchlings of eggs collected 19 weeks after infection of the hens showed a 60% reduction in oocyst output. In both experiments, the levels of immunoglobulin G (IgG) antibodies to all developmental stages in yolks or hatchling sera were very strongly correlated with maternally derived immunity to E. maxima. In contrast, parasite-specific IgM or IgA was not detectable, either in egg yolk or egg white. These results demonstrate the ability of IgG antibodies to protect against E. maxima in poultry, thus raising the possibility of using protective maternally derived IgG antibodies to identify potentially protective parasite antigens and indicating the feasibility of using maternal immunization as a means for parasite control.

Animals↗

PubMed1993

Prognostic value of clinical and radiological status on day 28 of life for subsequent course in very low birthweight (< 1,500g) babies with bronchopulmonary dysplasia.

To test the hypothesis that the short-term (approximately 6 months) course of babies with bronchopulmonary dysplasia (BPD) could be predicted from the clinical and radiological status on day 28 of life, we retrospectively examined the medical records of 79 infants born between 1985 and 1988 who required supplemental oxygen and/or ventilatory support on day 28. Chest roentgenographs taken close to day 28 (+/- 7 days) were scored on a scale of 0-10. Four babies died from causes not related to BPD. Four of the remaining 75 died from BPD, and the rest are alive. Forty-six of 71 were weaned from supplementary oxygen by 37 weeks corrected gestational age, and only 13/71 remained on supplemental oxygen after 40 weeks gestational age. To determine which variables contributed most to the outcome, defined as total days on supplemental oxygen, a multiple regression analysis was performed, including only those variables the tolerance of which exceeded 0.7 (sex, FiO2, ventilatory mode, and infectious status). FiO2 and ventilatory mode together predicted 15% of the variability in outcome, so that a high FiO2 and ventilator dependence on day 28 of life were highly correlated with a prolonged need for supplemental oxygen (F = 4.28, P < 0.05).

Bronchopulmonary Dysplasia↗

PubMed1992

Homology of a vesicular amine transporter to a gene conferring resistance to 1-methyl-4-phenylpyridinium.

The vesicular amine transporter (VAT) catalyzes transport and storage of catechol and indolamines into subcellular organelles in a wide variety of cells. It plays a central role in neurotransmission and is the primary target for several pharmacological agents. One of the drugs, reserpine, binds very tightly to the transporter and remains bound even after solubilization, a finding that has proven useful for purification of the transporter from bovine adrenal medulla in a fully functional state. The sequences of 26 N-terminal amino acids and of an additional 7-amino acid internal peptide are presented. Antibodies against a synthetic peptide based on the above sequences immunoprecipitate the transporter, confirming the conclusion that the peptide sequence is derived from bovine VAT. To our knowledge, documentation of sequences of vesicular neurotransmitter transporters has not been presented previously. In addition, the sequences obtained are highly homologous to the predicted sequence of a protein from PC12 cells that confers to Chinese hamster ovary cells resistance to 1-methyl-4-phenylpyridinium (MPP+), an agent that causes parkinsonism in model systems, confirming the hypothesis that the protein conferring resistance to MPP+ is a VAT.

1-Methyl-4-phenylpyridinium↗

PubMed1992

Developmental gene expression of a 230-kilodalton macrogamete-specific protein of the avian coccidial parasite, Eimeria maxima.

We prepared a cDNA library from gametocytes of Eimeria maxima and screened it using antibodies raised against an 82-kDa gametocyte antigen. One cDNA clone designated pEM230 was isolated and characterized. It encodes a portion of a 230-kDa gametocyte protein and its DNA sequence shows the presence of several tandem repeats of 42 bp. In order to determine the stage and sex specificity of the mRNA for the 230-kDa protein, Northern blotting and in situ hybridization studies were performed. The 230-kDa protein is encoded for by a 7 kb mRNA, which is expressed exclusively during the macrogamete stage with no detectable expression seen in any other stage of parasite development.

Amino Acid Sequence↗

PubMed1992

Maternal immunization with gametocyte antigens as a means of providing protective immunity against Eimeria maxima in chickens.

In the present study, we wished to demonstrate the ability of surface gametocyte antigens to induce protective immunity against Eimeria maxima infections in chickens. In order to accomplish this goal, we employed maternal immunization as a means of providing large amounts of specific antibodies to offspring chicks. Upon challenge with sporulated E. maxima oocysts, chicks from hens immunized with affinity-purified gametocyte antigens showed greatly reduced oocyst production compared with chicks from sham-immunized hens. These results suggest that maternal immunization with gametocyte antigens can be used as a means to provide transmission-blocking immunity against E. maxima infections.

Animals↗

PubMed1990

Passive immunization of chickens against Eimeria maxima infection with a monoclonal antibody developed against a gametocyte antigen.

Eimeria maxima gametocytes contain two major antigens with molecular masses of 56 and 82 kilodaltons (kDa) which are recognized by convalescent sera from immune chickens. Preparations enriched in these two antigens were used to immunize mice, and several monoclonal antibodies which specifically reacted with the 56-kDa antigen were produced. One of these monoclonal antibodies of the immunoglobulin M subclass, along with immune chicken sera raised against affinity-purified 56- and 82-kDa antigens, was used to passively immunize chicks. On the basis of the parameter of total oocyst output, it was found that these antibodies provided partial protection (40 to 50% inhibition) against E. maxima challenge infections.

Animals↗

PubMed1989

Antigenic proteins of Eimeria maxima gametocytes: cell-free translation and detection with recovered chicken serum.

RNA was extracted from isolated Eimeria maxima gametocytes and translated in a rabbit reticulocyte cell-free protein synthesis system. The major cell-free translation products from E. maxima gametocyte RNA ranged from 225 to 50 kDa, distinct and different from uninfected chicken intestine cell-free translation products. Rabbit antiserum to E. maxima gametocytes as well as recovered chicken sera specifically precipitated some of the major gametocyte cell-free products. A time course of infected intestine RNA indicated that these cell-free synthesized gametocyte antigens appear at 130 to 138 hr postinfection.

Animals↗

PubMed1989

Eimeria maxima: isolation of gametocytes and their immunogenicity in mice, rabbits, and chickens.

Eimeria maxima gametocytes were isolated from infected chicken intestinal tissue by treatment with hyaluronidase and subsequent filtration through polymon filters. The isolated gametocytes were analyzed by microscopical and biochemical methods and shown to be highly enriched. The antigenicity of the gametocytes was analyzed in mice, rabbits, and chickens by ELISA and indirect immunofluorescence. Contrary to published results, we have found gametocytes to be highly immunogenic in all animals tested.

Animals↗