Maternal and infant care: comparisons between Western Europe and the United States

A series of studies between 1986 and 1990 gathered data on maternal and infant care in ten Western European countries with lower infant mortality rates than the United States and compared the findings both within the European countries and in aggregate with the United States. Results from these studies reveal great variation among the study countries in how perinatal care is financed, staffed by professional and nonprofessional health workers, and provided by public clinics or private offices, and in the number of and locale of the recommended number of prenatal visits. Invariably consistent among the study countries is the nearly complete enrollment of childbearing women in early and continuous prenatal care, and the strong linkage of that care to a generous spectrum of social supports and financial benefits. None of the benefits generally pertains in the United States. The relevance of these observations for the United States suggests that current policies intended to lower economic barriers to a highly medicalized version of maternity care may yield disappointing results unless the perinatal sequence is linked to a more generous set of maternity-related social supports and financial benefits than is now contemplated.

cis-acting components in the replication origin from ribosomal DNA of Saccharomyces cerevisiae

The ribosomal DNA (rDNA) repeats of Saccharomyces cerevisiae contain an autonomously replicating sequence (ARS) that colocalizes with a chromosomal origin of replication. We show that a minimal sequence necessary for full ARS function corresponds to a 107-bp rDNA fragment which contains three 10-of-11-bp matches to the ARS consensus sequence. Point mutations in only one of the 10-of-11-bp matches, GTTTAT GTTTT, inactivate the rDNA ARS, indicating that this consensus sequence is essential. A perfect match to a revised ARS consensus is present but not essential. Sequences up to 9 bp 5' from the essential consensus are dispensable. A broad DNA region directly 3' to the essential consensus is required and is easily unwound as indicated by: (i) hypersensitivity to nicking of an approximately 100-bp region by mung bean nuclease in a negatively supercoiled plasmid and (ii) helical instability determined by thermodynamic analysis of the nucleotide sequence. A correlation between DNA helical instability and replication efficiency of wild-type and mutated ribosomal ARS derivatives suggests that a broad region 3' to the essential ARS consensus functions as a DNA unwinding element. Certain point mutations that do not stabilize the DNA helix in the 3' region but reduce ARS efficiency reveal an element distinct from, but overlapping, the DNA unwinding element. The nucleotide sequence of the functionally important constituents in the ARS appears to be conserved among the rDNA repeats in the chromosome.

Characterization of wave I of the electrically evoked auditory brainstem response in the guinea pig

This paper examines the first component of the electrically evoked auditory brainstem response (EABR) of the guinea pig. Short (20 microseconds/phase) and long (4000 microseconds/phase) duration rectangular current pulses were applied through a bipolar intracochlear electrode in acute preparations. Short-duration pulses evoked a synchronized response relatively free of stimulus artifact; long pulses facilitated examination of the integrative capacities of nerve fibers at relatively low current levels. In deafened control subjects, wave I of the EABR consistently demonstrated two positive peaks having different latency-level and adaptation recovery functions. The early component (wave Ia) showed less decrement in latency with increasing stimulus level and recovered faster in a forward-masking paradigm. Non-monotonicities in the adaptation recovery curves were also observed, more consistently in the wave Ib data. It is proposed that wave Ia arises from stimulation of the axons proximal to the spiral ganglion while wave Ib is initiated at the peripheral dendritic processes. Implications for human cochlear implant research are discussed.

The partition (par) locus of pSC101 is an enhancer of plasmid incompatibility

The incompatibility that pSC101-derived plasmids express toward each other is mediated by directly repeated sequences (iterons) located near the plasmid's replication origin. We report here that the pSC101 par locus, which stabilizes plasmid inheritance in dividing cell populations and alters DNA superhelicity, can function as a cis-acting enhancer of incompatibility, which we show is determined jointly by the copy number of the plasmid and the number of iterons per copy. A single synthetic 32 bp iteron sequence carried by the pUC19 plasmid confers strong pSC101-specific incompatibility in the absence of any other pSC101 sites but requires the par locus to express strong incompatibility when carried by a lower-copy-number plasmid. We propose a model by which the par locus can enhance the apparently antagonistic processes of incompatibility and pSC101 DNA replication while concurrently facilitating plasmid distribution during cell division.

