Invasion and high-elevation acclimation of the red imported fire ant, Solenopsis invicta, in the southern Blue Ridge Escarpment region of North America

The red imported fire ant (Solenopsis invicta) is a non-native invasive species that rapidly spread northward in the United States after its introduction from South America in the 1930s. Researchers predicted that the northward spread of this invasive ant would be limited by cold temperatures with increased latitude and greater elevation in the Blue Ridge Escarpment region of the United States. The presence of S. invicta at relatively high elevations north of their projected limits suggests greater cold tolerance than previously predicted; however, these populations might be ephemeral indications of strong dispersal abilities. In this study, we investigated potential physiological adaptations of S. invicta that would indicate acclimation to high elevation environments. We hypothesized that if S. invicta colonies can persist in colder climates than where they originated, we would find gradients in S. invicta worker cold tolerance along a montane elevational gradient. We also predicted that higher elevation S. invicta ants might incur greater physiological costs to persist in the colder climate, so we measured colony lipid content to assess health status. For comparison, we also collected physiological temperature tolerance data for the co-occurring dominant native woodland ant Aphaenogaster picea. We found that S. invicta occurring at higher elevations exhibited greater physiological tolerance for cold temperatures as compared to lower-elevation conspecifics–a cold tolerance pattern that paralleled of the native A. picea ants along the same gradient. Both S. invicta and A. picea similarly exhibited lower thermal tolerances for colder temperatures when moving up the elevational gradient, with A. picea consistently exhibiting a lower thermal tolerance overall. There was no change in S. invicta colony lipid content with elevation, suggesting that greater metabolic rates were not needed to sustain these ants at high elevations.

Deer overabundance in the USA: recent advances in population control

During the 20th century, deer (Odocoileus spp.) populations in many parts of the USA changed from locally extirpated to locally overabundant. In 1997, two comprehensive books were published on deer overabundance to help wildlife professionals understand the complex biological, ecological, sociopolitical, public, and legal issues associated with managing overabundant deer. Since then, there have been several advances in dealing with deer overabundance, which have been briefly summarised in this review article. Most notably, since 1997 ecologists have more definitively characterised the ecological consequences of chronically overabundant deer populations, not merely in terms of direct impacts on plant communities but also in terms of cascading effects on animal communities. While still acknowledging the complexity of the interactions that affect ecosystem services and states (e.g. top-down pathways, bottom-up forces, disturbance regimes), ecologists now believe that the presence of an apex predator can affect the density, as well as behaviour and physiology of ungulates, and thereby help maintain the natural structure and functioning of plant communities. In some situations, wildlife researchers in the USA have restored native predators or documented adaptive responses by colonising predators, both of which have helped reduce locally overabundant deer populations and helped restore plant community diversity. On the wildlife policy front, some state wildlife agencies have enacted new programs to manage overabundant deer in protected areas and in urban and suburban settings. Examples include special permits for lethal removal of urban deer, as well as public hunts using special weapons (e.g. crossbows) or sharpshooting programs to control deer in state parks. A better understanding of the human dimensions associated with deer overabundance has helped many agencies define appropriate public education programs. However, despite these efforts to educate stakeholders about deer overabundance, there have been legal challenges associated with programs designed to control deer populations in some suburban communities. Some nongovernmental organisations (NGOs) have implemented award-winning, classroom-based educational modules to help children learn how to live with deer. Some NGOs also have stressed the importance of hunting as an ecological service. Still other NGOs have worked to facilitate linkages and cover liability concerns to enable bowhunters to help control deer in suburban communities. There also have been major advances in the potential for managing overabundant deer with fertility control, including the recent approval of an immunocontraceptive vaccine for use in deer (GonaCon™). In summary, wildlife biologists now understand the complex issues associated with deer overabundance better and there are more ‘tools in the chest’, both in terms of agency policies and management procedures than in 1997. Yet, human dimensions, public education, and stakeholder concerns continue to be the most challenging aspects of managing deer overabundance. Therefore, this issue likely will continue to confront wildlife professionals for many decades to come, whether in the USA or other parts of the world.

