Splicing of the muscle-specific plasma membrane Ca(2+)-ATPase isoforms PMCA1c is associated with cell fusion in C2 myocytes

The regulation of intracellular calcium is essential for proper muscle function. Muscle cells have several mechanisms for dealing with the rapid and large changes in cytosolic calcium level that occur during contraction. Among these is the plasma membrane Ca(2+)-ATPase (PMCA), which pumps calcium from the cytosol to the extracellular space. We have previously shown that in human fetal muscle the PMCA1 isoforms present are PMCA1a-d, with PMCA1b and c predominating. Alternative splicing of mRNAs encoding proteins involved in muscle contraction is common in developing muscle. Therefore, we examined the expression of muscle-specific PMCA mRNAs in pre- and postfusion mouse C2 myoblasts. The housekeeping form of the CA(2+)-ATPase, PMCA1b, was found at all times and under all conditions. However, the other predominating isoform found in muscle, PMCA1c, was expressed on myotube formation. Simple cell-cell contact was not sufficient to induce PMCA1c expression, as cells plated at confluence but harvested before myotubule formation did not express PMCA1c. The induction of this muscle-specific Ca(2+)-ATPase at myotube formation suggests that it may play an important role in muscle function.

[The Sundholm infirmary. Management of disorders in individuals admitted to an institution for homeless persons]

The aim of this retrospective study was to describe diseases seen and treated at the infirmary at Sundholm, an institution for homeless people. In 1991 there were 124 admissions to the department. The problems treated were in 47 (37.9%) cases mainly related to alcohol abuse, in 26 (21%) cases medical or surgical diseases, in 12 (9.7%) drug abuse problems, in 10 (8.1%) psychoses and in five (4.0%) problems following crisis or trauma. In 24 (19.4%) admissions the health problems were due to various combinations of physical and psychiatric diseases and could not be classified further. In 96% of the admissions the patient was diagnosed as having one or more diagnosis concerning alcohol or drug abuse or major psychiatric disease. The infirmaries at the welfare homes in Denmark are a specialized alternative to more traditional treatment for the homeless.

An rps14 pseudogene is transcribed and edited in Arabidopsis mitochondria

Sequence analysis of the region upstream of the apocytochrome b (cob) gene in the Arabidopsis mitochondrial genome identifies an open reading frame with homology to ribosomal protein L5, (rpl5), and a pseudogene with similarity to ribosomal protein S14 (rps14) genes. Both cob and rpl5 genes have intact reading frames, but the rps14 homology is disrupted by a stop codon and a deleted nucleotide. The rpl5 gene, the rps14 pseudogene, and the cob gene are separated by one nucleotide and a 1604-nucleotide-long spacer respectively. A plastid-like tRNA(Ser) is encoded downstream from the cob gene. The entire region is transcribed into a 5-kb transcript, containing the rps14 pseudogene and the cob gene. Cob and rpl5 mRNAs are edited in several positions with different frequencies. The rps14 pseudogene is transcribed and edited in one position in common with other plants. Since no intact rps14 gene is found in the mitochondrial genome of Arabidopsis, the functional gene is presumably encoded in the nucleus.

Nursing specialty practice guidelines: the implications for clinical scholarship and early intervention practice. American Nurses' Association

Specialty practice guidelines provide the nursing profession with the opportunity to examine, document, and revise practice, thus contributing to clinical scholarship and nursing science. The development and evaluation of one particular specialty practice guideline, the Children with Special Health Care Needs Guidelines, and the implications for early intervention practice are described. Recommendations for clinical research and usage for the Education of the Handicapped Act Amendment of 1986 (Public Law 99-457) are included.

