Human herpesvirus-encoded MicroRNA in host-pathogen interaction

Human herpesviruses (HHV) are ubiquitous, linear dsDNA viruses that establish lifelong latency, disrupted by sporadic reactivation. HHV have evolved diverse ingenious mechanisms to evade robust host defenses. Incorporation of unique stem loop sequences that generate viral microRNAs (v-miRs) exemplifies one such evolutionary adaptation in HHV. These noncoding RNAs can control cellular and viral transcriptomes highlighting their ability in shaping host-HHV interactions. We summarize recent developments in functional characterization of HHV-encoded miRNAs in shaping the outcome of host-pathogen interaction. Non-immunogenic dissemination of v-miRs through exosomes confer added advantage to HHV in incessant modulation of host microenvironment. This review delineates the mechanistic role of v-miRs in facilitating viral persistence and tropism by targeting genes associated with cellular (apoptosis, angiogenesis, cell migration, etc.) and viral life cycle (latency, lytic and reactivation). Burgeoning evidences indicate plausible association of v-miRs in various immune-mediated diseases (nasopharyngeal carcinoma, neurological disorders, periodontal diseases, etc.) and herpesvirus-related malignancies indicating their broad-spectrum impact on host cellular pathways. We propose to exploit tisssue and systemic levels of v-miRs as diagnostic and prognostic markers for cancers and immune-mediated diseases. Therapeutic targeting of v-miRs will advance the promising outcomes of preclinical discoveries to bedside application.

Herpesviruses and MicroRNAs: New Pathogenesis Factors in Oral Infection and Disease?

The oral cavity incessantly encounters a plethora of microorganisms. Effective and efficient oral innate and adaptive immune responses are incumbent to maintain healthy mucosa. A higher prevalence of Human Herpesviruses (HHV), a family of large enveloped DNA viruses, has been reported in multiple oral inflammatory diseases suggesting their involvement in disease progression. However, the viral components contributing to oral disease remain obscure. MicroRNAs (miRNA) are non-protein coding, single stranded ribonucleic acid (RNA) molecules that post-transcriptionally regulate diverse messenger RNAs. Thus, miRNAs can control large repertoire of biological processes. Changes in miRNA expression are associated with various oral infections and diseases. Cellular miRNAs can act as pro- or anti-viral factors and dysregulation of host miRNA expression occurs during herpesviruses infection. This strongly suggest a critical role of cellular miRNAs in host-herpesvirus interaction. Interestingly, HHV also encode multiple miRNAs (called viral miRNAs) that may play key role in host-pathogen interaction by modulating both host biological pathways and controlling viral life cycle. Recent studies from our laboratory have identified viral miRNAs (v-miRs) in diseased oral tissue biopsies and demonstrate their immunomodulatory roles. This review discusses the association of miRNAs (both host and viral) and herpesviruses in the pathogenesis of oral inflammatory diseases.

In silico prediction of cellular gene targets of herpesvirus encoded microRNAs

Herpesviruses have evolved to encode multiple microRNAs [viral miRNAs (v-miRs)], a unique feature of this family of double stranded DNA (dsDNA) viruses. However, functional role of these v-miRs in host-pathogen interaction remains poorly studied. In this data, we examined the impact of oral disease associated v-miRs viz., miR-H1 [encoded by herpes simplex virus 1 (HSV1)] and miR-K12-3 [encoded by Kaposi sarcoma-associated herpesvirus (KSHV)] by identifying putative targets of viral miRNAs. We used our published microarray data (GSE107005) to identify the transcripts downregulated by the v-miRs. The 3′ untranslated region (UTR) of these genes were extracted using BioMart tool on Ensembl and subjected to RNA:RNA interaction employing RNA Hybrid. We obtained hundreds of potential and novel miR-H1 and miR-K12-3 binding sites on the 3′UTR of the genes downregulated by these v-miRs. The information can provide likely regulatory mechanisms of the candidate v-miRs through which they can exert biological impact during herpesvirus infection and pathogenesis.

