The neurobiological reward system in Prolonged Grief Disorder (PGD): A systematic review

Prolonged Grief Disorder (PGD) is a debilitating condition affecting between 7% and 10% of bereaved individuals. Past imaging and psychological studies have proposed links between PGD's characteristic symptoms - in particular, profound yearning - and the neural reward system. We conducted a systematic review to investigate this connection. On December 19, 2019, we searched six bibliographic databases for data on the neurobiology of grief and disordered grief. We excluded studies of the hypothalamic-pituitary-adrenal (HPA) axis, animal studies, and reviews. After abstract and full-text screening, twenty-four studies were included in the final review. We found diverse evidence for the activation of several reward-related regions of the brain in PGD. The data reviewed suggest that compared to normative grief, PGD involves a differential pattern of activity in the amygdala and orbitofrontal cortex (OFC); likely differential activity in the posterior cingulate cortex (PCC), rostral or subgenual anterior cingulate cortex (ACC), and basal ganglia overall, including the nucleus accumbens (NAc); and possible differential activity in the insula. It also appears that oxytocin signaling is altered in PGD, though the exact mechanism is unclear. Our findings appear to be consistent with, though not confirmative of, conceptualizing PGD as a disorder of reward, and identify directions for future research.

Chemsex and new HIV diagnosis in gay, bisexual and other men who have sex with men attending sexual health clinics

OBJECTIVES

The aim of the study was to analyse associations between chemsex and new HIV and sexually transmitted infection (STI) diagnoses among gay, bisexual and other men who have sex with men (GBMSM) accessing sexual health clinics.

METHODS

A retrospective case note review was carried out for all GBMSM attending two London sexual health clinics between 1 June 2014 and 31 July 2015.

RESULTS

Chemsex status was documented for 1734 of 1840 patients. Overall, 27.1% (n = 463) disclosed current recreational drug use, of whom 286 (16.5%) disclosed chemsex participation and 74 of 409 (18.1%) injected drugs. GBMSM who were already HIV positive were more likely to disclose chemsex participation [adjusted odds ratio (AOR) 2.55; 95% confidence interval (CI) 1.89-3.44; P < 0.001]. Those disclosing chemsex participation had higher odds of being newly diagnosed with HIV infection (AOR 5.06; 95% CI 2.56-10.02; P < 0.001), acute bacterial STIs (AOR 3.94; 95% CI 3.00-5.17; P < 0.001), rectal STIs (AOR 4.45; 95% CI 3.37-6.06; P < 0.001) and hepatitis C (AOR 9.16; 95% CI 2.31-36.27; P = 0.002). HIV-negative chemsex participants were also more likely to have accessed post-exposure prophylaxis for HIV in the study period and to report sex with a discordant HIV- or hepatitis C virus-infected partner (P < 0.001).

CONCLUSIONS

Chemsex disclosure in sexual health settings is associated with higher rates of STI diagnoses, including HIV infection and hepatitis C. GBMSM attending sexual health services should therefore be assessed for chemsex participation and disclosure should prompt health promotion, harm minimization and wellbeing interventions.

Development and evaluation of an online educational resource about cancer survivorship for cancer nurses: a mixed-methods sequential study

Cancer survivorship is recognised globally as a key issue. In spite of the key role played by nurses in survivorship care, there is an identified gap in nurse's knowledge in this area. This study reports on the development and evaluation of an educational resource for nurses working with people affected by cancer. The resource was designed using adult learning principles and includes a variety of learning materials and point of care resources. A mixed-methods sequential exploratory design was used to undertake an evaluation of the programme. This included the use of online surveys and semi-structured interviews with pilot participants. A total of 21 participants completed an online survey and 11 participants completed a telephone interview. Overall, the participants found the Cancer Survivorship resource to be engaging, practical and intuitive. A major theme emerging from the survey and interview data was that the resource was applicable to practice and useful in developing survivorship care plans. Respondents requested additional information be included on the role of various health professionals working in survivorship as well as guidelines on when to make referrals. This study provides evidence that the Cancer Survivorship tool may be a promising vehicle for delivering evidence-based education on survivorship care.

Routine use of gastrograffin enema prior to the reversal of a loop ileostomy

BACKGROUND/AIMS

Anastomotic failure occurs in up to 10% of patients following anterior resection. Selective use of a loop ileostomy may reduce the septic consequences of anastomotic leak. The use of gastrograffin enema to confirm the anastomotic integrity prior to ileostomy closure is still controversial. Our aim was to determine the impact of the routine use of gastrograffin enema on patients' management prior to ileostomy reversal.

