Experimental taphonomy of giant sulphur bacteria: implications for the interpretation of the embryo-like Ediacaran Doushantuo fossils

The Ediacaran Doushantuo biota has yielded fossils interpreted as eukaryotic organisms, either animal embryos or eukaryotes basal or distantly related to Metazoa. However, the fossils have been interpreted alternatively as giant sulphur bacteria similar to the extant Thiomargarita. To test this hypothesis, living and decayed Thiomargarita were compared with Doushantuo fossils and experimental taphonomic pathways were compared with modern embryos. In the fossils, as in eukaryotic cells, subcellular structures are distributed throughout cell volume; in Thiomargarita, a central vacuole encompasses approximately 98 per cent cell volume. Key features of the fossils, including putative lipid vesicles and nuclei, complex envelope ornament, and ornate outer vesicles are incompatible with living and decay morphologies observed in Thiomargarita. Microbial taphonomy of Thiomargarita also differed from that of embryos. Embryo tissues can be consumed and replaced by bacteria, forming a replica composed of a three-dimensional biofilm, a stable fabric for potential fossilization. Vacuolated Thiomargarita cells collapse easily and do not provide an internal substrate for bacteria. The findings do not support the hypothesis that giant sulphur bacteria are an appropriate interpretative model for the embryo-like Doushantuo fossils. However, sulphur bacteria may have mediated fossil mineralization and may provide a potential bacterial analogue for other macroscopic Precambrian remains.

Interactive computer-based interventions for sexual health promotion

BACKGROUND

Sexual health promotion is a major public health challenge; there is huge potential for health promotion via technology such as the Internet.

OBJECTIVES

To determine effects of interactive computer-based interventions (ICBI) for sexual health promotion, considering cognitive, behavioural, biological and economic outcomes.

SEARCH STRATEGY

We searched more than thirty databases for randomised controlled trials (RCTs) on ICBI and sexual health, including CENTRAL, DARE, MEDLINE, EMBASE, CINAHL, British Nursing Index, and PsycINFO. We also searched reference lists of published studies and contacted authors. All databases were searched from start date to November 2007, with no language restriction.

SELECTION CRITERIA

RCTs of interactive computer-based interventions for sexual health promotion, involving participants of any age, gender, sexual orientation, ethnicity or nationality. 'Interactive' was defined as packages that require contributions from users to produce tailored material and feedback that is personally relevant.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts, applied eligibility and quality criteria and extracted data. Results of RCTs were pooled using a random-effects model with standardised mean differences (SMDs) for continuous outcomes and odds ratios (ORs) for binary outcomes. We assessed heterogeneity using the I(2) statistic. Separate meta-analyses were conducted by type of comparator: 1) minimal intervention such as usual practice or leaflet, 2) face-to-face intervention or 3) a different design of ICBI; and by type of outcome (cognitive, behavioural, biological outcomes).

MAIN RESULTS

We identified 15 RCTs of ICBI conducted in various settings and populations (3917 participants). Comparing ICBI to 'minimal interventions' such as usual practice, meta-analyses showed statistically significant effects as follows: moderate effect on sexual health knowledge (SMD 0.72, 95% CI 0.27 to 1.18); small effect on safer sex self-efficacy (SMD 0.17, 95% CI 0.05 to 0.29); small effect on safer-sex intentions (SMD 0.16, 95% CI 0.02 to 0.30); and also an effect on sexual behaviour (OR 1.75, 95% CI 1.18 to 2.59). Data were insufficient for meta-analysis of biological outcomes and analysis of cost-effectiveness.In comparison with face-to-face sexual health interventions, meta-analysis was only possible for sexual health knowledge, showing that ICBI were more effective (SMD 0.36, 95% CI 0.13 to 0.58). Two further trials reported no difference in knowledge between ICBI and face-to-face intervention, but data were not available for pooling. There were insufficient data to analyse other types of outcome.No studies measured potential harms (apart from reporting any deterioration in measured outcomes).

AUTHORS' CONCLUSIONS

ICBI are effective tools for learning about sexual health, and they also show positive effects on self-efficacy, intention and sexual behaviour. More research is needed to establish whether ICBI can impact on biological outcomes, to understand how interventions might work, and whether they are cost-effective.

Light Flashes Observed by Astronauts on Apollo 11 through Apollo 17

The crew members on the last seven Apollo flights observed light flashes that are tentatively attributed to cosmic ray nuclei (atomic number >/= 6) penetrating the head and eyes of the observers. Analyses of the event rates for all missions has revealed an anomalously low rate for transearth coast observations with respect to translunar coast observations.

Could patients' coughing have communicative significance?

Medical discourse positions patients with coughs and colds negatively, so consulting health services with 'minor' respiratory illness is therefore more accountable than for other medical problems. Patients face dilemmas since they must persuade doctors of the doctorability of their illness without being seen as hypochondriacal, and they risk losing face if doctors decide that there is nothing much wrong. It is known that the placement of non-lexical features of talk such as laughing or crying can have interactional meaning. Using a data set of video-recorded doctor-patient cough and cold consultations, this study explores whether patients' coughing could have communicative significance. The study is a qualitative analysis of 33 consultations drawing on a constructionist, sociolinguistic analytic approach. Coughing is co-ordinated with talk rather than occurring randomly. Coughing helps patients to demonstrate the doctorability of their symptoms and to legitimize their claims for medical attention. Coughing is also associated with resistance to 'no problem' diagnoses, resulting in changes in the trajectory of talk (for example, soliciting more explanation from doctors and/or re-negotiation of doctors' investigation or treatment plans). Coughing is undoubtedly a manifestation of respiratory illness, but also has communicative significance in consultations for coughs and colds.

Women who report having sex with women: British national probability data on prevalence, sexual behaviors, and health outcomes

OBJECTIVES

We estimated the prevalence of same-sex experience among women and compared women reporting sex with women and men and women reporting sex exclusively with women with women reporting sex exclusively with men, in terms of sociodemographics and sexual, reproductive, and general health risk behaviors and outcomes.

