Young children's overgeneralizations with fixed transitivity verbs

The present study examined English-speaking children's tendency to make argument structure overgeneralization errors (e.g., I disappeared it). Children were exposed to several English verbs of fixed transitivity (exclusively intransitive or exclusively transitive) and then asked questions that encouraged them to overgeneralize usage of the verbs. Seventy-two children (24 in each of three age groups: 3, 4/5, and 8 years of age) experienced four actions performed by puppets. Each action had two verbs of similar meaning associated with it in the context of the experimental action: one more familiar to young children and one less familiar. Children at all ages were more likely to overgeneralize usage of verbs that were less familiar to them, supporting the hypothesis that children's usage of verbs in particular construction types becomes entrenched over time. As children solidly learn the transitivity status of particular verbs, they become more reluctant to use those verbs in other argument structure constructions.

Paediatric nosocomial urinary tract infection at a regional hospital

From a total of 26,603 admissions to the paediatric wards, 1360 paediatric nosocomial urinary tract infections (PNUTI) were identified during a 5-year retrospective chart review at the SFGH. The ages ranged from 3 days to 13 years, with 46% boys and 54% girls. The highest rates of PNUTI per service per 100 admissions were seen in the nursery (11.28) followed by paediatric surgery (2.89) and paediatric medicine (2.86). Although the greatest number of PNUTI occurred in the nursery, comparison between the years was not statistically significant. About 90% (1218 of 1360) of PNUTI occurred in catheterized patients. No documentation was found specifying the type of catheterization (intermittent or continuous). About 90% (1210 of 1360) of isolates were single organisms with Escherichia coli, Proteus mirabilis, Klebsiella spp. and Group B streptococci accounting for a total of approximately 70% of all pathogens. However, the composition of the most common isolate in each service differed. The most common isolate in the nursery was E. coli, in the paediatric medical and surgical services the most common isolates were Klebsiella spp. and Proteus mirabilis, respectively. Proteus mirabilis was isolated predominantly from boys with structural abnormality of the urethral tract. No PNUTIs were complicated by bacteraemia. The antibiotics with least effectiveness (in increasing order) for UTIs were cephalexin, ampicillin, trimethoprim, co-trimoxazole and tetracycline. The most effective antibiotics were nalidixic acid, gentamicin and amoxicillin-clavulanic acid.

Young children learn to produce passives with nonce verbs

Younger and older children (mean ages = 2 years 11 months and 3 years 5 months) learned 2 nonce verbs in a full passive or active transitive construction. When asked patient-focused questions encouraging passive-voice replies (e.g., "What happened to the ball?") or agent-focused questions encouraging active-voice replies (e.g., "What did Elmo do?"), children used a variety of strategies to meet the demands of the questions, usually without changing the construction in which the verb occurred. In Study 2 in which passive and active constructions were primed, 40% of the almost 3-year-old children used an active-introduced verb in a passive construction and 35% used a passive-introduced verb in an active transitive construction when discourse demands encouraged them to do so. Thus, before their 3rd birthdays, some children have an understanding of the passive and active transitive constructions general enough to support productive usages with newly learned verbs.

Young children learn to produce passives with nonce verbs

Younger and older children (mean ages = 2 years 11 months and 3 years 5 months) learned 2 nonce verbs in a full passive or active transitive construction. When asked patient-focused questions encouraging passive-voice replies (e.g., "What happened to the ball?") or agent-focused questions encouraging active-voice replies (e.g., "What did Elmo do?"), children used a variety of strategies to meet the demands of the questions, usually without changing the construction in which the verb occurred. In Study 2 in which passive and active constructions were primed, 40% of the almost 3-year-old children used an active-introduced verb in a passive construction and 35% used a passive-introduced verb in an active transitive construction when discourse demands encouraged them to do so. Thus, before their 3rd birthdays, some children have an understanding of the passive and active transitive constructions general enough to support productive usages with newly learned verbs.

Detection of excision nuclease in cell-free extracts from the adult mammalian brain

The autosomal recessive disorder xeroderma pigmentosum (XP) results from defects in the nucleotide excision repair (NER) pathway for DNA repair. NER normally repairs bulky DNA lesions, such as pyrimidine dimers resulting from UV radiation. XP patients have high rates of skin cancer, and some also develop progressive neurological degeneration. To better understand the mechanism of this neurodegeneration, I used a specific assay for the multicomponent excision nuclease of the NER pathway in cell-free extracts from the adult rat brain. Excision nuclease activity was detectable in whole-cell extracts prepared from the cerebellum, whereas extracts prepared from the forebrain, which has a lower density of cell nuclei, had much less activity. Nuclear extracts from both areas were equally capable of restoring activity to extracts from two different NER-deficient cell lines, despite large differences in the ratio of neurons to nonneuronal cells in the cerebellum and forebrain. These results indicate that the NER pathway is functional in neuronal cells in the adult brain. The implications of this finding for XP and other neurodegenerative diseases is discussed.