METHODS

A review of 81 patients who underwent low anterior resection with loop ileostomy for rectal cancer over 3 years.

RESULTS

Gastrograffin enema was performed in 69 patients (85.2%). The mean time from operation to gastrograffin enema was 22 weeks. Four patients (5.8%) had a positive radiological leak without clinical suspicion of anastomotic problems, 2 patients (2.9%) of these subsequently had the ileostomy closed despite the positive result, 2 patients (2.9%) had a gastrograffin enema repeated which showed no leak and the patients are awaiting reversal.

CONCLUSION

The incidence of positive radiological leak in uncomplicated patients is low; such patients had their loop ileostomies closed with or without serial gastrograffin enema. Routine gastrograffin enema in the absence of a clinical suspicion of anastomotic failure would appear to be of little value.

Reconstitution of regulated exocytosis in cell-free systems: a critical appraisal

Regulated exocytosis involves the tightly controlled fusion of a transport vesicle with the plasma membrane. It includes processes as diverse as the release of neurotransmitters from presynaptic nerve endings and the sperm-triggered deposition of a barrier preventing polyspermy in oocytes. Cell-free model systems have been developed for studying the biochemical events underlying exocytosis. They range from semi-intact permeabilized cells to the reconstitution of membrane fusion from isolated secretory vesicles and their target plasma membranes. Interest in such cell-free systems has recently been reinvigorated by new evidence suggesting that membrane fusion is mediated by a basic mechanism common to all intracellular fusion events. In this chapter, we review some of the literature in the light of these new developments and attempt to provide a critical discussion of the strengths and limitations of the various cell-free systems.

The psychosocial impact of bone marrow transplantation: a review of the literature

Bone marrow transplant (BMT) is a procedure used for the treatment of a variety of cancers and malignant diseases. Recovery from this intensive process requires a long-term course, often accompanied by acute morbidity which includes various distressing physical symptoms. Recent literature has begun to explore the impact of this procedure on quality of life and psychosocial issues. While survivorship is often associated with a highly rated global quality of life, recovery from BMT is accompanied by several psychosocial difficulties which negatively impact patients. Fatigue is a common complaint, often hindering recipients for several years following their transplant. As well, reports of psychological distress, psychiatric symptoms, and/or mood disturbances such as anxiety or depression are not uncommon. Many patients also indicate interruption of sexual activity and increased sexual difficulty for several months following BMT. While some investigators have begun to examine hormone replacement therapy (HRT) as a treatment option for reducing sexual dysfunction, there is a general paucity of literature evaluating interventions for BMT survivors. This article reviews the literature examining various quality of life aspects including fatigue, psychosocial difficulties, and sexual functioning of patients during recovery from BMT. Limitations of past research are discussed and directions for future research suggested.

In vitro exocytosis in sea urchin eggs requires a synaptobrevin-related protein

Sea urchin eggs provide an efficient in vitro model of exocytosis. We have identified proteins in sea urchin eggs that cross-react with antibodies to mammalian synaptobrevin, synaptotagmin, SNAP-25, syntaxin and rab3a. We show that these proteins are localized to the sea urchin egg cortex, using western blotting and immunocytochemistry. Tetanus toxin light chain cleaves the synaptobrevin-related protein in vitro and inhibits calcium-induced exocytosis. These data demonstrate a conservation between phyla of protein sequence and molecular mechanisms thought to facilitate exocytosis and show that the sea urchin egg provides a unique in vitro exocytotic model with which to study the conserved protein machinery of membrane fusion during secretion.

Identification and partial sequence analysis of novel annexins in Lytechinus pictus oocytes

The annexins are a major class of calcium-binding proteins with unknown functions. In an attempt to define novel model systems in which to study members of the annexin family, we have investigated the expression of annexins in eggs from the sea urchin Lytechinus pictus. Western blot analysis of L. pictus eggs using antisera raised against human annexins I, V and VI revealed the presence of immunoreactive proteins of approximately 34 kDa, 35 kDa and 68 kDa respectively. The sea urchin annexins behaved similarly to their mammalian counterparts, both during purification and in their ability to bind calcium-dependently to anionic phospholipids. Of the three sea urchin annexins, the 34 kDa form was most abundant, yielding sufficient quantities for peptide microsequencing. The amino acid sequences derived in this way showed the L. pictus annexin to be closely related both to mammalian annexin I and to annexins IX, X and XII from Drosophila and Hydra. However, N-terminal sequence from the L. pictus annexin showed it to be a novel member of the annexin super-gene family. The results are interesting in view of the complex evolution of the annexin gene family, and also point to the potential usefulness of echinoderm eggs as a model system in which to study annexin function.