The nad4L gene is encoded between exon c of nad5 and orf25 in the Arabidopsis mitochondrial genome

In the Arabidopsis thaliana mitochondrial genome the gene coding for subunit 4L of NADH dehydrogenase (nad4L) is located between exon c of the nad5 open reading frame and orf25. The physical proximity of these genes further supports the trans-splicing model for assembly of the nad5 mRNA. Some transcripts comprise the nad4L open reading frame cotranscribed with nad5 exon c and orf25, while other mRNAs contain only nad4L and orf25. Both open reading frames for nad4L and orf25 are edited in several positions with different frequencies.

Expression of plasma membrane calcium-pumping ATPase mRNAs in developing rat brain and adult brain subregions: evidence for stage-specific expression

The plasma membrane calcium-pumping ATPases (Ca(2+)-ATPases) maintain resting free cytosolic calcium concentrations in cells at the submicromolar level. These Ca(2+)-ATPases are encoded by four genes that can be alternately spliced to produce nine different mRNAs, each of which has a unique tissue-specific distribution. Examination of the expression of these mRNAs in rat brain during development revealed that transcripts from three of the four known genes are expressed by the end of gestation. However, the stage of transcription induction varies among the isoforms. The mRNA encoding plasma membrane Ca(2+)-ATPase (PMCA) 1b, the isoform though to maintain a housekeeping function, was present from embryonic day 10. The other alternatively spliced PMCA1 mRNAs, PMCA1a and c, which are preferentially expressed in the brain, did not appear until embryonic day 14. PMCA2a mRNA and the alternatively spliced PMCA2b and c transcripts were coordinately induced on embryonic day 18. The PMCA3a transcript first appeared on embryonic day 18 but did not reach steady-state levels until postnatal day 3, whereas production of PMCA3b mRNA first occurred on embryonic day 10 and reached steady-state expression by embryonic day 18. Several PMCA mRNAs tested varied in expression in specific regions of the brain that were examined at three postnatal time points.

Determination of the nucleotide sequence and chromosomal localization of the ATP2B2 gene encoding human Ca(2+)-pumping ATPase isoform PMCA2

The plasma membrane Ca(2+)-pumping ATPase (Ca(2+)-ATPase) is responsible for maintaining calcium homeostasis in eukaryotic cells. The Ca(2+)-ATPase is a family of pumps that are encoded by at least four genes. A cDNA for the human version of Ca(2+)-ATPase isoform PMCA2 was isolated and characterized. Comparison of the human and rat cDNA sequences showed that they were 95% homologous in the coding domain, and this homology was reflected in the deduced protein sequence where greater than 98% homology between the human and rat sequences was found. The amino acid differences that were found were almost all conservative. The PMCA2 cDNA was used to probe Southern blots of human-rodent somatic cell hybrid DNAs; the results indicated that the human PMCA2 gene was located on chromosome 3.

Learning and behavioral--emotional problems of children born preterm at second grade

A longitudinal prospective study examined the question, "which child and family factors discriminate between children born preterm who are characterized by the presence or absence of learning or behavioral-emotional problems at second grade?" Assessments were completed during the child's hospital stay at birth, at 4, 8, and 24 months, and 8 years of age for 68 children born preterm and their mothers. Discriminant analyses identified the variables that statistically maximized the differentiation between two groups of children defined to exhibit or not exhibit school age problems. Three categories of discriminators were used in the analyses: infant status, family interactive quality, and family context. The three significant discriminators were variables from the family categories. The results of this study highlight the importance of understanding the presence or absence of school age problems from a multivariate model of development that takes into account the quality of the child's interactions within the family during early childhood and school age and the current stress levels in the family context.

