One phase of the dormancy developmental pathway is critical for the evolution of insect seasonality.

Evolutionary change in the timing of dormancy enables animals and plants to adapt to changing seasonal environments and can result in ecological speciation. Despite its clear biological importance, the mechanisms underlying the evolution of dormancy timing in animals remain poorly understood because of a lack of anatomical landmarks to discern which phase of dormancy an individual is experiencing. Taking advantage of the nearly universal characteristic of metabolic suppression during insect dormancy (diapause), we use patterns of respiratory metabolism to document physiological landmarks of dormancy and test which of the distinct phases of the dormancy developmental pathway contribute to a month-long shift in diapause timing between a pair of incipient moth species. Here, we show that divergence in life cycle between the earlier-emerging E-strain and the later-emerging Z-strain of European corn borer (ECB) is clearly explained by a delay in the timing of the developmental transition from the diapause maintenance phase to the termination phase. Along with recent findings indicating that life-cycle differences between ECB strains stem from allelic variation at a single sex-linked locus, our results demonstrate how dramatic shifts in animal seasonality can result from simple developmental and genetic changes. Although characterizing the multiple phases of the diapause developmental programme in other locally adapted populations and species will undoubtedly yield surprises about the nature of animal dormancy, results in the ECB moth suggest that focusing on genetic variation in the timing of the dormancy termination phase may help explain how (or whether) organisms rapidly respond to global climate change, expand their ranges after accidental or managed introductions, undergo seasonal adaptation, or evolve into distinct species through allochronic isolation.

A constitutive model for muscle properties in a soft-bodied arthropod.

In this paper, we examine the mechanical properties of muscles in a soft-bodied arthropod under both passive and stimulated conditions. In particular, we examine the ventral interior lateral muscle of the tobacco hornworm caterpillar, Manduca sexta, and show that its response is qualitatively similar to the behaviour of particle-reinforced rubber. Both materials are capable of large nonlinear elastic deformations, show a hysteretic behaviour and display stress softening during the first few cycles of repeated loading. The Manduca muscle can therefore be considered as different elastic materials during loading and unloading and is best described using the theory of pseudo-elasticity. We summarize the basic equations for transversely isotropic pseudo-elastic materials, first for general deformations and then for the appropriate uniaxial specialization. The constitutive relation proposed is in good agreement with the experimental data for both the passive and the stimulated conditions.

Detection of group A streptococci in children under 3 years of age with pharyngitis.

OBJECTIVE: To determine the frequency of group A streptococcal pharyngitis in young preschool children presenting to the emergency department with upper respiratory tract infection. METHODS: A prospective, observational study performed between September 1995 and September 1997. Throat swabs were obtained on young children less than 3 years old with pharyngeal erythema as well as age- and time-matched controls without pharyngeal erythema or exudate. Signs and symptoms that were recorded included: age, temperature, pharyngeal erythema, tonsillar exudate, cervical adenopathy, scarlatini-form rash, rhinorrhea, school-aged child in the home, day care attendance. Swabs were inoculated on 5% sheep blood agar and incubated for 48 hours. Beta-hemolytic colonies were sero-grouped by latex agglutination. RESULTS: Seventy-eight children with pharyngeal erythema, and 152 controls had pharyngeal specimens obtained and signs or symptoms recorded. Under 2 years of age, the detection of group A streptococci was similar to controls. Detection of group A streptococci was significantly different from controls in children over 2 years of age. Ten (29%) of 35 children over 2 years were positive for group A streptococci compared to 2 (7%) of 29 controls of the same age group (P = 0.03, odds ratio 5, 95% CI: 1.2-24). Findings on clinical examination in children with pharyngeal erythema did not distinguish those that would be culture-positive for group A streptococci. CONCLUSION: In our emergency department, group A streptococci caused 30% of pharyngitis seen in children between 2 and 3 years of age. Diagnostic testing is recommended because physical examination may not accurately distinguish etiology in this age group.

Group A streptococcal pharyngitis in adults 30 to 65 years of age.