Effect of sodium fluoride on bone density in chickens

In addition to increasing bone volume, fluoride has been demonstrated to increase ash weight and mineral density. To determine whether newly formed or older bone is most affected by fluoride treatment, bone from chickens receiving fluoridated water was fractionated into lower density (recently formed) and higher density (more mature) specific gravity fractions. Fluoride was administered to the chickens for different lengths of time (4 or 13 weeks) or at varying doses for a 4-week period (0, 4.2, 16.8 mmol/liter drinking water). Fluoride treatment caused a shift in the mineral density profile, showing an increased proportion of mineral distribution in the more mature, higher density fractions. To determine whether this density gradient shift was due to increased maturation rate of bone or decreased resorption and mineralization rates, [3H]proline and 45Ca were injected 5 days and 24 hours prior to sacrifice, respectively. The distributions of both 3H or 45Ca, as percentages of total counts incorporated, were shifted by fluoride treatment into more mature, higher density fractions. Expressing the number of counts as a percent of the bone in each fraction (total hydroxyproline or Ca) revealed an increased incorporation of both 3H and 45Ca into the higher specific gravity fractions 2.0-2.2. These results suggest that fluoride treatment increases bone maturation and the rate of secondary mineralization in the cortical bone. Such changes in the quality of more mature, well-mineralized bone, in humans as well as animals, may have a significant influence on brittleness and strength.

Estate management and growth in higher education

Examines some of the implications of increasing numbers in higher education for the management of buildings and estates of the English polytechnics and colleges. Discusses the history of polytechnics and colleges, financial independence, growth, government and the PCFC, efficient use of property, rationalization, condition of the buildings, strategy, accommodation strategy, accountability, PCFC capital, and investment appraisal.

Effect of extended depot fluphenazine treatment and withdrawal on social and other behaviors of Cebus apella monkeys

To examine whether or not prolonged exposure to a depot neuroleptic has either residual or "tardive pathological" effects on normal behavior, 38 Cebus apella monkeys were observed daily for 108 weeks. The issue of stress influencing such effects was also addressed. During weeks 25-48 half of the monkeys received 0.22 mg/kg fluphenazine decanoate, IM, every 3 weeks, with the dose increased to 0.33 mg/kg during weeks 49-72. Behavioral measures were combined to form composite behavioral variables which quantify four major aspects of behavior: self- and environment-directed behavior, affiliation, aggression, and normal locomotor activity. Mean plasma fluphenazine levels at 48 h post-injection were 0.13 (+/- 0.03) ng/ml for injections 3-8 and 0.24 (+/- 0.07) ng/ml for injections 11-16. The pre-study null hypothesis that the four major aspects of behavior would not be adversely affected by this treatment during the drug-discontinuation phase of the study (weeks 73-108) was not statistically negated. There were highly significant decreases in self- and environment-directed behaviors and affiliation during the treatment periods, implying that treatment may contribute to the negative symptoms of treated schizophrenics. Stress reduced the above effects. Aggression showed some increase during early drug discontinuation, accentuated by stress. Recovery of normal (baseline) behavioral scores began by week 7 after the last treatment. Mild (bucco-lingual) tardive dyskinesias persisted in 30% of the animals for a prolonged time.

Optimal cardioplegia and 24-hour heart storage with simplified UW solution containing polyethylene glycol

