How to reduce processing times for site‐specific assessments from 29 to 5 days using a common‐sense approach: it does not have to be that hard

Researchers have reported limitations with research governance processes across Australia. This study aimed to streamline research governance processes across a local health district. Four basic principles were applied to remove non-value-adding and non-risk-mitigating processes. Average processing times were reduced from 29 to 5 days and end-user satisfaction was improved, all within the same staffing levels.

How to streamline the low and negligible research ethics and governance review process from 80 to 10 days: submission to decision

Most clinicians find research ethics and governance difficult and time consuming. This study aimed to develop a better local review process for low-risk research. We used real-time processing, leveraged local expertise and streamlined paperwork. As a result, turnaround times decreased from more than 80 days to 10 days, creating an efficient review process for low-risk projects.

Quality indicators for mental healthcare in the Danube region: results from a pilot feasibility study

Quality indicators are vital for monitoring the transformation of institution-based mental health services towards the provision of person-centered mental healthcare. While several mental healthcare quality indicators have been identified as relevant and valid, their actual usability and utility for routine monitoring healthcare quality over time is significantly determined by the availability and trustworthiness of the underlying data. In this feasibility study, quality indicators that have been systematically identified for use in the Danube region countries of Bulgaria, the Czech Republic, Hungary, and Serbia were measured on the basis of existing mental healthcare data in the four countries. Data were collected retrospectively by means of the best available, most standardized, trustworthy, and up-to-date data in each country. Out of 21 proposed quality indicators, 18 could be measured in Hungary, 17 could be measured in Bulgaria and in the Czech Republic, and 8 could be measured in Serbia. The results demonstrate that a majority of quality indicators can be measured in most of the countries by means of already existing data, thereby demonstrating the feasibility of quality measurement and regular quality monitoring. However, data availability and usability are scattered across countries and care sectors, which leads to variations in the quality of the quality indicators themselves. Making the planning and outputs of national mental healthcare reforms more transparent and evidence-based requires (trans-)national standardization of healthcare quality data, their routine availability and standardized assessment, and the regular reporting of quality indicators.

Healthcare professionals' perspectives on the role of dietitians within multidisciplinary head and neck cancer teams: A qualitative multi-site study

AIM

Evidence-based guidelines provide recommendations on how dietitians should work with patients with head and neck cancer for best outcomes. Research with healthcare professionals from head and neck cancer teams would provide insight into how these recommendations are implemented in practice. Therefore, the aim of this study was to explore how the role of the dietitian is perceived and enacted in different head and neck cancer teams from the perspective of healthcare professionals.

METHODS

This qualitative study recruited radiation oncologists, nurses, dietitians and speech pathologists from four different head and neck cancer teams in Australia and the United States. Data were collected via semi-structured interviews and analysed using a grounded-theory approach.

RESULTS

Seventeen radiation oncologists, 12 nurses, 11 dietitians and six speech pathologists participated. Perceptions on the role of dietitians were summarised by the category: "Providing expertise in nutritional care: A core role in head and neck cancer." Five categories summarised perceptions of factors that can influence how the role of the dietitian is enacted in practice: "having experience in head and neck cancer"; "initiating nutritional care plans and the role of doctors and nurses"; "clinic structuring"; "an evolving culture in healthcare services" and "the presence of evidence-based guidelines."

CONCLUSIONS

While dietitians can be perceived to be the experts in nutritional care, several factors influence how their role is enacted in head and neck cancer teams. Further research on patient nutritional outcomes and on clinic structures that best use dietetic expertise is required to strengthen recommendations on how dietitians should work with head and neck cancer patients internationally.