METHODS

We used a British probability survey (n=6399 women, aged 16 to 44 years) conducted from 1999 to 2001 with face-to-face interviewing and computer-assisted self-interviewing.

RESULTS

We found that 4.9% of the women reported same-sex partner(s) ever; 2.8% reported sex with women in the past 5 years (n=178); 85.0% of these women also reported male partner(s) in this time. Compared with women who reported sex exclusively with men, women who reported sex with women and men reported significantly greater male partner numbers, unsafe sex, smoking, alcohol consumption, and intravenous drug use and had an increased likelihood of induced abortion and sexually transmitted infection diagnoses (age-adjusted odds ratios=3.07 and 4.41, respectively).

CONCLUSIONS

For women, a history of sex with women may be a marker for increased risk of adverse sexual, reproductive, and general health outcomes compared with women who reported sex exclusively with men. A nonjudgmental review of female patients' sexual history should help practitioners discuss risks that women may face.

Bacterial vaginosis in lesbians and bisexual women

OBJECTIVE

To determine whether bacterial vaginosis (BV) is associated with sexual activity between women.

STUDY DESIGN

Cross-sectional survey of 708 new patients attending 2 sexual health clinics for lesbians and bisexual women in London, U.K. Questionnaire for demographic, sexual history, and sexual practice data linked with the results of genitourinary examination.

RESULTS

BV was common (31.4%). The odds of BV was significantly associated with larger numbers of female sexual partners (odds ratio [OR], 1.6; confidence interval [CI], 1.05-2.44 for > or = 11 compared with 1-5 partners) and with smoking (OR, 1.43; CI, 1.01-2.03), but not with sex with men or vaginal douching.

CONCLUSIONS

BV is common in women who have sex with women (WSW). The increasing odds of BV with larger numbers of female sexual partners suggest that BV may be sexually transmitted between women.

Sexually transmitted infections in women who have sex with women

OBJECTIVES

To describe the prevalence of sexually transmitted infection (STIs) in a sample of women who have sex with women (WSW) and to identify risk factors for the acquisition of STI.

METHOD

Cross sectional survey. Questionnaire for demographic, sexual history, and sexual practice data linked with the results of genitourinary examination. 708 new patients attending two sexual health clinics for lesbians and bisexual women in London were surveyed.

RESULTS

A majority of WSW reported sexual histories with men (82%). Bacterial vaginosis and candida species were commonly diagnosed (31.4% and 18.4% respectively). Genital warts, genital herpes, and trichomoniasis were infrequently diagnosed (1.6%, 1.1%, and 1.3% respectively). Chlamydia, pelvic inflammatory disease, and gonorrhoea infections were rare (0.6%, 0.3%, and 0.3% respectively) and diagnosed only in women who had histories of sex with men.

CONCLUSIONS

Although we have demonstrated a low prevalence of STI, WSW may have sexual histories with men as well as women or histories of injecting drug use, and are therefore vulnerable to sexually transmitted or blood borne infections. Diagnosis of trichomoniasis, genital herpes, and genital warts in three women who had no history of sex with men implies that sexual transmission between women is possible.

Sexual behaviour of lesbians and bisexual women

OBJECTIVES

To provide data about the sexual histories of a large sample of lesbians and bisexual women, to inform those who provide health care or carry out research with women who may be sexually active with other women.

DESIGN

Cross sectional survey.

SETTING/SUBJECTS

803 lesbians and bisexual women attending, as new patients, lesbian sexual health clinics, and 415 lesbians and bisexual women from a community sample.

MAIN OUTCOME MEASURES

Self reported sexual history and sexual practice with both male and female partners.

RESULTS

98% of the whole sample gave a history of sexual activity with women, 83% within the past year, with a median of one female partner in that year. 85% of the sample reported sexual activity with men; for most (70%) this was 4 or more years ago. First sexual experience tended to be with a man (median 18 years old), with first sexual experience with a woman a few years later (median 21 years). Oral sex, vaginal penetration with fingers, and mutual masturbation were the most commonly reported sexual practices between women. Vaginal penetration with penis or fingers and mutual masturbation were the most commonly reported sexual activities with men.

CONCLUSIONS

These data from the largest UK survey of sexual behaviour between women to date demonstrate that lesbians and bisexual women may have varied sexual histories with both male and female partners. A non-judgmental manner and careful sexual history taking without making assumptions should help clinicians to avoid misunderstandings, and to offer appropriate sexual health advice to lesbians and bisexual women.

Inside guidelines: comparative analysis of recommendations and evidence in diabetes guidelines from 13 countries

OBJECTIVE

To compare guidelines on diabetes from different countries in order to examine whether differences in recommendations could be explained by use of different research evidence.

RESEARCH DESIGN AND METHODS

We analyzed 15 clinical guidelines on type 2 diabetes from 13 countries using qualitative methods to compare the recommendations and bibliometric methods to measure the extent of overlap in citations used by different guidelines. A further qualitative analysis of recommendations and cited evidence for two specific issues in diabetes care explored the apparent discrepancy between recommendations and evidence.

RESULTS

The recommendations made in the guidelines were in agreement about the general management of type 2 diabetes, with some important differences in treatment details. There was little overlap in evidence cited by the guidelines, with 18% (185/1,033) of citations shared with any other guideline, and only 10 studies (1%) appearing in six or more guidelines. The measurable overlap in evidence between guidelines increases if multiple publications from the same study and the use of reviews are taken into account. Research originating from the U.S. predominated (40% of citations); however, nearly all (11/12) guidelines were significantly more likely to cite evidence originating from their own countries.

CONCLUSIONS

Despite the variation in cited evidence and preferential citation of evidence from a guideline's country of origin, we found a high degree of international consensus in recommendations made for the clinical care of type 2 diabetes. The influence of professional bodies such as the American Diabetes Association may be an important factor in explaining international consensus. Globalization of recommended management of diabetes is not a simple consequence of the globalization of research evidence.