BACKGROUND: Although the frequency of group A streptococcal pharyngitis in adults is assumed to be low, there is little information on frequency other than in military populations. METHODS: A prospective, observational study was done to determine the frequency of group A streptococcal pharyngitis in adults seen in the emergency department. Throat swabs were obtained on adults (30 to 65 years of age) with sore throat and pharyngitis on examination. Swabs were also obtained in a group of control subjects. RESULTS: Of the 148 adults with pharyngitis, 65 (44%) had throat specimens positive for group A streptococci. In the 50 control subjects, all throat cultures were negative for group A streptococci. A significant number of patients with group A streptococcal pharyngitis had school-aged children at home. CONCLUSION: The high rate of detection of group A streptococci in adults outside the military has not been previously reported.

Psoas abscess with sepsis mimicking traumatic hemorrhagic shock after a fall.

Abscess of the psoas muscle is infrequently encountered. An infectious emergency of this type usually presents in a nonspecific manner and thus poses a significant diagnostic challenge to the emergency physician. Diagnosis and specific treatment are often delayed, which can lead to increased mortality. This case report presents a patient with altered mental status and hypotension after a fall, who was initially managed as a trauma victim. Emergency department evaluation initially focused on a traumatic etiology of the above abnormalities. Subsequent assessment determined that the patient's condition was due to an underlying psoas abscess with sepsis. Appropriate anatomy, clinical presentation, and management are discussed in hopes of increasing physician awareness of this uncommon infectious condition.

Optical immunoassay for rapid detection of group A beta-hemolytic streptococci. Should culture be replaced?

OBJECTIVE: To evaluate an optical immunoassay rapid antigen test to detect group A beta-hemolytic streptococci directly from throat swab specimens. DESIGN: Criterion standard with "blinded" comparison. Double-swab pharyngeal samples were obtained; one swab was cultured and the other was used for the rapid antigen test. SETTING: Microbiology laboratory in a primary care center at a university teaching hospital. PATIENTS: Two hundred sixty-two outpatients with pharyngitis. MAIN OUTCOME MEASURE: The results of the optical immunoassay rapid antigen test were compared with results of standard aerobic culture. RESULTS: Sixty-two (24%) of 262 samples were culture-positive; 48 of these 62 were positive by the optical immunoassay rapid test (sensitivity, 77%). Of the 200 culture-negative samples, seven (4%) were positive by the rapid test (specificity, 96%). CONCLUSION: The optical immunoassay performed well, but like other rapid tests, is not sensitive enough to replace standard culture for detection of group A beta-hemolytic streptococci.

The role of epidural morphine in the postcesarean patient: efficacy and effects on bonding.

This study was designed to determine in postcesarean patients whether in addition to superior analgesic effects, epidural morphine administration results in secondary benefits in maternal well-being and maternal-infant interaction. Following elective cesarean section with bupivacaine epidural anesthesia, 40 healthy mothers received 5 mg preservative-free morphine sulfate in 10 ml of saline, either by the epidural (Group 1, n = 20) or the intravenous (Group 2, n = 20) route, in a randomized, double-blind fashion. Each received a simultaneous injection of saline by the alternate route. Analgesia in Group 1 lasted significantly longer (16.1 +/- 8.8 vs. 4.4 +/- 2.4 h, mean +/- SD; P less than 0.001), and morphine requirements in the first 24 h were significantly less (12.5 +/- 20 mg vs. 36 +/- 21 mg, P less than 0.001) than in Group 2. Seventy-four per cent of patients who received epidural morphine reported excellent analgesia, compared with only 32% of those who received intravenous morphine (P less than 0.05). Although Group 1 mothers ambulated 6 h earlier than those in Group 2 (P less than 0.02), there was no difference between the groups in time of first voiding, number of hours mothers slept, or duration of hospital stay. Mothers in both groups interacted with their infants equally well and for the same duration of time. Itching occurred in 58% of Group 1 patients and only 16% of Group 2 patients (P less than 0.01); the incidences of nausea, vomiting, and urinary retention were not statistically different between the groups. No respiratory depression was observed. Benefits of epidural morphine in this patient population appear limited to the provision of improved analgesia and earlier mobility.

Immune response of BALB/c X DBA/2F1 mice to a tumor allograft during pyran copolymer-induced tumor enhancement.