Herpesvirus-encoded microRNAs detected in human gingiva alter host cell transcriptome and regulate viral infection

MicroRNAs (miRNAs) are small, non-coding RNAs of ~18-25 nucleotides that have gained extensive attention as critical regulators in complex gene networks including immune cell lineage commitment, differentiation, maturation, and maintenance of immune homeostasis and function. Many viruses encode miRNAs that directly downregulate the expression of factors of the innate immune system, which includes proteins involved in promoting apoptosis and recruitment. In this study, we examined the expression profiles of three previously identified viral miRNAs (v-miRs) from the human herpesvirus (HHV) family, HSV-1 (miR-H1), KSHV (miR-K12-3-3p), and HCMV (miR-US4) in healthy and diseased periodontal tissues and observed increased levels of v-miRs in diseased tissues. To understand the significance of this increase, we overexpressed v-miRs in human oral keratinocytes (HOK), a common target for various HHV, and analyzed the impact of miR-H1 and miR-K12-3-3p on the host transcriptome. More than 1300 genes were altered in HOK overexpressing miR-H1 and miR-K12-3-3p. Global pathway analysis of deregulated genes identified several key cellular pathways that may favor viral persistence. Using bioinformatic analysis, we predicted hundreds of potential v-miR binding sites on genes downregulated by miR-H1 and miR-K12-3-3p and validated three novel target v-miR sites suggesting widespread direct and indirect modulation of numerous host genes/pathways by a single v-miR. Finally, in vitro HSV-1 infection assays showed that miR-H1 can regulate viral entry and infection in human oral keratinocytes (HOK). Overall, our results demonstrate clinical and functional relevance of pathogenic viral molecules viz., v-miRs that regulate both host and viral functions and may contribute to the pathogenesis of inflammatory oral diseases.

Viral miRNAs Alter Host Cell miRNA Profiles and Modulate Innate Immune Responses

Prevalence of the members of herpesvirus family in oral inflammatory diseases is increasingly acknowledged suggesting their likely role as an etiological factor. However, the underlying mechanisms remain obscure. In our recent miRNA profiling of healthy and diseased human tooth pulps, elevated expression of human herpesvirus encoded viral microRNAs (v-miRs) were identified. Based on the fold induction and significance values, we selected three v-miRs namely miR-K12-3-3p [Kaposi sarcoma-associated virus (KSHV)], miR-H1 [herpes simplex virus 1 (HSV1)], and miR-UL-70-3p [human cytomegalovirus (HCMV)] to further examine their impact on host cellular functions. We examined their impact on cellular miRNA profiles of primary human oral keratinocytes (HOK). Our results show differential expression of several host miRNAs in v-miR-transfected HOK. High levels of v-miRs were detected in exosomes derived from v-miR transfected HOK as well as the KSHV-infected cell lines. We show that HOK-derived exosomes release their contents into macrophages (Mφ) and alter expression of endogenous miRNAs. Concurrent expression analysis of precursor (pre)-miRNA and mature miRNA suggest transcriptional or posttranscriptional impact of v-miRs on the cellular miRNAs. Employing bioinformatics, we predicted several pathways targeted by deregulated cellular miRNAs that include cytoskeletal organization, endocytosis, and cellular signaling. We validated three novel targets of miR-K12-3-3p and miR-H1 that are involved in endocytic and intracellular trafficking pathways. To evaluate the functional consequence of this regulation, we performed phagocytic uptake of labeled bacteria and noticed significant attenuation in miR-H1 and miR-K12-3-3p but not miR-UL70-3p transfected primary human Mφ. Multiple cytokine analysis of E. coli challenged Mφ revealed marked reduction of secreted cytokine levels with important roles in innate and adaptive immune responses suggesting a role of v-miRs in immune subversion. Our findings reveal that oral disease associated v-miRs can dysregulate functions of key host cells that shape oral mucosal immunity thus exacerbating disease severity and progression.

