Predictors of planned retirement age: an application of Beehr's model

Given the aging workforce, understanding the retirement process is an area of increasing interest to organizations. T. A. Beehr's (1986) model of retirement behavior was used in this study as a basis for selecting personal, psychological, and organizational predictors of subsequent planned retirement age. In addition, potential differences in predictors of the planned retirement age of retirement-eligible and retirement-ineligible respondents were explored. Two hundred sixty-four respondents working for a large multinational firm completed 2 surveys on their attitudes toward work and retirement. Results showed that chronological age, employee health, and self-perceptions of the ability to adjust to retirement predicted subsequent planned retirement age. Interactions of the predictors with retirement eligibility are reported along with implications for retirement-planning programs.

Recombinant pro-regions from papain and papaya proteinase IV-are selective high affinity inhibitors of the mature papaya enzymes

Proteolytic enzymes require the presence of their pro-regions for correct folding. Of the four proteolytic enzymes from Carica papaya, papain and papaya proteinase IV (PPIV) have 68% sequence identity. We find that their pro-regions are even more similar, exhibiting 73.6% identity. cDNAs encoding the pro-regions of these two proteinases have been expressed in Escherichia coli independently from their mature enzymes. The recombinant pro-regions of papain and PPIV have been shown to be high affinity inhibitors of all four of the mature native papaya cysteine proteinases. Their inhibition constants are in the range 10(-6) - 10(-9) M. PPIV was inhibited two to three orders of magnitude less effectively than papain, chymopapain and caricain. The pro-region of PPIV, however, inhibited its own mature enzyme more effectively than did the pro-region of papain. Alignment of the sequences of the four papaya enzymes shows that there is a highly variable section towards the C-terminal of the pro-region. This region may therefore confer selectivity to the pro-regions for the individual proteolytic enzymes.

The characterization of liposomal glucose oxidase electrodes for the measurement of glucose

Many biosensors have been described for the measurement of glucose in order to monitor diabetic patients. Glucose oxidase has been used commonly in the construction of glucose sensors but the performance of this enzyme is limited by enzyme saturation kinetics, which restrict the measurement of clinically relevant glucose concentrations (0 to 25 mM). Diffusion limiting membranes have been described that result in the exposure of the enzyme to lower concentrations of glucose than are present in the bulk test solution. Recently a liposomal enzyme electrode was reported whereby glucose oxidase was encapsulated within liposomes so that the lipid bilayer was the diffusion limiting membrane. It was shown that the electrode response was defined by the lipid constituents of the liposome, and that a linear response to glucose could be achieved up to 40 mM. This paper describes research undertaken to improve the methods of production of a liposomal enzyme electrode. Improved immobilization of liposomes is demonstrated with the use of poly-L-lysine solution. The variation in electrode response with respect to the amount of glucose oxidase liposomally encapsulated is reported. The new method allows a greater number of sensors to be produced from a single batch of liposomes. Studies also show the biofouling effects of the lipid constituents of ruptured liposomes on the response of the electrode to glucose over time.

Sinister psychotics. Left-handedness in schizophrenia and affective disorder

The notion persists that psychotics, particularly schizophrenics, are less right-handed than the general population, and that this deviation is pathophysiologically important in some patients. We assessed handedness and psychopathology in 163 DSM-III schizophrenics, 103 affectives, and 112 normal subjects. Although schizophrenics were less right-handed than normal subjects, this difference was primarily due to more mixed handedness among schizoaffectives. Relationships between handedness and specific psychopathology were uninformative, and we conclude that handedness may not be an important consideration in the study of psychosis.

Revascularization of a human anterior cruciate ligament graft during the first two years of implantation

The blood supplies of 45 unimpinged, human anterior cruciate ligament grafts were studied during the first 2 years of implantation. Grafts were defined as unimpinged by the low signal intensity of the graft observed on a sagittal proton density magnetic resonance scan. Magnetic resonance imaging with the intravenous contrast agent gadolinium diethylenetriamine pentacetic acid was used to evaluate the blood supply of the hamstring autograft as well as the periligamentous tissues by assessment of enhancement patterns after administration of the agent. The unimpinged anterior cruciate ligament graft acquired no discernible blood supply during the 2 years of implantation. The graft retained the same hypovascular appearance as the normal posterior cruciate ligament. In contrast, the periligamentous soft tissues were richly vascularized and covered the graft by 1 month. The viability of an unimpinged, human anterior cruciate ligament graft may depend more on synovial diffusion than on revascularization.

Is evidence for homoeopathy reproducible?

