Dopamine receptors in equine ovarian tissues

Dopamine (DA) agonist and antagonist treatments can affect ovarian reproductive events in the mare. To support our theory that DA produces these effects by acting directly on the ovary, we analyzed equine ovarian tissues for the presence of dopamine receptor-1 (D1r) and dopamine receptor-2 (D2r) mRNA by reverse transcription polymerase chain reaction (RT-PCR) and D1r and D2r proteins by Western blot and immunohistochemistry (IHC). RT-PCR was performed on RNA isolated from ovarian cortex, medulla, granulosa/theca or corpus luteum (CL) tissues and from pituitary (D2r control) and renal artery (D1r control). D1r and D2r specific primers were designed from partial DNA sequences known for the horse (D2r) or conserved sequences from other species (D1r). Western blot analyses were conducted on CL, cortex and granulosa/theca samples and IHC was performed on CL tissues using D1r or D2r specific antibodies. The incidence of positive D2r mRNA was high in CL and ovarian cortex, low in granulosa/theca, and not detectable in ovarian medulla. Dopamine D1r mRNA incidence was high (50%) only in CL tissues. D1r and D2r antibody staining was positive for each tissue type analyzed by Western blot procedures. All CL tissues prepared by IHC showed positive staining for D1r and D2r proteins. Both DA receptor proteins appeared uniformly distributed throughout the CL tissue. These results indicate that equine ovarian tissues do possess D1r and D2r, and suggests that DA can act directly on ovarian tissues through its interaction with DA receptors.

Expression of Moloney murine leukemia virus RNase H rescues the growth defect of an Escherichia coli mutant

A 157-amino-acid fragment of Moloney murine leukemia virus reverse transcriptase encoding RNase H is shown to rescue the growth-defective phenotype of an Escherichia coli mutant. In vitro assays of the recombinant wild-type protein purified from the conditionally defective mutant confirm that it is catalytically active. Mutagenesis of one of the presumptive RNase H-catalytic residues results in production of a protein variant incapable of rescue and which lacks activity in vitro. Analyses of additional active site mutants demonstrate that their encoded variant proteins lack robust activity yet are able to rescue the bacterial mutant. These results suggest that genetic complementation may be useful for in vivo screening of mutant viral RNase H gene fragments and in evaluating their function under conditions that more closely mimic physiological conditions. The rescue system may also be useful in verifying the functional outcomes of mutations based on protein structural predictions and modeling.

Functional analysis of the domain organization of Trypanosoma brucei RNase HI

The structure-function relationship of Trypanosoma brucei RNase HI was investigated by evaluating the abilities of truncated forms of the enzyme to convert RNase H substrate to product. Our studies identify a 42-amino-acid noncanonical RNase HI spacer domain essential for function. We also show that the enzyme's nuclear localization domain is not required for RNase H activity but functions as an RNA binding domain which modulates the enzyme's Mn(2+)-dependent activity. These findings show that the enzyme's RNA binding/nuclear targeting and RNase H activities are organized into discrete N- and C-terminal domains with boundaries established by its spacer domain. This is the first report of the unusual structure to function relationship of a protozoal RNase H. This relationship may be conserved in other eukaryotic RNases H suggesting that criteria preserving their structure and function may be important to their roles in nucleic acid metabolism.

Prolonging life and allowing death: infants

Dilemmas about resuscitation and life-prolonging treatment for severely compromised infants have become increasingly complex as skills in neonatal care have developed. Quality of life and resource issues necessarily influence management. Our Institute of Medical Ethics working party, on whose behalf this paper is written, recognises that the ultimate responsibility for the final decision rests with the doctor in clinical charge of the infant. However, we advocate a team approach to decision-making, emphasising the important role of parents and nurses in the process. Assessing the relative burdens and benefits can be troubling, but doctors and parents need to retain a measure of discretion; legislation which would determine action in all cases is inappropriate. Caution should be exercised in involving committees in decision-making and, where they exist, their remit should remain to advise rather than to decide. Support for families who bear the consequences of their decisions is often inadequate, and facilitating access to such services is part of the wider responsibilities of the intensive care team. The authors believe that allowing death by withholding or withdrawing treatment is legitimate, where those closely involved in the care of the infant together deem the burdens to be unacceptable without compensating benefits for the infant. As part of the process accurate and careful recording is essential.