Physical dosimetric evaluations in the Apollo 16 microbial response experiment

Nine biological species, including viruses, bacteria, fungi, and nematodes, were exposed to various combinations of space vacuum, galactic radiation, and solar UV light during the Apollo 16 space flight. No major changes in number of surviving cells occurred, permitting detailed genetic and somatic studies of returned test subjects. To enable dose-response studies, solar UV was employed as a mutagenic source with cells exposed to full sunlight or to components of the UV spectrum at peak wavelengths of 254, 280, and 300 nanometers over a range of energy levels. Proper in-flight UV irradiation monitoring required the development of a potassium ferrioxalate actinometer and an anaerobic photographic emulsion dosimeter which were tested for the first time in space. Studies of the mutagenic activity of cosmic-ray particulate radiation environment required measurement of its components with several lithium fluoride thermoluminescent dosimeters and a package of passive nuclear-track detectors capable of recording high-energy multicharge particles. These detectors included cellulose nitrate, Lexan, Ilford G5, and silver chloride crystals. The nuclear track detectors measured the incident heavy particles with the recorded spherical fluences with LET350,H2O>100 keV x micrometers-1 to be 19.3 +/- 1.8 particles cm-2. This value was found to be lower than that recorded by detectors located in the Biostack and the passive personnel dosimeters worn by the astronauts, suggesting a somewhat greater average shielding.

Flux of high-LET cosmic-ray particles in manned space flight

On the Apollo and Skylab missions the high energy heavy ion (HZE) flux was measured by means of plastic nuclear track detectors. Measurements involve the fluxes of high linear energy transfer (LET), 6 < or approximately Z < or approximately 26 particles incident on astronauts and on several biological experiments. Partial results of these measurements are presented; the effects of shielding and solar modulation are discussed.

Outcome of limb amputations in wapiti: 13 cases (1995-2001)

The object of this investigation was to determine the outcome of limb amputation in wapiti. Medical records of 13 wapiti that underwent limb amputation were reviewed to determine age, weight, sex, injury preceding amputation, limb amputated, amputation location, length of hospital stay, complications, and outcome. Ages ranged from 3 months to 8 years and weights from 70 kg to 280 kg. All animals were female. Eleven animals sustained catastrophic long bone fractures prior to amputation. Five animals had front limb amputations and 8 had hind limb amputations. Of these animals, 1 with a front limb amputaiton and 5 with hind limb amputations survived. Postsurgical inability to stand is associated with hospitalization of > 1 day. Of the 13 wapiti reviewed, 5 with hind limb amputations have produced and reared offspring. Hind limb amputation can be considered a viable alternative to euthanasia when catastrophic orthopedic injuries occur in female wapiti.

Podotrochlear bursa endoscopy in the horse: a cadaver study

OBJECTIVES

To evaluate podotrochlear bursa (navicular bursa) endoscopy as a diagnostic technique in horses and to correlate observations to radiographic and pathologic findings.

STUDY DESIGN

Descriptive study.

SAMPLE POPULATION

Seventeen equine cadaver forelimbs.

METHODS

Five standard radiographic views of the navicular region and a bursographic study with lateromedial and caudal tangential radiographic views were taken of each forelimb. Radiographic scoring of the navicular bone (0, excellent; 1, good; 2, fair; 3, poor) was performed using a previously reported technique. Endoscopic examination was performed using a 30 degrees wide-angle forward oblique-viewing, 4-mm outside diameter (OD), arthroscope. Four examiners using recorded videotapes made independent evaluations of bursal endoscopy. The specimens were then dissected and examined to verify radiographic and endoscopic findings.

RESULTS

The distribution of radiographic scores (RS) were 0 (5 limbs), 1 (7), 2 (2), and 3 (3). Abnormal endoscopic findings (fibrillation of the deep digital flexor tendon, a defect in the navicular bone fibrocartilage, and synovial hyperplasia) were identified in 3 limbs (2 with an RS of 1, and 1 with an RS of 3). The endoscopic observations made in the two RS 1 bursae were not confirmed on gross examination, whereas they were in the RS 3 specimen, which also had the only abnormal bursogram. Evaluation of the bursa on the side ipsilateral to the arthroscope portal was difficult. Complications of the technique included inadvertent penetration of the distal interphalangeal joint and the digital sheath, and superficial scoring of the navicular bone fibrocartilage.

CONCLUSIONS

Podotrochlear bursa endoscopy is feasible and may be a useful technique in identifying early abnormalities associated with podotrochleosis.

CLINICAL RELEVANCE

In horses with podotrochleosis, endoscopic examination of the podotrochlear bursa may improve identification of pathologic changes within the bursa.

Comparison of 2 techniques for regional antibiotic delivery to the equine forelimb: intraosseous perfusion vs. intravenous perfusion

The purpose of this study was to compare the synovial fluid concentrations and pharmacokinetics of amikacin in the equine limb distal to the carpus following intraosseous and intravenous regional perfusion. The front limbs of 6 horses were randomly assigned to either intraosseous or intravenous perfusion. A tourniquet was placed distal to each carpus and the limb perfused with 500 mg of amikacin. Systemic blood samples and synovial fluid samples were collected over 70 min from the distal interphalangeal (DIP) joint, metacarpophalangeal joint, and digital flexor sheath. The tourniquet was removed following the 30 min sample collection. The mean peak amikacin concentration for the DIP joint was significantly higher with intravenous perfusion. There were no significant differences in time to peak concentration or elimination half-life between methods at each synovial structure. Each technique produced mean peak concentrations ranging from 5 to 50 times that of recommended peak serum concentrations for therapeutic efficacy.