Recent work has shown that UW may be better than standard cardioplegic solutions for short-term heart preservation. In this study we have used a rabbit heart model to evaluate a simplified UW solution in which penicillin, dexamethasone, insulin, allopurinol, and adenosine were omitted and 5% polyethylene glycol (PEG20M) was substituted for hydroxyethyl starch. The test systems consisted of 4-hr cardioplegic storage at 15 degrees C with repeated flushing every 30 min for 2 hr and 24-hr hypoxic low-flow microperfusion (3 ml/g/24 hr) at 0 degrees C. Control groups were arrested with a 15-25 ml flush in iced saline and immediately tested. Cardiac output (CO)* after preservation was measured in a working heart model using an acellular perfusate at 37 degrees C at an aortic pressure of 100 cm H2O. The CO (ml/g heart wt/min) were as follows--Controls: St. Thomas II 20.5 +/- 8.3 (5), UW 34.7 +/- 11.7 (16), PEG20M 41.8 +/- 4.4 (14); 4-hr cardioplegia: St. Thomas II 17.4 +/- 0.9 (4), Bretschneider HTK 14.9 +/- 7.0 (4), UW 25.2 +/- 11.5 (9), PEG20M 41.1 +/- 7.8 (8); 24-hr microperfusion: UW 25.4 +/- 11.1 (18), PEG20M 37.1 +/- 8.2 (18). Following cardioplegic or microperfusion preservation, PEG20M hearts functioned at control levels (P greater than 0.05) and were significantly superior to all other solutions, with approximately double the CO (P less than 0.05, all other groups). We conclude that for heart preservation, 5 components can be eliminated from UW and substitution of PEG20M for HES appears to have improved its performance.

Comparative study of antigen binding T cells separated by Vicia villosa or streptococcal antigen and the effect of HLA class II antigens

The antigen binding capacity and function of T cells which adhere to the lectin Vicia villosa (VV) or to streptococcal antigen (SA) have been studied. VV-adherent T8+ cells (T8+ VV+) bind 125I-SA whereas VV non-adherent T8+ cells (T8+ VV-) bind little SA. Similarly, SA-adherent T8+ cells (T8+ SA+) bind 125I-SA specifically, whereas SA-non-adherent T8+ cells (T8+ SA-) show little binding of 125I-SA. The SA binding T8+ VV+ or T8+ SA+ cells can present the antigen to T4+ helper cells which generate helper factors and these enhance anti-DNP-antibodies, when incubated with mouse spleen cells and DNP-SA. Parallel reconstitution studies with either T8+ VV- or T8+ SA- cells have revealed that both subpopulations of cells can suppress T4+ helper cell activity. Further reconstitution experiments between the T8+ VV+ (or T8+ SA+) antigen presenting cells and T8+ VV- (or T8+ SA-) suppressor cells suggest that the former can also prevent the latter cells from inhibiting T4 helper cells, so as to function as contrasuppressor cells. Cross-over, reconstitution studies between the VV and SA separated cells have confirmed that the T8+ VV+ and T8+ SA+ cells have similar functions, in SA binding, presenting and contrasuppressor activities. The dose-response curve of binding 125I-SA to T8+ cells is dependent on the HLA-DR type of cells and the binding of 125I-tetanus toxoid was similar to that of 125I-SA. Whereas DRw6- T cells bind predominantly 1,000 ng SA or tetanus toxoid, DRw6+ T cells bind 1 ng and to a lesser extent 1,000 ng of either antigen. HLA-DRw6+ subjects can be considered as high responders for their T cells bind optimally at low concentrations of antigens which induce helper and contrasuppressor functions. In contrast, HLA-DRw6-subjects can be considered as low responders, as their T cells bind optimally at high concentrations of antigens and only the latter induce helper and contrasuppressor functions.

The helper and suppressor functions of primate T cells elicited by a 185K streptococcal antigen, as compared with the helper function elicited by a 4K streptococcal antigen

Helper and suppressor functions of human T lymphocytes that act on antibody-forming B cells were elicited by a large 185K streptococcal cell wall antigen. However, a small 4K streptococcal peptide elicited helper but no suppressor function. These differences in the functional activities of the large and small m.w. streptococcal antigens (SA) were confirmed by direct immunisation of rhesus monkeys with the 185K-SA and 4K-SA. Sequential studies have shown that whereas the 185K-SA elicits dose-dependent helper and suppressor activities, the 4K-SA elicits only helper function. Cell-depletion studies with human cells suggest that removal of T8+ cells by killing with OK.T8 and complement leads to a loss of suppressor and a broadening in the concentration of 185K-SA, which elicits helper activity. Because the 4K-SA does not elicit suppression, removal of T8+ cells does not affect this function. However, similar depletion of T4+ cells results in loss of the helper activities, both with the 185K-SA and 4K-SA, and again a broadening in the concentration of the 185K-SA, which elicits suppression. Direct comparison by autoradiography between 125I-labeled 185K-SA and 4K-SA suggests that both antigens can bind directly to monocytes or T8+ VV+ cells. Furthermore, both antigens can induce helper function if T4+ cells are reconstituted with either monocytes or T8+ VV+ cells. Attempts will now be made to sequence the amino acid determinants of the 185K-SA, so as to define the epitopes responsible for the two major regulating functions elicited by this antigen.