Radiation Exposure from Diagnostic Imaging in a Cohort of Pediatric Transplant Recipients

Recipients of solid organ transplants (SOT) have extensive diagnostic imaging (DI). The purpose of this study was to quantify this exposure. Children from northern Alberta with SOTs at Stollery Children’s Hospital, Edmonton, Alberta January 1, 2006, to July 31, 2012, were included. Effective doses of radiation were estimated using published norms for DI performed post-transplant up to October 16, 2014. The 54 eligible children had 6215 DI studies (5628 plain films, 293 computerized tomography (CT) scans, 149 positron emission topography (PET) -CT scans, 47 nuclear medicine scans and 98 cardiac catheterizations). Children less than 5 years of age underwent more DI studies than did older children (median (IQR) 140 (66–210) vs 49 (19–105), p = 0.010). Children with post-transplant lymphoproliferative disorder (N = 8) had more CT scans (median (IQR) 13 (5.5–36) vs 1 (0–5), p<0.001) and PET-CT scans (median (IQR) 3.5 (1.5–8) vs 0 (0–0), p<0.001) than did other children. The estimated cumulative effective dose attributed to DI studies post-transplant was median (range) 78 (4.1–400) millisievert (mSv), and 19 of 54 children (35%; 95% confidence interval 24–49%) had a dose >100 mSv. In conclusion, a significant proportion of pediatric transplant recipients have sufficient radiation exposure post-transplant for DI to be at potential risk for radiation-induced malignancies.

A consortium of non-rhizobial endophytic microbes from Typha angustifolia functions as probiotic in rice and improves nitrogen metabolism

Endophytic microbes isolated from plants growing in nutrient-deficient environments often possess properties that improve nutrition of agriculturally important plants. A consortium of non-rhizobial endophytic microbes isolated from a macrophyte Typha angustifolia growing in the marginal wetlands associated with a Uranium mine was characterized for their beneficial effect on rice and the mechanisms of growth promotion were investigated. The microbes were identified and characterized for their potential plant growth promoting (PGP) properties. Effect of these microbes on nitrogen (N)-metabolism of rice was tested as Typha endophytes were predominantly (N)-fixing. Relative N-use efficiency and expression of genes involved in N-uptake and assimilation were investigated in treated plants. Evidence of horizontal gene transfer (HGT) of dinitrogen reductase gene was observed within the consortium from a Pseudomonas stutzeri strain. The consortium behaved as plant probiotic and showed substantial growth benefits to Typha, their natural host as well as to rice. Typha endophytes colonized rice endosphere significantly increasing biomass, shoot length and chlorophyll content in rice plants both under N-sufficient and N-deficient conditions. N-uptake and assimilation genes were upregulated in plants treated with the endophytes even after three weeks post infection. Our results suggested, HGT of nitrogen-fixation trait to be highly prevalent among endophytes isolated from nutrient-poor habitats of the uranium mine. A long-term nitrogen deficiency response in the treated plants was elicited by the consortium improving N-uptake, assimilation and relative N-use efficiency of rice plants. This appeared to be at least one of the main strategies of plant growth promotion.

A pilot study of scoliosis assessment using radiation free surface topography in children with GMFCS IV and V cerebral palsy

BACKGROUND

Prevalence of scoliosis in cerebral palsy (CP) parallels the extent of neurological impairment and causes significant morbidity. Monitoring is important but requires regular radiological investigation. Surface topography provides a non-radiological approach to scoliosis monitoring.

AIM

To evaluate validity, reproducibility and feasibility of Quantec(®) scans to monitor scoliosis in children with severe CP.

METHODS

Twenty non-ambulant children with CP, Gross Motor Function Classification System (GMFCS) grade IV/V had clinical, radiological and Quantec spinal assessment. The children were supported during scans using a seating system specifically designed for this study. Validity was assessed by comparing Quantec (Q) angle with gold standard (Cobb angle), reproducibility analysed using Bland-Altman plots and feasibility assessed using a questionnaire.

RESULTS

Prevalence of scoliosis on radiological examination was 65%. Of these children, 85% had curves with Cobb angle less than 28°. Quantec scanning was feasible with appropriate postural support. Mean (and standard deviation) for differences between Cobb and Quantec (Q) angle were 0.02° (6.2°) and for Quantec inter-observer variability were 0.5° (5.8°).

CONCLUSIONS

Quantec scanning was feasible, reproducible and had good validity when compared with Cobb angle in a supportive seating system. To consolidate these findings a further study needs to be undertaken with larger number of children with Cobb angles between 25° and 45°.