Visual specialization of an herbivore prey species, the white-tailed deer

To gain knowledge of visual specializations influencing the behavior of white-tailed deer ( Odocoileus virginianus (Zimmermann, 1780)), we examined gross eye characteristics, structural organization of the retina, and the density and distribution of cone photoreceptors. White-tailed deer possess ocular features similar to other ungulates including a horizontal slit pupil, reflective tapetum lucidum, typical retinal structure, and medium wavelength sensitive cone photoreceptors concentrated in a horizontal visual streak. The tapetum was found to cover the superior portion of the eye and overlapped the horizontal visual streak. Comparisons between fawns and adults did not reveal any differences in retinal thickness, retinal nuclei counts, or cone photoreceptor counts. While M-cones had increased density in the visual streak, S-cones were distributed evenly across the entire retina. Schematic eye calculations of a 0.5-year-old deer indicated a hyperopic eye (+7.96) with a F/# ranging from 5.55 to 1.39 for pupil diameters of 3 to 12 mm. As expected for a crepuscularly active prey species, the visual system of white-tailed deer is specialized for sensitivity in low-light conditions and detection of predators.

The management of acute myocardial infarction. Does thrombolysis have a place?

BACKGROUND

Myocardial infarction is a common life threatening medical emergency. The mortality remains around 10% and can be influenced by early reperfusion achieved either by thrombolysis or angioplasty.

OBJECTIVE

To outline the relative suitability and safety of thrombolysis as a treatment option for myocardial infarction.

DISCUSSION

Initial assessment and treatment are vitally important in improving outcome. Later risk factor modification remains an important factor in reducing future cardiac events.

Effects of applied currents on spontaneous epileptiform activity induced by low calcium in the rat hippocampus

It is known that both applied and endogenous electrical fields can modulate neuronal activity. In this study, we have demonstrated that anodic current injections can inhibit spontaneous epileptiform events in the absence of synaptic transmission. Activity was induced with low-Ca2+ (0.2 mM) artificial cerebrospinal fluid (ACSF) and detected with a voltage threshold detector. At the onset of an event, a current was injected into the stratum pyramidale via a tungsten electrode positioned within 150 micron of the recording site. Data was recorded with a glass pipette electrode. The results show that spontaneous epileptiform activity can be fully suppressed by subthreshold anodic currents with an average amplitude of 3.9 microA and a minimum amplitude of 1 microA. In addition, we observed that some events could be blocked by current pulses with shorter durations than the duration of the event itself. The possibility that increased tissue resistance could contribute to the efficacy of the currents was tested by measuring the step-potential increase evoked by anodic current injections. The data show a significant increase in the amplitude of the evoked potential after introduction of a low-Ca2+ medium, suggesting that tissue resistance is increasing. These results indicate that low-amplitude, subthreshold current pulses are sufficient to block epileptiform activity in a low-Ca2+ environment. The increased tissue resistance induced by sustained exposure to a low-Ca2+ medium could contribute to the low current amplitudes required to block the epileptiform events.

Minimally invasive coronary artery bypass surgery without cardiopulmonary bypass

OBJECTIVE

To report on the initial results of minimally invasive direct coronary artery bypass surgery (MIDCAB) without cardiopulmonary bypass. This is a potential alternative to conventional coronary artery bypass graft surgery, recently introduced to Australia.

DESIGN

Prospective survey of patient data.

SETTING

Royal Melbourne Hospital campus, Melbourne, Victoria, July 1996 to June 1997.

PATIENTS

The first 23 consecutive patients to have a MIDCAB procedure without cardiopulmonary bypass via a small left thoracotomy. The left anterior descending coronary artery was revascularised with the left internal mammary artery. All patients had either recurrent stenosis after previous angioplasty or anatomy unsuitable for angioplasty.

OUTCOME MEASURES

Operative morbidity and mortality; graft patency; and patient symptom relief and reoperation rates.

RESULTS

Mean age of patients was 57.9 years (range, 29-81), and mean follow-up was 4.0 months (range, 1-10). There was no operative mortality, cardiac infarction or stroke. Mean postoperative stay in the Intensive Care Unit was 30.7 hours and in hospital, 5.3 days. Only one patient needed a blood transfusion (packed red cells). Initial patency of the grafts was confirmed by either angiography (five) or continuous pulse-wave Doppler (23). One patient underwent angioplasty for a stenosis distal to the anastomosis, and two patients (9%) required reoperation for recurrent angina.