Nosocomial infections in a rural regional hospital in a developing country: infection rates by site, service, cost, and infection control practices

OBJECTIVE

To assess the prevalence of nosocomial infections at a rural government hospital from 1992 to 1995.

DESIGN

Retrospective review of data from 1992 to 1995 regarding rates of nosocomial infections, cost to government, and infection control practices.

SETTING

653-bed rural hospital providing primary and tertiary care.

PATIENTS

Patients admitted to the hospital between 1992 and 1995 who were found with hospital-acquired infections during their stay.

INTERVENTIONS

None.

RESULTS

Over the 4-year period, 7,158 nosocomial infections were identified from 72,532 patients (10.0/100 admissions). High nosocomial infection rates were found on the intensive-care unit (67/100 admissions), urology (30/100 admissions), neurosurgery (29.5/100 admissions), and newborn nursery (28.4/100 admissions). Urinary tract infections (4.1/100 admissions) accounted for most nosocomial infections (42%), followed by postoperative wound infections (26.8%) with a rate of 2.6/100 admissions. Nosocomial pneumonias and bloodstream infections also were common with 13.2% and 8.0%, respectively. The highest rates occurred on the intensive-care unit for both pneumonia (26.4/100 admissions) and bloodstream infection (7.0/100 admissions). The cost to the government for nosocomial infections was estimated at US $697,000 annually (US $1=$6 Trinidad and Tobago). Poor infection control practices, inadequate handwashing facilities, lack of supplies, and nonexistent garbage cans on most wards were quite evident.

CONCLUSIONS

Strict adherence to proper infection control practices, such as handwashing techniques, and improvement of facilities are crucial steps in preventing cross-infections in the hospital environment. Implementing these measures may substantially reduce the massive drain on the hospital budget in treating nosocomial infections. The saved revenue could go toward improvement of ward facilities and reduction of overcrowding, thus further reducing cross-infection.

Stimulation of expression of the oxytocin gene in rat supraoptic neurons at parturition

We measured expression of the oxytocin gene in the supraoptic nucleus (SON) during pregnancy, parturition and lactation to examine its relationship to states of accumulation or depletion of oxytocin stores and to conditions of strong excitation of oxytocin neurons. The primary transcript (heterogeneous nuclear RNA, hnRNA) of the oxytocin gene was measured using a 3H-cDNA probe against intron 1 for in situ hybridisation. Autoradiographs of the SON showed the hnRNA as discrete clumps of silver grains within the nucleus of each neuron. The number of cells expressing oxytocin hnRNA did not change during pregnancy but increased during parturition; 10-day lactating animals showed similar increases. Oxytocin mRNA was also measured by in situ hybridisation using a 3H- or 35S-labelled oligonucleotide probe against exon C: hybridisation was seen over the cytoplasm of supraoptic neurons, but no differences were measured between virgin, mid-pregnant, preparturient, parturient or 2-day lactating rats. The data suggest that enhanced oxytocin gene transcription is not necessary to increase oxytocin stores in pregnancy. However, acute stimulation of magnocellular oxytocin neurons at parturition, which strongly increases neuron activity and secretion, results in a rapid increase in the number of cells expressing oxytocin hnRNA, and increased expression is sustained in lactation.

Expression of long-patch and short-patch DNA mismatch repair proteins in the embryonic and adult mammalian brain

Expression of the DNA mismatch repair (MMR) pathway was examined in the adult and developing rat brain. Rat homologues of human GTBP and MSH2, which are essential components of the post-replicative DNA MMR system, were identified in nuclear extracts from the adult and developing rat brain. Developmental studies showed that both GTBP and MSH2 levels were higher in nuclei isolated from the embryonic brain (day 16) than adult brain. However, this difference was not as dramatic as the difference in the number of proliferating cells. Levels of thymine DNA glycosylase (TDG), the enzyme which catalyzes the first step in short patch G:T mismatch repair, were also decreased in adult compared to embryonic brain. In the adult brain, MMR proteins were elevated in nuclear extracts enriched for neuronal nuclei. These results suggest that adult brain cells have the capacity to carry out DNA mismatch repair, in spite of a lack of ongoing DNA replication.

