Infection dynamics of Salmonella Infantis vary considerably between chicken lines

AbstractSalmonella (S.) Infantis is the most common serovar in broilers and broiler meat in the European Union. In the field, fast-growing broilers are reported to be more affected than slow-growing and layer birds. The present study investigated the infection dynamics and immunological response of four chicken lines in the course of a S. Infantis infection. Two commercial chicken lines, Ross 308 and Hubbard ISA-JA-757, and two experimentally chicken lines, specific pathogen free (SPF) layers and broilers, were infected at 2 days of age. Investigations focused on faecal shedding, bacterial colonisation, humoral and cellular immune response in the blood. Ross and SPF broilers were mainly attributed as high shedders followed by Hubbard. SPF layers showed the least shedding. This is in agreement with the caecal colonisation, SPF layers harboured significant less bacteria. Systemic spread of S. Infantis to liver and spleen was highest in Ross being statistically significant at 7 days of age compared to the other lines. Spread of infection to in-contact birds, was noticed 5 days post infection in every line. Antibody response occurred in every chicken line from day 21 of age onwards. In contrast to the other chicken lines, significant differences in T cell subsets and monocytes/macrophages were found between infected and negative Hubbard birds at 7 days of age. Uninfected SPF birds had significant higher immune cell counts (T cell subsets, B cells and monocytes /macrophages) compared to uninfected commercial birds, a fact important for future experimental settings. The results illustrate that the infection dynamics of S. Infantis is influenced by the chicken line resulting in a higher risk of transmission to humans from fast-growing broilers.

Litigation related to anaesthesia: analysis of claims against the NHS in England 2008-2018 and comparison against previous claim patterns

We reviewed all 1230 claims against anaesthesia notified to NHS Resolution (formerly the NHS Litigation Authority, 1995-2017) in England between 2008 and 2018. Claims were categorised by incident type, severity (whether physical or psychological), and cost, and comparisons were made against a similar published analysis of data from 1995 to 2007. While the annual number of claims against anaesthesia increased by 62% from the earlier period, anaesthesia now accounts for smaller proportions of all claims submitted to NHS Resolution (1.5% vs. 2.5%) and of the total cost of all claims (0.7% vs. 2.4%). The absolute costs related to anaesthesia claims rose over 300%, totalling £145 million between 2008 and 2018, but the mean cost per closed claim (retail price index adjusted) fell by 6% to £74,883. The most common clinical categories were regional anaesthesia (24%), inadequate anaesthesia (20%) and drug administration (20%). Claims related to airway management, central venous catheterisation and cardiac arrest remained infrequent but severe and costly. The proportion of claims relating to regional anaesthesia and obstetric anaesthesia fell significantly, but claims relating to peripheral nerve blockade doubled. Our analysis includes categories relating to organisational and human factors which are present in a substantial proportion of claims; categories with the highest mean cost per claim included delayed care, planning, monitoring and consent. Overall, the specialty of anaesthesia is at low risk of litigation. Our analysis provides important insights into current and changing patterns in claim distributions that may help improve the quality of patient care and reduce future litigation. We recommend the establishment of a structure for national review and learning from all cases of litigation.

A provincial assessment of readiness for paediatric emergencies: What are the existing resource gaps in Alberta?

OBJECTIVES

A large proportion of all emergency visits for paediatric patients across Canada are to general emergency departments (EDs). These centres may not be adequately equipped to provide optimal care for high acuity paediatric emergencies. The objective of this study was to determine paediatric readiness for general EDs and urgent care centres (UCCs) across Alberta and provide each centre with an overall weighted Paediatric Readiness Score (WPRS).

METHODS

A paediatric readiness assessment consisting of 55-questions normalized on a 100-point scale was used to survey 107 general EDs, UCCs, and tertiary paediatric EDs in Alberta, Canada. It addresses six primary categories, including Coordination of Patient Care, Physician/Nurse Staffing and Training, Quality Improvement Activities, Patient Safety Initiatives, Policies and Procedures, and Equipment and Supplies. Descriptive statistics were used to present the WPRS score among different groups. Linear regression models were used to explore factors associated with the score.