Modeling human lymphoid precursor cell gene therapy in the SCID-hu mouse

Gene therapy of human T-lymphocyte disorders, including acquired immunodeficiency syndrome (AIDS), would be greatly facilitated by the development of an in vivo system in which transduced human hematopoietic stem cells can be used to reconstitute the T-lymphoid compartment. Here we use the SCID-hu mouse as a recipient for human CD34+ hematopoietic progenitor cells transduced in vitro with a retroviral vector carrying the neomycin resistance gene (neoR). The transduced cells engraft and reconstitute the lymphoid compartments of the human thymus implant with as few as 5 x 10(4) CD34+ cells. The neoR gene was expressed at low levels in human thymocytes and there was no apparent effect on thymocyte differentiation as a result of vector transduction. Thus, this SCID-hu mouse system is the first in vivo model showing human thymopoiesis after transduction of exogenous vectors, and should allow preclinical testing of gene therapeutic reagents designed to function in human cells of the T-lymphoid lineage. Because human immunodeficiency virus type 1 infection induces depletion of human thymocytes in SCID-hu mice, this system may be particularly valuable in evaluating efficacy of gene therapies to combat AIDS.

Functional complementation of an Escherichia coli ribonuclease H mutation by a cloned genomic fragment from the trypanosomatid Crithidia fasciculata

A gene designated Cfa RNH1 has been cloned by complementation of an RNase H deficiency in an Escherichia coli rnhA mutant by using a genomic DNA library from the trypanosomatid Crithidia fasciculata. The encoded RNase H is predicted to have 494 amino acid residues and a molecular mass of 53.7 kDa. The carboxyl half of the protein is homologous to the 155-residue E. coli RNase HI (41% identity) and the 166-residue Saccharomyces cerevisiae RNase HI (33% identity). The recombinant protein has been purified as a six-histidine-tagged fusion protein by metal chelate chromatography and was shown to have RNase H activity. Antibodies against the recombinant protein recognize proteins of approximately 65 kDa and 56 kDa on Western blots of C. fasciculata extracts. These results demonstrate the feasibility of cloning trypanosome genes by complementation of appropriate E. coli mutants with genomic DNA libraries.

Glutactin, a novel Drosophila basement membrane-related glycoprotein with sequence similarity to serine esterases

Glutactin, a new acidic sulfated glycoprotein, was isolated from Drosophila Kc cell culture media. Immunofluorescence microscopy located it to embryonic basement membranes, particularly to the sequentially invaginated envelope of the central nervous system, muscle apodemes and dorsal median cell processes. Its chromosome locus is 29D. The nucleic acid sequence coding for the 1023 residue long polypeptide contains one intron and was confirmed by partial amino acid sequencing. Glutactin has a signal peptide and an amino domain of greater than 500 residues that strongly resembles acetylcholine esterases and other serine esterases, but lacks the catalytically critical serine residue. The amino and carboxyl domains of glutactin are separated by 13 contiguous threonine residues. Glutamine and glutamic acid make up 44% of glutactin's very acidic carboxyl domain. Glutactin preferentially binds Ca2+ in the presence of excess Mg2+ and four of its tyrosines are O-sulfated. Several similarities with mammalian entactin caused our previous, preliminary mention of glutactin as a putative Drosophila entactin, but sequence comparison now shows them to be different proteins.