An evaluation of chemical arthrodesis of the proximal interphalangeal joint in the horse by using monoiodoacetate

The use of monoiodoacetate (MIA) for arthrodesis of the proximal interphalangeal joint (PIJ) and the effect of exercise on the degree of fusion were investigated. Eight horses received 3 injections (Weeks 0, 3, 6) of MIA (2 mL; 60 mg/mL) into the right or left front PIJ. Peri-operatively, the horses received phenylbutazone, butorphanol, and abaxial sesamoidean nerve blocks to relieve pain. During the study, the horses were monitored for general health, lameness, and swelling around the injection area. Radiographs were taken biweekly to evaluate bony fusion. Horses were randomly divided into non-exercised and exercised groups. Exercise consisted of 20 minutes of trotting on a treadmill (4 m/s), 3 days per week for 13 weeks. The horses were euthanized at 24 weeks. Slab sections of the PIJ were evaluated grossly and radiographically for bony fusion. Histologic examinations were performed to evaluate articular cartilage. Three horses were excluded from the study after developing soft tissue necrosis around the injection site, septic arthritis, and necrotic tendinitis. The remaining horses remained healthy, developed a grade 1 to 4 lameness with minimal to severe swelling in the PIJ region. All 5 horses showed radiographic evidence of bony fusion, however, no fusion was present when injected joints were examined on postmortem examination. Histologic examination revealed thinning of the cartilage, diffuse necrosis of chondrocytes, with the calcified zone intact. Subjectively, exercise did not influence the degree of cartilage destruction. Based on this study, chemical arthrodesis cannot be advocated in clinical cases because of the high complication rate and lack of bony fusion.

Lesbians and cervical screening

Confusion exists in clinical practice about whether lesbians should be offered routine cervical smears. We found cervical smear abnormalities in a sample of 624 lesbians, including those who had never been sexually active with men. These findings suggest that lesbians should be routinely offered cervical cytology as part of the national screening programme. Evidence of human papilloma virus (HPV) infection in the 'exclusively lesbian' group indicates that sexual transmission of HPV may occur between women. The belief by some lesbians that they have less need for cervical smears, coupled with poor uptake of cervical screening by a significant proportion, demonstrates a need for education of lesbians and health service providers.

Age-related changes to the molecular and cellular components of equine flexor tendons

Specific tendons show a high incidence of partial central core rupture which is preceded by degeneration. In the performance horse, the superficial digital flexor tendon (SDFT) is most often affected. We have described previously the molecular changes that are associated with degeneration in the central core region of the equine SDFT. The pathophysiological mechanism leading to change in synthetic activity of central zone cells in degenerated tendons is not known. In this study, we test the hypothesis that ageing results in matrix composition changes within the central zone of the SDFT. Extracellular matrix composition and cellularity were analysed in equine SDFTs collected from Thoroughbred horses and compared with a flexor tendon which rarely shows degenerative change and subsequent injury (deep digital flexor tendon, DDFT). Data were examined for age-related changes to central and peripheral zone tissue of the SDFT and DDFT. Ageing in both tendons (SDFT and DDFT) resulted in a significant increase in collagen-linked fluorescence and a decrease in cellularity in the DDFT but not the SDFT. The central zone tissue from the SDFT had a significantly higher proportion of type III collagen than the peripheral zone of the tendon. The highest level of type III collagen was found in the central zone tissue of the SDFT from the older group of horses and this may represent the early stages of a degenerative change. Collagen content did not differ between the 2 flexor tendons; however, there were differences in collagen type and organisation. The SDFT had a higher type III collagen content, higher levels of the mature trifunctional collagen crosslink hydroxylysylpyridinoline, lower total chondroitin sulphate equivalent glycosaminoglycan content, smaller diameter collagen fibrils and a higher cellularity than the DDFT. In conclusion, differences in macromolecular composition exist between the flexor tendons and ageing contributes to a tendon specific change in composition.

Effect of feed rate and drill speed on temperatures in equine cortical bone

OBJECTIVE

To examine the amount of heat generated in equine cortical bone by a 6.2-mm drill, using low- and high-speed and controlled feed rate drilling.

SAMPLE POPULATION

10 metacarpal bones harvested from five 2-year-old draft-type horses.

PROCEDURE

Drilling on metacarpal bones was done using a machine shop mill with which the feed rate and drill speed could be precisely controlled. Bones were drilled, using 6 combinations of feed rate (1, 2, and 3 mm advance/s) and drill speed (317 and 1,242 revolutions/min [rpm], with maximal temperatures recorded by thermocouples placed 1, 1.5, and 2 mm from the drill. Maximal temperatures were evaluated for the effect of feed rate, drill speed, cortical thickness, and distance from the drill, using linear regression analysis.

RESULTS

Increasing feed rate from 1 to 2 and from 2 to 3 mm/s significantly decreased mean maximal temperature. Increasing drill speed from 317 to 1242 rpm significantly increased mean maximal temperature. Increasing cortical thickness significantly increased mean maximal temperature, and increasing the distance from the drill hole significantly decreased mean maximal temperatures.

CONCLUSIONS

On the basis of our results, we recommend using low drill speeds while applying sufficient axial force to advance the drill as rapidly as possible through the bone.

CLINICAL RELEVANCE

Results of using this in vitro model suggest that temperatures at the drill-bone interface may be sufficiently high to result in significant thermal necrosis when drilling equine cortical bone.

Management of limb fractures in wapiti (Cervus elaphus): 22 cases (1993-1997)

OBJECTIVE

To determine treatment and outcome of a series of wapiti (elk) with fractures of the limbs.

DESIGN

Retrospective study.

ANIMALS

22 wapiti.

PROCEDURE

Medical records were reviewed to determine affected limb and bone, fracture configuration, method of treatment, outcome, and complications.

RESULTS

2 animals had fractures of the humerus; 8 had fractures of the radius, ulna, or both; 5 had fractures of the third metacarpal bone; 3 had fractures of the tibia; 2 had fractures of the femur; and 2 had fractures of the tarsal bones. Most fractures (n = 11) were closed, displaced, nonarticular fractures; 6 fractures were open. Four animals died or were euthanatized prior to fracture treatment, 2 were not treated because fractures had already healed, and 14 underwent fracture repair. In the remaining 2 animals, the affected limb was amputated. Five animals developed nonfatal complications (wound dehiscence, osteomyelitis [2 animals], delayed union, and malunion) and 2 developed fatal complications (gastrocnemius rupture and femoral fracture during recovery). Overall, 16 animals were discharged from the hospital, and all were doing well at follow-up, 2 months to 4 years after discharge.