[Homeless psychiatric patients, a study of registration of clients in hostels and foster homes]

In November 1990 a prevalence study and a one month incidence study of previous admissions to psychiatric hospitals or wards were carried out among clients in hostels and care homes in three Danish counties. The study includes Aarhus county, the county of Northern Jutland and the municipality of Copenhagen. Both incidence and prevalence were of approximately the same magnitude in the three counties, between 50% and 75%. When clients who at their latest discharge from a psychiatric hospital or ward were diagnosed alcoholics or drug abusers were excluded the figures were reduced to 25-33%. Eight per cent of the total of 1008 persons investigated (90% males, 10% females) had previously been diagnosed as schizophrenic. Twenty-three per cent of the patients previously admitted to psychiatric hospitals or hostels were admitted to ward or care homes within 24 hours of discharge from hospital and 29% within one month. Among the patients discharged from psychiatric hospitals or wards within two years previous to their present admission to hostels or care homes, 70% were between 25 and 44 years old, 8% younger than 25 years.

Analysis of the tissue-specific distribution of mRNAs encoding the plasma membrane calcium-pumping ATPases and characterization of an alternately spliced form of PMCA4 at the cDNA and genomic levels

The plasma membrane Ca(2+)-pumping ATPase (Ca(2+)-ATPase) mRNAs are encoded on four different genes designated PMCA1-PMCA4. The primary transcripts from some of these genes are known to be alternately spliced in the region encoding the regulatory domains of the enzymes. The known alternately spliced forms of these Ca(2+)-ATPase mRNAs and a new spliced variant of PMCA4 (PMCA4b), presented here, represent at least nine different mRNAs encoding the Ca(2+)-ATPases. In this report, the examination of the tissue-specific distribution of these alternately spliced mRNAs using polymerase chain reaction amplification of cDNA coupled with Southern blotting revealed that each spliced variant had a unique tissue distribution. PMCA1b and PMCA4a were present in all tissues examined. PMCA1a, PMCA1b, and PMCA4b were expressed in excitable tissues, whereas PMCA1d was expressed only in muscle tissues. PMCA2 was found in liver, adrenal gland, spinal cord, and brain. PMCA3a was present in spinal cord, and PMCA3b in thymus, adrenal gland, spinal cord, and brain. The mRNA for a new spliced variant of PMCA4 (PMCA4b) was detected in this study. Complementary DNAs for this isoform were isolated and characterized from human and bovine brain. This alternately spliced form of the PMCA4 mRNA contained an exon inserted at the splice junction immediately following the sequence encoding the calmodulin-binding domain. As has also been shown for PMCA1a, this insertion produced a shift in the reading frame at the 3'-end of the PMCA4 mRNA that yielded a sequence encoding a Ca(2+)-ATPase lacking a large portion of the C-terminal regulatory domain. When the human PMCA4 gene spanning this region of variable exon splicing was sequenced, it confirmed the intron-exon boundaries where alternate splicing occurs to produce PMCA4a and PMCA4b.

[Homeless individuals admitted to a psychiatric hospital]

This investigation reveals that 10% of the patients admitted to Sankt Hans Hospital in Roskilde during a period of three months were homeless and that the homeless patients are among the younger patients. Relatively more of the homeless patients are men. Women are represented by just under one third and these are primarily among the youngest. The homeless patients are mainly severely mentally ill. The majority of diagnoses are of psychoses. Compared with the entire group of hospitalized patients in which loneliness and poor social network are also pronounced, the homeless patients are among the most unfortunate. Homeless patients are, on an average, hospitalized for briefer periods that the hospital patients as a whole and the psychiatric hospital has apparently only limited possibilities of helping homeless patients. No therapeutic aftercare is available for half of these patients. The great majority are discharged to homelessness again. It is essential that a reasonable combination of therapeutic and housing possibilities is instituted for these patients e.g. in the form of offers of various forms of housing of more or less collective form, graduated as regards size and staffing and depending upon the needs and wishes of the individual patients.