RESULTS

The overall response rate was 59.8%. The median overall WPRS (/100) for all general EDs and UCCs was 48.4 ([interquartile range {IQR}] 17.6). Factors that were correlated with overall score included high paediatric patient volume (24.28, 95% confidence interval [CI]: 10.52 to 38.04) and involvement in a simulation education outreach program (9.38, 95% CI: 1.11 to 17.66).

CONCLUSION

Based on this survey, the WPRS of EDs and UCCs across Alberta suggest a need to improve readiness to respond to high acuity paediatric emergencies in these settings.

Patient-Reported Pain Outcomes for Children Attending an Emergency Department With Limb Injury

OBJECTIVES

The aim of this study was to describe patient-reported pain outcomes at various stages of an emergency department (ED) visit for pediatric limb injury.

METHODS

This prospective cohort consisted of 905 patients aged 4 to 17 years with acute limb injury and a minimum initial pain score of 4/10. Patients reported pain scores and treatments offered and received at each stage of their ED visit. Multiple logistic regression was used to identify predictors for severe pain on initial assessment and moderate or severe pain at ED discharge.

RESULTS

The initial median pain score was 6/10 (interquartile range, 4-6) and decreased at discharge to 4/10 (interquartile range, 2-6). Stages of the ED visit where the highest proportion of patients reported severe pain (score, ≥8 of 10) were fracture reduction (26.0% [19/73]; 95% confidence interval [CI], 17.1%-37.5%), intravenous insertion (24.4% [11/45]; 95% CI, 13.8%-39.6%), and x-ray (23.7% [158/668]; 95% CI, 20.6%-27.0%). Predictors of severe pain at initial assessment included younger age (odds ratio [OR], 0.92; 95% CI, 0.87-0.97), female sex (OR, 0.58; 95% CI, 0.40-0.84), and presence of fracture (OR, 1.58; 95% CI, 1.07-2.33) whereas, at discharge, older age (OR, 1.14; 95% CI, 1.06-1.23) predicted moderate/severe pain (score, ≥4 of 10).

CONCLUSIONS

These results on the location and predictors of severe pain during an ED visit for limb injury can be used to target interventions to improve pain management and patient outcomes.

Simulation-based medical education can be used to improve the mental health competency of emergency physicians

OBJECTIVE

We explored the feasibility of developing, running and evaluating a simulation-based medical education (SBME) workshop to improve the knowledge, skills and attitudes of emergency department (ED) doctors when called on to assess patients in psychiatric crisis.

METHOD

We designed a four-hour workshop incorporating SBME and a blend of pre-reading, short didactic elements and multiple-choice questions (MCQs). Emergency department nurses (operating as SBME faculty) used prepared scripts to portray patients presenting in psychiatric crisis. They were interviewed in front of, and by, ED doctors. We collected structured course evaluations, Debriefing Assessment for Simulation in Healthcare (DASH) scores, and pre- and post-course MCQs.

RESULTS

The pilot workshop was delivered to 12 ED registrars using only existing resources of the Psychiatry and Emergency Departments. Participants highly valued both 'level of appropriateness' (Likert rating μ = 4.8/5.0) and 'overall usefulness' (μ = 4.7/5.0) of the programme. They reported an improved understanding of the mental state and of relevant legal issues and rated the debriefings highly (participant DASH rating: n = 193; score μ = 6.3/7.0). Median MCQ scores improved non-significantly pre- and post-course (7.5/12 vs 10/12, p = 0.261).

CONCLUSION

An SBME workshop with these aims could be delivered and evaluated using the existing resources of the Psychiatry and Emergency Departments.

What are the risk factors for injuries and injury prevention strategies for skiers and snowboarders in terrain parks and half-pipes? A systematic review

OBJECTIVE

To synthesise the current evidence regarding the risk factors, the injury prevention strategies and the profile of injured skiers and snowboarders in terrain parks (TPs) and half-pipes (HPs).

DESIGN

Systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines.

DATA SOURCES

Literature searches from six electronic databases and manual searches were performed.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Inclusion criteria were: (1) publication based on original data; (2) injuries sustained in TPs or HPs; (3) recreational skiing or snowboarding injuries; (4) observational or experimental study design with a comparison group.