CLINICAL IMPLICATIONS

In wapiti, limb fractures can be successfully treated by means of internal or external fixation. The high rate of fracture healing, even among wapiti with open fractures, should encourage veterinarians to repair limb fractures in wapiti.

Effect of ischemia and reperfusion on neutrophil accumulation in equine microvascular tissue flaps

OBJECTIVE

To investigate neutrophil accumulation after ischemia and reperfusion (IR) in microvascular tissue flaps in horses.

STUDY DESIGN

Randomized controlled experiment.

SAMPLE POPULATION

A total of 8 horses between 1 and 10 years of age, 4 of each sex.

METHODS

Control and experimental myocutaneous island flaps based on the superficial branch of the deep circumflex iliac vessels were dissected on each horse. Atraumatic vascular clamps were applied to the pedicle of the experimental flap for 90 minutes and then removed to allow reperfusion. Based on the assumption that rapid infiltration of neutrophils into affected tissues is a hallmark of IR injury, radiolabeled autogenous leukocytes were used to indirectly quantify neutrophil accumulation in flap tissues. Labeled leukocytes were administered through a jugular catheter 30 minutes before flap reperfusion. Biopsies were collected from each flap over a 6 hour postischemia time period; in group 1 (n = 4) from 0 to 6 hours postischemia, and in group 2 (n = 4) from 24 to 30 hours postischemia. Biopsies were examined scintigraphically and histologically for evidence of neutrophil infiltration.

RESULTS

All control flaps survived and 6 of 8 experimental flaps survived. There was no significant evidence of acute neutrophil infiltration into flap tissues after reperfusion in either group.

CONCLUSIONS

The results of this study suggest that equine myocutaneous flap tissues can survive a 90-minute ischemic period and reperfusion. No significant evidence of the occurrence of IR injury in flap tissues was found.

CLINICAL RELEVANCE

The reasons for the previously reported failures of equine free tissue transfer remain uncertain, but they do not appear to be caused by neutrophil mediated injury associated with ischemia and reperfusion.

Osteochondritis dessicans and subchondral cystic lesions in draft horses: a retrospective study

The clinical features, radiographic findings, treatment, and outcome in 51 draft horses with osteochondritis dessicans (OCD) or subchondral cystic lesions (SC) are reported. Clydesdale and Percheron were the most commonly affected breeds, and affected animals represented only 5% of the hospital population of draft horses. Horses were most frequently affected in the tibiotarsal joints and 73% (24 of 33 cases) of the horses with tibiotarsal effusion were affected bilaterally. Osteochondritis dessicans of the distal intermediate ridge was the most common lesion found in the tibiotarsal joint. The stifle was also frequently affected; 87% (13 of 15 cases) of horses with femoropatellar OCD only were lame, and lesions were most commonly located on the lateral trochlear ridge. Sixteen cases were managed conservatively, 30 received surgery, and 5 were euthanized. Lameness, effusion, or both clinical signs resolved in more than 50% of surgically treated cases, but clinical signs improved in 30% of conservatively-managed cases.

External skeletal fixation for treatment of comminuted fractures in wapiti: 5 cases

External skeletal fixators were used successfully to treat severely comminuted fractures in 5 wapiti.

Comparison of media and sera used for in vitro culture of equine superficial digital flexor tendon explants

OBJECTIVE

To compare the effects of different commercial nutrient media and sera on protein synthesis and maintenance of cellular density in cultures of the equine superficial digital flexor tendon (SDFT).

ANIMALS

8 healthy 2- to 4-year-old horses.

PROCEDURE

First Dulbecco's modified Eagle's medium, Ham's F12 nutrient mixture, RPMI 1640 medium, minimum essential medium with Earle's salts, minimum essential medium with Hanks' salts, and a Dulbecco's modified Eagle's medium/Ham's F12 nutrient mixture with 10% fetal bovine serum (FBS) were compared. Then FBS, fetal equine serum, and donor horse serum, each at 5, 10, and 15% in RPMI 1640 medium, were compared. Explants were cultured in roller bottles at 37 C and aerated (50% O2/45% N2/5% CO2) daily. Rates of [3H]-proline incorporation were used as a measure of the rates of total protein and collagen synthesis on days 13 and 28. Matrix cellular density of explants at days 14 and 28 was measured by computerized image analysis.

RESULTS

Equine SDFT explants were cultured in all media for up to 4 weeks. Proline incorporation was greatest in Ham's F12 nutrient mixture and in RPMI 1640 medium, with the concentration of proline in medium correlating to the in vitro response. Total proline incorporation was greater in 15% FBS than in 5 or 10% FBS. Other differences among sera were not detected. Matrix cell density in 15% donor horse serum was equivalent to that in uncultured controls and higher than that in most other sera at week 2.

CONCLUSION

The in vitro SDFT culture system described may be used in future studies to enhance knowledge of the biological and biochemical characteristics of intrinsic tendon healing.

Comparison of herniorrhaphy versus clamping of umbilical hernias in horses: a retrospective study of 93 cases (1982-1994)

Many uncomplicated umbilical hernias have been managed successfully in foals by the application of a hernia clamp. Isolated reports of complications following clamp application have led some authors to suggest that it is an unsuitable method of treatment. Little information has been published comparing the complication rates associated with the use of hernia clamps and herniorrhaphy in the treatment of umbilical hernias. The purpose of this retrospective study was to report the characteristics of clinical cases of umbilical hernia and to compare the complication rates following these 2 treatment approaches. Information was collected from records or from owners to identify the occurrence of complications and owner satisfaction following treatment. Of 93 cases, 10 complicated and 18 uncomplicated hernias were treated by herniorrhaphy, 40 uncomplicated hernias were treated by clamping, 1 originally uncomplicated hernia was treated by both techniques, and 24 cases were untreated. Nineteen percent of uncomplicated hernias treated by herniorrhaphy, and 19% of those clamped developed minor complications. This study demonstrates that although minor complications may be associated with either technique, they generally do not result in significant morbidity.