Targeted yield concept and a framework of fertilizer recommendation in irrigated rice domains of subtropical India

Soil test crop response (STCR) correlation studies were carried out in Vindhyan alluvial plain during 2001 to 2004 taking IR-36 as test crop to quantify rice production in the context of the variability of soil properties and use of balanced fertilizers based on targeted yield concept. The soils were developed on gently sloping alluvial plain with different physiographic settings and notable variation in drainage condition. Soil properties show moderate variation in texture (loamy to clay), organic carbon content (4.4 to 9.8 g/kg), cation exchange capacity (10.2 to 22.4 cmol (p+)/kg) and pH (5.3 to 6.4). Soil fertility status for N is low to medium (224 to 348 kg/ha), P is medium to high (87 to 320 kg/ha) and K ranges from medium to high (158 to 678 kg/ha). Database regarding nutrient requirement in kg/t of grain produce (NR), the percent contribution from the soil available nutrients [CS (%)] and the percent contribution from the applied fertilizer nutrients [CF (%)] were computed for calibrating and formulating fertilizer recommendations. Validity of the yield target for 7 and 8 t/ha was tested in farmers' fields and yields targets varied at less than 10%. The percent achievement of targets aimed at different level was more than 90%, indicating soil test based fertilizer recommendation approach was economically viable within the agro-ecological zone with relatively uniform cropping practices and socio-economic conditions.

Glucose metabolism in traumatic brain injury: a combined microdialysis and [18F]-2-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) study

Following traumatic brain injury, as a consequence of ionic disturbances and neurochemical cascades, glucose metabolism is affected. [18F]-2-Fluoro-2-deoxy-D-glucose (FDG) Positron Emission Tomography (FDG-PET) provides a measure of global and regional cerebral metabolic rate of glucose (rCMRglc), but only during the time of the scan. Microdialysis monitors energy metabolites over extended time periods, but only in a small focal volume of the brain. Our objective in this study is to assess the association of parameters derived from these techniques when applied to patients with traumatic brain injury. Eleven sedated, ventilated patients receiving intracranial pressure monitoring and managed using Addenbrooke's Neurosciences Critical Care Unit protocols were monitored. Dialysate values for glucose, lactate, pyruvate, and glutamate, and the lactate to glucose (L/G), lactate to pyruvate (L/P) and pyruvate to glucose (P/G) ratios were determined and correlated with rCMRglc. FDG-PET scans were performed within 24 hours (five patients), or between 1 and 4 days (two patients) or after 4 days (six patients). Two patients were rescanned 4 and 7 days after their initial scan. A 20 mm region of interest (ROI) was defined on co-registered CT scan on two contiguous slices around the microdialysis catheter. Mean (+/-sd) for rCMRglc was 19.1 +/- 5.5 micromol/100 g/min, and the corresponding microdialysis values were: glucose 1.4 +/- 1.4 mmol/ L; lactate 5.3 +/- 3.6 mmol/L; pyruvate 164.1 +/- 142.3 micromol/L; glutamate 15.0 +/- 14.7 micromol/L; L/G 11.0 +/- 16.0; L/P 27.3 +/- 7.9 and P/G 381 +/- 660. There were significant relations between rCMRglc and dialysate lactate (r = 0.58, P = 0.04); pyruvate (r = 0.57, P = 0.04), L/G (r = 0.55, P = 0.05), and the P/G (r = 0.56, P = 0.05) but not between rCMRglc and dialysate glucose, L/P or glutamate in this data set. The results suggest that increases in glucose utilization as assessed by FDG-PET in these patients albeit in mainly healthy tissue are associated with increases in dialysate lactate, pyruvate, L/G and the P/G ratio perhaps indicating a general rise in metabolism rather than a shift towards non-oxidative metabolism. Further observations are required with regions of interest (microdialysis catheters positioned) adjacent to mass lesions notably contusions.

Subdural haematoma and effusion in infancy: an epidemiological study

AIM

To determine incidence, aetiology, and clinical features of subdural haematoma and effusion (SDH/E) in infancy throughout the British Isles.

METHODS

Cases were notified to the British Paediatric Surveillance Unit over 12 months by paediatricians, neurosurgeons, and paediatric and forensic pathologists.