Widespread expression and estrogen regulation of PPEIA-3' nuclear RNA in the rat brain

We previously identified a novel nuclear RNA species derived from the preproenkephalin (PPE) gene. This transcript, which we have named PPEIA-3' RNA, hybridizes with probes directed at a region of PPE intron A downstream of an alternative germ-cell transcription start site, but does not contain PPE protein coding sequences. We now report that estrogen treatment of ovariectomized rats increases the expression of conventional PPE heteronuclear RNA, and also induces the expression of PPEIA-3' RNA, apparently in separate cell populations within the ventromedial nucleus of the hypothalamus. Further, we show that cells expressing PPEIA-3' are found in several neuronal groups in the rat forebrain and brainstem, with a distinct topographical distribution. High densities of PPEIA-3' containing cells are found in the reticular thalamic nucleus, the basal forebrain, the vestibular complex, the deep cerebellar nuclei, and the trapezoid body, a pattern that parallels the distribution of atypical nuclear RNAs described by other groups. These results suggest that this diverse neuronal population shares a common set of nuclear factors responsible for the expression and retention of this atypical RNA transcript. The implication of these results for cell-specific gene transcription and regulation in the brain and the possible relationship of PPEIA-3' RNA and other atypical nuclear RNAs is discussed.

Preproenkephalin mRNA is regulated by an interaction between steroid hormones and nociceptive stimulation

The expression of preproenkephalin (PPE) mRNA has previously been shown to be regulated by steroid hormones in the ventromedial nucleus of the hypothalamus (VMH) and to be regulated by noxious stimuli in the dorsal horn of the spinal cord (DH). The present in situ hybridization study in ovariectomized rats showed that PPE mRNA expression in both the VMH and the lumbar DH, responds to the interaction between a noxious peripheral stimulus and ovarian steroid hormones. In the VMH, either estradiol or estradiol + progesterone increased the mean PPE mRNA content per cell by 100% compared with vehicle-treated rats. Unilateral hindpaw injection of 5% formalin, as compared to saline, significantly increased mean PPE mRNA content per VMH cell in rats treated with vehicle or estradiol but not those treated with estradiol + progesterone. Regression analysis for mean PPE mRNA content per VMH cell as a function of intensity of hindpaw inflammation showed a significant positive correlation coefficient after vehicle and estradiol treatment (P < 0.02) but a strong trend towards a negative correlation coefficient after estradiol + progesterone treatment (P < 0.06). ANOVA for homogeneity of regression coefficients showed a significant difference across hormone groups (P < 0.01). In the lumbar DH, mean PPE mRNA content per cell was greater in rats injected with formalin than with saline and was greatest in rats given steroids + formalin. Mean PPE mRNA content per DH cell was greater ipsilateral than contralateral to the formalin injection in estradiol-treated rats, but no laterality difference was seen in the other hormone groups. No significant differences in mean PPE mRNA levels per DH cell were found among the rats treated with saline + hormone, saline + vehicle, formalin + vehicle, or uninjected rats. For all hormone groups combined, mean PPE mRNA per DH cell showed a significant positive regression on intensity of hindpaw inflammation (P < 0.05). Taken together these data are consistent with reports of increased pain threshold during pregnancy, descending control of antinociception from the basomedial hypothalamus and positive correlations between VMH levels of PPE mRNA and lordosis, a behavior evoked by somatosensory stimulation below nociceptive threshold.

DNA damage, DNA repair, and alcohol toxicity--a review

Alcohol (ethanol) is clearly a toxic substance when consumed in excess. Chronic alcohol abuse results in a variety of pathological effects, including damage to the liver and brain, as well as other organs, and is associated with an increased risk of certain types of cancers. Alcohol consumption by pregnant women can result in fetal alcohol effects and fetal alcohol syndrome. All of these toxic effects are well documented. What is needed at present is a complete understanding of the molecular mechanisms by which alcohol causes these toxic effects. Such an understanding may lead to better treatments of some of these toxic effects. This review, focuses on the possibility that toxic effects of ethanol are mediated, at least in part, by damage to DNA. In particular, I emphasize data on the production of endogenous DNA-damaging molecules as a result of alcohol consumption and metabolism. Specific examples of DNA-damaging molecules to be considered are reactive oxygen species, including oxygen radicals, lipid peroxidation products, and acetaldehyde. The relevant DNA repair pathways that protect cells against DNA damage produced by these molecules will also be reviewed. The goal of this review is to integrate recent results from the fields of mutagenesis and DNA repair with the alcohol toxicity literature, with the aim of stimulating research into the role of DNA damage in different types of alcohol toxicity and the role of DNA repair in protecting cells from alcohol-related damage.

Human articular cartilage storage in cell culture medium: guidelines for storage of fresh osteochondral allografts

The viability of transplanted articular cartilage is one of the determinants of outcome following the transplantation of osteochondral allografts. Disappointing results from cryopreservation have led to the practice of fresh transplantation of articular segments, especially for posttraumatic defects. To date, no studies have demonstrated in vitro viability rates for refrigerated human cartilage awaiting transplantation. This study evaluates the effects of storage on the viability of human chondrocytes using cell culture medium. Human articular cartilage obtained from notchplasties was stored for up to 48 hours in cell culture medium. Radioactive 35S-sulfate uptake was determined at 0, 24, and 48 hours, as a measure of protein, synthesis, and chondrocyte viability. Specimens were stored at 4 degrees C in culture medium. Results showed an average decrease in 35S-sulfate uptake of 0.8% at 24 hours and 6.4% at 48 hours, indicating a high level of chondrocyte viability after refrigeration. Because transplantation typically is performed within 24 hours of tissue harvest, it appears that nearly 100% of chondrocytes should survive fresh transplantation.