Arthrodesis of the scapulohumeral joint in a horse

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An examination of the occurrence of surgical wound infection following equine orthopaedic surgery (1981-1990)

Post operative surgical wound infection rates were determined 452 cases of equine orthopaedic surgery performed at the Western College of Veterinary Medicine, Saskatoon, Saskatchewan, between January 1, 1981 and December 31, 1990. Only surgical procedures classified as clean or clean-contaminated by the National Research Council were included in this study. The overall post operative infection rate was 10.0% (45 of 452). Clean surgeries (n = 433) had an 8.1% infection rate while clean-contaminated surgeries (n = 19) had a 52.6% infection rate. Information collected from the medical records was used in univariate and multivariate logistic regression models to evaluate significant determinates of post operative infection. Significant determinates of post operative infection were: surgical classification, orthopaedic involvement, duration of surgery, administration of preoperative antibiotics and gender. Clean-contaminated surgeries had an increased risk of infection compared to clean surgeries (odds ratio (OR) = 24.3), procedures involving long bones had an increased risk of infection compared to procedures involving articular surfaces (OR = 5.1), surgeries lasting 90 minutes or longer had an increased risk of infection compared to those less than 90 minutes (OR = 3.6), administration of preoperative antibiotics was associated with an increased risk of infection (OR = 4.6) and female patients were 2.6 times more likely to develop post operative infection than male patients.

A comparison of systolic blood pressure measurement obtained using a pulse oximeter, and direct systolic pressure measurement in anesthetized sows

Systolic blood pressure measurement obtained with a pulse oximeter has been compared to values obtained by other indirect methods in man. Direct pressure measurement is subject to less error than indirect techniques. This study was designed to compare systolic pressure values obtained using a pulse oximeter, with values obtained by direct arterial pressure measurement. The pulse oximeter waveform was used as an indication of perfusion. A blood pressure cuff was applied proximal to the pulse oximeter probe. The cuff was inflated until the oximeter waveform disappeared, this value was recorded as the systolic pressure at the disappearance of the waveform (SPD). The cuff was inflated to a pressure > 200 mmHg, then gradually deflated until the waveform reappeared, this value was recorded as the systolic pressure at reappearance of the waveform (SPR). The average of the two values, SPD and SPR, was calculated and recorded as SPA. The study was performed in sows (n = 21) undergoing cesarean section under epidural anesthesia and IV sedation. A total of 280 measurements were made of SPD, SPR and SPA. Regression analysis of SPA and direct measurement revealed a correlation coefficient (r) of 0.81. Calculation of mean difference (bias) and standard deviation of the bias (precision) for direct pressure--SPA revealed a value of 1.3 +/- 12.1. When compared with direct measurement, the correlation of this technique was similar to that recorded for other indirect techniques used in small animals. This indicates that this technique would be useful for following systolic pressure trends.(ABSTRACT TRUNCATED AT 250 WORDS)

Single-dose pharmacokinetics of cefazolin in bovine synovial fluid after intravenous regional injection

The pharmacokinetic properties of cefazolin in the synovial fluid of the tibiotarsal joint were determined in 10 healthy mature cattle after intravenous regional injections of 250 mg cefazolin. A pneumatic tourniquet was positioned proximal to the tibiotarsal joint and the intravenous injection was performed distal to the tourniquet. Synovial fluid concentrations of cefazolin increased in the first 30 min and fluctuated between 54.7 +/- 11.0 micrograms/ml (mean +/- SEM) and 73.2 +/- 13.2 micrograms/ml in the following 90 min while the tourniquet remained inflated. After tourniquet removal, synovial fluid concentration-time curves followed first-order one-compartment model decay in most of the animals with an elimination half-life of 0.82 h (harmonic mean). Therapeutic concentrations of cefazolin in the synovial fluid of normal joints were reached and this injection technique could be used as an alternative to systemic administration of antibiotics to provide adequate concentrations in a localized area.

Managing Sheep for Optimum Productivity in Astrebla Pastures in North-West Queensland

A yearly management program for sheep in north-west Queensland has increased lambing percentage by > 20% compared with the district average. Greasy wool production of ewes over 4 years (1988-91) averaged 4.3 kg and wethers over 2 years (1990-91) averaged 5.7 kg. Managing sheep using this program increased wool production of the flock compared with the district average. The economic advantages of running breeding ewes or wethers was influenced by wool and sheep markets. During low wool prices ($2.82/kg net selling costs, 1990; $2.44/kg net selling costs, 1991) it was estimated that a 65% lamb weaning rate was needed for returns from the ewe and wether flock to be equal. Gross margins ($/DSE) for the ewe flock were 21.80, 17.07, 8.53 and 5.42 in years 1988, 1989, 1990, 1991 respectively and 5.82 and 5.01 for wethers in 1990 and 1991 respectively. Gross margin ($/DSE) of combined ewe and wether enterprises on properties representing the district, averaged 16.50, 14.20, 8.00 and 5.00 in years 1988, 1989, 1990 and 1991 respectively. The management program implemented at Toorak generated higher gross margins than the district average particularly during the years of higher wool prices.

