Population crises and population cycles

To prevent a population irretrievably depleting its resources, mammals have evolved a behavioural and physiological response to population crisis. When a mammalian population becomes dangerously dense, there is a reversal of behaviour. Co-operation and parental behaviour are replaced by competition, dominance and aggressive violence, leading to high mortality, especially of females and young, and a reduced population. The stress of overpopulation and the resulting violence impairs both the immune and the reproductive systems. Hence epidemics complete the crash of the population, and reproduction is slowed for three or four generations, giving the resources ample time to recover. In some mammal species, crisis and crisis response recur regularly, leading to cycles of population growth and relapse, oscillating about a fixed mean. Population crisis response and population cycles have been equally prominent in the history of human societies. But in man successive advances in food production have made possible growing populations, though with every such advance population soon outgrew resources again. Hence human cycles have been superimposed on a rising curve, producing a saw-tooth graph. Because advances in food production amounted to sudden disturbances in the relations between human populations and their environments, the crisis response in man has failed to avert famine and resource damage. In the large human societies evolved since the coming of settled agriculture and cities, the basic effects of violence, epidemics, famine and resource damage have been mediated by such specifically human disasters as inflation, unemployment, and political tyranny. An account of past crises, periods of relative relief from population pressure, and resulting cycles, is given for a number of regions: China, North Africa and Western Asia, the northern Mediterranean, and north-western Europe. The paper ends with an account of the present world-wide population crisis, and the solution made possible by Malthus's discovery that, unlike animals, we can choose to check population growth by reducing the birth-rate, instead of raising the death-rate, as in other mammals, by the population crisis response.

Implications for improving risk communication through various channels: a discussion

The news media need to improve their coverage of new and old cancer risks, avoiding sensational reporting of minor risks and underreporting of major ones. However, efforts to communicate about cancer risk to the general public need to go far beyond the traditional print and broadcast outlets into more innovative, personalized channels that can better educate individuals about the risks they face and what they can do about them.

Living can be hazardous to your health: how the news media cover cancer risks

For more than two decades, the news media has bombarded the public with often conflicting information about health risks, contributing to an atmosphere of hype and hysteria about cancer and other diseases. Improvements in media reporting of health risks require greater efforts by both those who cover the news and those who create it. Guidelines for bringing more perspective and balance to media coverage of risk are provided. These include putting cancer in context with other diseases, explaining absolute and relative risks, differentiating between individual and population risks, stressing the degree of uncertainty of new research and how it fits with previous data, covering the process as well as end results of science, understanding different media constraints and needs, and taking into account the diverse backgrounds and needs of the target audience-the general public.

User satisfaction with realtime teleneurology

User satisfaction (i.e. that of patients, medical staff at a remote hospital and medical staff at a neurological centre) with realtime teleneurology consultations was studied prospectively. Twenty-five patients with neurological problems admitted to a hospital without permanent neurological cover were assessed from a neurological centre by specialist neurologists using realtime video-links transmitting at 384 kbit/s. All users reported high levels of satisfaction with the technical aspects of the consultations. Patients, almost universally, reported confidence in teleneurology as a means of dealing with their presenting complaints. Similarly, medical staff at either site felt confident in managing patients using teleneurology and almost always felt that a telephone consultation would not have achieved as good an outcome. No major organizational problems were identified. These findings suggest overall user satisfaction with realtime teleneurology for managing patients with neurological problems admitted to hospitals that do not have resident neurologists.

Spontaneous rupture of adrenal myelolipoma: spiral CT appearance

We report the helical computed tomographic findings of a symptomatic giant (11 cm) adrenal myelolipoma with spontaneous extracapsular hemorrhage. Narrow collimation (3 mm) imaging and three-dimensional reconstructions were useful to fully characterize the components and location of the lesion. A literature search showed a striking male and right-sided predominance for spontaneously hemorrhagic myelolipomas.

Standard Kausch-Whipple pancreatoduodenectomy

Despite the increasing number of clinical trials in pancreatic cancer there are no widely accepted definitions of different types of resection for pancreatic cancer. An agreed definition of the standard Kausch-Whipple pancreatoduodenectomy was derived by a group of international experts at a meeting in Castelfranco Veneto, Italy, in May 1998. The lymph node groups to be removed en bloc with the pancreatoduodenectomy and described using the Japanese Pancreas Society classification were as follows: 13a and 13b; 17a and 17b; 12b1, 12b2 and 12c; and 14a and 14b. Limited segmental major venous resection and adjacent organ resection, if required, may be included as part of a standard pancreatoduodenectomy. The pylorus-preserving procedure also may be included as part of standard resection, but not for tumours of the anterior-superior part of the head of the pancreas. Wider adoption of the definition of standard Kausch-Whipple resection will enable a more objective comparative analysis of the radicality of resection between institutions and permit a more coherant analysis on the type of surgery undertaken in multicentre adjuvant studies.