RESULTS

A total of 186 infants (121 boys, 65 girls) aged 0-2 years were identified. Annual incidence of SDH/E for the UK and Republic of Ireland is 12.54/100,000 aged 0-2 (95% CI 10.3 to 14.62) and 24.1/100,000 aged 0-1 (95% CI 20.89 to 28.18). A total of 106 infants suffered non-accidental head injury (NAHI), 7 accidental head injury, 26 a perinatal cause, 7 a non-traumatic medical condition, 23 meningitis, and in 17 the cause was undetermined; 35 infants died. Significant differences were found in injury pattern, body weight, and Townsend score between NAHI and SDH/E from other cause. There were fewer diagnostic investigations in non-NAHI cases. Delay in diagnosis of greater than a week occurred in 48/181.

CONCLUSION

SDH/E is a significant cause of morbidity and mortality in infancy. NAHI is the predominant cause of SDH/E. SDH/E can present in a non-specific and varied way and must be considered in any infant who is unwell. Determining the cause of the SDH/E in some cases continues to present a diagnostic challenge.

Review of policies and guidelines on infant feeding in emergencies: common ground and gaps

Recent crises in regions where exclusive breastfeeding is not the norm have highlighted the importance of effective policies and guidelines on infant feeding in emergencies. In 1993, UNICEF compiled a collection of policy and guideline documents relating to the feeding of infants in emergency situations. In June 2000 Save the Children, UK, UNICEF and the Institute of Child Health undertook a review of those documents, updating the list and identifying the common ground that exists among the different policies. The review also analysed the consistency of the policy framework, and highlighted important areas where guidelines are missing or unclear. This article is an attempt to share more widely the main issues arising from this review. The key conclusions were that, in general, there is consensus on what constitutes best practice in infant feeding, however, the lack of clarity in the respective responsibilities of key UN agencies (in particular UNICEF, UNHCR and WFP) over issues relating to co-ordination of activities which affect infant-feeding interventions constrains the implementation of systems to support best practice. Furthermore, the weak evidence base on effective and appropriate intervention strategies for supporting optimal infant feeding in emergencies means that there is poor understanding of the practical tasks needed to support mothers and minimise infant morbidity and mortality. We, therefore, have two key recommendations: first that the operational UN agencies, primarily UNICEF, examine the options for improving co-ordination on a range of activities to uphold best practice of infant feeding in emergencies; second, that urgent attention be given to developing and supporting operational research on the promotion of optimal infant-feeding interventions.

From policy to practice: challenges in infant feeding in emergencies during the Balkan crisis

The preparation and dissemination of policy statements are necessary but insufficient to prevent the inappropriate use of infant-feeding products in emergencies. The widespread failure of humanitarian agencies operating in the Balkan crisis to act in accordance with international policies and recommendations provides a recent example of the failure to translate infant-feeding policies into practice. This article explores the underlying reasons behind the failures which include: (1) the weak institutionalisation of policies; (2) the massive quantities of unsolicited donations of infant-feeding products: (3) the absence of monitoring systems; (4) inadequate co-ordination mechanisms; (5) the high costs of correcting mistakes; and (6) the cumulative effects of poor practice. Efforts to uphold best practice during the crisis are also documented. Finally, the article identifies actions that could be undertaken in advance of and during future emergencies to enhance the application of infant feeding policies in emergencies.

Adolescent nutrition in a rural community in Bangladesh

The objective of this study was to assess the nutritional status of adolescent boys and girls in a rural community in Bangladesh. Between December 1996 and January 1997, a cross-sectional survey was carried out in 803 households, each containing at least one adolescent, sampled consecutively from four purposely-selected villages in Rupganj Thana, Narayanganj district. Initially, the guardians of 1483 healthy and unmarried 10-17 year old adolescents (51% boys and 49% girls) were interviewed about family structure and socio-economic status. Out of these children, 906 (47% boys and 53% girls) from 597 households were weighed, had their height and MUAC measured and were clinically examined. Blood was then collected from 861 adolescents for haemoglobin estimation. The median monthly income per person in these 597 families was approximately Taka 554 (US $12). Twenty seven per cent of the household heads were labourers, 21% were solvent farmers, 14% ran small scale businesses and 6% were unemployed. Sixty seven per cent of adolescents were thin (defined as BMI < 5th centile of WHO recommended reference) with 75% boys and 59% girls being affected. The percentage of thin adolescents fell from 95% at age 10 years to 12% at age 17 years. The prevalence of stunting (height for age < 3rd centile NCHS/WHO) was 48% for both boys and girls and rose from 34% at age 10 to 65% at age 17. On clinical examination angular stomatitis was present in 46%, 27% had glossitis, 38% had pallor, 11% had dental caries, 3.2% had an conspicuously enlarged thyroid and 2.1% had eye changes of vitamin A deficiency. According to INACG (International Nutritional Anaemia Consultative Group, 1985) cut-off values, 94% of the boys and 98% of the girls were anaemic. We conclude that rural Bangladesh adolescents suffer from high rates of malnutrition and almost universal anaemia. Nutritional interventions to target this population are urgently required.