Papilin: a Drosophila proteoglycan-like sulfated glycoprotein from basement membranes

A sulfated glycoprotein was isolated from the culture media of Drosophila Kc cells and named papilin. Affinity purified antibodies against this protein localized it primarily to the basement membranes of embryos. The antibodies cross-reacted with another material which was not sulfated and appeared to be the core protein of papilin, which is proteoglycan-like. After reduction, papilin electrophoresed in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a broad band of about 900,000 apparent molecular weight and the core protein as a narrow band of approximately 400,000. The core protein was formed by some cell lines and by other cells on incubation with 1 mM 4-methylumbelliferyl xyloside, which inhibited formation of the proteoglycan-like form. The buoyant density of papilin in CsCl/4 M guanidine hydrochloride is 1.4 g/ml, that of the core protein is much less. Papilin forms oligomers linked by disulfide bridges, as shown by sodium dodecyl sulfate-agarose gel electrophoresis and electron microscopy. The protomer is a 225 +/- 15-nm thread which is disulfide-linked into a loop with fine, protruding thread ends. Oligomers form clover-leaf-like structures. The protein contains 22% combined serine and threonine residues and 25% combined aspartic and glutamic residues. 10 g of polypeptide has attached 6.4 g of glucosamine, 3.1 g of galactosamine, 6.1 g of uronic acid, and 2.7 g of neutral sugars. There are about 80 O-linked carbohydrate chains/core protein molecule. Sulfate is attached to these chains. The O-linkage is through an unidentified neutral sugar. Papilin is largely resistant to common glycosidases and several proteases. The degree of sulfation varies with the sulfate concentration of the incubation medium. This proteoglycan-like glycoprotein differs substantially from corresponding proteoglycans found in vertebrate basement membranes, in contrast to Drosophila basement membrane laminin and collagen IV which have been conserved evolutionarily.

Drosophila laminin: characterization and localization

Drosophila laminin was isolated from the medium of Drosophila Kc cell cultures. It was purified by velocity sedimentation, gel filtration, and chromatography. Drosophila laminin is a disulfide-linked molecule consisting of three chains with apparent molecular masses of 400, 215, and 185 kD. In electron micrographs, it has the cross-shaped appearance with globular domains characteristic of vertebrate laminin with closely similar dimensions. The amino acid composition and lectin-binding properties of Drosophila laminin are given. Polyclonal antibodies to Drosophila laminin were prepared and their specificity was established. In developing embryos immunofluorescence staining was detected between 6 and 8 h of development; and in sections of 8-9-h and older embryos immunostaining was seen at sites where basement membranes are present surrounding internal organs, muscles, underlying the hypodermal epithelium, and in the nervous system. Basement membrane staining was also seen in larva and adults. Cells from Drosophila embryos dissociated at the cellular blastoderm stage were grown in culture and some specific, differentiated cells synthesized laminin after several hours of culture as shown by immunofluorescence. The significance of the evolutionary conservation of the structure of this basement membrane component is discussed.

Selective vitamin B12 malabsorption without anaemia but with profound failure to thrive

A 7-month-old boy presented with vomiting and failure to thrive associated with proteinuria, methylmalonic aciduria and macrocytosis, but without anaemia. Plasma vitamin B12 levels were normal by a radio-dilution method. He was treated as an inborn error of metabolism with intramuscular cyanocobalamin and a low protein diet. However when treatment was withdrawn he remained well for 11 months before relapsing with vomiting and weight loss. Re-investigation again showed methylmalonic aciduria, but the haemoglobin was low and plasma vitamin B12 levels by a specific method showed them to be reduced. Studies of vitamin B12 absorption showed the picture of selective malabsorption. He was started on regular cyanocobalamin injections.

The impact of maternal serum alpha fetoprotein screening on open neural tube defect births in north-east Scotland

Over the three years period 1980-1982, 18 256 pregnancies in the Grampian Region of N-E Scotland including the islands of Orkney and Shetland were screened for raised levels of maternal serum alpha fetoprotein (MSAFP) in the second trimester. Thirty six cases of fetal open neural tube defect in singletons were detected (18 anencephaly and 18 spina bifida). Four additional cases of open spina bifida were associated with normal MSAFP levels although two of these were detected by amniotic fluid AFP measurement when amniocentesis was carried out because of previous NTD history. A further three cases of open spina bifida and two of anencephaly occurred in unscreened pregnancies. The MSAFP screening programme alone was thus instrumental in reducing the birth incidence of open neural tube defects by 36 out of 45 cases (80 per cent) in singletons.