We tested, under independent conditions, the reproducibility of evidence from two previous trials that homoeopathy differs from placebo. The test model was again homoeopathic immunotherapy. 28 patients with allergic asthma, most of them sensitive to house-dust mite, were randomly allocated to receive either oral homoeopathic immunotherapy to their principal allergen or identical placebo. The test treatments were given as a complement to their unaltered conventional care. A daily visual analogue scale of overall symptom intensity was the outcome measure. A difference in visual analogue score in favour of homoeopathic immunotherapy appeared within one week of starting treatment and persisted for up to 8 weeks (p = 0.003). There were similar trends in respiratory function and bronchial reactivity tests. A meta-analysis of all three trials strengthened the evidence that homoeopathy does more than placebo (p = 0.0004). Is the reproducibility of evidence in favour of homoeopathy proof of its activity or proof of the clinical trial's capacity to produce false-positive results?

Family study of schizophrenia and personality

The purpose of this study was to determine whether the abnormal characteristics observed in relatives of schizophrenics represent variations in normal personality. Relatives (N = 340) of patients with schizophrenia, affective disorder, and medical or surgical conditions were personally interviewed about psychiatric symptoms and completed the Multidimensional Personality Questionnaire. Relatives who were themselves ill had elevated scores on some scales. Relatives of schizophrenics had normal scores on all personality scales, but relatives of affectively ill probands differed from other relatives on Well-Being and measures of Negative Emotionality. When schizophrenic probands were subtyped by symptoms, relatives of emotionally blunted schizophrenics were found to have slightly lower scores on Social Closeness than did relatives of controls. Overall, these results suggest that schizophrenia is unrelated to normal personality.

Characterisation of the cDNA clones of two beta-tubulin genes and their expression in the potato plant (Solanum tuberosum L.)

The cDNA clones of two potato beta-tubulin genes were isolated from a tuberising stolon tip library. Analysis of 20 positive clones showed that they represented one or another of two different but very similar beta-tubulin genes, designated TUBST1 and TUBST2. The expression pattern of beta-tubulin genes in the potato plant was investigated by RNA blot analysis and by RT-PCR. Southern analysis of potato genomic DNA with coding and non-coding beta-tubulin probes revealed that there are multiple beta-tubulin genes in the potato genome and that there is likely to be considerable divergence in the 3' non-coding sequences. Phylogenetic analysis of plant beta-tubulin genes is described.

Are schizophrenia and affective disorder related?: the problem of schizoaffective disorder and the discrimination of the psychoses by signs and symptoms

Schizophrenia and affective disorder are separately classified. Schizoaffective disorder has been considered a variant of these, or representing several diseases. Some hypothesize a psychosis continuum. One test of these contrasting views involves discriminating the psychoses by their classic symptoms. We used discriminant function analyses to assess the ability of systematically recorded psychopathology to distinguish 167 DSM-III schizophrenics from 74 affectives. We divided the schizophrenics into chronic and schizoaffective subgroups. We discriminated chronic schizophrenics from affectives, but schizoaffectives overlapped both groups. Schizoaffective/unipolars were like chronic schizophrenics, and schizoaffective/bipolars were like affectives. However, these discriminations also substantially overlapped, and among non-affective positive features formal thought disorder was best at discrimination. Our findings do not fully support the present classification system, and suggest that its emphasis on hallucinations and delusions is overvalued.

An unequivocal example of cysteine proteinase activity affected by multiple electrostatic interactions

The role of electrostatic interactions between the ionizable Asp158 and the active site thiolate-imidazolium ion pair of some cysteine proteinases has been the subject of controversy for some time. This study reports the expression of wild type procaricain and Asp158Glu, Asp158Asn and Asp158Ala mutants from Escherichia coli. Purification of autocatalytically matured enzymes yielded sufficient fully active material for pH (kcat/Km) profiles to be obtained. Use of both uncharged and charged substrates allowed the effects of different reactive enzyme species to be separated from the complications of electrostatic effects between enzyme and substrate. At least three ionizations are detectable in the acid limb of wild type caricain and the Glu and Asn mutants. Only two pKa values, however, are detectable in the acid limb using the Ala mutant. Comparison of pH activity profiles shows that whilst an ionizable residue at position 158 is not essential for the formation of the thiolate-imidazolium ion pair, it does form a substantial part of the electrostatic field responsible for increased catalytic competence. Changing the position of this ionizable group in any way reduces activity. Complete removal of the charged group reduces catalytic competence even further. This work indicates that hydronations distant to the active site are contributing to the electrostatic effects leading to multiple active ionization states of the enzyme.