Collaborative, interprofessional nutritional care within head and neck cancer teams: an international multi-site qualitative study

Evidence-based guidelines (EBGs) for patients with head and neck cancer (HNC) recommend that nutritional care is delivered by an interprofessional team inclusive of dietitians, doctors, nurses, and speech pathologists. Barriers to collaboration exist within interprofessional teams. However, research on this is currently lacking in the HNC setting, particularly with regard to the provision of nutritional care. This study aimed to explore what facilitates collaborative nutritional care for patients with HNC from the perspectives of different healthcare professionals. This qualitative study used a grounded theory approach. Healthcare professionals from two radiotherapy departments in the United States and two in Australia were interviewed. Forty-six interviews were completed with 17 radiation-oncologists, 12 nurses, eleven dietitians, and 6 speech-pathologists. Collaborative nutritional care for patients with HNC was underpinned by three categories and six sub-categories: access to dietitians (facilitated by funding for dietitians and the strength of evidence), communication (facilitated by team meetings, communication systems, and multidisciplinary clinics), and role-clarity (facilitated by non-clinical activities and respect). This study highlights opportunities for enhancing collaborative nutritional care within HNC teams. Further studies on the impact of the dietitian, interprofessional education, team meetings, and multidisciplinary clinics are required to promote collaborative nutritional care for HNC patients.

Improving knowledge translation for increased engagement and impact in healthcare

Ineffective knowledge dissemination contributes to clinical practice and service improvements not being realised. Meaningful knowledge translation can occur through the understanding and matching of appropriate communication mediums that are relevant for different stakeholders or audiences. To this end, we present a dissemination instrument, the 'REAch and Diffusion of health iMprovement Evidence' (README) checklist, for the communication of research findings, integrating both traditional and newer communication mediums. Additionally, we propose a 'Strategic Translation and Engagement Planning' (STEP) tool, for use when deciding which mediums to select. The STEP tool challenges the need for communicating complex and simple information against the desire for passive or active stakeholder interaction. Used collaboratively by academics and health professionals, README and STEP can promote co-production of research, subsequent diffusion of knowledge, and develop the capacity and skills of all stakeholders.

Feasibility of home-based dietetic intervention to improve the nutritional status of older adults post-hospital discharge

AIM

To determine if a model of home-based dietetic care improves dietary intake and weight status in a specific group of older adults post-hospitalisation.

METHODS

The Department of Veterans' Affairs clients aged 65 years and over were recruited from hospitals in a regional area of New South Wales, Australia (n = 32 men, n = 36 women). Nutritional status was assessed at home at baseline (within two weeks post-discharge) and three months post-discharge using a diet history, a food frequency checklist and Mini Nutritional Assessment (MNA). Personalised dietary advice was provided by a single dietitian according to participants' nutritional status.

RESULTS

Mean body weight improved significantly (P = 0.048), as well as mean MNA score (21.9 ± 3.5 vs 25.2 ± 3.1) (P < 0.001). Mean energy, protein and micronutrient intakes were adequate at baseline and three months, except for vitamin D. At three months, the underweight group (body mass index (BMI) < 23 kg/m² ) had significantly higher mean protein intake per body weight (1.7 ± 0.4 g/kg) compared to those who were a desirable weight (BMI 23-27 kg/m² ) (1.4 ± 0.3 g/kg) or overweight (BMI>27 kg/m² ) (1.1 ± 0.3 g/kg) peers (P < 0.001). There was significant improvement in energy intake contributed from oral nutrition supplements (+95.5 ± 388.2 kJ/day) and milk (+259.6 ± 659.8 kJ/day).

CONCLUSIONS

Dietetic intervention improved nutritional status 3 months after hospital discharge in older adults living in the community.

Consumer support for healthy food and drink vending machines in public places

OBJECTIVE

To investigate the feasibility of introducing vending machines for healthier food into public places, and to examine the effectiveness of two front-of-pack labelling systems in the vending machine context.

METHODS

A survey was conducted with 120 students from a university and 120 employees, patients and visitors of a hospital in regional NSW, Australia. Questions explored vending machine use, attitudes towards healthier snack products and price, and the performance of front-of-pack labelling formats for vending machine products.