An anxiolytic action of oxytocin is enhanced by estrogen in the mouse

The established role of oxytocin (OT) in facilitation of steroid-modulated reproductive and affiliative behaviors led to the speculation that it may have anxiolytic actions under certain hormonal conditions. NIH-Swiss mice were tested for responsiveness to OT in two behavioral tests of anxiety, the holeboard apparatus and elevated plus-maze. Dose-response assessment indicated that 3 mg/kg was the optimal dose for peripherally administered (IP) OT on the elevated plus-maze. There were no consistent effects at any dose on the holeboard apparatus. In ovariectomized mice pretreated with estradiol (E2), peripherally administered OT increased the number of entrances onto the open arms, as well as the amount of time on the open arms compared to other groups (ANOVA; p < 0.05). There was little to no effect of OT in ovariectomized animals not pretreated with E2. When OT was administered intracerebroventricularly (ICV), there was an increase in entrances and time on the open arms compared to that of females infused with arginine vasopressin (AVP). This increase was apparent in ovariectomized females, but was further enhanced in those pretreated with E2 (ANOVA; p < 0.05). In contrast, the combination of E2 pretreatment and ICV AVP decreased the number of entrances and time spent on the open arms of the elevated plus-maze compared to those receiving OT, suggesting an estrogen-modulated anxiogenic action of AVP. Analyses of [125]I-OVTA binding density indicated a significant increase in binding density in the lateral septum of E2-treated females compared to OIL-treated controls (ANOVA; p < 0.05). There was no effect of E2 treatment on [125]I-OVTA binding density in the amygdala or ventromedial nucleus of the hypothalamus. Taken together, these data indicate that OT exerts an anxiolytic action that is enhanced in the presence of circulating estrogen. This behavioral effect may be mediated by estrogen-induced increases in OT binding density in the lateral septum and may be important to the facilitation of social interactions.

What do children know about the universal quantifiers all and each?

Children's comprehension of the universal quantifiers all and each was explored in a series of experiments using a picture selection task. The first experiment examined children's ability to restrict a quantifier to the noun phrase it modifies. The second and third experiments examined children's ability to associate collective, distributive, and exhaustive representations with sentences containing universal quantifiers. The collective representation corresponds to the "group" meaning (for All the flowers are in a vase all of the flowers are in the same vase). The distributive representation implies a pairing (e.g., each flower paired with a vase for Each flower is in a vase). The exhaustive representation exhausts both sets (e.g., for The flowers are in the vases all the flowers are in vases and all the vases have flowers in them). Four- to 10-year-olds children had little difficulty restricting the quantifier all to the noun it modified in a task which required them to attend to the group feature of all. In contrast, only 9- and 10-year-olds were able to solve the task when the quantifier was each and the pictures showed entities in partial one-to-one correspondence. Children showed a preference for associating collective pictures with sentences containing all and distributive pictures with sentences containing each. The results suggest that between the ages of 5 and 10 years, children's semantic representations undergo less radical changes than others have proposed. Instead, developmental change may occur gradually as children acquire linguistic cues which map onto existing semantic representations.

DNA mismatch repair and DNA methylation in adult brain neurons

DNA repair is essential for maintaining the integrity of the nucleotide sequence of cellular DNA over time. Although much information has accumulated recently on the mechanisms of DNA repair in cultured cells, little is known about the DNA repair capabilities of cells in the adult brain. In the present study, we have investigated the capacity of nuclear extracts from adult rodent brain neurons to carry out DNA mismatch repair. We focused on the repair of G.T and G.U mismatches, which are caused by deamination of 5-methyl cytosine to thymine, or cytosine to uracil, respectively, because these are the only types of mismatches that can arise in nondividing cells. We found that nuclear extracts from adult brain neurons can correct G.T and G.U mismatches, restoring them to G:C base pairs. Several other types of DNA mismatches could not be processed. These data provide the first direct demonstration that neurons in the adult mammalian brain have the capability to carry out DNA mismatch repair. We also we report that adult brain contains high levels of DNA methyltransferase (MTase) activity. We propose that one function of DNA MTase in the adult brain is to remethylate newly incorporated cytosine residues from G.T mismatch repair after deamination of 5-methyl cytosine, thereby maintaining the original pattern of DNA methylation. The high levels of brain DNA MTase suggest further that this enzyme has additional functions in the brain.