Abnormal neuritic architecture identified by Di-I in Pick's disease

The fluorescent stain Di-I combined with confocal microscopy identified an abnormal neuritic pattern in the cortices of frontal and anterior temporal lobes in postmortem tissues from patients with Pick's disease (PD). Focal, dense neuritic aggregates 50 to 200 microns in diameter were scattered throughout all cortical layers. The three-dimensional analysis provided by confocal microscopy revealed the neuritic clusters to consist of enlarged, randomly arrayed, dystrophic neurites that were not associated with amyloid deposits, astrocytic processes or capillaries. In the intervening neuropil, there were fewer neurites compared to controls. The occipital cortex, which is unaffected in PD, showed a neuritic architecture comparable to normal controls as did affected brain tissues from patients with Alzheimer's disease or remote, ischemic infarction. This neuritic pattern is, thus far, unique to PD and may reflect the loss of specific subpopulations of cortical neurons and proliferation of neurites of the remaining neurons.

Trends in HIV prevalence among disadvantaged youth. Survey results from a national job training program, 1988 through 1992

OBJECTIVE

To describe trends in the prevalence of human immunodeficiency virus (HIV) among socially and educationally disadvantaged US youth.

DESIGN

Analysis of demographic and geographic trends of HIV infection among Job Corps students from January 1988 through December 1992.

SETTING

The Job Corps is a national training program for disadvantaged and out-of-school youth. POPULATION SCREENED: Youths aged 16 to 21 years who entered the Job Corps residential training centers during the survey period.

MAIN OUTCOME MEASURE

Trends in prevalence of HIV infection among Job Corps students stratified by sex, age, race, and region of the country.

RESULTS

Of the 269,956 Job Corps students screened, 812 (0.3%) tested positive for the antibody to HIV type 1. Seroprevalence of HIV for young men decreased from 3.6 per 1000 in 1988 to 2.2 per 1000 in 1992 (chi 2 test for trend, P < .001). Seroprevalence for young women increased from 2.1 per 1000 in 1988 to 4.2 per 1000 in 1990 (P = .001), with seroprevalence remaining stable from 1990 through 1992. The decreasing trends in HIV prevalence among men and increasing trends among women were primarily due to changes in seroprevalence in African-American students.

CONCLUSIONS

The overall prevalence of HIV infection of three per 1000 is high, given the youth of Job Corps students. The significant rise in HIV rates among female Job Corps students provides evidence of the increasing risk of infection for socioeconomically disadvantaged young women. Reasons for the declining trend in HIV prevalence among male Job Corps students are not clear. Efforts to prevent the spread of HIV infection among adolescents must focus on the group that is hardest to reach--out-of-school and impoverished youth.

Transgenic mouse model for neurocristopathy: Schwannomas and facial bone tumors

We have characterized a strain of double transgenic mice with simian virus 40 large tumor antigen and prokaryotic lacZ under the control of the myelin basic protein promoter that develops spindle-cell sarcomas and osteogenic sarcomas at 5-7 months of age. Although poorly differentiated, the spindle-cell sarcomas were characterized as malignant Schwannomas based on their neural association, the presence of basal lamina, and expression of Schwann cell-specific genes. The osteogenic sarcomas were often multiple and appeared predominantly in the facial bones, less frequently in the ribs and vertebral column, and only rarely in the appendicular skeleton. Benign osteoblastic lesions were often observed adjacent to these sarcomas. Both the osteoblastic cells in the facial skeleton and Schwann cells are regarded as neural crest derivatives. The biological properties and anatomical location of these tumors suggest that they may share a common origin from the neural crest or its derivatives. R.P. Bolande [Hum. Pathol. (1974) 5, 409-429] introduced the term neurocristopathy as a unifying concept to describe such lesions arising from the neural crest or its derivatives. Cell lines established from both bone and Schwann cell tumors arising in these transgenic mice express simian virus 40 large tumor antigen mRNA as well as functional large tumor antigen. Such cell lines are potentially valuable in the search for markers that identify mammalian neural crest derivatives.