RESULTS

No study explored the risk factors in HPs or the prevention strategies in TPs or HPs. From the literature retrieved, there is strong evidence that skiing or snowboarding in a TP is a risk factor for head, neck, back and severe injuries. Two papers assessed the risk factors for injuries in TPs, mainly demonstrating that features promoting aerial manoeuvres or a large drop to the ground were associated with higher feature-specific injury rates. The profile of injured skiers and snowboarders in TPs described in the literature suggested some evidence of associations between factors including activity, sex, skill level, helmet use, age and TP injuries.

SUMMARY/CONCLUSIONS

This systematic review demonstrates the need for studies identifying the risk factors for injuries to skiers and snowboarders and on interventions to reduce the risk of injury in TPs and HPs. Studies addressing the issue of TP design should be considered.

PROSPERO REGISTRATION NUMBER

CRD42016045206.

Ski and snowboard school programs: Injury surveillance and risk factors for grade-specific injury

The objective of our study was to evaluate incidence rates and profile of school program ski and snowboard-related injuries by school grade group using a historical cohort design. Injuries were identified via Accident Report Forms completed by ski patrollers. Severe injury was defined as those with ambulance evacuation or recommending patient transport to hospital. Poisson regression analysis was used to examine the school grade group-specific injury rates adjusting for risk factors (sex, activity, ability, and socioeconomic status) and accounting for the effect of clustering by school. Forty of 107 (37%) injuries reported were severe. Adolescents (grades 7-12) had higher crude injury rates (91 of 10 000 student-days) than children (grades 1-3: 25 of 10 000 student-days; grades 4-6: 65 of 10 000 student-days). Those in grades 1-3 had no severe injuries. Although the rate of injury was lower in grades 1-3, there were no statistically significant grade group differences in adjusted analyses. Snowboarders had a higher rate of injury compared with skiers, while higher ability level was protective. Participants in grades 1-3 had the lowest crude and adjusted injury rates. Students in grades 7-12 had the highest rate of overall and severe injuries. These results will inform evidence-based guidelines for school ski/snowboard program participation by school-aged children.

Controlled hypotension in day care functional endoscopic sinus surgery: A comparison between esmolol and dexmedetomidine: A prospective, double-blind, and randomized study

Background:

Functional endoscopic sinus surgery (FESS) is the cornerstone of therapeutic management for nasal pathologies. This study is to compare the ability of preoperative and intraoperative esmolol versus dexmedetomidine for producing induced hypotension during FESS in adults in a day care setting.

Materials and Methods:

Sixty patients (20-45 years) posted for FESS under general anesthesia were randomly divided into Group E (n = 30) receiving esmolol, loading dose 1 mg/kg over 1 min followed by 0.5 mg/kg/h infusion during maintenance and Group D (n = 30) receiving dexmedetomidine 1 μg/kg over 15 min before induction of anesthesia followed by 0.5 μg/Kg/h infusion during maintenance, respectively. Nasal bleeding and Surgeon's satisfaction score; amount and number of patients receiving fentanyl and nitroglycerine for analgesia and deliberate hypotension, Postanesthesia Care Unit (PACU) and hospital stay; hemodynamic parameters and side effects were recorded for each patient.

Results:

Significantly less number and dosage of nitroglycerine was required (P = 0.0032 and 0.0001, respectively) in Group D compared to that in Group E. Again the number and dosage of patients requiring fentanyl were significantly lower in Group D. However, the duration of controlled hypotension was almost similar in both the groups. Group D patients suffered from significantly less nasal bleeding, and surgeon's satisfaction score was also high in this group. Discharge from PACU and hospital were significantly earlier in Group D. Intraoperative hemodynamics were quite comparable (P > 0.05) without any appreciable side effects.

Conclusion:

Dexmedetomidine found to be providing more effectively controlled hypotension and analgesia and thus allowing less nasal bleeding as well as more surgeons’ satisfaction score.

Pain relief after ambulatory hand surgery: A comparison between dexmedetomidine and clonidine as adjuvant in axillary brachial plexus block: A prospective, double-blinded, randomized controlled study

BACKGROUND

For ages various adjuvants have been tried to prolong axillary brachial plexus block. We compared the effect of adding dexmedetomidine versus clonidine to ropivacaine for axillary brachial plexus blockade. The primary endpoints were the onset and duration of sensory and motor block and duration of analgesia.