The cost-effectiveness of teleneurology consultations for patients admitted to hospitals without neurologists on site. 1: A retrospective comparison of the case-mix and management at two rural hospitals

We are currently evaluating the use of telemedicine for improving the care of patients admitted with neurological symptoms to hospitals that do not have specialist neurologists on site. To do this we have been comparing the outcome of patients admitted to two small hospitals. In one hospital all patients with neurological symptoms are seen by a neurologist at a distance using an interactive video-link transmitting at 384 kbit/s; in the other patients with neurological problems are managed as per usual practices. For the results of this study to be valid, it is essential that the case-mix and process of management for neurological patients are similar at the two hospitals. We therefore compared the case-mix, process of management, and outcome for all patients admitted over a four-month period to either hospital who had been coded using ICD-10 as having a final diagnosis of a neurological condition. No appreciable differences were noted between the two hospitals for measures of case-mix or outcome. Likewise, most measures of process were similar, although there was a significant difference for the overall length of hospital episode between the two hospitals. When patients with prolonged hospital episodes were excluded, or only patients with a diagnosis of headache, epilepsy or transient ischaemic attack were considered (who as a group made up the bulk of neurological admissions), the difference in the length of hospital episode was not significant. It should therefore be possible for us to estimate the effect of telemedicine on the management of patients with neurological problems.

Minority cancer patients and their providers: pain management attitudes and practice

BACKGROUND

The goals of the current studies were: 1) to determine the pain treatment needs of socioeconomically disadvantaged African-American and Hispanic patients with recurrent or metastatic cancer and 2) to assess the attitudes of health care professionals who treat them.

METHODS

In the first study 108 African-American and Hispanic patients with metastatic or recurrent cancer and pain completed a survey about their pain intensity, pain interference, and attitudes toward analgesic medications. Physicians also rated their patients' pain and the adequacy of the patients' current analgesic prescriptions was assessed. In the second study 55 physicians and nurses who treat these patients completed a questionnaire regarding cancer pain and its management in their practice settings.

RESULTS

Approximately 28% of the Hispanic and 31% of the African-American patients received analgesics of insufficient strength to manage their pain. Although the majority of patients received appropriate analgesics, 65% reported severe pain. Physicians underestimated pain severity for 64% of the Hispanic and 74% of the African-American patients. Physicians were more likely to underestimate the pain severity of female patients than male patients. Inadequate pain assessment, patient reluctance to report pain, and lack of staff time were perceived as barriers to pain management.

CONCLUSIONS

Although the data suggest recent improvements in analgesic prescribing practices for African-American and Hispanic cancer patients, the majority of patients reported high levels of pain and limited pain relief from analgesic medications. Inadequate pain assessment remains a major barrier to optimal cancer pain treatment.

Fibrosing colonopathy in an adult owing to over use of pancreatic enzyme supplements

A woman, then in her late 20s, underwent a cholecystectomy in 1962 for gallstone disease and subsequent common bile duct stones were managed endoscopically. However, because of unrelenting pain, a pylorus preserving pancreaticoduodenectomy was done in 1990 and in the following years the patient took large amounts of pancreatic enzyme supplements. She developed large bowel obstruction in 1997 and a right hemicolectomy was undertaken. Histology confirmed fibrosing colonopathy of the ascending colon and caecum. Her pancreatic enzyme dose was reduced and her subsequent course has been uncomplicated.

Inattentional blindness versus inattentional amnesia for fixated but ignored words

People often are unable to report the content of ignored information, but it is unknown whether this reflects a complete failure to perceive it (inattentional blindness) or merely that it is rapidly forgotten (inattentional amnesia). Here functional imaging is used to address this issue by measuring brain activity for unattended words. When attention is fully engaged with other material, the brain no longer differentiates between meaningful words and random letters, even when they are looked at directly. These results demonstrate true inattentional blindness for words and show that visual recognition wholly depends on attention even for highly familiar and meaningful stimuli at the center of gaze.

Contrast polarity and face recognition in the human fusiform gyrus

Functional imaging has revealed face-responsive visual areas in the human fusiform gyrus, but their role in recognizing familiar individuals remains controversial. Face recognition is particularly impaired by reversing contrast polarity of the image, even though this preserves all edges and spatial frequencies. Here, combined influences of familiarity and priming on face processing were examined as contrast polarity was manipulated. Our fMRI results show that bilateral posterior areas in fusiform gyrus responded more strongly for faces with positive than with negative contrast polarity. An anterior, right-lateralized fusiform region is activated when a given face stimulus becomes recognizable as a well-known individual.