RESULTS

Most participants viewed the current range of snacks and drinks as "too unhealthy" (snacks 87.5%; drinks 56.7%). Nuts and muesli bars were the most liked healthier vending machine snack. Higher proportions of participants were able to identify the healthier snack in three of the five product comparisons when products were accompanied with any type of front-of-pack label (all p<0.01); however, participants were less likely to be able to identify the healthier product in the drinks comparison when a front-of-pack guide was present.

CONCLUSION

Respondents were interested in a range of healthier snacks for vending machines. Front-of-pack label formats on vending machines may assist consumers to identify healthier products.

IMPLICATIONS

Public settings, such as universities and hospitals, should support consumers to make healthy dietary choices by improving food environments.

Feasibility of implementing routine nutritional screening for older adults in Australian general practices: a mixed-methods study

BACKGROUND

Nutrition screening in older adults is not routinely performed in Australian primary care settings. Low awareness of the extent of malnutrition in this patient group, lack of training and time constraints are major barriers that practice staff face. This study aimed to demonstrate the feasibility of including a validated nutrition screening tool and accompanying nutrition resource kit for use with older patients attending general practice. Secondary aims were to assess nutrition-related knowledge of staff and to identify the extent of malnutrition in this patient group.

METHODS

Nine general practitioners, two general practice registrars and 11 practice nurses from three participating general practices in a rural, regional and metropolitan area within a local health district of New South Wales, Australia were recruited by convenience sampling.

RESULTS

Four key themes were determined regarding the feasibility of performing MNA -SF: ease of use; incorporation into existing practice; benefit to patients' health; and patients' perception of MNA-SF. Two key themes related to the nutrition resource kit: applicability and improvement. These findings were supported by open ended questionnaire responses. Knowledge scores of staff significantly improved from baseline (52% to 66%; P < 0.05). Of the 143 patients that had been screened, 4.2% (n = 6) were classified as malnourished, 26.6% (n = 38) 'at risk' of malnutrition and 69.2% (n = 99) as well-nourished.

CONCLUSION

It is feasible to include the MNA-SF and a nutrition resource kit within routine general practice, but further refinement of patients' electronic clinical records in general practice software would streamline this process.

Pregnancy and Glycemic Index Outcomes study: effects of low glycemic index compared with conventional dietary advice on selected pregnancy outcomes

BACKGROUND

Eating carbohydrate foods with a high glycemic index (GI) has been postulated to result in fetoplacental overgrowth and higher infant body fat. A diet with a low glycemic index (LGI) has been shown to reduce birth percentiles and the ponderal index (PI).

OBJECTIVES

We investigated whether offering LGI dietary advice at the first antenatal visit would result in a lower fetal birth weight, birth percentile, and PI than providing healthy eating (HE) advice. This advice had to be presented within the resources of routine antenatal care.

DESIGN

The Pregnancy and Glycemic Index Outcomes study was a 2-arm, parallel-design, randomized, controlled trial that compared the effects of LGI dietary advice with HE advice on pregnancy outcomes. Eligible volunteers who attended for routine antenatal care at <20 wk of gestation were randomly assigned to either group.

RESULTS

A total of 691 women were enrolled, and 576 women had final data considered. In the LGI group, the GI was reduced from a mean (± SEM) of 56 ± 0.3 at enrollment to 52 ± 0.3 (P < 0.001) at the final assessment. There were no significant differences in primary outcomes of fetal birth weight, birth percentile, or PI. In a multivariate regression analysis, the glycemic load was the only significant dietary predictor (P = 0.046) of primary outcomes but explained <1% of all variation.

CONCLUSION

A low-intensity dietary intervention with an LGI diet compared with an HE diet in pregnancy did not result in any significant differences in birth weight, fetal percentile, or PI.

'We are all time poor' -- is routine nutrition screening of older patients feasible?

BACKGROUND

Despite clinical guidelines that recommend routine nutrition screening of older patients, this does not generally occur in the Australian general practice setting. This study aimed to identify perceived barriers and opportunities to implementing nutrition screening of older people in general practice.

