Variations in UDP-N-acetylglucosamine and UDP-N-acetylmuramyl-pentapeptide pools in Escherichia coli after inhibition of protein synthesis

The pool levels of the nucleotide precursors of peptidoglycan were analyzed after inhibition of protein synthesis in various Escherichia coli strains. In all cases UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-N-acetylmuramyl-pentapeptide (UDP-MurNAc-pentapeptide) cell pools increased upon treatment with chloramphenicol or tetracycline. Similar results were observed after the treatment of K-12 strains with valine. Since the intermediate nucleotide precursors did not accumulate after the arrest of protein synthesis and since a feedback mechanism was unlikely, the increases of the UDP-MurNAc-pentapeptide pool appeared as a consequence of that of the UDP-GlcNAc pool by the unrestricted functioning of the intermediate steps of the pathway. The highest increase (sixfold) of UDP-GlcNAc was observed with strain K-12 HfrH growing in minimal medium and treated with chloramphenicol. When a pair of isogenic Rel+ and Rel- strains were considered, both the UDP-GlcNAc and UDP-MurNAc-pentapeptide pools increased upon treatment with chloramphenicol or valine. However, the UDP-GlcNAc pool of the Rel+ strain was at a high natural level, which increased only moderately (20%) after the addition of valine. The increase of the UDP-GlcNAc pool after the various treatments could be due to an effect on some upstream step by an unknown mechanism. The possible correlations of the variations of the precursor pools with the rate of synthesis and extent of cross-linking of peptidoglycan were also considered.

Multilayered distribution of peptidoglycan in the periplasmic space of Escherichia coli

When a staining technique using phosphotungstic acid (PTA) in 10% (w/v) chromic acid was applied to cells of Escherichia coli, the periplasmic space was seen as a dark 15-nm-thick layer of uniform appearance and constant width. Our observations are consistent with peptidoglycan being the main material stained. Isolated sacculi as well as purified peptidoglycan (protein free) were also stained by the same procedure, the thickness of the peptidoglycan being 8.8 +/- 1.8 and 6.6 +/- 1.5 nm, respectively. The increased thickness of the PTA-stained layer in stationary phase cells correlated well with the increased thickness of isolated sacculi or purified peptidoglycan and with the increased amount of peptidoglycan in such cells. Thickness measurements on isolated peptidoglycan were compatible with a two to three layer structure for material from exponential phase cells and with a four to five layer structure for that from stationary phase cells. Furthermore, the results indicated an uneven distribution of peptidoglycan material in the periplasmic space, the peptidoglycan spanning the space from the inner to the outer membrane.

Acylation of proteins by myristic acid in isolated mitochondria

Isolated and highly purified mitochondria from rat liver were incubated with [1-14C]myristate, solubilized in boiling sodium dodecyl sulfate, and analyzed by polyacrylamide gel electrophoresis and autoradiography. Six to eight protein bands were found to be radioactively labeled. If the mitochondria were heated for 5 min at 95 degrees C prior to incubation with this fatty acid, no labeling was observed. By preexposing the mitochondria to unlabeled fatty acids of varying chain lengths, the extent of labeling by [1-14C]myristate was reduced in a chain length-dependent manner, exhibiting maximal inhibition at lauric acid. Reversibility of the labeling was demonstrated by chasing the incorporated radioactivity with unlabeled fatty acids of varying chain length, resulting in a maximal displacement of the tracer again by lauric acid. Fractionation of the labeled mitochondria into mitochondrial matrix and inner mitochondrial membrane components before or after labeling showed that the modified proteins are located inside the inner mitochondrial membrane. In both cases, the pattern of labeling was different from the one observed with intact mitochondria. The labeled bands in the gel were sensitive to alkaline methanol or hydroxylamine treatment. The radioactivity recovered after this treatment co-migrated with myristic acid on thin layer chromatography plates. The chain length specificity and the rapid reversibility of the observed acylation argue for a new type of reaction, different from the acylation observed in whole cells. The possible involvement of the acylated proteins in the regulation of oxidative phosphorylation is discussed.