CONCLUSIONS

MIDCAB can be performed safely, and patient recovery is faster than after conventional coronary artery surgery.

Assessment of left ventricular function after radiofrequency and direct current atrioventricular node ablation

BACKGROUND

There is limited information available regarding the effect of catheter ablation of the antioventricular (AV) junction on left ventricular (LV) function. Both deterioration and improvement in LV function have been reported following direct current (DC) ablation of the AV junction. The deterioration of LV function following DC ablation of the AV junction may be due to the accompanying barotrauma, DC arcing and direct coagulation, or even the effects of chronic ventricular pacing. If this deterioration of LV function was a result of the accompanying effects of DC shock, the use of radiofrequency ablation (RF) should not result in deterioration of LV function.

AIM

To study LV function before and after different methods of AV junction ablation and in patients with chronic ventricular pacing without AV junction ablation.

MATERIAL

This study assessed LV function in patients following RF ablation, low energy DC ablation of the AV junction and compared the results with our previously reported finding in patients who had AV junction ablation using high energy DC shock. A group of patients undergoing permanent single chamber ventricular pacemaker implantation without AV junction ablation were selected as controls.

METHODS

All patients were paced in the ventricle at 110 beats/minute during LV function assessment by radionuclide angiography. Global LV function and segmental wall motion abnormalities were assessed before, immediately following and three months after ablation.

RESULTS

In the high energy DC ablation group, a fall in global LV function (50 +/- 3.0% to 43 +/- 3.0%, p = 0.02) and impairment of segmental wall motion were detected. Low energy DC ablation resulted in segmental wall motion impairment similar to high energy DC but without affecting global ejection fraction (47.0% +/- 6.7 to 45.5% +/- 3.1, p > 0.05). Neither RF ablation (44.0% +/- 3.3 to 45.3% +/- 3.5, p > 0.05), nor chronic pacing (46.7% +/- 4.9 to 47.0% +/- 2.9 p > 0.05) had any effect on global or segmental LV function.

CONCLUSIONS

Low energy DC or RF ablation of the AV junction does not affect global LV ejection fraction. The deterioration of global LV function after high energy DC shock ablation appears to be related to the accompanying effects of DC energy and not to the effects of chronic ventricular pacing.

Comparison of Pneumocystis carinii detection by toluidine blue O staining, direct immunofluorescence and DNA amplification in sputum specimens from HIV positive patients

Pneumocystis carinii pneumonia (PCP) is the commonest opportunistic infection in AIDS patients. By using the polymerase chain reaction (PCR), specific DNA sequences can be amplified and used in diagnosis of infections such as PCP where the causative pathogen is both difficult to grow and present in low numbers. Twenty HIV positive patients were investigated for PCP. Twenty sputa (15 induced and 5 expectorated) had toluidine blue O staining, direct immunofluorescence and PCR performed for Pneumocystis carinii in a blinded fashion. PCR was performed using primers pAZ102-E 5' GATGGCTGTTTCCAAGCCCA 3' and pAZ102-H 5' GTGTACGTTGCAAAGTACTC 3' from the gene coding for Pneumocystis carinii mitochondrial ribosomal RNA with a specific 346 base-pair sequence being amplified from positive specimens. Ten of the patients had Pneumocystis carinii shown by conventional tests and PCR. Another 3 patients were positive only by PCR, all had evidence of infection with Pneumocystis carinii; the first was positive by subsequent conventional stains, the second was treated for bacterial bronchitis but had a non-resolving chest infection with PCP found on postmortem after 4 mths, the third had a typical interstitial infiltrate on CXR and responded to empiric PCP treatment. PCR is more sensitive than toluidine blue O staining and direct immunofluorescence in detecting Pneumocystis carinii in sputum from HIV patients and may become the diagnostic method of choice for PCP.