Maternal serum alpha fetoprotein in monozygotic and dizygotic twin pregnancies

Maternal serum alpha-fetoprotein (MSAFP) values in the second trimester have been related to pregnancy outcome for 100 normal twin pairs, 42 monozygous (MZ) and 58 dizygous (DZ), liveborn after 28 weeks gestation. The median MSAFP value was 1.9 multiples of the median value (MOM) for uncomplicated singleton pregnancies. Both very low and very high MSAFP values were associated with twins of low birthweight. MSAFP values were higher in MZ than DZ twin pregnancies particularly those with dizygotes of like-sex. This effect was even more marked when only dichorionic like-sex twin pairs were compared.

Maternal serum alpha-fetoprotein levels in low birth weight singleton pregnancies

Maternal serum alpha fetoprotein (MSAFP) measurement between 16 and 21 weeks gestation is used to define a group of women with an increased risk of fetal abnormality, particularly open neural tube defect. The test is strongly gestation dependent and women with high MSAFP levels require sonar scan examination to define gestation, exclude twins and examine the fetus for obvious malformation or death. It has been reported that women with no primary cause for raised MSAFP have an increased incidence of low birth weight babies. Conflicting reports have separately ascribed these to premature delivery and to intra-uterine growth retardation. We have studied the relationship between MSAFP and low birth weight infants with respect to both prematurity and retarded fetal growth. MSAFP values were expressed as multiples of the appropriate weekly median (MOM) values relating to normal pregnancies with normal outcomes at term. For our normal population an MSAFP value of 2 MOM is the 95% centile, i.e. 5% of normal outcome pregnancies of sure gestation will have MSAFP values in the second trimester which are at or above 2 MOM. Information was available on 389 women whose infants were liveborn singletons weighing 2.5 kg or less. 33 (8.5%) of these women had MSAFP greater than 2 MOM (p less than 0.005) and of the 145 women whose babies weighed less than 2 kg, 17 (11.7%) had MSAFP at this level (p less than 0.001) Tab. I).(ABSTRACT TRUNCATED AT 250 WORDS)

A continuous biological process to decolorize bleach plant effluents

Although almost every U.S. pulp mill has a biological wastewater treatment system, these systems based on bacteria, are largely ineffective in the removal of color. For this reason, we have attempted to utilize Phanerochaete chrysosporium, a fungus known to degrade lignin, as the primary organism in a novel waste treatment scheme named the MyCoR Process. Color from bleached Kraft mills originates principally from the first extraction stage of the bleach plant. It is this waste stream which is sent to the MyCoR Process reactor, a rotating biological contactor, for decolorization. We have found that under optimal conditions up to 2,000 color units/L/day can be removed from the waste stream. There is also a concomitant removal of COD and BOD. In addition, chlorolignins originating from the bleaching process were found to be dechlorinated; this is of interest to those concerned with the impact of bleach plant effluents on the environment. The process uses conventional wastewater treatment equipment. However, the use of a pure culture of fungus in a secondary metabolic state has not been attempted previously in a waste treatment scheme. Minor equipment modification and close operator attention may therefore be required. A preliminary economic analysis shows that the MyCoR Process, in its present state, would cost about US$30/metric ton of bleached Kraft pulp produced. This cost will decrease as improved or new strains of fungi are developed for the process.

The right to be allowed to die

The unbridled use of modern medical skills and technology in preserving life at all costs has stimulated interest in expressing a 'right to die' by the legally competent patient who is anxious to protect his autonomy. Some recent decisions by American courts are seen to threaten this 'right to die' of competent patients and imply that legally incompetent patients including children should not have this right under any circumstances, even when expressed on their behalf by guardians, nearest relatives or parents. It is argued that this is contrary to 'natural justice' as viewed by most people. It should be possible to develop procedures which are protective of the basic 'right to life' of the incompetent yet will recognise circumstances where they could be allowed to die. This paper was presented at the 1983 annual conference of the London Medical Group, 'Human Rights in Medicine'.