Predictors of outcome after radiofrequency catheter ablation of the atrioventricular node for atrial fibrillation and congestive heart failure

BACKGROUND

Although radiofrequency catheter ablation of the atrioventricular (AV) node is an established treatment for atrial fibrillation (AF) with uncontrolled ventricular response, factors that predict clinical outcome in patients with associated congestive heart failure (CHF) are unknown.

METHODS AND RESULTS

AV node ablation and permanent pacemaker implantation was performed in 44 consecutive patients (mean age 71+/-10 years) with CHF and AF associated with uncontrolled ventricular response. Immediately before ablation, mean left ventricular ejection fraction (EF) measured by 2-dimensional echocardiogram was 34.6%+/-9.8%, mean exercise tolerance time was 2.6+/-1.8 minutes, and mean quality of life score was 62.3+/-19.7. Complete AV block was achieved in all 44 patients but was complicated by death in 1 patient from cardiogenic shock soon after ablation. By 1 month after ablation, EF increased to 43.8%+/-13.7% (P < .01), exercise tolerance time was 4.0+/-2.5 minutes (P < .01), and mean quality of life score decreased to 35.6+/-18.1 (P < .01). Improved cardiac performance (increase in EF > or = 9% over baseline EF) was detected in 20 (45%) of the patients. During a mean follow-up of 17+/-9 months, 5 patients died suddenly of presumed ventricular tachyarrhythmia and 4 others died of progressive CHF. Multivariate Cox survival analysis identified baseline EF < or = 30%, presence of significant mitral regurgitation (>2+) before ablation, and failure to exhibit improved cardiac performance by 1 month after ablation as the only independent predictors of death.

CONCLUSIONS

Baseline variables and failure of EF to improve soon after AV node ablation identifies patients with CHF and AF who have a high mortality rate. Adjunctive therapy to reduce sudden death and progressive heart failure should be evaluated in this subgroup.

Comparison of the effects of AV nodal ablation versus AV nodal modification in patients with congestive heart failure and uncontrolled atrial fibrillation

Radiofrequency (RF) catheter ablation of the atrioventricular node (AVN) and implantation of a ventricular pacemaker can improve cardiac performance in patients with congestive heart failure (CHF) and uncontrolled atrial fibrillation (AF). Alternatively, RF catheter modification of the AVN has been proposed to slow ventricular response during AF without requirement for permanent pacing. Among 44 consecutive patients (mean age 69.7 +/- 10.2 years) with drug resistant chronic AF, 22 (group I) had AVN ablation with permanent ventricular pacemaker implantation, while 22 patients had attempted AVN modification. Complete AV block was obtained in all group I patients while only seven (32%) AVN modification patients (group II) had permanent slowing of ventricular rate. Among patients in group I, mean left ventricular ejection fraction (EF) increased from 32.2% +/- 8.8% before ablation to 41.9% +/- 14.6% 4-weeks postablation (P < 0.01); exercise tolerance time (ETT) increased from 2.9 +/- 2.2 minutes to 4.5 +/- 2.9 minutes (P < 0.01); and quality-of-life score decreased from 66.1 +/- 22.6 to 36.9 +/- 17.1 (P < 0.01). By comparison, there was only a small increase in ETT in the seven successful group II patients (2.4 +/- 1.8 minutes to 3.0 +/- 1.9 minutes; P < 0.05) and there was no significant change in EF or quality-of-life. While AVN ablation can occasionally have transient adverse effects, it is more effective than AVN modification for improving cardiac performance in selected patients with CHF and AF.