The helper and suppressor functions of primate T cells elicited by a 185K streptococcal antigen, as compared with the helper function elicited by a 4K streptococcal antigen

Helper and suppressor functions of human T lymphocytes that act on antibody-forming B cells were elicited by a large 185K streptococcal cell wall antigen. However, a small 4K streptococcal peptide elicited helper but no suppressor function. These differences in the functional activities of the large and small m.w. streptococcal antigens (SA) were confirmed by direct immunisation of rhesus monkeys with the 185K-SA and 4K-SA. Sequential studies have shown that whereas the 185K-SA elicits dose-dependent helper and suppressor activities, the 4K-SA elicits only helper function. Cell-depletion studies with human cells suggest that removal of T8+ cells by killing with OK.T8 and complement leads to a loss of suppressor and a broadening in the concentration of 185K-SA, which elicits helper activity. Because the 4K-SA does not elicit suppression, removal of T8+ cells does not affect this function. However, similar depletion of T4+ cells results in loss of the helper activities, both with the 185K-SA and 4K-SA, and again a broadening in the concentration of the 185K-SA, which elicits suppression. Direct comparison by autoradiography between 125I-labeled 185K-SA and 4K-SA suggests that both antigens can bind directly to monocytes or T8+ VV+ cells. Furthermore, both antigens can induce helper function if T4+ cells are reconstituted with either monocytes or T8+ VV+ cells. Attempts will now be made to sequence the amino acid determinants of the 185K-SA, so as to define the epitopes responsible for the two major regulating functions elicited by this antigen.

The role of a human antigen specific T8+ cell subset in antigen presentation, helper function and contrasuppression

Regulation of the human immune response was studied by sequential separation of subsets of T cells, followed by assessment of their helper and suppressor functions in a series of reconstitution experiments. T8+ lymphocytes were separated by panning on streptococcal antigen (SA) coated plates into T8+ SA-adherent cells (T8+SA+) and T8+ SA-non-adherent cells (T8+SA-). The helper and suppressor functions of the T8+SA+ and T8+SA- cells, reconstituted with T4+ helper cells were then studied by a direct antibody forming cell assay. T4+ cells will not induce helper activity by 1000 ng SA alone but require the accessory function of monocytes (Mo). However, replacing Mo by T8+SA+ cells will elicit a similar helper activity by T4+ cells and SA as that induced by Mo. In addition to the antigen-specific presentation and induction of helper activity, the T8+SA+ subset displays the properties of antigen-specific contrasuppressor cells. Thus, reconstitution of T4+ cells and T8+SA- (suppressor cells) with T8+SA+ and 1000 ng SA induces helper and no suppressor activity. Substitution of Mo for the T8+SA+ cells converts the helper to a predominantly suppressor-cell function. T8+SA- cells elicit suppression with 1 ng SA in the absence of accessory cells and reconstitution with Mo, T8+SA+ or T4+ cells failed to affect the suppressor activity. Total reconstitution of the four principle subsets of T4+, T8+SA+, T8+SA- cells and Mo elicited similar antigen dose-dependent responses as those of the unseparated mononuclear cells. It seems that all four cell subsets are required for optimal immunoregulation. We suggest that the T8+SA+ can present antigen to T4+ helper cells and induce helper activity, but in addition these cells can prevent the suppressor subset of T8+ cells from inhibiting T4+ helper cells and function as contrasuppressor cells. The mechanism of these functions is not known but HLA class II antigens might play an essential role in antigen binding, presentation and contrasuppression of the T8+SA+ cells, as the latter are significantly enriched in Ia+ cells.