Auditory system degeneration in Alzheimer's disease

We observed a highly topographically specific and consistent pattern of degeneration in the auditory system of Alzheimer's disease (AD) patients. Senile plaques (SP) and neurofibrillary tangles (NFT) were distributed throughout the ventral nucleus of the medial geniculate body (MGB) and the central nucleus of the inferior colliculus (IC) in nine of nine AD patients. Adjacent nuclei within the MGB and IC were consistently spared. NFT and SP were also present in the primary auditory and the auditory association cortices. In all control tissues, there were neither SP nor NFT in any of the above sites. The cochlear nuclei were normal in tissues from both AD and control patients. The ventral nucleus of the MGB is the major thalamic relay station for auditory function and receives fibers from neurons of the central nucleus of the IC, with projections arranged tonotopically in a laminar pattern corresponding to a gradient of high-to-low frequency ranges. The degenerative changes distributed throughout these nuclei suggest that neuronal loss may include all frequency ranges in AD. In contrast, the clinical features of presbycusis in elderly patients include only high-frequency loss due to lesions peripherally in the cochlea or auditory nerves, rather than in the central auditory nuclei. These histologic changes in the brains of AD patients may provide an additional basis for altered cognitive function due to primary sensory deafferentation.

Electrically evoked auditory brainstem response to stimulation of different sites in the cochlea

It is often assumed that stimulation of the eighth nerve with brief current pulses results in a highly synchronous discharge of action potentials from the ensemble of excited nerve fibers. Latency data derived from the electrically evoked auditory brainstem response (EABR) of the guinea pig and human indicate that there is a baso-apical gradient of response latencies in both species. Place-specific stimulation of different regions of the guinea pig cochlea was achieved by positioning a narrowly spaced bipolar electrode into each of the four spiral turns. Peak latencies of EABR waves I and III both revealed longer latencies with increasing distance from the base. Different amplitude growth functions were obtained from each turn. Place-specific stimulation in humans implanted with the Nucleus 22-electrode device was achieved by presenting current pulses across electrodes spaced 1.5 mm apart. A gradient of wave V latencies was observed in all subjects studied. The presence of a latency gradient would influence results obtained in efforts to correlate evoked potential amplitude measures with nerve survival. It may also provide information useful in characterizing the surviving fiber population in human implant subjects.

Calphotin: a Drosophila photoreceptor cell calcium-binding protein

Monoclonal antibody 23E9 identifies a calcium-binding protein, calphotin, in photoreceptor cells of the Drosophila melanogaster compound eyes and ocelli. The antigen is restricted to a defined cytoplasmic region; it is not present in the rhabdomeres, nuclei, mitochondria, or rough endoplasmic reticulum. A corresponding cDNA recognizes a 3-kb mRNA with retinal specificity similar to the antigen and maps to band 86E/F-87A/B on chromosome 3. An open reading frame of 2595 bp encodes an estimated 85-kDa protein of unusual amino acid composition, with > 50% proline, alanine, and valine and very few basic residues. The C-terminal segment contains a leucine zipper motif uninterrupted by prolines. We found no significant similarities with the GenBank or National Biomedical Resource Foundation data bases. The location of the protein within a distinct cytoplasmic region suggests that it might function as a calcium-sequestering "sponge" to regulate the amount of free cytoplasmic calcium.

The use of primidone in neonates with theophylline-resistant apnea

OBJECTIVE

To determine whether primidone reduced the occurrence of apnea of prematurity in neonates with apnea resistant to theophylline.

DESIGN

Retrospective review.

SETTING

Neonatal intensive care unit.

PARTICIPANTS

Sixteen premature infants (mean age, 27.8 weeks) in whom apnea and bradycardia recurred despite therapeutic levels of theophylline. Six of the patients were receiving assisted ventilation.

INTERVENTION

Administration of primidone (10 to 15 mg/kg per day) orally or by nasogastric tube at a mean age of 35 days.

RESULTS

Apnea and bradycardia decreased significantly 24 to 72 hours after initiation of primidone treatment (by 68% and 69%, respectively) compared with pretreatment events. We obtained similar results after a separate analysis of the 10 patients who had been weaned from assisted ventilation before treatment with primidone. No toxic reactions were observed.

CONCLUSIONS

Primidone represents a possible adjuvant therapy in theophylline-resistant apnea of prematurity. Caution is advised, because of primidone's complex pharmacologic characteristics, until there are further controlled prospective studies.

MR quantification of cerebral ventricular volume using a semiautomated algorithm

PURPOSE

A semiautomated border identification algorithm, insensitive to user bias, is evaluated for accuracy and speed in the measurement of ventricular volumes from three-dimensional MR images.

METHODS

A three-dimensional gradient-echo technique was implemented on a Signa clinical imaging system. Data from phantoms and patients were analyzed for volume using a segmentation algorithm designed with: 1) correction for partial volume averaging; 2) insensitivity to user bias; and 3) speed. Accuracy, precision, and intra- and interobserver variability were determined.