Tropical pasture hay utilization with slaframine and cottonseed meal: ruminal characteristics and digesta passage in wethers

Sixteen mature, ruminally cannulated wethers (average BW = 41 +/- 1 kg) were fed a low-quality hay diet with or without a cottonseed meal (CSM) supplement and the parasympathomimetic agonist slaframine (SF). Treatments were basal diet (Mitchell grass hay, 4.8% CP, 46.8% ADF) available on an ad libitum basis, basal diet plus SF (8 micrograms/kg BW, 2 x daily i.m. injection), basal diet plus CSM (41.0% CP; 100 g/d), or basal diet plus SF and CSM. Treatments were arranged as a 2 x 2 factorial within a replicated 4 x 4 Latin square with 20-d periods followed by a 10-d adjustment during which only the basal diet was fed. All measurements were performed within the final 10 d of each period. Slaframine increased salivary flow by 10 to 35% (P < .07), ruminal fluid dilution rate by 8 to 11% (P < .10), and pH by 3 to 4% (P < .001). A twofold increase (P < .05) in ruminal cellulolytic bacteria numbers occurred in SF-treated wethers. Despite these SF-induced changes in the ruminal environment, whole-tract apparent nutrient digestibility, N and mineral balance, and ruminal VFA concentrations were not changed. Cottonseed meal increased forage intake by 34 to 54% (P < .001) and DM digestibility by 30% (P < .001). Cottonseed meal supplementation of a Mitchell grass hay diet improved nutritional status and attenuated live weight loss.

Mechanical properties of suture materials in vitro and after in vivo implantation in horses

Tensile testing of reproducible loops of size 5 braided polyester, size 2 polyglycolic acid, size 2 monofilament nylon, and size 2 polydioxanone sutures was performed in vitro and after subcutaneous implantation in horses for 7, 14, and 28 days. Maximum breaking strength, energy absorption, and percentage elongation to breakage point were measured. Size 5 braided polyester had the highest maximum breaking strength and energy absorption over 28 days. Polydioxanone had better mechanical performance over 28 days than did polyglycolic acid. On day 28, none of these parameters was measurable in polyglycolic acid. Monofilament nylon had the lowest breaking strength of the three materials tested on day 28.

Proximal interphalangeal arthrodesis in the horse. A retrospective study and a modified screw technique

Arthrodesis of the proximal interphalangeal joint was used to treat lameness resulting from osteoarthrosis and for closed subluxation in 35 horses. Six horses had bilateral arthrodeses. Several conventional internal fixation techniques and a three converging screw method were used. Criteria for success included the horse performing its previous or intended athletic activity and the owner being satisfied with the outcome. Using these criteria, a successful outcome was obtained in 65% of the 26 animals in which adequate follow-up was available. A successful outcome was observed in four of six horses with bilateral arthrodeses. The internal fixation technique used did not influence the success rate, and the duration of postoperative casting was similar in successful and unsuccessful cases. The success rate of proximal interphalangeal arthrodeses was 46% in the fore limbs and 83% in the hind limbs. Complications included infection, cast ulcers, bone or implant failure, implant loosening, and laminitis.

A retrospective study of 51 cases of abdominal problems in the calf: etiology, diagnosis and prognosis

A retrospective study of 51 calves less than two months of age showing signs of abdominal pain or presented because of abdominal distension was carried out to evaluate the relationship between etiological, diagnostic, and prognostic characteristics. We found that the age of the calf differed with the type of lesion present. Calves under eight days of age had a 73% incidence of lesions which required surgical therapy. Atresia of part of the intestinal tract was the most frequently diagnosed problem, In eight-day to two-month-old calves, medical causes of colic were more common; only 26% of cases had lesions that required surgical correction. Gaseous distension of the abomasum and intestine was the most frequent cause of colic in older calves. Other abdominal problems observed in this study included abomasal ulceration and abomasal torsion.Mortality was more common in calves with surgical problems. Of the 21 calves with surgical problems, 76% died compared with a 20% mortality rate in the 30 calves with medical problems. Because of the high incidence of surgical problems in young calves, mortality was 69% in calves under eight days of age and only 33% in older calves. The chance of recovery decreased with the severity of hypothermia and dehydration. Most calves (75%) which were recumbent at presentation died, whereas only 29% of calves which were alert and able to stand at presentation died. Hematological findings indicative of severe inflammation were poor prognostic signs. Heart rate and the apparent severity of abdominal pain were not useful prognostic indicators.

Balloon-tipped catheter arterial occlusion for prevention of hemorrhage caused by guttural pouch mycosis: 13 cases (1982-1985)

Epistaxis, caused by guttural pouch mycosis, was treated by balloon-tipped catheter and ligature occlusion of the involved arteries in 13 horses. In 7 horses, more than one artery was catheterized. Serious postoperative hemorrhage was prevented in all horses. Long-term endoscopic follow-up examination was possible in 8 horses, and all had complete regression of the fungal lesion as early as 5 weeks after surgery. Six of the 8 horses did not receive medical treatment. Problems related to the use of the balloon-tipped catheter technique were rare. There were incisional infections in 3 horses, catheter breakage during removal occurred twice, and in one horse, a catheter was inappropriately placed.

Bilateral carpus valgus with cranial bowing of the distal radius in a foal

Bilateral carpus valgus with concomitant outward rotation and cranial bowing of the distal radii was diagnosed in a crossbred foal. The foal was not lame on admission and showed no radiographic evidence of carpal bone abnormalities. Surgery was limited to the most severely affected leg, and consisted of a combination of growth promotion (periosteal transection and stripping) and temporary physeal retardation (transphyseal bridging) procedures. Correction of the valgus deformity was nearly complete in the operated limb and substantial improvement was observed in the cranial bowing and outward rotation in both limbs, five months postoperatively.

Bovine peritoneum: fibrinolytic activity and adhesion formation

The fibrinolytic activity of peritoneum was evaluated in 4-month-old calves before and after peritoneal trauma. In each calf, a peritoneal resection, abrasion, sutured incision, and nonsutured incision were performed. These 4 trauma sites were evaluated for fibrinolytic activity and adhesion formation at 1 of 6 posttrauma intervals (1, 2, 3, 5, 8, or 14 days). Peritoneal plasminogen activator and fibrinolytic inhibitor activities from pre- and posttrauma samples were evaluated, using a fibrin-slide incubation technique. Calf peritoneal specimens consistently had fibrinolytic inhibitor activity, but did not have plasminogen activator activity. Significant differences were not found between fibrinolytic activity before or after trauma and a significant correlation was not found between fibrinolytic activity and the presence of or severity of adhesions.