Helper and suppressor functions of human mononuclear cells depleted of antigen-binding T8+ cells

We have utilized the antigen-binding function of a subset of T8+ cells to remove these cells in vitro from human peripheral blood mononuclear cells. This was carried out by treating the cells with streptococcal antigen (SA), monoclonal anti-SA antibody and complement. The concentration of SA binding to T8+ cells differs with the HLA-DR type of the cells: 1 ng SA binds to DRw6+ cells and elicits T helper activity, whereas 1000 ng SA elicits T suppressor activity, in an assay for antibody-forming cells. After depletion of the antigen-binding cells by the SA-specific complement-dependent killing technique, the helper function of the DRw6+ cells was lost but suppression was elicited not only by 1000 ng but also by 1 ng SA. Similarly, DRw6- cells which bind 1000 ng SA to elicit helper activity and 1 ng to elicit suppression, when depleted of the SA-binding cells, resulted in loss of helper activity but again, suppression could be elicited by both 1000 and 1 ng SA. We suggest that treatment of mononuclear cells with antigen, the specific antibody and complement removes the T8+ antigen-binding cells which present antigen to T helper cells and results in the loss of helper function. Suppressor function is however, not only retained with the original concentration of SA but also expressed with that required to elicit helper function in the untreated cells. These findings are consistent with our hypothesis that the antigen-binding and presenting T8+ cells also function as contrasuppressor cells. Thus, the T8+ subset of cells have a dual function, to present antigen and to activate T helper cell function, and to prevent suppressor cells from inhibiting the helper cells.

Separation and characterization of a subset of human T8+ cells which function as antigen-presenting and contrasuppressor cells

The lectin Vicia villosa (VV) binds preferentially a subset of T cells. Separated VV-adherent cells (AC) do not generate helper function alone, but when added to VV-non-adherent cells (NAC), they can present streptococcal antigen (SA) and induce helper function as effectively as monocytes, at a ratio of 1 VV-AC to 4 VV-NAC. Further separation into a T8+ subset of VV-AC and reconstitution with T4+ helper cells (HC) has established that the T8+ VV-AC induces T4+ cells to helper activity. However, in addition to antigen presentation, the T8+ subset of VV-AC has a contrasuppressor function, for it can prevent T8+ suppressor cells from inhibiting T4+ HC function. The results suggest that a T8+ subset can present antigen to T4+ HC, activate helper function and prevent suppression. The T8+ VV-AC may have considerable biological significance in its dual function of countering the dominant suppressor activity and presenting antigen to induce helper activity.

Detection of cross-reacting murine I-J like determinants on a human subset of T8+ antigen binding, presenting and contrasuppressor cells

Murine I-J gene products have been found in T suppressor cells (SC) and factors, macrophages and contrasuppressor cells (CSC). However, a human counterpart of the murine I-J has not been reported. As there is strong evidence that some murine anti-Ia antisera cross-react with human Ia antigens, the possibility was tested that mouse anti-I-J antibodies might cross-react with corresponding human class II determinants. Indeed, this revealed that three anti-I-J monoclonal antibodies (MoAb) and two antisera tested react with human mononuclear cells and that a significantly greater proportion of T8+ than T4+ cells or monocytes (Mo) react with the I-J antibodies. This was corroborated by autoradiography with significant inhibition of 125I-SA (streptococcal antigen) binding to T8+ cells but not to Mo by the MoAb or antisera to murine I-J. Functional reconstitution experiments of T4+ helper cells with the SA binding and presenting T8+ Vicia villosa adherent cells (VV-AC) and assessment of specific antibody forming cells to SA suggest that the antigen presenting function of this T8+ subset can be significantly inhibited by killing with the MoAb to I-J and complement. Furthermore, the subset of T8+ VV-AC also functions as CSC, for killing with MoAb to I-J and complement significantly inhibited the contrasuppressor function. This is consistent with the presence of I-J gene products in murine CSC. However, similar treatment of T8+ VV-NAC (non-adherent cells) or monocytes (Mo) failed to affect the suppressor or accessory helper function of these cells, respectively. Phenotypic characterization, inhibition of 125I-SA binding and reconstitution experiments for helper and suppressor functions, suggest that a subset of T8+ antigen binding, presenting and CSC may express determinants cross-reacting with murine I-J molecules.