Estrogen modulation of mRNA levels for the two forms of glutamic acid decarboxylase (GAD) in female rat brain

Two separate forms of glutamic acid decarboxylase, now termed GAD65 and GAD67, are the rate limiting enzymes for synthesis of gamma-aminobutyric acid (GABA). Because of the significance of GABA to neuroendocrine processes, numerous attempts have been made to determine the impact of gonadal steroids on enzyme functioning with inconclusive results. Therefore, we attempted to determine the impact of estradiol on mRNA levels for each form of GAD by quantitative in situ hybridization histochemistry in various brain regions. Ovariectomized rats were treated with estradiol benzoate or oil vehicle on 2 consecutive days and the brains collected on the third day. DNA probes specific for GAD65 and GAD67 were radiolabeled with CTP32 using asymmetric polymerase chain reaction. Results of in situ hybridizations for each probe on alternate sections from the same animals were analyzed for magnocellular preoptic area (McPOA), dorsal medial nucleus of the hypothalamus (DMN), zona incerta (ZI), and midbrain central gray (MCG). In the McPOA, estradiol exerted opposite effects on the frequency distribution of pixels per cell for two GAD mRNA probes, significantly increasing GAD65 (P < .05) and decreasing GAD67 (P < .01; Kolmogorov-Smirnov). In the DMN, estradiol treatment significantly increased GAD67 by 60% (P < .05; two-way ANOVA) but decreased GAD65 mRNA by 73% (P < .01). Note the direction of effects are opposite between McPOA and DMN. In MCG, analysis showed no estradiol effect on GAD mRNA levels/cells, but the proportion of cells expressing detectable levels of GAD65 or GAD67 increased by 33-40% in estradiol-treated rats (chi 2, P < .001).

The evolution of pharmacy residency training programs and corresponding standards of accreditation

Practice-based pharmacy training has a long history, particularly in institutional pharmacy practice. Formal pharmacy residency training programs and accreditation standards were first developed in the early 1960s. Practitioners now practice in a much different environment. Residency programs and accreditation standards have changed dramatically to meet the needs of practitioners, patients, and employers. The authors trace the evolution of programs from general internships through clinical practice and specialty residencies and fellowships and the development of standards and competency-based training.

Changes in preproenkephalin messenger RNA level in the rat ventromedial hypothalamus during the estrous cycle

To gain a better understanding of the relationship between the female rat reproductive system and preproenkephalin (PPE) expressing neurons under physiological conditions, we examined changes in PPE mRNA levels in the mediobasal hypothalamus during the rat estrous cycle by means of northern blotting and in situ hybridization histochemistry (ISHH). In the Northern blot studies, we found that PPE mRNA levels in the mediobasal hypothalamus were significantly increased by noon of proestrus compared to those in the morning and stayed high until diestrus day 1, and returned toward low levels on diestrous day 2. In contrast, measured as controls, glyceraldehyde-3-phosphate-dehydrogenase mRNA levels were significantly higher on proestrus regardless of time of day compared to diestrus day 2, and levels of calcineurin mRNA on proestrous and estrous were significantly lower than diestrous day 1 and day 2. ISHH studies revealed that these changes in PPE mRNA levels were specific in the ventromedial hypothalamic nucleus pars ventrolateralis (VMHVL), since we could not see any significant changes in signal in other parts including ventromedial hypothalamic nucleus pars dorsomedialis and arcuate hypothalamic nucleus. In the VMHVL, PPE mRNA levels in the afternoon of proestrous were significantly higher than those in the afternoon of diestrous day 2 whereas no significant change in PPE mRNA was observed in the caudate-putamen. The present study provides additional information relevant to possible implications of PPE gene expression in female reproductive systems, since changes in PPE mRNA levels may be associated with estrogen as well as progesterone or other hormonal concentrations during the estrous cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Luteinizing hormone-releasing hormone receptor messenger ribonucleic acid expression in the rat pituitary during lactation and the estrous cycle

To study mechanisms underlying the modulation of luteinizing hormone-releasing hormone receptor (LHRH-R) during lactation and the estrous cycle, we used a reverse transcriptase-polymerase chain reaction (RT-PCR) procedure to generate a probe for rat LHRH-R messenger RNA (mRNA). Using primers based on the mouse sequence, we amplified an approximately 300 bp fragment from rat pituitary complementary DNA. This PCR product was shown to be part of LHRH-R cDNA by direct sequencing and by comparing to the rat LHRH-R cDNA reported recently. Then, this PCR fragment was used as a probe for northern blotting analysis. The level of LHRH-R mRNA in the pituitary was significantly decreased during lactation, by approximately 80%, compared to that of ovariectomized and intact (diestrous and metestrous cycling) rats while no statistical difference in glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) mRNA level was observed between groups. During the estrous cycle, the level of LHRH-R mRNA in the pituitary was about two-fold higher on diestrous day 2 and the morning of proestrus than that on diestrous day 1 and quickly returned toward control level by noon of proestrus. In addition, we found that GAPDH mRNA levels from a so-called housekeeping gene often thought to be unchanged under different conditions, were significantly higher on proestrus while levels of 18S rRNA were not significantly changed. The large decrease in LHRH-R mRNA during lactation could account for the changes in LHRH binding previously reported.