X-ray Study of M II(ClO4)2.6H2O (M II = Zn, Ni): Twinning, Disorder and Phase Transitions

X-ray studies of zinc and nickel perchlorate hexahydrate, Zn(ClO4)2.6H2O and Ni(ClO4)2.6H2O, respectively, at different temperatures have been carried out to correlate the structural changes with phase transitions in the compounds. The crystals are pseudohexagonal (P63 mc), exhibiting a three-component orthorhombic twinning (Pmn21). At high temperatures a slight deviation of the b/a ratio of the three twinned orthorhombic cells from 31/2 results in a three-component splitting of each spot in the X-ray photograph, which on cooling to room temperature coalesce into single ones, thus restoring the original b/a ratio. The diffuse streaks disappear in the high-temperature photographs due to a decrease in the probability of error in repetition along the b axes of the three orthorhombic cells with temperature. A successful refinement of the heat-treated ordered Zn(ClO4)2.6H2O crystal verifies the continuous perchlorate–water arrangement and three-component twinning of the orthorhombic cell. Low-temperature X-ray photographs indicate no structural change.

Optimism, social support, and premenstrual dysphoria

The relationships between dispositional optimism, social support, and mood and performance symptoms associated with the premenstrum were examined in a sample of 101 adult women. Optimism and satisfaction with one's level of social support were positively correlated. Optimism was related inversely to mood-related symptoms, even after controlling for the effects of social support. Optimism did not correlate with premenstrual performance impairment. Social support did not correlate with any premenstrual symptoms.

Young women's sexual risk taking behaviour: re-visiting the influences of sexual self-efficacy and sexual self-esteem

This study investigates the influences on young women's sexual risk taking of (a) attitudes such as sexual self-efficacy and sexual self-esteem and (b) personal and sexual characteristics, such as age, the age of first sexual experience, the number of sexual partners and reported overall amount of sex. Three hundred and thirty-one young women participated in this study. With respect to regular sexual relationships, the results show that risk taking behaviour is directly and positively associated with sexual self-esteem. The effect of sexual self-efficacy on risk taking in regular relationships, however, is indirect and positive, being mediated by the overall amount of sexual activity. In contrast, with respect to casual sexual relationships, risk taking behaviour is negatively associated with self-esteem and positively associated with sexual self-efficacy. In addition, sexual self-esteem influences casual risk taking indirectly and positively, the effect being mediated by the overall amount of sexual activity. The findings in relation to sexual self-esteem and sexual self-efficacy are contrary to the expectations that these variables would be negatively associated with sexual risk taking behaviours. The implications for safe sex education are discussed.

Effect of massive small bowel resection on gastric acid secretion in the rat

The phenomenon of a transitory gastric acid hypersecretory state after extensive bowel resection is well established. Its time of onset, however, is unknown. The purpose of this study was to determine the immediate effect of massive small bowel resection (MSBR) on gastric acid secretion (GAS). An anesthetized innervated rat model was prepared with gastric and jugular cannulae. Three groups of animals were studied: group I (n = 12), basal unstimulated state; group II (n = 12), pentagastrin (Pg) 16 micrograms/kg h-1 stimulated; and group III (n = 16), 5% liver extract meal (LEM) stimulated. Each group consisted of experimental animals that underwent 95% MSBR from proximal jejunum to terminal ileum and control animals that remained intact. Acid output was determined by extragastric titration with 0.1 M NaOH. Blood was taken for basal and postprandial serum gastrin levels. Basal acid output (mueq/10 min) significantly increased immediately after MSBR in all groups (p less than .01). Ninety minutes following MSBR, acid outputs were significantly elevated in basal and Pg-stimulated but not LEM-stimulated rats. Serum gastrin increased from 30 +/- 1 to 56 +/- 6 pg/mL (p less than .01) in group I rats and from 81 +/- 28 to 129 +/- 13 pg/mL in group III rats (p = NS). We conclude that GAS increases immediately after MSBR in group I and II rats. This increase in GAS may be mediated by gastrin release.