Levonorgestrel implants as a contraceptive in captive white-tailed deer

Silastic implants containing levonorgestrel (LNG) were evaluated as a contraceptive in captive white-tailed deer (Odocoileus virginianus). Six adult females and six female fawns received either six or nine implants in autumn. Each implant contained 36 mg of LNG. Blood was analyzed by radioimmunoassay to determine LNG release profile for 5 mo post-implantation. Serum LNG concentrations rose significantly (P = 0.0005) 3 days post-implantation, leveled off after 7 days, and did not change (P = 0.5913) during the remaining 5 mo. Mean (+/- SE) LNG concentrations for all months were higher (P = 0.0377) in adult and fawn females implanted with nine versus six rods (138.1 +/- 14.4 versus 56.7 +/- 12.3 pg/ml, respectively). Serum LNG levels did not differ between adults and fawns. Five of the six implanted adult females had normal estrous cyclicity; three of these five adult females became pregnant in the first year. Four implanted females (two yearlings and two adults) were monitored during a second year, and housed with a fertile buck; three of them became pregnant. We do not recommend the use of LNG in deer.

High urinary cannabinoids from a hashish body packer

A body packer swallowed 39 condoms containing a total of 518 g hashish oil. He was arrested on entry into Canada. Two days later, a urine sample was obtained. Total cannabinoid concentrations by TDx and Emit II were 10,200 ng/mL and 11,400 ng/mL, respectively. The concentration of 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid by gas chromatography/mass spectrometry was 1140 ng/mL.

Infusion of atherogenic lipoprotein particles increases hepatic lipase activity in the rabbit

Hepatic lipase plays a key role in the turnover of potentially atherogenic lipoprotein remnants and in determining the relative distribution of high density lipoprotein (HDL) particle size subclasses. Rabbits fed a cholesterol-enriched diet have been found to accumulate potentially atherogenic chylomicron remnants and beta-very low density lipoprotein (beta-VLDL) and show a rapid increase in liver and postheparin plasma hepatic lipase activity. To determine whether the particles that accumulate during cholesterol feeding are a stimulus for this increase in hepatic lipase activity, we infused normal chow-fed rabbits with a chylomicron remnant plus beta-VLDL-enriched plasma fraction isolated from rabbits fed 0.5% cholesterol-supplemented chow. The infusion of this plasma fraction for 4 h increased hepatic lipase activity up to 2.9-fold over control rabbits and resulted in a loss of larger sized HDL particles consistent with the action of hepatic lipase. The increase in activity was significantly correlated with the concentration of infusate phospholipid, unesterified cholesterol, and esterified cholesterol, but not with the infusate triglyceride concentration. The change in the plasma cholesterol concentration of recipient rabbits, which reflects the degree of lipoprotein accumulation in these rabbits, was also significantly correlated with the change in hepatic lipase activity. However, a chylomicron remnant and beta-VLDL-depleted fraction of plasma from cholesterol-fed rabbits did not increase hepatic lipase activity. Furthermore, triglyceride presented as an artificial lipid emulsion (Intralipid) was not able to stimulate hepatic lipase activity, although triglyceride is a substrate for hepatic lipase.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative evaluation of cryptococcal latex tests

One hundred and seven specimens (24 CSF and 83 sera) from 90 patients were tested for the presence of Cryptococcus neoformans antigen using the Fairfield Hospital in-house latex agglutination technique and the IMMY and Meridian commercial latex agglutination kits. Forty one specimens (14 CSF and 27 sera) from 27 patients with culture-proven cryptococcosis were positive by both the Fairfield and IMMY latex tests. Thirty nine of these specimens were positive by the Meridian latex test. Two were negative. Sixty six specimens (10 CSF and 56 sera) from 63 patients not known to have cryptococcosis were negative by all 3 tests.

The regulation of hepatic lipase and cholesteryl ester transfer protein activity in the cholesterol fed rabbit

Hepatic lipase (HL) and cholesteryl ester transfer protein (CETP) activities are both increased in the rabbit by cholesterol feeding. The in vivo regulation of HL and CETP were explored by examining changes in specific steady-state mRNA levels upon cholesterol feeding. On feeding rabbits cholesterol, HL activity increased 3-fold after 2 days and remained at 2.6-times the control value at 28 days. Specific rabbit HL mRNA levels were assessed by dot blot analysis of liver poly (A)+ RNA hybridized with the human HL cDNA. No significant changes in liver HL mRNA accompanied the increase in activity seen at days 2 and 7. At day 28 a modest rise of 46% was observed. A significant rise in CETP activity, evident 7 days after the commencement of cholesterol feeding, was maintained until day 28 when it was 2.4-times the control value. Using the human CETP cDNA as probe, rabbit liver CETP mRNA was also found to increase by day 7, rising to 3.7-times control by day 28. The strong temporal relationship between the rise in CETP activity and mRNA (r = 0.55, P = 0.02) suggests that the regulation of CETP may be primarily effected by the levels of specific mRNA. In contrast, the discordance between levels of lipase activity and mRNA suggests that post-transcriptional events may be more important in the regulation of HL in the cholesterol fed rabbit.