MATERIALS AND METHODS

A total of 90 patients (20-40 years) posted for ambulatory elective hand surgery under axillary brachial plexus block were divided into two equal groups (groups ropivacaine dexmedetomidine [RD] and ropivacaine clonidine [RC]) in a randomized, double-blind fashion. In group RD (n = 45) 30 ml 0.5% ropivacaine + 100 μg of dexmedetomidine and group RC (n = 45) 30 ml 0.5% ropivacaine + 75 μg clonidine were administered in axillary plexus block. Sensory and motor block onset times and block durations, time to first analgesic use, total analgesic need, postoperative visual analog scale (VAS), hemodynamics and side-effects were recorded for each patient.

RESULTS

Though with similar demographic profile in both groups, sensory and motor block in group RD (P < 0.05) was earlier than group RC. Sensory and motor block duration and time to first analgesic use were significantly longer and the total need for rescue analgesics was lower in group RD (P < 0.05) than group RC. Postoperative VAS value at 18 h were significantly lower in group RD (P < 0.05). Intraoperative hemodynamics were insignificantly lower in group RD (P < 0.05) without any appreciable side-effects.

CONCLUSION

It can be concluded that adding dexmedetomidine to axillary plexus block increases the sensory and motor block duration and time to first analgesic use, and decreases total analgesic use with no side-effects.

Induced hypotension in ambulatory functional endoscopic sinus surgery: A comparison between dexmedetomidine and clonidine as premedication. A prospective, double-blind, and randomized study

Background:

Functional endoscopic sinus surgery (FESS) is the mainstay of a therapeutic technique for nasal pathologies. This study is to compare the ability of preoperative dexmedetomidine versus clonidine for producing controlled hypotensive anesthesia during FESS in adults in an ambulatory care setting.

Materials and Methods:

Sixty patients (25-50 years) posted for ambulatory FESS procedures under general anesthesia were randomly divided into Group C and D (n = 33 each) receiving dexmedetomidine 1 μg/kg and clonidine 1.5 μg/kg, respectively; both diluted in 100 ml saline solution 15 min before anesthetic induction. Nasal bleeding and surgeon's satisfaction score; amount and number of patients receiving fentanyl and nitroglycerine for analgesia and deliberate hypotension, duration of hypotension, post anesthesia care unit (PACU) and hospital stay; hemodynamic parameters and side effects were recorded for each patient.

Results:

Number and dosage of nitroglycerine used was significantly (P = 0.034 and 0.0001 respectively) lower in Group D compared to that in Group C. Similarly, number of patients requiring fentanyl and dosage of same was significantly lower in Group D. But, the duration of controlled hypotension was almost similar in both the groups. Group D patients suffered from significantly less nasal bleeding and surgeon's satisfaction score was also high in this group. Discharge from PACU was significantly earlier in Group D, but hospital discharge timing was quite comparable among two groups. Intraoperative hemodynamics was significantly lower in Group D (P < 0.05) without any appreciable side effects.

Conclusion:

Dexmedetomidine found to be providing more effectively controlled hypotension and analgesia, and thus, allowing less nasal bleeding as well as more surgeons’ satisfaction score.

Detection of dermatophytes in healthy companion dogs and cats in eastern India

In recent times increasing occurrence of dermatophytosis, especially among the school children in eastern India was evidenced along with increased tendency of keeping companion animals such as dogs and cats. This study was undertaken to detect the occurrence of dermatophytes with antifungal susceptibility among the companion animals. A total of 1501 healthy companion animals comprising 1209 dogs and 292 cats belonged to individual owners in and around Kolkata (West Bengal, India) were examined for the evidence of dermatophytosis during 2011-2013. The collected samples were subjected to direct examination by standard KOH mount technique. The samples were inoculated into both Sabouraud dextrose agar (SDA) with 0.05% chloramphenicol and 0.5% cycloheximide and dermatophyte test medium (DTM). Each of the fungal isolate was identified based upon its colony characteristics and hyphal and conidial cells it produced. Antifungal susceptibility of the isolates was tested by broth micro dilution assay using fluconazole, ketoconazole, itraconazole, miconazole, griseofulvin and amphotericin-B antifungals. Among the 1209 samples from dogs and 292 samples from cats, 253 (20.93%) and 109 (37.33%) samples were positive for dermatophytes by direct examination. Three identified species of dermatophytes with predominant occurrence were Microsporum canis, Microsporum gypseum and Trichophyton mentagrophytes. Ketoconazole (0.06-0.5 µgm/ml), itraconazole (0.03-0.5 µgm/ml) and amphotericin-B (0.03-0.5 µgm/ml) showed lowest MIC values against M. canis, T. mentagrophytes and M. gypseum, respectively. This is the first systemic report of dermatophytes in healthy companion animals with large numbers of samples in India.