Late infections of the foot due to incomplete removal of foreign bodies: a report of two cases

Foreign bodies in the foot can remain silent for years before presentation. We describe two foreign body infections in the feet of two patients more than 18 years after the initial insult. These cases emphasize the need for careful evaluation of patients with an unexplained infection in the foot, and thorough debridement, when surgical treatment is necessary.

Detection of messenger RNA and low-abundance heteronuclear RNA with single-stranded DNA probes produced by amplified primer extension labeling

We describe a procedure for detection of low-abundance cellular RNAs by in situ hybridization histochemistry, using single-stranded DNA probes produced by amplified primer extension labeling with Taq polymerase. We have used this approach to detect a number of high- and low-abundance RNA species and have found it to be a simple and reproducible method of obtaining sensitive probes for in situ hybridization studies. For example, DNA probes generated by amplified primer extension labeling can detect low-abundance heteronuclear RNAs in individual neurons. Since this procedure does not involve recombinant DNA technology or microbiological facilities, it should prove useful to a wide variety of investigators studying the regulation of gene expression at the cellular level.

Cell-specific expression of preproenkephalin intronic heteronuclear RNA in the rat forebrain

Using in situ hybridization with multiple probes to the rat preproenkephalin gene, we have identified a novel population of cells in the reticular thalamic nucleus and basal forebrain which express RNA derived from the preproenkephalin gene. These cells contain nuclear RNA from downstream of an alternate transcription start site in intron A of the preproenkephalin gene (Kilpatrick et al., Mol. Cell Biol., 10 (1990) 3717-3726), while in the same cells preproenkephalin exon 2 RNA is undetectable. The results suggest that in this population of cells, preproenkephalin gene transcription initiates from the intron A initiation site, and is regulated by an additional mechanism which results in the accumulation of nuclear preproenkephalin intron A-derived heteronuclear RNA. The anatomical distribution of these cells indicates that they may be involved in the control of cerebral cortical function.

Prolactin receptor messenger RNA is synthesized by the epithelial cells of the choroid plexus

To identify cellular sites of prolactin receptor messenger RNA synthesis in the rat brain, we used a combined reverse transcriptase-polymerase chain reaction protocol to generate single stranded DNA probes for in situ hybridization. The results of these experiments identify the epithelial cells of the choroid plexus as a major site of prolactin receptor gene expression in the rat central nervous system.

Drug therapy of diabetic neuropathy

Neuropathy is the most common and perhaps the most devastating complication associated with diabetes. Although many theories regarding the pathogenesis of diabetic neuropathies have been proposed, the most popular theory focuses on the accumulation of sorbitol in the nerve cell through the "polyol pathway." Treatment for diabetic neuropathy remains inadequate. Newer agents such as the aldose reductase inhibitors show some promise in halting and perhaps reversing the pathogenesis of this complication; however, these agents remain investigational. Currently, the most reasonable approach involves the use of agents to control pain and other symptoms associated with this progressive disease.

Oxytocin Messenger Ribonucleic Acid Levels in the Medial Preoptic Area are Increased During Lactation

Abstract The peptide hormone oxytocin has an important role in parturition, lactation and maternal behavior. The present study employed in situ hybridization histochemistry to determine whether oxytocin messenger ribonucleic acid (mRNA) levels in cells in the medial preoptic area, a brain area known to control maternal behavior, change during pregnancy and lactation in the rat. Female rats were perfused on either Day 18 or 22 of pregnancy or Day 5 of lactation. Ovariectomized female rats were included as an additional control group. Cells expressing oxytocin mRNA were detected by in situ hybridization using an [(125) l]-labeled 38 base synthetic oligodeoxynucleotide probe complementary to the C-terminal coding region of the preprooxytocin. Relative differences in oxytocin mRNA levels were determined by silver grain counting of labeled cells. A group of oxytocin neurons in the dorsal medial preoptic area, called the lateral subcommissural nucleus, showed elevated oxytocin mRNA levels in lactating animals relative to ail other groups. Oxytocin mRNA levels in the neurons of the periventricular nucleus of the preoptic area did not change across pregnancy and lactation. This result extends the findings of others showing elevated oxytocin mRNA levels in magnocellular nuclei of lactating animals. The results are discussed in terms of the possible role of oxytocin cells in the medial preoptic area in the expression of maternal behavior.