METHODS

Twenty-five in-depth individual interviews were conducted with general practitioners, general practice registrars and practice nurses. Interviews were audio-recorded, transcribed verbatim and analysed thematically. Observations were performed to identify opportunities to conduct nutrition screening within general practice workflow.

RESULTS

The primary identified barrier to screening related to time constraints, which was further validated by the observational component of the study. The main opportunity for screening was seen to be within the existing Australian Government Medicare Benefits Schedule Primary Care Item, 'Health assessment for people aged 75 years and older'.

DISCUSSION

Incorporation of a validated and short nutrition screening instrument into the existing Health assessment was identified as the most feasible way to encourage the uptake of nutrition screening in general practice.

Does a low glycaemic index (GI) diet cost more during pregnancy?

&#160;The aim of this study was to examine the monetary cost of dietary change among pregnant women before and after receiving low glycaemic index (GI) dietary advice. The pregnant women in this study were a subgroup of participants in the Pregnancy and Glycaemic Index Outcomes (PREGGIO) study. Twenty women from the low GI dietary advice group, who had completed their pregnancies, were randomly chosen. All these women had completed three day food records at 12&#8211;16 weeks and again around 36 weeks of gestation. Consumer food prices were applied to recorded dietary intake data. The mean &#177; SD GI of the diet reduced from 55.1 &#177; 4.3 to 51.6 &#177; 3.9 (p = 0.003). The daily cost of the diet (AUD) was 9.1 &#177; 2.7 at enrolment and 9.5 &#177; 2.1 prior to delivery was not significantly different (p = 0.52). There were also no significant differences in the daily energy intake (p = 0.2) or the daily cost per MJ (p = 0.16). Women were able to follow low GI dietary advice during pregnancy with no significant increase in the daily costs.

Co-overexpression of bcl-2 and c-myc in uterine cervix carcinomas and premalignant lesions

To establish the role of co-overexpression of bcl-2 and c-myc protooncogenes in uterine cervix carcinogenesis, we examined 138 tissue samples of low grade cervical squamous intraepithelial lesions (SIL), high grade SIL, portio vaginalis uteri (PVU) carcinoma in situ and PVU invasive carcinoma, stage IA-IIA (study group) and 36 samples without SIL or malignancy (control group). The expression of bcl-2 and c-myc was detected immunohistochemically using a monoclonal antibody. Fisher's exact test (P<0.05) was used to assess statistical significance. Overexpression of bcl-2 was found to increase in direct relation to the grade of the cervical lesions. High sensitivity was of great diagnostic significance for the detection of these types of changes in the uterine cervix. On the basis of high predictive values it can be said that in patients with bcl-2 overexpression there is a great possibility that they have premalignant or malignant changes in the uterine cervix. Co-overexpression of bcl-2 and c-myc oncogenes was found only in patients with PVU invasive carcinoma (6/26-23.0%). Statistically significant difference was not found in the frequency of co-overexpression in patients with PVU invasive carcinoma in relation to the control group (Fisher's test; P=0.064). The method's sensitivity of determining these oncogenes with the aim of detecting PVU invasive carcinoma was 23%, while specificity was 72.2%. On the basis of high predictive values (100%), speaking in statistical terms, it can be concluded that all patients with co-overexpression of bcl-2 and c-myc oncogenes will have PVU invasive carcinoma. We confirmed in our research that co-overexpression of bcl-2 and c-myc oncogenes was increased only in PVU invasive carcinoma. However, a more extensive series of samples and additional tests are required to establish the prognostic significance of bcl-2 and c-myc co-overexpression in cervical carcinogenesis.

Older rehabilitation patients are at high risk of malnutrition: evidence from a large Australian database

BACKGROUND/OBJECTIVES

Routine nutrition screening is recommended for all older patients admitted to hospital however data on the prevalence of malnutrition in rehabilitation settings is sparse. This study assessed the nutritional status of older patients admitted to rehabilitation hospitals over a 5 year period and described the association between nutritional status and length of hospital stay (LOS) in this context. The usefulness of a recently revised version of the shortened MNA (MNA-SF) was also investigated.