The light-harvesting system of Euglena gracilis during the cell cycle

The apoproteins of the light-harvesting chlorophyll-protein complexes LHCI and CP29 (apparent molecular weights of 27 kDa and 29 kDa, respectively) of Euglena gracilis were identified immunologically. Both complexes are present in the thylakoids of autotrophically cultured Euglena cells during the whole cell cycle. The relative amount of each apoprotein tends to increase towards the end of the cell cycle. The light-harvesting chlorophyll-protein complex of photosystem II, LHCII, of E. gracilis contains chlorophyll a, chlorophyll b, neoxanthin, diadinoxanthin and beta-carotene. Its chlorophyll a/b ratio is about 1.7 during the whole cell cycle. About 9 h after cell division the ratio of diadinoxanthin to chlorophyll a is doubled for a time of 3-4 h. The relevance of this increase during one developmental stage is discussed in relation to the insertion and-or assembly of newly synthesized LHCII.

[Mentally ill homeless persons]

Homelessness is a social problem but it is frequently associated with other problems connected with health. Abuse of illegal and legal intoxicants and severe mental illness among homeless persons make it increasingly difficult to provide support and help for homeless persons solely by means of social measures. Mentally ill homeless individuals are frequently well known both by the social authorities and by the staff of psychiatric hospitals. They have frequently been offered the traditional forms of help and therapeutic measures traditionally employed without this resulting in "cure and stability" and they are frequently left to their own devices. Many of the mentally ill homeless persons have some form of addiction which renders their existence more difficult. Hostels and homes for care do not traditionally offer homes for this type of clientele but this may prove necessary. It will be necessary to provide new measures, e.g. domiciliary forms for this group but without a multidisciplinary therapeutic team and without cooperation between the social services and the health services this can scarcely prove successful.

A cDNA clone encoding a 10.8 kDa photosystem I polypeptide of barley

A cDNA clone encoding the barley photosystem I polypeptide which migrates with an apparent molecular mass of 16 kDa on SDS-polyacrylamide gels has been isolated. The 634 bp sequence of this clone has been determined and contains one large open reading frame coding for a 15,457 Da precursor polypeptide. The molecular mass of the mature polypeptide is 10,821 Da. The amino acid sequence of the transit peptide indicates that the polypeptide is routed towards the stroma side of the thylakoid membrane. The hydropathy plot of the polypeptide shows no membrane-spanning regions.

Hydrogen exchange kinetics of bovine pancreatic trypsin inhibitor beta-sheet protons in trypsin-bovine pancreatic trypsin inhibitor, trypsinogen-bovine pancreatic trypsin inhibitor, and trypsinogen-isoleucylvaline-bovine pancreatic trypsin inhibitor

Hydrogen exchange rates of six beta-sheet peptide amide protons in bovine pancreatic trypsin inhibitor (BPTI) have been measured in free BPTI and in the complexes trypsinogen-BPTI, trypsinogen-Ile-Val-BPTI, bovine trypsin-BPTI, and porcine trypsin-BPTI. Exchange rates in the complexes are slower for Ile-18, Arg-20, Gln-31, Phe-33, Tyr-35, and Phe-45 NH, but the magnitude of the effect is highly variable. The ratio of the exchange rate constant in free BPTI to the exchange rate constant in the complex, k/kcpIx, ranges from 3 to much greater than 10(3). Gln-31, Phe-45, and Phe-33 NH exchange rate constants are the same in each of the complexes. For Ile-18 and Tyr-35, k/kcpIx is much greater than 10(3) for the trypsin complexes but is in the range 14-43 for the trypsinogen complexes. Only the Arg-20 NH exchange rate shows significant differences between trypsinogen-BPTI and trypsinogen-Ile-Val-BPTI and between porcine and bovine trypsin-BPTI.