Pharmacokinetics of methotrexate administered by intramuscular and subcutaneous injections in patients with rheumatoid arthritis

The serum concentrations and the pharmacokinetics of low-dose methotrexate (MTX) were compared after both intramuscular (IM) and subcutaneous (SQ) injections in 5 patients with rheumatoid arthritis. Values for the observed peak concentration, the time to the observed peak concentration, and the area under the time versus concentration curve for IM injections were not significantly different from these values for SQ injections. These results suggest that IM and SQ are interchangeable routes of administration. SQ administration may be a more convenient and less painful way of administering low-dose MTX.

Estrogen alters oxytocin mRNA levels in the preoptic area

Abstract Estrogen has numerous effects on immunoreactive levels of oxytocin (OXT) centrally, particularly in the preoptic lateral subcommissural nucleus (LSN). In this study in situ hybridization of a 38-base oligodeoxyribonucleotide (38mer) complementary to OXT mRNA revealed that estrogen treatment altered the pattern of OXT production in the rostral LSN and the more caudal anterior commissural nucleus. Rats were injected with 20 ng estradiol benzoate or sesame oil vehicle im 4 and 5 days after ovariectomy. On the sixth day all animals were perfused with paraformaldehyde-glutaraldehyde and their brains sectioned to 10 mum thickness in a -10 degrees C cryostat. Coronal brain sections were taken from four parallel levels of the preoptic-anterior hypothalamic area. These sections were mounted and hybridized in situ to a [l(125)]-labeled 38mer for 16 h at 37 degrees C. Washed and dried slides were processed for autoradiography and analyzed with a light microscope. The effect of estrogen on OXT production differed between the rostral and caudal sections in both the LSN and periventricular (PeV) areas. Estrogen significantly increased OXT mRNA levels in LSN cells while decreasing hybridization in the anterior commissural nucleus cells. Changes in frequency patterns in the PeV paralleled those in the LSN with a significant drop of hybridization in the caudal PeV. Neurons hybridizing 38mer probe were also found in several other areas including the ventral medial preoptic area, lateral hypothalamus, bed nucleus of the stria terminalis and the nucleus triangularis septi. OXT mRNA levels were affected by estrogen treatments and this effect differed between the preoptic area and anterior hypothalamus. The sensitivity of LSN oxytocinergic cells to estrogen has implications for estrogen-sensitive OXT-enhanced reproductive behaviors.

The Medical Assistant, 6th edition M Kinn and E Derge The Medical Assistant, 6th edition W B Saunders 878pp £21.00 0-7216- 1731-X

Written for the American equivalent of nursing auxiliaries, The Medical Assistant: Administrative and Clinical has a logical format, is well illustrated and the information is easy to find because of the additional detailed contents list and index. The UK nursing auxiliary would find two of the three sections relevant.

Insulin-like growth factor II messenger ribonucleic acids are synthesized in the choroid plexus of the rat brain

Previous studies demonstrating the presence of immunoreactive insulin-like growth factors (IGFs) and their receptors in the brain suggest a role of the IGFs in the central nervous system. IGF-II has been implicated as the predominant IGF in brain of mature animals based on studies of immunoreactive peptide and of IGF-II mRNAs. To obtain information about the sites of synthesis of IGF-II in adult rat brain, a 32P-labeled 31 base long synthetic oligodeoxyribonucleotide complementary in sequence to trailer peptide coding sequences in rat IGF-II mRNA (IGF-II 31 mer) was hybridized with coronal sections of fixed rat brain. The IGF-II 31 mer showed specific hybridization with the choroid plexus throughout rat brain, whereas in other brain regions, structures or cells, hybridization was not discernibly above background. These findings suggest that the choroid plexus is a primary site of synthesis of IGF-II, a probable source of IGF-II in cerebrospinal fluid, and a potential source of IGF-II for actions on target cells within the adult rat brain.

Revision total hip arthroplasty with osseous allograft reconstruction. A clinical and roentgenographic analysis

One hundred twelve irradiation-sterilized, -70 degrees frozen allografts have been used in 72 patients who were available for follow-up study in a prospective analysis of allograft revision total hip arthroplasty. Clinical objectives were achieved in 85% of patients with a follow-up period ranging from six to 72 months. Based on clinical and roentgenographic analysis, specific recommendations are made to further improve the success rate of revision total hip arthroplasty associated with protrusio, shelf, acetabular, calcar, and large fragment femoral allografts.