Why we know so little about prenatal care nationwide: an assessment of required methodology

Policymakers, advocates, providers, recipients, and health services researchers all would agree that too little is known about the nature and effects of specific components of prenatal care. In the process of designing a national, longitudinal study of pregnancy and childbirth, we surfaced some methodological dilemmas that help to explain why so little is known. This article explores two of the major problems: (1) selecting a valid scientific sample of pregnant women and (2) collecting data from providers and women. From this analysis, seven methodological questions, which should be investigated through empirical field studies, are identified. Those field studies are essential if future research into the content of prenatal care is to achieve an acceptable level of methodological rigor.

Prednisolone acetate-gentamicin combination following cataract surgery

One-hundred-eleven patients participated in a 21-day, open-label study to evaluate the therapeutic efficacy and safety of a prednisolone acetate 1%-gentamicin 0.3% ophthalmic suspension to control inflammation and prevent infection after cataract surgery. Beginning the day after surgery, the medication was instilled qid for the next 21 days. No postoperative infection was noted, and postoperative inflammation, which was mild immediately after surgery, decreased steadily during follow-up. The results of this study suggest that a prednisolone acetate-gentamicin combination used for three weeks after cataract surgery is safe and has a positive therapeutic effect on postoperative inflammation and infection.

[Pilot studies with a serotonin agonist (AH 25086 B). Efficacy and tolerance in acute migraine attacks.]

AH 25086 B is a selective agonist of the newly determined 5-HT(1) receptors, which are sited mainly in the intracranial section of the carotid artery. According to experimental studies, the effect of AH 25086 B is decidedly more highly selective than that of ergotamine; the blood flow through the arteriovenous anastomoses of the internal carotid artery is clearly reduced, while the blood flow through the capillaries supplying the brain is increased. With AH 25086 B administered in an infusion rapid abolition of migraine attacks already in progress proved possible. The first 12 patients worldwide to receive this preparation were treated, some on several occasions, for a total of 21 migraine attacks: 7 received one infusion, 3 received two, 1 three, and 1 patient received five infusions. There were some side-effects with some infusions: nausea (18), vomiting (9), and photophobia (19). On average it took 31 min (range 10-60 min) for the headache to be relieved, regardless of the duration of migraine symptoms before the start of treatment. This was not a controlled study, but the results (14 very good, 6 good or satisfactory, in 21 attacks treated) were better than could have been expected by chance. Tolerance of the preparation was good, all side-effects being transitory and mild; with dosages up to 1.6 mug kg(-1) min(-1) no changes were seen in heart rate or blood pressure.

Mothball toxicity

Accidental mothball ingestion is very common in children. Mothballs consist either of naphthalene or paradichlorobenzene, the toxicities of which are very different. This article focuses on the management of mothball ingestion with reference to these major ingredients.

Boric acid toxicity

Although boric acid was widely used therapeutically in the past and resulted in significant toxicity, the past few years have seen a decline in its usage. Ninety-nine per cent boric acid powder is now being used as a household pesticide. Physicians therefore should be aware of the potential for boric acid toxicity.

Camphor toxicity

Camphor is present in several over-the-counter compounds of questionable use and therefore may be ingested by small children. Because seizures may follow ingestion of certain amounts, appropriate treatment is needed, including the use of anticonvulsants.

Controlled evaluation of rural regional perinatal care: developmental and neurologic outcomes at 1 year

The effectiveness of a rural regionalized perinatal care (RPC) program was evaluated by a controlled, population-based design. The RPC program, begun in a carefully selected study region in July 1975, evolved into a system of care which included the following major components: identification of high-risk pregnancies and high-risk newborn infants; obstetric and newborn consultation and referral services between Level I, II, and III centers; professional education for physicians, nurses, and other health professionals; and nutrition and social work consultation. Substantial resources were made available from 1975 to 1980 to implement this "total package" of RPC. A matched, control region was identified which, except for the RPC program, was as comparable as possible to the study region. It was hypothesized that the RPC intervention would have the following effects when the study region was compared with the control region: reduction in fetal and neonatal mortality, no increase in postneonatal mortality, and reduction in obstetric and newborn morbidity. These findings were reported previously. This paper presents results of hypothesized reductions in adverse developmental, neurologic, maternal-infant attachment, and selected physical health outcomes. A sample of 447 infants was assessed by an extensive battery of instruments at 1 year, adjusted for gestational age. The most notable findings were mothers' reports of receptive language development and observations of maternal attachment behaviors that significantly favored the study region. No significant differences between study and control regions were observed for Bayley Mental and Motor Scores, abnormal neurologic signs, and the physical health measures.(ABSTRACT TRUNCATED AT 250 WORDS)