Rabbit hepatic lipase cDNA sequence: low activity is associated with low messenger RNA levels

We have investigated a possible mechanism for the reported low activity of hepatic lipase (HL) in the rabbit by cloning and sequencing the cDNA for rabbit HL and using the clone to quantify mRNA levels. A 1.6 kb cDNA clone was sequenced and found to encode the mature protein of 477 amino acids and 20 amino acids of the hydrophobic leader peptide. A high degree of amino acid sequence identity was demonstrated with human (81%) and rat (79%) HL. The putative active site was well conserved, and mutations reported to reduce activity in HL or lipoprotein lipase were not present in the rabbit sequence. The activity and mRNA levels were compared with those of the rat, an animal possessing relatively high HL activity. In post-heparin plasma of the rat, HL activity was nine times greater than in that of the rabbit (24.9 +/- 1.6 units per ml plasma, n = 5 vs. 2.7 +/- 0.1, n = 5, P = 0.0001). Comparison of mRNA levels was made by dot blot analysis of liver poly (A+) RNA obtained from each species and probed with either rabbit or rat HL cDNA, labeled to the same specific radioactivity. Specific HL mRNA levels were found to be nine times greater in the rat than in the rabbit (8.90 +/- 0.11 units, n = 5 vs. 1.00 +/- 0.01, n = 5, P = 0.0001). Thus, low hepatic lipase activity in the rabbit is associated with low mRNA levels, suggesting that the observed species difference in activity is due to differences in the level of mRNA.

Ventricular dysfunction following direct-current shock atrioventricular junction ablation

Catheter-induced His bundle ablation for refractory supraventricular arrhythmias is most commonly performed with direct-current shock energy of 200-300 joules. The high energy pulse delivered by direct-current shock produces a lesion in the atrioventricular node by fulguration, with the residual energy being dissipated as a pressure wave. The effect of direct-current shock His bundle ablation on global and regional ventricular function was assessed in 14 consecutive patients by radionuclide ventriculography performed before and after ablation and again three months later. All studies were performed with ventricular pacing at 110 bpm. Global left ventricular ejection fraction was found to be significantly reduced at the three month study (0.43 +/- 0.03 vs 0.50 +/- 0.03, pre ablation, p = 0.02). A significant reduction in wall-motion score was also seen in six of the seven patients who had normal wall motion in pacing rhythm prior to ablation. Deterioration was mainly seen at the left and right ventricular apices. The observed reduction in ventricular function that follows direct-current shock His bundle ablation may result from myocardial damage from electro-coagulation or from barotrauma and supports continued investigation into alternative, less traumatic energy sources for the procedure.

Comparison of silver sulfadiazine 1% with chlorhexidine digluconate 0.2% to silver sulfadiazine 1% alone in the prophylactic topical antibacterial treatment of burns

Wound bacterial colonization in 118 patients treated with chlorhexidine digluconate 0.2% in silver sulfadiazine 1% applied daily to the burn wounds was compared to that of 135 comparable patients similarly treated with silver sulfadiazine 1%. With chlorhexidine digluconate 0.2% in silver sulfadiazine 1%, colonization by Staphylococcus aureus was less frequent (38%) than with silver sulfadiazine (54%, p = 0.016). No statistical difference was found for colonization by Enterococcus faecalis, Pseudomonas aeruginosa, or Enterobacter cloacae. Washing of the wounds of 65 patients with chlorhexidine gluconate 4% during daily dressing changes was associated with reduced wound colonization by S. aureus (35% versus 51%, p = 0.03) and P. aeruginosa (8% versus 16%, p = 0.08) when compared to the 188 washed with nonantibacterial soap. Chlorhexidine, whether added to the topical agent silver sulfadiazine (chlorhexidine digluconate 0.2%) or in the bath soap (chlorhexidine gluconate 4%), decreased colonization by S. aureus.