Growth hormone dependence of somatomedin-C/insulin-like growth factor-I and insulin-like growth factor-II messenger ribonucleic acids

The GH dependence of somatomedin-C/insulin-like growth factor I (Sm-C/IGF-I) and insulin like growth factor II (IGF-II) mRNAs was investigated by Northern blot hybridizations of polyadenylated RNAs from liver, pancreas, and brain of normal rats, untreated hypophysectomized rats, and hypophysectomized rats 4 h or 8 h after an ip injection of human GH (hGH). Using a 32P-labeled human Sm-C/IGF-I cDNA as probe, four Sm-C/IGF-I mRNAs of 7.5, 4.7, 1.7, and 1.2 kilobases (kb) were detected in rat liver and pancreas but were not detectable in brain. In both liver and pancreas, the abundance of these Sm-C/IGF-I mRNAs was 8- to 10-fold lower in hypophysectomized rats than in normal rats. Within 4 h after injection of hGH into hypophysectomized animals, the abundance of liver and pancreatic Sm-C/IGF-I mRNAs was restored to normal. A human IGF-II cDNA was used as a probe for rat IGF-II mRNAs which were found to be very low in abundance in rat liver and showed no evidence of regulation by GH status. In pancreas, IGF-II mRNA abundance was below the detection limit of the hybridization procedures. The brain contained two IGF-II mRNAs of 4.7 and 3.9 kb that were 5-fold lower in abundance in hypophysectomized rats than in normal rats. These brain IGF-II mRNAs were not, however, restored to normal abundance at 4 or 8 h after ip hGH injection into hypophysectomized animals. To investigate further, the effect of GH status on abundance of Sm-C/IGF-I and IGF-II mRNAs in rat brain, a second experiment was performed that differed from the first in that hypophysectomized rats were given an injection of hGH into the lateral ventricle (intracerebroventricular injection) and a rat Sm-C/IGF-I genomic probe was used to analyze Sm-C/IGF-I mRNAs. In this experiment, a 7.5 kb Sm-C/IGF-I mRNA was detected in brain polyadenylated RNAs. The abundance of the 7.5 kb mRNA was 4-fold lower in hypophysectomized rats than in normal rats and was increased to 80% of normal within 4 h after icv administration of hGH to hypophysectomized animals. As in the first experiment, the abundance of the 4.7 and 3.9 kb brain IGF-II mRNAs was lower than normal in hypophysectomized rats. Brain IGF-II mRNAs were increased to 50% of normal in hypophysectomized rats given an icv injection of hGH but within 8 h after the injection rather than at 4 h as with Sm-C/IGF-I mRNAs.

Effect of lesion location within the medial preoptic-anterior hypothalamic continuum on maternal and male sexual behaviors in female rats

Lesions of the medial preoptic-anterior hypothalamic continuum (MPOA-AH) are known to disrupt both maternal behavior and male sexual behavior in the rat. In order to test the hypothesis that the two behaviors involve different neural systems in the MPOA-AH, small bilateral lesions were made in different anterior-posterior locations in the MPOA-AH of maternal-sensitized, testosterone-treated female rats, and the effects of these lesions on maternal and male sexual behaviors were assessed. Lesions centering in the MPOA disrupted maternal behavior (pup retrieval, nest building, and nursing), with anterior MPOA lesions being more effective (on pup retrieval and nest building) than posterior MPOA lesions. Lesions centering in the AH had little or no effect on maternal behavior. By contrast, male sexual behavior (mounting) was strongly disrupted by lesions in either the MPOA or the AH, with lesions in the rostral AH being most effective.

Tibial component fixation in deficient tibial bone stock

A stylized wedge-shaped defect was created in the medial plateau of autopsy specimens of the tibia to evaluate methods for fixation in total knee arthroplasty. A series of tibial components was inserted by five different methods. With each method loading of up to 1780 N axially and a varus load of 1340 N at 28 Newton-meters were assessed. The vertical deflections of the medial and lateral sides of the tray relative to the bone were measured while bending of the stem was recorded with strain gauges. The greatest deflections occurred when cement alone filled the defect; only slight improvement resulted from the addition of two cancellous screws to buttress the metal tray. Further improvement occurred when solid spacers of Plexiglas or metal were used. Finally, the most secure support was obtained with an integral custom-made tibial component. A central stem 70 mm long carried 23%-38% of the axial load, considered useful in the situation of deficient proximal bone. A metal wedge was considered an acceptable alternative to a custom-made component and may prove useful in the reconstruction of tibial bone stock defects.

Effect of lesion location within the medial preoptic-anterior hypothalamic continuum on maternal and male sexual behaviors in female rats

Lesions of the medial preoptic-anterior hypothalamic continuum (MPOA-AH) are known to disrupt both maternal behavior and male sexual behavior in the rat. In order to test the hypothesis that the two behaviors involve different neural systems in the MPOA-AH, small bilateral lesions were made in different anterior-posterior locations in the MPOA-AH of maternal-sensitized, testosterone-treated female rats, and the effects of these lesions on maternal and male sexual behaviors were assessed. Lesions centering in the MPOA disrupted maternal behavior (pup retrieval, nest building, and nursing), with anterior MPOA lesions being more effective (on pup retrieval and nest building) than posterior MPOA lesions. Lesions centering in the AH had little or no effect on maternal behavior. By contrast, male sexual behavior (mounting) was strongly disrupted by lesions in either the MPOA or the AH, with lesions in the rostral AH being most effective.