Exploring the experience of type 2 diabetes in urban aboriginal people

The experience of diabetes among urban Aboriginal people (status and non-status Indians) was explored through a qualitative study. Because researchers have focused almost exclusively on Aboriginal people living on reserves or in isolated rural communities in Canada, this study conducted face-to-face interviews with participants (n = 20) living in the city of Winnipeg, Manitoba. The data generated 3 themes: diabetes as an omnipresent and uncontrollable disease; beyond high sugar: diabetes revealed in bodily damage; and the good, the bad, and the unhelpful: interactions with health-care providers. Findings from this study and previous research support the existence of a pan-Aboriginal model of diabetes. This contemporary cultural stance appears to transcend geography and has implications for the prevention and treatment approaches used in programs and health services for Aboriginal people living with diabetes.

Relation of disability costs to function: spinal cord injury

OBJECTIVE

This study evaluated the validity of the Functional Independence Measure (FIM instrument) in predicting (1) the number of minutes of daily assistance provided, (2) the cost of durable goods currently used, and (3) the number of paid helper hours provided daily to persons with spinal cord injury living in the community.

DESIGN

A cross-sectional study.

SUBJECTS

One hundred nine persons with spinal cord injury who were a median 6 years postdischarge from initial medical rehabilitation.

RESULTS

A significant inverse linear relationship was observed between FIM scores and the square root values of the three cost-related measures. The FIM-18 and the FIM motor scores were the best single predictors of the square root of minutes of assistance (paid and/or unpaid) per day, explaining 85% of variance. The FIM motor measure was the best single predictor of square root of cost of durable goods, explaining 29% of variance. The Self-Care, FIM motor, and FIM-18 scores equally predicted square root of hours of paid help per day, explaining 58% of variance.

CONCLUSION

The findings indicate FIM-related scores predict the amount of assistance needed and certain costs for persons with spinal cord injury disability.

MDR1 gene expression in primary and advanced breast cancer

P-glycoprotein (Pgp)-associated multidrug resistance (MDR) is related to intrinsic and acquired cross resistance to anthracyclines, vinca alkaloids, and other antineoplastic antibiotics. Expression of MDR1 is widely considered to play an important role in conferring resistance to adjuvant chemotherapy in women with breast tumor cells in women with disseminated disease, although data supporting this view is, at best, conflicting. The expression of MDR1 gene and its gene product, P-glycoprotein, was investigated in primary and advanced breast cancers (both previously untreated and previously treated on specific treatment protocols) to assess the role of P-glycoprotein in determining responsiveness to adjuvant chemotherapy. Expression was assessed by immunohistochemistry, reverse transcription-PCR (RT-PCR), Northern Blot and Western Blot. MDR1 mRNA was detected in 40% of the breast cancers tested by RT-PCR with 40 cycles of PCR amplification. When reducing the PCR amplification cycles to 28, the MDR1 gene expression signal disappeared from breast cancers of the highest expressers; however, known MDR1 positive control normal tissues, such as adrenal, kidney, and liver continued to show an expression product. Western and Northern blots failed to demonstrate the MDR1 gene product, P-glycoprotein, in these breast cancers. In contrast, physiologic levels of P-glycoprotein was clearly detected in normal adrenal, kidney, and liver by these techniques. Immunohistochemistry confirmed that breast carcinoma cells lacked P-glycoprotein expression; however, interstitial mononuclear cells, morphologically consistent with lymphocytes or macrophages did show immunostaining in some of these breast tumors. MDR1 gene expression identified by RT-PCR was not correlated either with response to paclitaxel therapy (29 patients able to be evaluated, p = 0.34, Fisher Exact Test) or overall survival (32 breast cancer patients with clinical follow-up information, p = 0.336, log rank). In conclusion, P-glycoprotein was not expressed in breast carcinoma cells at significant levels, although it was expressed in stomal lymphocytes or macrophages. These results suggest that P-glycoprotein does not play a significant role in multidrug resistance of breast cancer.

The identification and characterization of a novel splicing protein, Isy1p, of Saccharomyces cerevisiae

We have identified a novel splicing factor, Isy1p, through two-hybrid screens for interacting proteins involved in nuclear pre-mRNA splicing. Isy1p was tagged and demonstrated to be part of the splicing machinery, associated with spliceosomes throughout the splicing reactions. At least a portion of the Isy1 protein population is associated with snRNAs; low levels of U5 and U6 snRNAs are coimmunoprecipitated specifically with Isy1p. When the ISY1 gene was knocked out, no defect in vegetative growth was observed. Using a sensitive in vivo splicing assay, however, we observed lower splicing efficiency in the isy1 null mutant compared to wild-type, indicating that Isy1 p is important in the optimization of splicing.