Coronary angioplasty for chronic total occlusion reduces the need for subsequent coronary bypass surgery

Coronary angioplasty was performed in 44 consecutive patients with total occlusion that lasted longer than 1 week. The primary success rate was 59%. Angiographic restudy in 25 of the 26 successful patients (96%) revealed restenosis in 17 patients (65%), which was asymptomatic in seven (44%). Significant correlates of restenosis were mean luminal stenosis at the conclusion of the procedure and symptom recurrence. Clinical follow-up at a mean of 31 +/- 12 months revealed that coronary artery bypass surgery was more frequent in patients who had an unsuccessful initial angioplasty procedure (7/18 vs 3/26; p = 0.04). Nine patients (35%) who had an initially successful procedure required a second angioplasty for symptomatic restenosis. Angioplasty for totally occluded coronary arteries has a high incidence of restenosis that is often asymptomatic. This procedure can, however, lead to a reduction in the need for coronary artery bypass surgery for symptom control.

Major burns managed without blood or blood products

Four major burns (two flame, one scald, one electrical) were managed without administration of blood or plasma. Serial changes in hemoglobin, and serum albumin and total protein measurements were compared with those of controlled patients matched in age and total body surface area burned who were treated by standard methods. Hemoglobin values were lower but within one standard deviation, although serum protein and albumin measurements fell more than one standard deviation below mean values observed in control patients at comparable times after burn injury. Important treatment principles that were instrumental to recovery include a high-calorie, high-protein diet, iron supplementation, use of pediatric blood sampling techniques, and monitoring for and prophylaxis against infection while allowing eschar to separate spontaneously rather than performing early debridement. Amputation of mummified electrically burned limbs at more proximal levels, including marginally viable muscle, is recommended to minimize infection and decrease blood loss associated with customary conservative serial debridements.

Early and late results of balloon valvuloplasty for severe aortic stenosis

Balloon aortic valvuloplasty has been used as treatment for selected patients with severe aortic stenosis. We report our experience of 11 procedures, performed on ten patients between October 1987 and June 1988. The peak aortic systolic gradient was reduced by 53% from 77 +/- 22 to 37 +/- 14 mmHg (p less than 0.0001) whilst cardiac output did not change significantly (4.1 +/- 1.7 to 3.8 +/- 1.6 (p less than 0.0001) whilst cardiac output did not change significantly (4.1 +/- 1.7 to 3.8 +/- 1.6 L/min). Aortic valve area was increased by 50%, from 0.4 +/- 0.2 to 0.6 +/- 0.2 cm2 (p less than 0.0001). Initial symptomatic improvement was achieved in eight patients. Echocardiographically demonstrated aortic regurgitation did not increase after valvuloplasty. There were no deaths during the procedure, no embolic events and no femoral artery complications. The mean follow-up for survivors was 9 +/- 3 months. Five patients died and three had symptom recurrence at an average of 13 weeks (six-24 weeks). Only two patients reported a continued improvement in symptoms. Balloon aortic valvuloplasty produced a small increase in aortic valve area and a satisfactory initial clinical response, but there was a high incidence of symptom recurrence. The procedure may have a role in the short-term palliation of severely symptomatic patients who are unable to have aortic valve replacement.

Heterotopic bone formation in the patient with burn injuries. A retrospective assessment of contributing factors and methods of investigation

The incidence of heterotopic bone formation in seven of 25 patients with burn injuries who required endotracheal intubation and ventilation for smoke inhalation injury was believed to be unacceptably high. Factors in the affected patients distinguishing them from those unaffected were sought. Total protein levels were found to be higher in the affected group. This may correlate with the calciuretic response to protein loading reported previously. Of the affected patients, four demonstrated extreme agitation and resisted physiotherapy. Only one of the 18 nonaffected patients was equally agitated and resistant (p less than 0.05). The additional joint trauma sustained by the affected patients may contribute to the development of heterotopic bone. In bone scans in 18 consecutive patients deemed to be at risk, all showed increased radioactivity at multiple joints. Only seven patients developed heterotopic bone. Bone scans are not sufficiently specific to be used as a diagnostic tool in detecting heterotopic bone.