Detection and characterization of zoonotic dermatophytes from dogs and cats in and around Kolkata

Aim:

The ringworms of pet dogs, cats, and stray animals (dogs, cats, and other animals) could be a potential source of zoonotic infections causing a serious public health problem in the busy city Kolkata. The pet owners are more susceptible to get this infection from their pets, because of the close contact with them as dermatophytosis is very much prevalent in those pets. So, this study was aimed to check the prevalence of dermatophytosis in dogs, cats, and in pet owners.

Materials and Methods:

A total of 362 clinically suspected cases of dermatophytosis from dogs (123 in number), cats (202 in number), and human beings (37 in number) were collected and studied from in and around Kolkata to detect the presence of significant dermatophytes. Direct microscopy and cultural examination of the isolates were performed following standard methodology. Identification and characterization of the isolates were done by different biochemical tests.

Results:

Samples (n=285) having significant dermatophytic fungal infections were found to be of highest number in cats (158, 55.5%) than in dogs (108, 37.8%) and humans (19, 6.7%), respectively. The incidence of Microsporum canis (60.0%) was the highest from affecting dogs, cats, and human beings in comparison to Microsporum gypseum (22.5%), Trichophyton mentagrophytes (15.8%) and Trichophyton rubrum (1.7%). Detection of T. rubrum was only from human cases in this study, whereas the presence of rest three were slightly higher in cats than that of the dogs and humans in this present study. The incidences were higher in young animals and in humans of the age group of 21-30 years, during the rainy season (from April to August) and also in in-contact human beings.

Conclusion:

M. canis was the most commonly pathogen among all causing dermatophytosis in animals and also in the pet owners. M. gypseum and T. mentagrophytes were other pathogens associated with these infections. These infections were more prevalent in the rainy seasons and in in-contact human patients or pet owners.

Decoherence window and electron-nuclear cross relaxation in the molecular magnet V15

Rabi oscillations in the V(15) single molecule magnet embedded in the surfactant (CH(3))(2)[CH(3)(CH(2))(16)CH(2)](2)N(+) have been studied at different microwave powers. An intense damping peak is observed when the Rabi frequency Ω(R) falls in the vicinity of the Larmor frequency of protons ω(N). The experiments are interpreted by a model showing that the damping (or Rabi) time τ(R) is directly associated with decoherence caused by electron-nuclear cross relaxation in the rotating reference frame. This decoherence induces energy dissipation in the range ω(N) - σ(e) < Ω(R) < ω(N), where σ(e) is the mean superhyperfine field induced by protons at V(15). Weaker decoherence without dissipation takes place outside this window. Specific estimations suggest that this rapid cross relaxation in a resonant microwave field, observed for the first time in V(15), should also take place, e.g., in Fe(8) and Mn(12).

Nasal carriage rate of methicillin resistant Staphylococcus aureus among at National Medical College Teaching Hospital, Birgunj, Nepal