Characterisation of the S-adenosylmethionine decarboxylase (SAMDC) gene of potato

S-adenosylmethionine decarboxylase (SAMDC) is involved in the biosynthesis of the polyamines, spermidine and spermine. Recently, we reported the isolation of a putative cDNA clone of the SAMDC clone of potato (Plant Mol Biol 20; 641-651). In order to confirm that the potato genes does encode SAMDC, a complementation experiment with a yeast strain that possesses a null mutation in the SAMDC gene was performed. The yeast strain contains a deletion-insertion mutation in the SAMDC gene and has an absolute requirement for the addition of exogenous spermidine for growth. When the full-length potato cDNA was expressed in the mutant yeast strain there was no longer a requirement for exogenous spermidine. Immunoblotting experiments suggest that the potato SAMDC gene product has an apparent molecular mass of 39 kDa. Expression of the SAMDC gene was high in the young and actively dividing tissues and low in the mature and non-dividing tissues of both vegetative and reproductive organs. Additionally, isolation and characterisation of the corresponding genomic clone is reported. The gene has one intron in its 5'-untranslated sequence but otherwise the transcribed portion is identical to the cDNA clone.

Family study of schizophrenia and personality

The purpose of this study was to determine whether the abnormal characteristics observed in relatives of schizophrenics represent variations in normal personality. Relatives (N = 340) of patients with schizophrenia, affective disorder, and medical or surgical conditions were personally interviewed about psychiatric symptoms and completed the Multidimensional Personality Questionnaire. Relatives who were themselves ill had elevated scores on some scales. Relatives of schizophrenics had normal scores on all personality scales, but relatives of affectively ill probands differed from other relatives on Well-Being and measures of Negative Emotionality. When schizophrenic probands were subtyped by symptoms, relatives of emotionally blunted schizophrenics were found to have slightly lower scores on Social Closeness than did relatives of controls. Overall, these results suggest that schizophrenia is unrelated to normal personality.

Personality and self-report of cognitive functioning

We examined the relationship of trait personality dimensions (negative affectivity and positive affectivity) on self-report of cognitive functioning. Ninety-six subjects who were screened to be without evidence of psychiatric or neurologic disorder, and who had previously completed the Tellegen Differential Personality Questionnaire (mean interval = 2 years) were sent a self-report questionnaire of cognitive functioning (MASQ). As predicted, negative affectivity (NA) was more strongly related to self-appraisal of cognitive functioning than was positive affectivity (PA); subjects with higher NA scores acknowledged more cognitive difficulties. Negative affectivity was also a stronger predictor of cognitive self-report than was self-report of current sad mood state. The implications of these findings for the examination of self-appraisal and accuracy of self-report are discussed.

Microbial predation in coupled chemostats: a global study of two coupled nonlinear oscillators

Predator-prey systems in continuously operated chemostats exhibit sustained oscillations over a wide range of operating conditions. When two such chemostats interact through flow exchange, the interplay of the oscillation frequencies gives rise to a wealth of dynamic behavior patterns. Using numerical bifurcation techniques, we perform a detailed computational study of these patterns and the transitions between them as the coupling strength and relative frequencies of the two chemostats vary. We concentrate on certain strong resonance phenomena between the two frequencies as well as their mutual extinction and provide a representative sampling of possible phase portraits for our model system. Our observations corroborate recent mathematical results and case studies of coupled nonlinear chemical oscillators in which regions of mutual extinction as well as the Arnol'd structure for two-parameter families of maps of the plane have been observed. We highlight certain unexpected features of the operating diagram discovered through our computational study and discuss their implication for the dynamic response of the chemostat system.

Psychosensory features in mood disorder: a preliminary report

The purpose of this study was to determine the prevalence of psychosensory features in mood disorder patients, and to investigate the relationship between psychosensory features and classic psychopathology. We evaluated 50 mood disorder patients (39 bipolar, 11 schizoaffective) for the presence of psychosensory features and psychopathology. We assessed psychosensory features separately using the Profile of Psychomotor Symptoms. We obtained additional information regarding each patient's psychiatric and drug history, family history, and electroencephalogram. Seven (14.0%) experienced three or more recent psychosensory features, and 12 (24.0%) reported three or more past psychosensory features. The presence of alcohol and drug abuse, number of medications, and electroencephalographic abnormality had no effect on the prevalence of psychosensory features. Psychosensory features significantly (rs = .53, P < .001) correlated with hallucinations, but not with other psychopathology (P > NS). Psychosensory features are not uncommon in mood disorders and have a strong relationship with hallucinations. Our findings also suggest that the presence of psychosensory features in mood disorder suggests episode severity and not a specific subgroup.

Adult respiratory distress syndrome complicating intravenous infusion of low-molecular weight dextran

Respiratory failure is one of the most uncommon and serious adverse drug reactions. Low-molecular-weight-dextran (Dextran-40) is a useful adjunctive anti-platelet agent in the setting of coronary angioplasty and intracoronary stent placement. We report the occurrence of the adult respiratory distress syndrome following intravenous infusion of Dextran-40.