Visceral helminth communities of an insular population of feral swine

Nine species of helminths, all nematodes, were recovered from the viscera of 48 feral swine (Sus scrofa) from Cumberland Island, Georgia. Both the overdispersed frequency distributions and the abundances of the four common species of helminths (Stephanurus dentatus, Metastrongylus apri, M. pudendotectus and Gongylonema pulchrum) did not vary significantly across the main and interactive effects of host sex and/or seasons. Whether or not the present low population densities of feral swine on Cumberland Island has influenced the pattern of fluctuations in abundances of helminth species across seasons as often observed in helminth communities from other hosts was not resolved. The apparent recent decline in prevalences and abundances, and the loss of certain species from the helminth communities of feral swine on the island may be explained partially by the decreasing transmission potentials of direct life cycle species caused by a recent marked reduction of numbers of individuals in the host population. Conversely, the apparent increased prevalence and abundance of three species of helminths (S. dentatus, M. apri and M. pudendotectus) may be related to their common utilization of earthworms as paratenic or intermediate hosts. Gongylonema pulchrum was the only helminth in which abundances seemed to remain unchanged. This was the only species that was not strictly host specific to feral swine. We found no evidence that helminth infections were responsible for morbidity or mortality in this feral swine population.

Y-derived sequences detected in a 45,X male by in situ hybridization

A two-month-old boy with normal genitalia and descended testes was referred for a suspected hematological disorder. Cytogenetic analysis showed a 45,X chromosome constitution. In situ hybridization with the Y-derived probe 50f (provided by Professor Marc Fellous) was performed utilizing metaphase chromosomes to determine whether Y material could be detected. A significant amount of label (17 of 150 cells) was found on chromosome 5p suggesting a 5;Y translocation. This translocation was verified by high-resolution G-banded and G-11-stained chromosomes.

Visceral helminth communities of sympatric mule and white-tailed deer from the Davis Mountains of Texas

Hybridizing populations of mule (Odocoileus hemionus) and white-tailed deer (O. virginianus) from the Davis Mountains of Texas were examined to determine similarities in species composition of their helminth communities and if abundances of helminth species in those communities varied across host species and seasonal factors. Only three cestode and three nematode species were recovered. There were very low abundances of species and little diversity in the helminth communities of both hosts. Common helminth species were shared by both deer, and the significant variance in abundances of three of the four most common helminth species appeared to result from differences in habitat preferences of the respective hosts. Our results indicated that analyses of helminth communities of deer from this geographical area do not provide a useful quantification technique for determining deer condition, degree of hybridization, or levels of intraspecific competition.

Emergency external cardiac pacing in life-threatening bradyarrhythmias

We report seven cases of life-threatening bradyarrhythmias in which successful external cardiac pacing was established with a minimal delay, enabling more definitive transvenous pacing to be effected later.

Effects of season and physical condition on the gastrointestinal helminth community of white-tailed deer from the Texas Edwards Plateau

Eighty-six adult female white-tailed deer, Odocoileus virginianus (Zimmermann), collected over a 12-mo period in the Texas Edwards Plateau, harbored six species of nematodes (Haemonchus contortus, Gongylonema pulchrum, Oesophagostomum venulosum, Ostertagia ostertagi, Cooperia sp., and Apteragia odocoilei), and two cestodes (Moniezia sp. and Taenia hydatigena). The patterns of distribution of the three common species of gastrointestinal helminths (H. contortus, O. venulosum, and G. pulchrum) were overdispersed. When analyzed for the main and interactive effects of the extrinsic and intrinsic variables of season and physical condition, respectively, aggregated abundances in H. contortus and O. venulosum appeared to result from the main effect of seasonal changes operating over the collective populations of these two species rather than from the intrinsic factor of physical condition operating within selected subpopulations. Abomasal parasite counts do not appear to be a useful index for monitoring herd condition of white-tailed deer from this geographic region.