Present study was conducted to assess the nasal carriage rate of methicilin resistant Staphylococcus aureus (MRSA) among patients, visitors/patient attendants and healthcare personnel at National Medical College Teaching Hospital, Birgunj, Nepal. A total of 112 nasal swabs (patients: 31, visitors/patient attendants: 61, and healthcare personnel: 20) were subjected to bacteriological investigation following standard protocol. S. aureus isolates were identified by mannitol fermentation and coagulase positivity. Antimicrobial susceptibility test was performed by Kirby-Bauer's disc diffusion method on Muller-Hinton agar medium. S. aureus was isolated in 14 (12.5%) of participants (M: 11.3%, F: 13.6%). Highest nasal colonization rate was found among healthcare personnel (25.0%) followed by the visitors/patient attendants (13.1%) and the patients (3.2%) (P>0.05). Highest positive rate was observed in the age group d"14 years (33.3%), followed by 15 to 50 years (13.2%) and >50 years (5.6%) (P>0.05). Out of 14 S. aureus isolates, 57.1% were methicillin resistant, prevalence rate of MRSA among total subjects being 7.1%. MRSA prevalence rate were 5.6% and 8.5% in total male and female participants, respectively (P>0.05). Highest MRSA prevalence rate was among health-care personnel (10.0%), followed by visitors/patient attendants (8.2%) and the patients (3.2%) (P>0.05). All MRSA isolates were resistant to Ampicillin, followed by Cephalexin (37.5%), Ciprofloxacin (37.5%), Tetracycline (37.5%), Gentamycin (25.0%), Erythromycin (0.0%) and Vancomycin (0.0%). High rate of nasal MRSA carriage rate found in this study indicates the need for standard infection control to prevent MRSA transmission.

Bone tissue ablation with sub-microS pulses of a Q-switch CO(2) laser: histological examination of thermal side effects

. The goal of this study is an in vitro evaluation of thermal side-effects by the application of short sub- micro s CO(2) laser pulses in combination with an air-water spray on different types of bone tissue. A mechanically Q-switched CO(2) laser delivered 300 ns pulses at 9.6 micro m wavelength, which were focused down to a spot size of 440 micro m on the tissue (a corresponding energy density of 9 J/cm(2)). Bone samples (blocks from pig femur, rib, or cartilage) were moved through the beam repeatedly until 1-5 mm deep cuts were produced. An air driven water spray was applied to prevent the tissue dehydration. Subsequent visual and histological examinations revealed no carbonisation, melting traces or fissuring of the tissue. An extremely narrow, 2-6 micro m thick thermally altered layer was observed at the cut border in compacta and cartilage. No accumulation of the thermal damage occurred with increasing cut depth. Laser incisions in trabecular tissue were accompanied with a 100-200 micro m thick zone of thermal necrosis in bone marrow. The difference from compacta and cartilage can be explained considering the particular character of the spreading of the ablation products in the trabecular meshwork. Minor thermal side effects make the Q-switched and probably other short pulsed CO(2) laser systems interesting for hard tissue surgery.

Effects of haloperidol and SCH 23390 on acoustic startle in animals depleted of dopamine as neonates: implications for neuropsychiatric syndromes

Animals depleted of dopamine (DA) in the neonatal period and tested in adulthood exhibit some similarities to patients with schizophrenia, including increased sensitivity to DA agonists, altered sensitivity to DA receptor antagonists, and abnormalities of the acoustic startle response (ASR). In this study, we examined the contributions of D1-like and D2-like DA receptors to ASR measures in animals depleted of DA as neonates. Male rat pups received intracerebroventricular injections of 6-hydroxydopamine (DA depleted) or its vehicle (controls) at 3 days of age. Animals underwent startle testing as adults (60-75 days of age) after administration of DA antagonists (haloperidol: 0.1 or 0.3 mg/kg, SCH 23390:0.01 or 0.05 mg/kg) with and without DA agonist administration (apomorphine 0.5 mg/kg). ASR amplitude and prepulse inhibition (PPI: percentage decrease in startle amplitude due to a low intensity prepulse) were measured. DA depleted animals showed increased ASR amplitude and reduced PPI compared to controls. Administration of D1-like or D2-like DA antagonists significantly reduced overall ASR and increased PPI in both control and DA depleted animals, with DA depleted animals showing a relatively greater sensitivity to the D1-like antagonist SCH 23390. Findings are discussed in terms of the role of residual DA in mediating ASR phenomena in depleted animals, differences between D1/D2 DA receptor mediation of ASR compared to other behaviors in DA depleted animals, and potential implications for neuropsychiatric syndromes such as schizophrenia.