Effects of acid-etching on the tensile properties of demineralized dentin matrix

OBJECTIVES

Little research has been done to evaluate the effects of acids commonly used in adhesive dentistry, on the tensile properties of the demineralized dentin matrix. The purpose of this study was to evaluate the effects of a number of acidic conditioners on the ultimate tensile strength (UTS) and modulus of elasticity (E) of human coronal dentin matrix.

METHODS

Small hour-glass shaped (for UTS) or l-beam shaped (for determination of E) were prepared from mid-coronal dentin of extracted human third molars. After protecting the ends with varnish, the middle of the specimens was completely demineralized in 0.5 M EDTA (pH 7). UTS was determined by tensile stressing to failure. Modulus of elasticity was calculated from stress strain curves. The results were analyzed by ANOVA and Student-Neuman-Keuls test at the 95% confidence level.

RESULTS

Brief (ca. 1-2 min) exposure of demineralized dentin matrix to acids had no measurable effects on its tensile properties. Ten-minute exposures to 2.5% and 17.5% nitric acid lowered (p < 0.05) the UTS compared to phosphate buffered saline (PBS)-exposed controls. Exposure of the decalcified dentin to 10% citric acid containing 3% ferric chloride, 10% citric acid, 37% phosphoric acid or 17.5% nitric acid containing 3% ferric chloride for 10 min had no effect on UTS. None of these acids consistently lowered stiffness.

SIGNIFICANCE

The results indicate that relatively long exposures to acids are required to alter the tensile properties of demineralized dentin. It is unlikely that the brief exposures to acids that are used in adhesive dentistry would acutely weaken the physical properties of demineralized dentin. However, long-term studies should be done to determine if such treatment increases the susceptibility of the matrix to hydrolysis.

Murine MPS I: insights into the pathogenesis of Hurler syndrome

Mucopolysaccharidosis type I (MPS I) is an autosomal recessive disease resulting from deficiency of the lysosomal enzyme alpha-L-iduronidase. A murine model which shows complete deficiency in alpha-L-iduronidase activity has been developed and shows phenotypic features similar to severe MPS I in humans. Here we report on the long-term clinical, biochemical, and pathological course of MPS I in mice with emphasis on the skeletal and central nervous system (CNS) manifestations. Affected mice show a progressive clinical course with the development of coarse features, altered growth characteristics and a shortened life span. Progressive lysosomal accumulation is seen in all tissues. Skeletal manifestations represent the earliest clinical finding in MPS I mice with histologic analysis of growth plate and cortical bone revealing evidence that significant early pathology is present. Analysis of the CNS has revealed the novel finding of progressive neuronal loss within the cerebellum. In addition, brain tissue from MPS I mice shows increased levels of GM2 and GM3 gangliosides. This murine model clearly shows phenotypic and pathologic features which mimic those seen in severe human MPS I and should be an invaluable tool for the study of the pathogenesis of generalized storage disorders.

Discriminative stimulus properties of low doses of ethanol in humans

Discriminative stimulus properties of low doses of ethanol were evaluated in humans using established behavioural drug discrimination procedures. Twenty-five moderate drinkers (12 females and 13 males) were trained to discriminate placebo from 0.2 g/kg ethanol in 200 ml tonic water mixed with Tabasco sauce and drunk in portions of 50 ml every 15 s. Seventeen of the subjects (ten females and seven males) were able to reach criterion performance (at least 80% correct responses). Generalisation responding across ethanol doses of 0 (placebo), 0.025, 0.05, 0.1 and 0.2 g/kg was examined the day after training using a procedure in which subjects reported the extent to which the test stimulus resembled the training dose. At the end of each generalisation session, self ratings of mood changes, physiological responses and performance in a working memory and a time estimation task were evaluated. Subjects were able to distinguish the three higher doses of ethanol from placebo. Self ratings indicated that subjects' ability to distinguish ethanol from placebo was related, at the highest dose, to change of taste, but to feelings of light-headedness at the lower doses. Ethanol administration influenced skin conductance measurements but there was no relationship found between changes in skin conductance and the ethanol discriminative stimulus. These data suggest a difference in the nature of the discriminative stimulus of ethanol between high (training) and low (generalising) doses as indicated in the subjective reports.

The new varicella vaccine: efficacy, safety, and administration

Since the FDA has given approval for the manufacture of a varicella vaccine (Varivax), nurses are beginning to administer the vaccine to children. Over 11,000 healthy and immunocompromised children have been immunized since 1979. Varivax has been found to be 95% to 100% effective in conferring immunity for at least 10 years, and it appears to be a safe vaccine. This article presents a review of the research literature on clinical trials of Varivax, and the risks, benefits, and projected cost of the vaccine. Precautions, contraindications, and guidelines for administration are tabled and discussed in a sample case using the Health Belief Model as a theoretical framework. The article includes a discussion of areas for further research and implications for nursing.