Factors affecting the helminth community structure of adult collared peccaries in southern Texas

Four species of nematodes (Gongylonema pulchrum, Parabronema pecariae, Texicospirura turki, and Physocephalus sexalatus) and one species of cestode (Moniezia sp.) comprised the helminth fauna of adult collared peccaries (Tayassu tajacu) from the plains in southern Texas. The community structure of the helminth fauna of peccaries from this region was basically dissimilar to that from the more humid Gulf coastal prairies of southern Texas in composition (by the conspicuous absence of certain species) and relative abundance of shared species. The distributions of each of the three common species of helminths (G. pulchrum, T. turki, and P. sexalatus) were overdispersed. The effects of selected habitat variables operating across host subpopulations (delineated by condition and sex) and of the extrinsic variable of season on the dispersion patterns of the three common species of helminths were examined. The hypothesis that heterogeneity within the host population, rather than across the collective host population, is the main factor generating overdispersion in natural parasite populations was not confirmed for the three common species of helminths. Overdispersion in P. sexalatus resulted from seasonal changes across the collective host population, with the greatest abundances occurring during the cool season. Aggregated abundances of G. pulchrum resulted from variation generated across host sex subpopulations, while the dispersion patterns of T. turki appeared to be unaffected by the habitat variables examined in this study.

Seasonal variations in physiological indices of adult female white-tailed deer in Texas

Seasonal variations in blood chemistry, urine chemistry, fat reserves, and crude protein levels of rumen contents were determined for free-ranging adult female white-tailed deer (Odocoileus virginianus Zimmermann) in central Texas. Seasonal variations (P less than 0.05) existed for serum total protein, albumin, globulin, albumin/globulin ratios, blood urea nitrogen (BUN), cholesterol, alkaline phosphatase, creatinine, phosphorus, and sodium; and urinary urea/creatinine (U/C) ratios, rumen crude protein, the kidney fat index (KFI), femur marrow fat (FMF), and dressed weights. Variations in BUN, urinary U/C ratios, dressed weights, KFI, and FMF were attributed partially to the nutritional demands of late gestation and lactation.

Helminth fauna of sandhill crane populations in Texas

Three species of trematode [Orchipedium jolliei Schell, 1967; Prohyptiamus grusi Kocan, Waldrup, Ramakka, and Iverson, 1982; Echinostoma revolutum (Froelich, 1802)], three species of nematode (Tetrameres grusi Shumakovich, 1946; Synhimanthus sp.; Contracaecum sp.), and one species of cestode (Anomotaenia sp.) were recovered from 146 sandhill cranes, Grus canadensis (Linnaeus), collected in Alaska, Canada, and two areas in Texas. The only common and abundant species were O. jolliei and T grusi. Of cranes collected in Texas, those that came from the Canadian breeding grounds had significantly greater abundances of O. jolliei and T. grusi than those from Alaska. However, cluster analysis using rank abundances of helminth species across the four geographic regions and stepwise multiple discriminant analysis using the grouping variable of the presence or absence of a subspecies-specific pancreatic protein indicated that classification of cranes into populations based on helminth abundances was impractical as a management technique.

Urine sampling techniques for captive white-tailed deer

Three urine sampling techniques were employed in nutritional experiments with captive white-tailed deer (Odocoileus virginianus). Urethral catheterization permitted successful urine collection from females. Furosemide induced urination in male fawns 36.4 +/- 3.1 min (SE) after injection. Significant (P less than 0.05) variation in the responses of individual fawns to this drug were detected. Xylazine hydrochloride induced urination in adult males 91.8 +/- 4.7 min after injection. Significant (P less than 0.01) differences in responses to this drug were detected among individual deer and sample months. The applicability of these urine sampling techniques is discussed.

Laparotomy for staging of Hodgkins' disease

Laparotomy was used for staging Hodgkin's disease in a selected group of 71 patients over a 9-year period at the Cancer Control Agency of British Columbia. Operative results altered the staging in 30 patients and the treatment in 28 patients. Negative lymphangiograms were found to predict accurately the absence of abdominal lymph-node involvement. No investigation was as accurate as laparotomy in identifying subdiaphragmatic Hodgkin's disease. There were no operative deaths and the overall morbidity was 18%. The value of staging laparotomy depends on the adjustment of therapy to match the changes in staging made as a result of this procedure. Of specific advantage is the avoidance of unnecessary chemotherapy. Improved long-term survival as a result of staging laparotomy has yet to be proven.