Immunoneutralization of somatostatin and neurotensin: effect on gastric acid secretion

Cell lines producing monoclonal antibodies to somatostatin and neurotensin, designated S-10 and NT-C5, respectively, have recently been generated. The purpose of the present immunoneutralization study in urethan-anesthetized gastric fistula rats is 1) to examine the ability of these antibodies to block the inhibitory effect of their target peptides on meal-stimulated gastric acid secretion and 2) to use these antibodies as probes to determine whether somatostatin and/or neurotensin are involved in the inhibition of gastric acid secretion produced by intraduodenal, intra-ileal, and intracolonic fat infusions. The results demonstrate that both S-10 and NT-C5 successfully bound exogenous somatostatin and neurotensin in vivo. S-10 but not NT-C5 prevented the inhibition of gastric acid secretion produced by intraduodenal fat. NT-C5 but not S-10 prevented the inhibition of gastric acid secretion produced by intra-ileal fat. Neither S-10 nor NT-C5 prevented the inhibition of gastric acid secretion produced by intracolonic fat. We conclude that somatostatin is associated with proximal and neurotensin with distal small bowel intestinal fat-induced inhibition of gastric acid secretion.

Vagal control of gastrin release in the dog: pathways for stimulation and inhibition

The vagus has a dual effect on gastrin: it both stimulates and inhibits its release. To determine the gastric vagal pathways for these opposing effects, plasma gastrin and acid responses to meal (intragastric titration of 15% liver extract, pH 5.5) and to insulin (0.5 U regular insulin intravenously) were studied in seven dogs in three consecutive stages: a control stage, after antral vagotomy (AV), and after subsequent proximal gastric vagotomy (PGV). AV abolished the plasma gastrin response to insulin but had no effect on either basal or meal-stimulated gastrin release. Subsequent PGV caused significant elevation in basal plasma gastrin concentration, no further change in the gastrin response to insulin, but a significant increase in meal-stimulated gastrin release. AV decreased acid response to insulin nonsignificantly and had no effect on meal-stimulated acid secretion. Subsequent PGV reduced by 90% the acid response to insulin, had negligible effect on the gastric fistula acid response to meal, but increased Heidenhain pouch response sixfold. These studies show that vagal stimulation of gastrin release is mediated along direct antral vagal pathways, while vagal inhibition requires intact vagal fibers to the proximal stomach. The mechanism by which the fundic vagal pathways exert an inhibitory influence on the G cell in the antrum is yet to be elucidated.

Somatostatin-14 and -28: clearance and potency on gastric function in dogs

To examine the significance of somatostatin-14 (S-14) and somatostatin-28 (S-28) in gastric physiology, we compared their relative potencies on acid secretion in the dog. On a molar infusion basis, S-14 and S-28 appeared to be equipotent, causing 50% inhibition of peptone meal-stimulated acid secretion at a dose of 400 pmol . kg-1 . h-1. However, comparison of the plasma half lives (t 1/2) of the two peptides revealed that S-28 disappeared at a much slower rate (t 1/2 = 2.84 +/- 0.15 min, mean +/- SE, n = 7) than S-14 (t 1/2 = 0.57 +/- 0.06 min). When acid-inhibitory effect was compared against increment in plasma concentrations produced by peptide infusion, S-14 was roughly 10-fold more potent than S-28. No alteration of gastrin response to peptone was observed at a dose of S-14 or S-28 that completely abolished acid secretion, suggesting that regulation of acid secretion is not mediated by gastrin inhibition. Thus, S-14 is a potent and possibly important physiological inhibitor of gastric acid secretion. Although circulating S-28 may have importance in regulation of some biological functions, it appears to play a less prominent role in regulation of gastric secretion.

Appendicitis: a historical review

The author traces the history of appendicitis through the successive stages of its evolution--from the early anatomic descriptions of the appendix by Leonardo da Vinci and Vesalius to Louyer-Villermay's recognition of the fatal course that appendiceal inflammation may take; through the confusion of typhlitis and perityphlitis, until Reginald Fitz at the end of the last century classified its pathology and the disease appendicitis was born. The author has described the efforts of the early surgeons as they grew to understand the symptomatology of appendicitis and to realize that only by early operation could the tragic outcome of delay be averted. Credit is given to those whose contributions have advanced the frontiers of surgery-- Lawson Tait was the first to diagnose and remove a diseased appendix in 1880 in England and Abraham Groves the first on the North American continent, in 1883, in Ontario. Within a decade, the early surgical treatment of appendicitis became established. The writings of men like Charles McBurney and John B. Murphy are shown to be as pertinent today as they were at the turn of the century.