Stage-Specific State I-State II Transitions during the Cell Cycle of Euglena gracilis

In synchronized Euglena gracilis (light-dark regime of 14:10 hours) the successive formation of the photosynthetic apparatus during cell ontogeny is correlated with large changes in photosynthetic efficiency (P Brandt, B von Kessel 1983 Plant Physiol 72: 616-619; B Kohnke, P Brandt 1984 Biochim Biophys Acta 766: 156-160). This observation led us to investigate the functional association of the chlorophyll a/b light-harvesting protein complex (LHCP) with photosystem I or II, because changes in energy flow to photosystem I or II and in energy transfer between the two photosystems can be a reason for these alterations. As criterion for the association of the LHCP with photosystem I or II, state transitions were determined after 15 minutes preillumination using wave-lengths of 725 or 620 nanometers. The state transitions were determined from measurements of fluorescence induction at room temperature, and fluorescence kinetics at 77 K. According to the obtained data (a) mobile LHCP is present only between the 6th and the 10th hour of the light-time of the cell cycle and (b) this functional relation of the LHCP to photosystem I only at this stage of Euglena chloroplast development is not accompanied by a decrease in stacking. A model for the organization of the newly inserted LHCP within the photosynthetic apparatus of E. gracilis is discussed.

Induction of the De Novo Formation of the Photosystem I-Related Light-Harvesting Chlorophyll Protein Complex LHCPa by Photoheterotrophic Nutrition

The green alga Chlamydobotrys stellata contains in addition to the normal light-harvesting chlorophyll protein complex LHCPb a special LHCPa which is free of chlorophyll b and connected only to photosystem I (Brandt, Zufall, Wiessner 1983 Plant Physiol 71: 128-131). The kinetics of these two LHCP forms were analyzed during the transition in nutrition of the alga from autotrophy to photoheterotrophy, e.g. the replacement of CO(2) by acetate as carbon source. As shown by incorporation experiments with [(14)C]acetate, this change in nutrition leads to an increased synthesis of LHCPa, whereas the synthesis of the photosystem II-related LHCPb decreases. The increase of the LHCPa synthesis starts immediately after the onset of photoheterotrophic nutrition together with the synthesis of the chlorophyll protein complex CPI. There is no interchange of complex components between LHCPa and LHCPb during the depletion of the latter. The formation of LHCPa is discussed with respect to the regulation of gene expression.

Cooperation of cytoplasmic and plastidial translation in formation of the photosynthetic apparatus and its stage-specific efficiency

In synchronized Euglena gracilis, strain Z, the synthesis of the apoproteins for the chlorophyll-protein-complexes CPI, CPa, and LHCP is light-dependent and takes place in the light period in a characteristic consecutive fashion: CPI at 1 to 2 hours, CPa at 7 to 12 hours, and LHCP at 8 to 12 hours. The syntheses sequence of the chlorophyll-protein-complexes coincides with the efficiency alterations of the photosynthetic apparatus of E. gracilis during the light period of the cell cycle. In particular, the synthesis onset of the photosystem II-related polypeptides CPa and LHCP aligns with the decrease of oxygen evolution at 6 hours of the light period and is discussed as reorganization process in the thylakoids.

Relation between the Light-Harvesting Chlorophyll a-Protein Complex LHCPa and Photosystem I in the Alga Chlamydobotrys stellata

The light-harvesting chlorophyll protein system of the alga Chlamydobotrys stellata consists of an as yet uncharacterized algal chlorophyll a-protein, called LHCPa, and a common photosystem II-related chlorophyll a/b-protein, called LHCPb (Brandt, Kaiser-Jarry, Wiessner 1982 Biochim Biophys Acta 679: 404-409). For further characterization, this LHCPa was isolated from the organism by polyacrylamide isoelectrofocusing and reelectrophoresis. It contains only chlorophyll a and has only one apoprotein (32,000 daltons). When separated from autotrophically grown cells, its absorption peak is at 674 nm and its isoelectric point at 5.3. Photoheterotrophic cultivation of the algae shifts the absorption maximum of LHCPa to 679 nm and its isoelectric point to 4.8. This LHCPa is a component of photosystem I particles. In relation to the total chlorophyll a content, the amount of LHCPa is low in autotrophic algae, but increases under photoheterotrophic growth conditions, where the organisms do not have the ability to assimilate CO(2) photosynthetically.