The management and use of data on maternal and child health and crippled children: a survey

With the advent of the Maternal and Child Health Services Block Grant, both maternal and child health programs and crippled children's (CC) programs at the State level have assumed greater responsibility for identifying populations in need, planning appropriate services for them, and monitoring progress toward program objectives. To determine the capabilities of eight Southeastern States to produce and apply the data necessary to accomplish those tasks, a survey of data systems available to, and used by, perinatal and CC programs in the Southeast was undertaken. Findings of the survey suggested that the data available to perinatal programs were more useful for planning and evaluation than those available to CC programs, primarily due to the vital statistics data systems in each State. The major data management needs of the region include (a) measuring the health status of populations served by public perinatal programs, (b) measuring services received by population groups considered in need of public perinatal care, (c) estimating the incidence and prevalence of handicapping conditions among children, and (d) measuring the outcomes of CC programs. If these shortcomings are addressed, the programs will be in better positions for effective planning and evaluation. To improve data management and utilization capabilities, the programs may need to engage technical assistance and consultation from sources outside their service-oriented agencies.

Low birth weight and preterm birth: the emerging importance of prevention

This article on LBW and preterm birth was prepared for this issue, "Interdisciplinary Strategies for Prevention", recognizing its US focus in relation to a European audience. Although the pregnancy and infant health magnitude of the problem is greater in North America, its multifactorial nature and serious impacts are experienced worldwide. Emphasis has been placed on its high costs vis-à-vis neonatal mortality, childhood morbidity, and medical care expenditures for tertiary level management. Three preventive health care strategies, linked to an attractive sociobehavioral model, are presented. The model displays multiple risk factors and their interrelationships, including the pathophysiologic events that lead to LBW and preterm birth. Acknowledging the primacy of basic societal level changes, the strategies nonetheless are based in the health care services. They call for interdisciplinary interventions as a part of preconceptual and prenatal health care. Such approaches as reduction of stress and other risk behaviors, improved nutrition, family planning and social services as well as strengthening family and community support systems are suggested. In addition a secondary prevention strategy dependent on identification of pregnant women at high risk of LBW and preterm birth is described. Early recognition by patients and providers of signs of uterine irritability may enable prevention of preterm birth by prompt treatment with tocolytic agents. Evidence relevant to the effectiveness of the preconceptual and prenatal care interventions, insofar as it is available, is cited.

A controlled evaluation of rural regional perinatal care: impact on mortality and morbidity

The impact of a rural regional perinatal care (RPC) program was assessed by a quasi-experimental, controlled, population-based design. Outcome measures included changes in five-year average fetal and neonatal mortality rates as well as short-term obstetric and newborn morbidity. Declines in fetal and neonatal as well as birthweight specific mortality rates were observed for both pilot and control regions, for both races, and especially for 1501-2500 g infants. However, comparisons of preprogram (1966-74) and postprogram (1975-80) average yearly changes showed no statistically significant differences between regions. While the incidence of prenatal morbidity was the same for both regions, intrapartum and newborn morbidity significantly favored the pilot region. These results were difficult to interpret. Program relevant implications of the findings in relation to rural RPC in North Carolina are discussed. Specific benefits appeared to be associated with the development of two high-risk maternity clinics and a Level II center capability in the pilot region. The importance of community support and public/private sector cooperation in relation to RPC is noted.

Hyperinsulinaemia in non-cirrhotic haemochromatosis: impaired hepatic insulin degradation?

This study investigated early alterations of glucose metabolism in idiopathic haemochromatosis. Circulating concentrations of glucose, insulin, C-peptide, glucagon, and gastric inhibitory polypeptide (GIP) were measured after a 100-g oral glucose load in 10 men with idiopathic haemochromatosis in the non-cirrhotic stage of the disease. All had normal glucose tolerance and normal body weight. Ten matched healthy subjects were studied as controls. Insulin concentrations increased to significantly higher levels in patients with idiopathic haemochromatosis than in the control subjects from 30 to 180 min after the glucose load (p less than or equal to 0.01), while fasting insulin concentrations were not significantly different (p greater than 0.05). Concentrations of glucose, glucagon, C-peptide, and GIP were not significantly different at any time (p greater than 0.05). Thus, patients with idiopathic haemochromatosis show hyperinsulinaemia and hence insulin resistance without impaired glucose tolerance in the non-cirrhotic stage. Since pancreatic insulin secretion (C-peptide), glucagon secretion, and the entero-insulinar axis (GIP) are not impaired in these non-cirrhotic patients with idiopathic haemochromatosis, iron accumulation in the hepatocytes may be responsible for the impaired insulin effect and may cause impaired hepatic insulin extraction.