Patterns of speech disorders in schizophrenia and mania

Formal thought disorder (FTD), defined as abnormal speech, has been associated with schizophrenia and likened to fluent aphasia. Whether FTD differentiates subtypes of schizophrenics and discriminates schizophrenics from other patients is unclear. We studied this issue by analyzing ratings of FTD of 170 schizophrenics and 62 manics. Eighty percent of emotionally blunted schizophrenics had FTD compared with 6.5% of manics. Factor analysis revealed verbiage disturbance and disorganized speech factors (44% of the variance). We assessed the discriminating ability of these factors, and compared these results to those from factors derived from Andreasen's positive/negative FTD construct, and to factors derived from speech and language diagnostic criteria for schizophrenia and mania in the proposed DSM-IV. Overall classifications were similar (91%, 91%, and 88%, respectively). We also found that FTD was related to emotional blunting, but not to other psychopathology.

Review article: coccidiosis of domestic ruminants

Coccidiosis in ruminants results from complex interactions between hosts and parasites with many external factors influencing the severity of disease. The study of ruminant coccidiosis is still very much in its infancy despite the advances made in recent years in determining life cycles, pathogenesis, epidemiology and control. Many of the life cycles of the species, considered to be of lesser importance, have still to be elucidated and controversy still exists concerning the pathogenicity of some of these species. Outbreaks of coccidiosis occur with ever increasing frequency yet few drugs exist for prevention. Only limited investigations have been undertaken on immunological methods of control. This paper seeks to review the current knowledge on the biology and control of the coccidial species affecting cattle, sheep and goats.

Combined modality treatment using BID radiation for locally advanced non-small cell lung carcinoma

BACKGROUND

From February 1988 to August 1991, 82 patients were treated on Phase II trial of split-course multimodality treatment for locally advanced, non-small cell lung cancer (NSCLC).

METHODS

Treatment consisted of twice-daily radiation (150 cGy/fraction) delivered with concomitant infusional cisplatin, etoposide, and fluorouracil for 1 week every third week. Patients were classified before initial treatment as either potentially resectable (eligible for surgery [ES]) or ineligible for surgery (IES). The ES group consisted of 38 Stage IIIA and 7 Stage IIIB patients. The IES group had 5 patients staged as IIIA and 32 staged as IIIB. Most patients were staged clinically. ES patients received three cycles of treatment (39 Gy) before resection. IES patients received four cycles (60 Gy) delivered with curative intent.

RESULTS

Thirty-nine of 45 ES patients underwent resection. The pathologic response rate was 27%. Three-year actuarial local control was 86% for 41 evaluable ES patients. Three-year actuarial survival for the whole ES group was 39%, with a median follow-up for living patients of 32 months. The IES group faired less well, with an 18% 3-year actuarial survival. Treatment was well tolerated with a median weight loss of one-half pound, mild or moderate pneumonitis in 5%, mild esophagitis in 15%, and severe nausea and/or vomiting in 10% of patients. Treatment-related mortality was 5%.

CONCLUSIONS

Patients treated with conventional radiation alone for Stage III NSCLC are rarely cured. This well tolerated Phase II study demonstrated encouraging results for such patients. Both local control and survival appeared promising, especially in patients rendered resectable after combined-modality treatment.

Variations in oocyst output associated with Cryptosporidium baileyi infections in chickens

Groups of birds, aged 2, 16 and 30 days, were experimentally infected with 400, 20,000 or 1,000,000 oocysts of Cryptosporidium baileyi. The faecal oocyst output for each group was determined by collection of faeces on Days 0, 5, 7 and 13-21 post-infection (p.i.). The duration of patency of infection, as determined by oocyst excretion, declined more rapidly in the older age groups but persisted longer in birds challenged with the lower oocyst numbers.

The problem of missing clinical data for research in psychopathology: some solution guidelines

There are no guidelines to help psychiatric researchers statistically adjust for missing data. We discuss the problems resulting from missing values, and illustrate some of them with examples from our work. Using structured instruments, we obtained clinical information from 241 patients. Some instrument items were not rated, and these did not occur randomly: hallucinations and delusions were most frequently unrated, especially in chronic schizophrenics, and patients with high scores for other psychopathology. Systematically assigning an intermediate value between present and absent to nonrated items was a satisfactory solution, unaffected by nonrandom missing values. This simple solution was equivalent to a complicated one (vectoring) in discriminating patients. When relationships between variables are linear, we recommend the intermediate value method as a practical solution to missing values. We stress that missing values do not mean missing information, and the most common response to missing values (dropping subjects) is least informative.