Periorbital skull fractures in five horses

Periorbital skull fractures were diagnosed in 5 horses, and were associated with ophthalmic complications including corneal ulceration, uveitis, and entrapment of the eye by retrobulbar bone fragments. Physical examination was of greater diagnostic use than radiography. Surgical repair was performed on all horses and was associated with a more favorable postoperative appearance in horses treated acutely; however, the cosmetic results were considered acceptable in all horses. Major postoperative complications were not observed.

Bovine arthritides. Classification, diagnosis, prognosis, and treatment

Bovine arthritides are an important aspect of food animal practice, and a good understanding of these conditions allows the practitioner to develop effective treatment regimens. This article discusses the complexities of joint diseases and the problems associated with their diagnoses and treatments.

Herniation of small intestine through the right lateral ligament of the bladder in a bull

A three year old Charolais bull was examined because of anorexia and depression of five days duration and progressive abdominal distention. Intestinal obstruction was diagnosed. A right flank celiotomy allowed diagnosis and correction of a herniated jejunoileal loop through the right lateral ligament of the bladder. An annular constriction located in mid-ileum was by-passed by ileocecal side-to-side anastomosis. The bull's appetite and fecal production returned to normal within 72 hours of surgery. Ten months following discharge the bull was reported to be well.

Management of proximal sesamoid bone fractures in the horse

The case records of 49 horses with proximal sesamoid bone fracture were studied. The population consisted of 20 Thoroughbreds, 20 Standardbreds, 5 Quarter Horses, 2 Arabians, and 2 grade horses. The fractured bones were classified into 5 categories: apical fractures, basilar fractures, abaxial fractures, middle one-third fractures, and bilateral comminuted-distracted fractures. Apical fractures occurred most frequently in the Standardbred, with the prevalence of medial fracture being equal to that of lateral fracture. Basilar fractures occurred predominantly in the Thoroughbred, with the highest prevalence in the lateral sesamoid bone of the right front fetlock. Bilateral comminuted-distracted fractures also occurred primarily in the right front fetlock. The prognosis following surgical removal of apical fractures appeared to be superior to that for stall rest alone. The prognosis for basilar fractures was poor.

Subluxation of the carpus in thirteen horses

The records of 13 horses of various breeds with subluxation of the radiocarpal, intercarpal or carpometacarpal joint, or combinations of these were reviewed. Subluxation was most common at the carpometacarpal joint (n = 10) and concomitant fractures of individual carpal bones or metacarpus II and IV were seen (n = 12).Treatment comprised of immobilization in a full leg plaster cast for from four to 18 weeks. Three animals were euthanized, two because of cast complications and one because of a request by the owner. The remaining ten were saved to function as breeding animals.

Unusual Bone Healing in a White-tailed Deer

Two sequential fractures in the left hind leg of a deer and their treatments are described. The first, a tibial fracture was treated using an intramedullary pin with full cerclage wires supported by a plaster cast. This fracture healed uneventfully. A subsequent second fracture involving the distal metatarsus was stabilized by external fixation. This fracture healed with the formation of a periosteal involucrumlike structure which encased the full length of the metatarsal bone. This involucrum was thought to be due to a sub-periosteal hematoma.

Attempts at surgical correction of unusual colonic fistulae in the horse

Two incidents of penetrating wounds into the abdominal cavity of horses are presented. In both events these had resulted in penetraton of the intestinal tract. Both animals had received only minimal veterinary attention in the acute stage and had survived with the formation of intestinal fistulae.Attempts at surgical repair resulted in failure in one animal and in closure of the fistula in the second with some subsequent cosmetic defect.

Biotransformation of sisomicin to gentamicin C2b

Sisomicin was transformed to gentamicin C(2b) by Micromonospora rhodorangea NRRL 5326. The mechanisms involved in the biotransformation are the 6'-N-methylation and the (4'-5')-reduction. The progression of the methylation was followed by the isotope technique, but the reduction reaction was not monitored.

Light Flashes Observed by Astronauts on Skylab 4

Two dedicated light flash observing sessions were conducted by one of the crewmen during the Skylab 4 mission. Analyses of his observations reveal a strong correlation between flash frequency and primary cosmic-ray flux, and an even stronger correlation between flash frequency and the South Atlantic Anomaly (SAA) region of the inner belt trapped radiation. Calculations indicate that an all-proton inner belt probably cannot produce the observed SAA flash rate, and they suggest that there may exist a previously unobserved inner belt flux of multiply charged nuclei.

Binding of aminoglycoside antibiotics to filtration materials

An investigation to study adsorption of gentamicin and other related aminoglycoside antibiotics to cellulose, diatomaceous earth (Celite), and Seitz filter sheets was carried out. Experiments with five aminoglycosides indicated that 30 to 100% of these antibiotics was adsorbed to cellulose depending on the ratio of antibiotic to adsorbent, and the total quantity could not be removed by acidification. Similarly, a study with gentamicin found adsorption to diatomaceous earth to be in the range of 33 to 98%. Neomycin and gentamicin were also readily adsorbed to Seitz filter sheets. The data indicate that large losses may occur during filtration of these antibiotics under certain conditions, and care should be taken to properly evaluate results during studies with these compounds in the presence of adsorbent materials.

Heavy cosmic-ray exposure of Apollo astronauts

A comprehensive study of the heavy-particle cosmic-ray exposure received by the individual astronauts during the nine lunar Apollo missions reveals a significant variation in the exposure as a function of shielding and the phase of the solar cycle. The data are useful in planning for future long-range missions and in estimating the expected biological damage.

Binding of aminoglycosides to feces

Gentamicin and several other basic antibiotics were examined for their ability to adsorb to dog feces. It was found that 44 to 90% of all antibiotics studied were adsorbed to feces depending on the ratio of antibiotic to fecal material. Attempts to extract these antibiotics by acid treatment after adsorption onto feces were only partially successful since large portions of the bound materials were not removed.