Myosin isozyme changes in the heart following constriction of the ascending aorta of a 25-day old rat

When a constricting band is placed around the ascending aorta of young (25-day old) rats, all chambers of the heart eventually produce hypertrophy. Both the left and right ventricles show strong shifts toward an isozyme pattern in which V3 is predominant, similar to that seen in models where hypertrophy is induced in adult rats. The hypertrophied atria however, show no detectable change in the native myosin isozymes or the light chain subunits.

Measuring the impact of programs for mothers and infants on prenatal care and low birth weight: the value of refined analyses

During the past two decades, intervention strategies designed to improve the health status of mothers and infants have been widely disseminated, yet relatively few have been evaluated for effectiveness. Moreover, most reported investigations have involved straightforward comparisons of aggregate data, employing various degrees of methodological control. In this study, vital statistics data were used to assess the effects of the North Carolina Maternity and Infant Care (MIC) Project on use of prenatal care and low birth weight. A weighted least squares procedure was used to control for selected maternal characteristics and identify significant interactions. Analyses of total population data indicated only minor MIC effects. However, more careful scrutiny of subpopulation data suggests that MIC impacts differed across categories of maternal risk status, with the greatest influence observed among mothers and infants at greatest risk. These findings raise several questions regarding the genesis of differential effects and suggest areas of special concern in conducting, interpreting, and using evaluations of programs for mothers and infants.

Decline in neonatal mortality, 1968 to 1977: better babies or better care?

A state's declining neonatal mortality rate was studied over the decade 1968 to 1977 to determine how much of the decrease resulted from improved risk characteristics in the newborn population. A shift was found over time, mostly among white births, toward higher birth weights and longer gestations. Overall, there was a 19% reduction in the low-birth-weight rate. Considerable improvement in birth weight-specific mortality was also found, especially in babies weighing 1,000 to 2,500 g during the last 5 years of the study. A neonatal risk matrix model was applied to the changes over time to separate the improvement due to shifts in population risk characteristics from that due to better care of the newborn. Thirty-four percent of the decade's decrease in NMR was attributable to changes in the birth weight and gestational age makeup of the newborn population. This "better babies" component was more prominent early in the decade and among the white population.

Characterization of translational-control ribonucleic acid isolated from embryonic chick muscle

Myosin heavy chain (MHC) mRNP particles have been purified from 13-day chick embryonic skeletal muscle by a combination of sucrose density gradient centrifugation and metrizamide buoyant density centrifugation. Associated with the mRNPs are at least three distinct low molecular weight RNA molecules including translational-control RNA (tcRNA). This particular RNA contains 102 nucleotides and is uridine and guanine rich, and its nucleotide sequence has been determined. tcRNA102 is capable of inhibiting the translation of the mRNAs with which it is associated upon preincubation in stoichiometric amounts. Under these conditions, endogenous reticulocyte mRNA is not inhibited. Under appropriate salt and temperature conditions, tcRNA102 is capable of reassociating with myosin heavy chain (MHC) mRNA, thus altering the sedimentation characteristics of the mRNA. This suggests that the mRNA-tcRNA102 interactions alter the secondary structure of the mRNA. In addition, tcRNA102 does not associate with ribosomal RNA or globin mRNA, suggesting that some degree of specificity is involved with the RNA-RNA interactions.

Analysis of interrupted time series mortality trends: an example to evaluate regionalized perinatal care

Interrupted time series designs are frequently employed to evaluate program impact. Analysis strategies to determine if shifts have occurred are not well known. The case where statistical fluctuations (errors) may be assumed independent is considered, and a segmented regression methodology presented. The method discussed ia applied to the assessment of changes in local and state perinatal postneonatal mortality to identify historical trends and will be used to evaluate the impact of the North Carolina Regionalized Perinatal Care Program when seven years of post-program mortality data become available. The perinatal program region is contrasted with a control region to provide a basis for interpretation of differences noted. Relevant segmented regression models provided good fits to the data and highlighted mortality trends over the last 30 years. Considerable racial differences in these trends were identified, particularly for postneonatal mortality. Segmented regression is considered relevant for the analysis of interrupted time series designs in other applications when errors can be taken to be independent. Thus, the methodology may be regarded as a general statistical tool for evaluation purposes.