Neonatal acne vulgaris: a possible feature of the fetal hydantoin syndrome

A baby with the fetal hydantoin syndrome was found to have acne vulgaris of the face. Hydantoin taken by epileptic women during pregnancy may cause neonatal acne in the offspring.

Is it necessary to warm infants' feeds?

The effect of temperature on gastric emptying after milk feeds was studied in 31 newborn infants. Test meals were a commercially prepared modified cows' milk (a) at body temperature and (b) at room temperature. Our results suggest that temperature has no effect on gastric emptying.

Deciding the care of severely malformed or dying infants

Suffering patients (when able), grieving families and compassionate physicians have always sought the least detrimental alternative while deciding care in the face of tragedy. Modern medical technology has brought great benefits to patients but has blurred traditional concepts of life and death and created new dilemmas for practising doctors. While this technology has given doctors great control over living and dying, their dominance in critical decision making is being challenged. More and more their decisions are liable to public and legal scrutiny, intense publicity by the news media and exploitation by lobbyists with opposing aims. Increasing pressure of this kind may deflect the physician form his primary responsibility to patients and their families. For infants with gross malformations or a distressing terminal illness we believe that the parents and their doctors must be allowed primary decisional power even if the chosen course of action involves the death of the infant. Choices for death should be permitted but only after suitable family and professional consultation. Some general guidelines are suggested. As these situations are so varied and so complex, much latitude in decision-making should be expected and tolerated.

On deciding the care of severely handicapped or dying persons: with particular reference to infants

Two philosophies of deciding the care of severely handicapped or dying persons are commonly used. The first is "disease-oriented" which places death in the extreme negative position. The second is "person-oriented" which regards some kinds of severely compromised living as worse than death. The first philosophy is convenient for the development and the use of medical technology but its unbridled application commonly dehumanizes patients and aggravates suffering. The second philosophy may protect persons from the indignities of pointless treatment or the cruelties of disease. But its use in some respects is illegal and may be unwise; also, in caring for infants, children, and incompetent adults, the second philosophy creates special problems since the patient himself cannot participate in decision-making. In deciding which philosophy to follow in a given situation we believe the patient (when able), the sorrowing family, and the concerned physician are the best judges. Since these persons vary widely, they must be entrusted with more freedom to change or to ignore commonly accepted principles if the values of patients and families in the many unique situations of living, illness, and dying are to be protected. We believe with few exceptions that these persons are now worthy of this trust and with experience they would use it with growing wisdom.

Cellular mechanisms involved in cyclic stromal renewal of the uterus. II. The albino rat

During the first four days postpartum, heterophils (polymorphonuclear leucocytes) and macrophages occur in the intercellular compartement of the luminal epithelium of the uterine endometrium. Cytochemical and ultrastructural evidence indicates that transepithelial emigration of these stromal cells to the uterine cavity is occurring. This event takes place while the luminal epithelium is proliferating in response to the estrogenic stimulus of the postpartum estrus. Heterophil emigration precedes that of the macrophages and is most conspicuous during days 1 and 2. Although it has been established that collagen fibrils occur in uterine phagocytes (Schwarz and Güldner, '67) assumed to be macrographes (Parakkal, '69, '72), their precise role in collagen degradation remains undefined. It seems likely that the emigrating macrophages, heavily laden with phagolysosomal derivatives and lipid droplets, are hauling the remnants of the intercellular substance out of the endometrium during days 2-4 postpartum. Ultrastructural evidence indicates that the emigrating macrophage punctures the basal lamina and passes through the intercellular compartment of the luminal epithelium by active penetration. Another mode of macrophagic egress operates in the deep stroma of the endometrium and myometrium where lymphatic drainage occurs. Macrophages accumulate in the perilymphatic stroma as well as within lymphatic vessels. Thus macrophagic emigration through the luminal epithelium and lymphatic vessels may provide a cellular mechanism for elimination of the intercellular stromal substance in the regressing uterus. Transepithelial emigration is a mechanism which operates also in the marsupial uterus (Padykula and Taylor, '76), and thus may be a fundamental mechanism among subprimate mammals that fulfills in part the function that menstruation effects in primates.