Effects of haloperidol and SCH 23390 on acoustic startle and prepulse inhibition under basal and stimulated conditions

1. Adult Sprague-Dawley rats underwent startle testing for assessment of baseline startle amplitude and prepulse inhibition (PPI) of the startle reflex. 2. Animals were tested after administration of either: saline, a selective D1 dopamine (DA) receptor antagonist, a relatively selective D2 DA antagonist, or combined low dose D1 and D2 antagonists. 3. Changes due to antagonists were assessed with and without administration of the D1/D2 agonist apomorphine. 4. Testing without apomorphine stimulation showed that both D1 and D2 antagonists reduce baseline startle and enhance PPI. Further, the two antagonists exhibited a synergistic interaction. 5. Testing with apomorphine showed that D1 and D2 antagonists reduce apomorphine-induced startle enhancement. Again, the two exhibited a synergistic interaction. 6. For PPI, the D2 but not D1 antagonist reduced the apomorphine effect. However, the D1 antagonist potentiated the effect of the D2 antagonist.

Sensory gating in rats depleted of dopamine as neonates: potential relevance to findings in schizophrenic patients

Based on a recent hypothesis of reduced subcortical dopaminergic tone, evidence of early neurodevelopmental deviation, and acoustic startle abnormalities in schizophrenia, we examined acoustic startle in adult animals depleted of dopamine (DA) as neonates. Male rat pups received intracerebroventricular injections of either 6-hydroxydopamine (6-OHDA, 100 micrograms) or its vehicle on postnatal day 3. At 60 days of age, baseline startle and prepulse inhibition (PPI) of startle were assessed in a no injection condition, with all other animals receiving injections of saline or the DA agonist, apomorphine. Acoustic startle was elicited using 120 db white noise bursts alone or preceded by prepulses of 75, 80, and 85 db. Animals treated with 6-OHDA exhibited a 93% depletion of striatal DA compared to vehicle-treated controls. Whereas DA depleted animals did not differ from controls in the no injection condition, they showed greater baseline startle and reduced PPI compared to controls after saline injections. Depleted animals also showed exaggerated responses to apomorphine, with greater increases in baseline startle, loss of habituation, and decreased PPI compared to controls. Findings indicate that neonatal DA depletions lead to increased baseline startle and impaired sensory gating in adulthood after saline injections and dopamine agonists compared to controls. These findings may be relevant to a subgroup of psychotic patients that exhibit similar startle abnormalities as well as signs of hypodopaminergic function.

Family history and brain morphology in schizophrenia: an MRI study

This study examined neuroanatomical differences between male schizophrenic patients with a family history of psychosis (n = 16) and those without such a history (n = 15). Intracranial area, cerebral area, ventricular size, and cortical atrophy were assessed using magnetic resonance imaging (MRI). Third ventricular enlargement was more prevalent in patients than controls (n = 15). Familial and nonfamilial patients differed significantly. Reduced cranial and cerebral areas without ventricular enlargement characterized familial patients, whereas nonfamilial patients showed marked lateral ventricular enlargement without a reduction in cranial/cerebral size.

Relationships among isolates of oral haemophili as determined by DNA-DNA hybridization

In order to assess the relationships among strains of the genera Actinobacillus and Haemophilus, DNAs from 50 strains of these genera were isolated and purified. The guanine plus cytosine (G + C) content of DNAs from strains of Haemophilus segnis and Haemophilus parainfluenzae were determined by thermal denaturation. DNA-DNA homologies were measured using labelled probes from one strain representing Haemophilus segnis (strain ATCC 10977), and two strains representing Haemophilus parainfluenzae (strains ATCC 9796 and ATCC 7901). Strains isolated as H. segnis had a G + C content of 39.0 to 42.9% and were 49-92% homologous with the ATCC 10977 DNA probe. All of the strains freshly isolated as H. parainfluenzae were 70-81% homologous with the ATCC 9796 DNA probe and had a G + C content of 34.9 to 38.3%. Strain ATCC 7901 was 11% homologous with the ATCC 9796 DNA probe, had a G + C content of 42.4%, and was 65-78% homologous to DNA from strains identified as Haemophilus aphrophilus and Haemophilus paraphrophilus. From these results we conclude that strain ATCC 7901 is a mislabelled strain of H. paraphrophilus. The results of multiple DNA-DNA hybridizations indicated that separate species designations were appropriate for H. segnis, H. parainfluenzae, Actinobacillus actinomycetemcomitans ("Haemophilus actinomycetemcomitans"), and H. aphrophilus. H. aphrophilus and H. paraphrophilus were closely related organisms and did not fulfill the generally accepted criteria for designation as separate species.