Sequential development of helper and suppressor functions, antibody titers and functional avidities to a streptococcal antigen in rhesus monkeys

Sequential development of antibody titer, functional avidity, helper and suppressor activities were investigated in rhesus monkeys. These were immunized with a single dose of 0.1 microgram to 10 mg of a streptococcal protein antigen (SA) in aluminium hydroxide. The IgG antibody titers followed the classical pattern first established in mice, of high-dose and low-dose tolerance with intermediate doses of immunity. This was correlated with a similar pattern of functional avidity of IgG antibodies, as measured by a dissociation assay. Helper and suppressor functions were assayed in parallel by inducing the corresponding factors from monkey lymphocytes in Marbrook flasks and testing the factors which cross the species barrier in cooperative cultures with CBA mouse spleen B cells. A progressive modulation of helper and suppressor activities was elicited by the increasing doses of SA, during the initial 28 days after immunization. Thus, dominant suppressor with minimal helper activity, IgG antibody titer and functional avidity were elicited by 0.1 microgram SA. However, 1 or 10 micrograms SA induced dominant helper with minimal or transient suppressor activity and high IgG antibody titers and functional avidity. Somewhat intermediate responses were elicited by 100 micrograms SA, but 1 mg and especially 10 mg SA induced dominant suppressor and minimal helper activity, with low IgG antibody titers and functional avidities. When the immune response was established, about 28 days after immunization, the intermediate dose of SA elicited IgG antibodies with high titer and functional avidity, high T cell helper but low suppressor activities. In contrast, both high- and low-dose SA induced partial tolerance, with low IgG antibody titer, functional avidity and T cell helper activity. These studies suggest cyclical development of helper and suppressor functions during the 4 weeks after immunization. The emergence of a dominant helper or suppressor function is antigen dose dependent.

A comparative trial of intra-nasal beclomethasone dipropionate and sodium cromoglycate in patients with chronic perennial rhinitis

A double-blind crossover study has compared intra-nasal sodium cromoglycate (SCG) with beclomethasone dipropionate (BDP), and both drugs with placebo, in fifty-two chronic perennial rhinitis patients. BDP was significantly more effective in relieving symptoms than SCG (76.9% and 50% of the patients improved respectively, P < 0.01). Both drugs were more active than placebos but while BDP was very clearly more effective (P < 0.0005) SCG was only marginally better than its placebo (P < 0.05, Fisher; P = 0.068, chi 2). BDP was selected by 56% of the patients as the best agent for continuing therapy at the end of the trial. By contrast SCG was preferred by the same number of patients as chose the two placebos (11.5%).

Effects of craniofacial structures on mouse palatal closure in vitro

Heads of Swiss-Webster mouse fetuses of four ages spanning days 12-13 of gestation, were partially dissected by removing the brain (B), tongue (T) and mandible (M) alone or in combination (BT, BM, BTM). Preparations were suspended in a gassed, circulating culture system such that palatal closure must take place against gravity. Closure occurred earlier than in vivo and required the posterior half of the mandible be intact and the tongue removed.

Automated enzymic determination of ethanol in blood, serum, and urine with a miniature centrifugal analyzer

We describe an automated spectrophotometric reaction-rate method for determination of ethanol in serum and urine with a miniature centrifugal analyzer. The theanol is selectively oxidized in the presence of alcochol dehydrogenase and NAD+ to form NADH, which is measured by the rate of change of its absorbance. Reaction rates are determined automatically, and unknown concentrations are calculated from a computer-generated working curve based on aqueous ethanol standards. Blood, serum, or urine specimens need not be deproteinized. The method permits duplicate analysis of at least 30 samples per hour. Coefficients of variation and relative errors are about 2-3% for ethanol concentrations of 0.3-3.0 mug per 2 mul of sample. Analytical recovery of ethanol added to serum is 92-103% (average, 98.5%). Comparisons with distillation-oxidation, gas-chromatographic, and conventional enzymic procedures give satisfactory agreement.

Automated enzymic determination of ethanol in blood, serum, and urine with a miniature centrifugal analyzer

We describe an automated spectrophotometric reaction-rate method for determination of ethanol in serum and urine with a miniature centrifugal analyzer. The theanol is selectively oxidized in the presence of alcochol dehydrogenase and NAD+ to form NADH, which is measured by the rate of change of its absorbance. Reaction rates are determined automatically, and unknown concentrations are calculated from a computer-generated working curve based on aqueous ethanol standards. Blood, serum, or urine specimens need not be deproteinized. The method permits duplicate analysis of at least 30 samples per hour. Coefficients of variation and relative errors are about 2-3% for ethanol concentrations of 0.3-3.0 mug per 2 mul of sample. Analytical recovery of ethanol added to serum is 92-103% (average, 98.5%). Comparisons with distillation-oxidation, gas-chromatographic, and conventional enzymic procedures give satisfactory agreement.