RESULTS

Average error for phantom studies was 4% to 6%, or 1 to 2 cc across the volumes, which ranged from normal to mild hydrocephalus (< 60 cc). Patient studies showed intra- and interobserver error of 2.3% and 7.8%, respectively. The correction for partial volume averaging resulted in a threefold decrease in error. Data were acquired and reconstructed within 7 minutes. Experienced radiologists required less than 15 minutes to perform each analysis.

CONCLUSIONS

This algorithm allows accurate measurement of ventricular volumes in an efficient, minimally supervised manner.

Improved recovery of immature myocardium with L-glutamate blood cardioplegia

Enhancement of myocardial recovery with glutamate-enriched cold blood potassium cardioplegia (BPC) was evaluated using an isolated working heart model. Three groups of hearts from immature rabbits were subjected to 20 minutes of warm (37 degrees C) ischemia to allow energy depletion, followed by 90 minutes of hypothermic (10 degrees C) ischemia. Myocardial protection provided during hypothermia consisted of cardioplegia infusion, at 50 mm Hg every 30 minutes at 4 degrees C, of either St. Thomas' Hospital solution (group 1, n = 6), oxygenated BPC (group 2, n = 7), or oxygenated BPC enriched with 20 mmol/L L-glutamate (group 3, n = 7). Percent recovery of aortic flow was 87.6% +/- 6.3% (results expressed as mean +/- standard error of the mean) in group 3, which was significantly better than for either group 1 (63.4% +/- 4.0%) or group 2 (47.0% +/- 3.5%) (p < 0.05 by analysis of variance). Group 3 hearts had significantly better recovery of myocardial energy stores (mumol/g dry weight) compared with group 1 or 2 hearts: adenosine triphosphate, 17.8 +/- 1.1 versus 12.4 +/- 1.5 and 12.1 +/- 0.4; creatine phosphate, 25.9 +/- 1.8 versus 17.8 +/- 1.8 and 20.3 +/- 0.7; and glycogen, 140.7 +/- 12.6 versus 98.7 +/- 9.9 and 60.7 +/- 9.9 (p < 0.05). Glutamate-enriched BPC provided excellent myocardial protection after ischemia in this immature model, and this study quantitatively supports the use of glutamate-enriched BPC in neonatal clinical practice.

The impact of critical events of the 1980s on core functions for a selected group of local health departments

Directors of 14 public health departments were surveyed for their perceptions on the impact of 20 critical events of the 1980s on public health performance. The departments were selected in 1979 from among those that were highly regarded by public health experts for exemplary performance, especially with regard to personal health services. The departments were the subjects of intensive case studies in 1979, 1983, and again in 1992. The public health functions that were most benefited in the 1980s were assessment and policy development. The assurance function was equivocally affected. Greatest positive impact was exerted by the acquired immunodeficiency syndrome-human immunodeficiency virus epidemic, by increase in fee income, and by the Institute of Medicine report, "The Future of Public Health." Negative influences, especially on the assurance function were exerted by loss of Federal grants, demographic changes, substance abuse, and economic downturn. Other critical events had equivocal or idiosyncratic effects. Analysis of public health practice according to the functions of assessment, policy development, and assurance appears to have utility for purposes of evaluation and planning.

Magnetic resonance imaging and pathological correlates of meningiomas

We examined the relationships between specific magnetic resonance imaging features and certain gross and microscopic characteristics of meningiomas, including vascularity, gross texture (consistency), and venous sinus involvement. Magnetic resonance imaging scans, surgery reports, and the histopathological findings of tumors were examined retrospectively in 54 patients. Sinus involvement was accurately predicted on T1-weighted images in 9 of 10 cases (P = 0.001) and tumors with cystic changes in 3 of 3 cases. T1-weighted images were not useful for predicting vascularity unless actual flow voids could be visualized (five of six cases). There was no correlation between T1 signal intensity, tumor consistency, or histological findings. In tumors without detectable vascularity on T1-weighted images, hyperintensity relative to gray matter on T2-weighted images was correlated with increased vascularity (P = 0.004). Tumors with soft consistency (P = 0.007), cellular atypia, invasion, angioblastic, or melanocytic components were also hyperintense, compared with gray matter on T2-weighted images (P = 0.0266). Aggressive meningiomas were found to be more vascular (P = 0.045). No correlation was found between the degree of surrounding edema or contrast enhancement with histopathological findings, vascularity, or consistency.