Possible role for calmodulin in insulin release. Studies with trifluoperazine in rat pancreatic islets

The role of calmodulin in insulin secretion from rat pancreatic islets has been examined by the use of trifluoperazine, an inhibitor of calmodulin-Ca++-directed functions. It was found that 30 microM trifluoperazine caused 50% inhibition, and 100 microM, up to 73% inhibition of 16.7 mM glucose-stimulated insulin release. 100 microM trifluoperazine caused a similar inhibition of 10 mM glyceraldehyde-stimulated release. Therefore, the site of action of trifluoperazine in glucose stimulus-secretion coupling appears to be after the trioses. As trifluoperazine had no effect upon insulin release stimulated by 1 mM 3-isobutyl-1-methylxanthine, the inhibitory effect of trifluoperazine appears to be rather specific. Further, the process of exocytosis per se is not affected. It was also found that although trifluoperazine inhibited the effect of glucose to stimulate insulin release, it did not affect the synergism between glucose and 3-isobutyl-1-methylxanthine to potentiate insulin release. It may be concluded that trifluoperazine selectively inhibits one part of the mechanism by which glucose stimulates insulin release. Calmodulin plays a role in the stimulation of insulin release by glucose at a site between metabolism of trioses and elevation of cytosol Ca++, but is not involved in the final process of exocytosis.

Hospital and home support during infancy: impact on maternal attachment, child abuse and neglect, and health care utilization

Effects of early and extended postpartum contact and paraprofessional home visits on maternal attachment, reports of child abuse and neglect, and health care utilization were determined by random assignment of 321 low-income women to intervention or control groups immediately after delivery. Observations of maternal attachment were made at four months and 12 months. Hospital, health and welfare agency records, and interviews were used to determine reports of child abuse and neglect and health care utilization. After establishing a control for maternal background variables, early and extended contact explained statistically significant but small amounts of variance in several of the attachment measures. There were no statistically significant effects of the home visit interventions on maternal attachment, and neither intervention was related to reports of child abuse and neglect and health care utilization. Although the study supported earlier findings that early and extended contact has a significant effect, additional interventions are needed to support mother-infant attachment.

Cellular attachment as a sensitive indicator of the effects of diagnostic ultrasound exposure on cultured human cells

Dispersed cultured human cells (T-1 kidney, FL embryonic kidney, ES amniotic, and JHA amniotic) were seeded into plastic Petri dishes, incubated for 45 minutes, exposed to a clinical ultrasound source [total power output, 1.76 +/- 0.18 (S.D.) mW] for 0.25-60 minutes, and the medium replaced. Attachment was significantly reduced after only 0.50 minute of exposure. For all exposures, sensitivity of the JHA amniotic cells was greater than that of the kidney lines. Like incremental reduction in attachment, differential sensitivity among cell lines became less pronounced with protracted exposures. Thus cellular attachment is a sensitive parameter for studying the effects of diagnostic ultrasound.

The evaluation of Regionalized Perinatal Health Care Programs

A survey, conducted in the summer of 1974, to determine the extent of regionalized perinatal care in the United States revealed 28 states to have programs in operation. Evaluation was a common concern of these programs. A model for the evaluation of Regionalized Perinatal Care Programs is presented here with the North Carolina program used as an example. Evaluation was mandated as an integral component of the program in North Carolina, and this model has been developed in response to that mandate.

Thyroxine and triiodothyronine influence cultured throid cells: alterations of morphology and mucosubstances

Further experimentation with the steer thyroid cell line indicates that the formation of "follicles" is enhanced by exposure to 8.9 X 10(-7) M thyroxine (T4) or triiodothyronine (T3) for 96 hr. The production of mucosubstances by the cultured thyroid cells is also increased by treating with T4 or T3, effects demonstrable after staining with PAS-alcian blue at pH 2.5. It is suggested that these in vitro effects bear on morphological organization and synthetic activity of the thyroid gland as well as on autoregulation and intraglandular homeostasis that may occur in situ.