A new in vitro system for studying secondary palate development

An in vitro system was devised which supports palate development in partially dissected embryonic mouse heads. The heads were suspended in the culture chamber so that they were not held in a fixed orientation and were constantly surrounded with a fluid medium. Under these circumstances the developing palate must effect closure without the aid of gravitational forces. The culture medium was constantly circulated, gassed with 95% O2, 5% CO2 using hollow fiber gas permeation devices, and kept at 34 degrees C. Swiss-Webster mouse embryos of 12 days 12-18 h (ca. 48 h prior to expected in vivo closure) or 13 days 8-14 h (ca. 24 h prior to closure) were used to test the ability of the system to support palatal development. Embryonic heads were dissected in one of two ways before culture: brain and tongue removed, or brain, tongue and mandible removed. After 24 h in culture, preparations of either age with only the brain and tongue removed had made substantially greater progress than their counterparts with the brain, tongue and mandible removed. With only the brain and tongue removed, the palatal shelves were contacting, adhered or fused in 67% of the older embryos of the same age cultured with the brain, tongue and mandible removed had shelves that were not fully elevated and still separated by a moderate gap. Thus for maximal progress in the present system, the oral cavity must be intact except for the tongue.

A new in vitro system for studying secondary palate development

An in vitro system was devised which supports palate development in partially dissected embryonic mouse heads. The heads were suspended in the culture chamber so that they were not held in a fixed orientation and were constantly surrounded with a fluid medium. Under these circumstances the developing palate must effect closure without the aid of gravitational forces. The culture medium was constantly circulated, gassed with 95% O2, 5% CO2 using hollow fiber gas permeation devices, and kept at 34°C. Swiss-Webster mouse embryos of 12 days 12–18 h (ca. 48 h prior to expected in vivo closure) or 13 days 8–14 h (ca. 24 h prior to closure) were used to test the ability of the system to support palatal development. Embryonic heads were dissected in one of two ways before culture: brain and tongue removed, or brain, tongue and mandible removed. After 24 h in culture, preparations of either age with only the brain and tongue removed had made substantially greater progress than their counterparts with the brain, tongue and mandible removed. With only the brain and tongue removed, the palatal shelves were contacting, adhered or fused in 67 % of the older embryos, whereas most of the embryos of the same age cultured with the brain, tongue and mandible removed had shelves that were not fully elevated and still separated by a moderate gap. Thus for maximal progress in the present system, the oral cavity must be intact except for the tongue.

A Versatile Minidisc Module for a Centrifugal Analyzer

We have developed a centrifugal minidisc module, which extends the versatility of the centrifugal analyzer system with respect to radiation sources, wavelength selectors, radiation detectors, and the analysis performed by the system. The motor, brake, power supply, and control circuitry for the sample/reagent minidisc unit has been repackaged in a compact module, which is easily attached to an optical reference base. Appropriate wavelength selectors, source, and detector modules can then be easily aligned with the minidisc module. Use of a programmable ultraviolet—visible monochromator can provide the automated wavelength selection necessary for application to simultaneous multi-type analyses. Design features of the centrifugal minidisc module are presented, and its versatility is illustrated.

Incorporation of a High-Speed Decimal Data Processor into a Centrifugal Analyzer

We incorporated a new high-speed data processor into a centrifugal analyzer system. The data processor is compact and inexpensive, yet it is capable of performing the essential control and data-manipulation functions that are usually performed by a minicomputer. The ease with which the system can be programmed to perform a typical analytical procedure is illustrated. The interaction of system components during the analysis is described, with emphasis on the role of the processor. Analytical results are presented.

A Centrifugal Analyzer with a New All-Digital Measurement System

An accurate, all-digital measurement system has been developed for use in a centrifugal analyzer system. The output of the radiation detector is converted directly to a digital count by a new type of charge-to-count converter. The converter is characterized by exceptional linearity and stability, and has a wide dynamic range. A gating and counting unit integrates the output of the charge-to-count converter and simultaneously measures the period of integration. The integration effectively discriminates against noise and allows an optimum amount of information to be extracted from the signal during the measurement period. Measurement of the integration period reduces requirements for synchronization and control devices, thus simplifying overall analyzer design. Control and data manipulation functions are performed by a minicomputer. The programs were written in OS/8 FORTRAN. The basic measurement principles of the new system and test results are described.