The immune response of BALB/c x DBA/2 F1 mice to a transplantable Moloney leukemia virus-induced tumor allograft (MBL-2) was studied to determine the mechanism of pyran copolymer-induced tumor enhancement. The relative levels of humoral, lymphocyte, and macrophage response were followed chronologically by in vitro cytotoxic microassays using 51Cr-labeled target cells. Although pyran increased the titer of humoral cytotoxic antibody, levels of humoral factors capable of abrogating lymphocytoxicity were not enhanced. Furthermore, splenic lymphocyte-mediated cytotoxicity, although slightly diminished in pyran-treated mice, was not significantly affected. Macrophages harvested from allograft-bearing animals exhibited marked tumoricidal activity, which was augmented by pyran treatment. This macrophage-associated activity was specific for MBL-2 cells and not attributable to cytotoxins elaborated into the culture medium. Pyran slightly activated macrophages from nonsensitized mice to become cytotoxic for MBL-2 cells; activation was not T-cell dependent. However, strikingly fewer macrophages infiltrated the allograft in pyran-treated animals as judged by both histopathology and direct measurement. The defect in the migration or deposit of macrophages at the allograft site may have contributed to tumor enhancement.

Effect of calories on appetite for palatable food in obese and nonobese humans.

Palatable food stimuli were presented to 11 obese and 11 nonobese male human subjects (in three experiments) 1 hr after ingestion of 900-calorie liquid lunches and (on separate days) indentically tasting 450-calorie liquid lunches of equal volume. Salivary responses to the presentation of the stimuli (i.e., appetite) by the nonobese were inhibited by the high-calorie meal, but those by the obses were less inhibited. Hunger ratings were unaffected by calories in either group. Food stimuli were rated as more appetizing by the nonobese after high-calorie meals, but not so by the obese. Parallels with animal findings suggest that salivary responses reflect lateral hypothalamic activity.

Detection in colorectal carcinoma patients of antibody cytotoxic to established cell strains derived from carcinoma of the human colon and rectum.

Sera from eight of 15 patients with colonic carcinoma exhibited demonstrable cytotoxicity against an established cell strain derived from adenocarcinoma of the ileocecum, HCT-8. Sera from 12 of 16 patients with rectal carcinoma were cytotoxic for an established cell strain derived from an adenocarcinoma of the rectum, HRT-18. Patients with colonic carcinoma exhibited serum cytotoxicity against only the colonic target cells, whereas patients with rectal carcinoma gave significant cytotoxicity against both cell strains. This cytotoxicity was shown to be complement-dependent and appeared to be specific for colonic and/or rectal carcinoma cells. Although the cells produced carcinoembryonic antigen (CEA) in vitro, the cytotoxic antibody response in these patients did not appear to be directed against CEA. Serum cytotoxicity was not demonstrated against two other cell strains, HCT-48 and HT-29, derived from adenocarcinomas of the human colon, except for a reaction against a blood-group-related antigen. These cell strains had comparable levels of cell-associated CEA. The routine titration of cytotoxic antibody against these established cell cultures may provide meaningful information on the host's immune response to colorectal neoplasms.

Effect of levamisole (NSC-177023) on DNA synthesis by lymphocytes from immunosuppressed C57BL mice.

The effect of in vivo treatment of C57BL mice with BCNU and/or levamisole on the in vitro DNA synthetic capacity of their spleen cells was studied as a measure of cell-mediated immune function. BCNU treatment was suppressive to spleen cell DNA synthesis; conversely, treatment with levamisole was stimulatory. Levamisole treatment 5-8 days after BCNU treatment resulted in significant recovery of DNA synthetic capacity. Multiple doses of levamisole were not more effective than single doses. Allogeneic stimulation of BCNU-suppressed lymphocytes was not consistently increased by levamisole treatment.

Antigenic and biochemical characterization of the C-type particle of the stable porcine kidney cell line PK-15.

The C-type particles observed by electron microscopy in PK-15 cells were demonstrated to have biochemical and biophysical properties associated with the oncornavirus group: density of 1:16 in a sucrose gradient, 70S RNA, and the RNA-dependent DNA polymerase. The group-specific interspecies antigen, gs-3, was not present. Evidence of a latent infection with a porcine parvovirus was also obtained.