Avian leucocytozoidae. I. Morphometric variation in three species of Leucocytozoon and some taxonomic implications

The variability of nine morphometric parameters of Leucocytozoon simondi, L. dubreuili, and L. fringillinarum was studied with respect to variability (a) within a single bird; (b) within a single bird at different times; (c) between different birds of the same species: (d) between the same species of birds of different populations; and (e) between different species of birds. The results indicated that the variability of the parasites was of the same order of magnitude for all situations studied. Leucocytozoon dubreuili, L. fringillinarum, and the round phase of L. simondi could not be separated on the basis of measurements alone. It was concluded that the morphometric characteristics were not valid criteria for species differentiation. These studies result in the proposed synonymy of Leucocytozoon anseris with L. simondi, and of L. anellobiae, L. bouffardi, L. cambournaci, L. gentili, L. monardi, L. roubaudi, and L. seabrae with L. fringillinarum.

Avia Haemoproteidase. 5. The haemoproteids of the family Threskiornithidae

The haemoproteids of the avian family Threskiornithidae (ibises and spoonbills) are reviewed. Two species, Haemoproteus pelouroi Tendeiro, 1947 and H. plataleae de Mello, 1935 are considered to be valid; these two species are redescribed, illustrated, and compared with similar species in the Gruidae (cranes). Records of Haemoproteus in the ibises and spoonbills are summarized. Haemoproteus galatheae Laird and Laird, 1959 is rejected as a synonym of H. plataleae.

Avian Haemoproteidae. 4. Description of Haemoproteus telfordi sp. nov., and a review of the haemoproteids of the families Gruidae and Otidae

Haemoproteus telfordi sp. nov. is described from the crane, Lissotis melanogaster (Rüppell), from Katanga Province, Zaire. The haemoproteids of the families Gruidae and Otidae are reviewed and redescribed; Haemoproteus antigonis de Mello, 1935 and Haemoproteus balearicae Peirce, 1973 are compared with H. tendeiroi Travassos Santos Dias, 1953 and H. telfordi sp. nov. The hosts and distribution of the haemoproteids of these families are summarized.

Infants, children, and informed consent

Obtaining informed consent for non-therapeutic experimentation on infants and children has ethical and legal implications that cause great controversy. There is some danger that worthy research will be inhibited if current ethical codes are interpreted too strictly, yet infants, children, and other vulnerable groups clearly must be protected from exploitation as research subjects. It is suggested that permission from parents coupled with integrity of the investigator will remain the child's best protection, but several additional protective mechanisms are available and should be used. Some guidelines for non-therapeutic research are suggested which should not only provide adequate protection for infants and young children involved in research projects, but allow investigators reasonable freedom to prosecute worthy research vital to continued improvements in child care.

Hematozoa of passeriform birds from insular Newfoundland

A total of 2675 passeriform birds of 56 species were examined for blood parasites in insular Newfoundland during the period 1969–1972; 1872 (70%) harbored one or more species/genera of hematozoa. The genus Leucocytozoon, represented by L. dubreuili, L. fringillinarum, L. majoris, and L. sahkaroffi, occurred in 65% of the birds; and mixed infections involving these four species occurred commonly. Haemoproteids occurred in 22% of the sample, represented by Haemoproteus (Parahaemoproteus) fringillae, H. orizivora, and H. fallisi. Trypanosoma avium and T. calmettei occurred in 17.5% of the birds; members of the genus Plasmodium and microfilariae were uncommon. Prevalence of blood parasites in immature and adult birds was similar, and the prevalence was also similar in migratory and non-migratory species. The rate of parasite occurrence was remarkably similar from year to year in one area where the annual sample was large. Prevalence of parasites varied widely from locale to locale, and in some areas, low prevalence could be explained by absence of vectors.