METHODS

A retrospective analysis was conducted of patients aged 65 + y admitted to two rehabilitation hospitals in New South Wales, Australia between 1st March 2003-30th June 2004, and 11th January 2005-10th December 2008. Nutritional status was determined on admission by trained dietitians using the full MNA instrument and the MNA-SF. Information on diagnosis-related grouping and length of stay (LOS) was obtained.

RESULTS

Data was available for 2076 patients with a mean age of 80.6 (27.7) y. Thirty-three percent and 51.5% of patients were classified as malnourished and at nutritional risk, respectively. Controlling for date of admission and diagnosis related grouping, LOS was higher in malnourished and at risk groups compared to their well nourished peers (P < 0.001) by 18.5 and 12.4 days, respectively. MNA-SF demonstrated high sensitivity but relatively low specificity against the full MNA.

CONCLUSION

The majority of older patients in the rehabilitation setting are nutritionally compromised which adversely influences LOS. In order to encourage more widespread screening, the MNA-SF may be able to replace the full MNA.

Quality of Life of Patients Suffering from Schizophrenia Treated with Clozapine and Risperidone

Background:

Quality of life (QoL) is considered an important outcome in the treatment of schizophrenia and is linked with clinical and social recovery. Until recently treatments of schizophrenia have focused mainly on reducing positive symptoms, often leaving patients with numerous residual difficulties. It's been expected that atypical antipsychotics improve QoL equally as they improve clinical outcome of the patients with schizophrenia.

Objectives:

To compare clinical improvement and QoL of patients treated with risperidone and clozapine two months after the beginning of treatment.

Methods:

The sample included 40 patients (17 males and 23 females, mean age 33.1) with diagnosis of schizophrenia according to ICD-X. the patients were treated with either risperidone (n=20) or clozapine (n=20). the PANSS and CGI scales for clinical status were applied at the beginning of the treatment and two months later. the QoL was assessed by the WHOQOL-BREF.

Results:

Analysis of data has shown a significant difference for all four domains (physical, psychological, social relationships and environment) at WHOQOL-BREF scale for both medications after two months, but no difference between the two antipsychotics. the patients treated with clozapine had significantly higher scores on PANSS at the beginning of treatment. PANSS and CGI applied after two months have not shown differences between the medications.

Conclusion:

Both clozapine and risperidone had equal and statistically significant effect in reducing the symptoms of schizophrenia measured by PANSS and CGI in two months period, as well as in improving the quality of life. However no difference was found between the two medications.

Assessing the older person: is the MNA a more appropriate nutritional assessment tool than the SGA?

OBJECTIVES

A study was undertaken to determine which nutritional assessment tool would be better in assessing changes in nutritional status over time in hospitalised older patients. The two tools used were the Mini Nutritional Assessment (MNA) and the Subjective Global Assessment (SGA).

DESIGN

Single blind, prospective study conducted over a 60-day period.

SETTING

Five regional hospitals within Southern New South Wales, Australia.

SUBJECTS

There were 43 patients at the commencement of the study, then 28 patients at day 30 and 20 patients at day 60.

METHODS

All patients over 65 years of age admitted to the five hospitals during May 2001 were eligible. The only exclusions were those patients admitted to palliative care or with severe dementia. Two dietitians saw each patient. Each dietitian assessed the patient using his or her assigned nutritional assessment tool either the SGA or the MNA. All dietitians were randomly assigned the tool at the commencement of the study. They were familiarised with the use of the tool by participating in a workshop prior to the start of the study.

RESULT

The MNA was able to detect greater numbers of malnourished subjects when compared to the SGA. This finding was consistent across Day 0, 30 and 60 and statistically significant (p<0.05) at all time periods.

CONCLUSIONS

This study has shown the MNA to be a more appropriate nutrition assessment tool for older patients when compared to the SGA. The MNA is better able to identify severely malnourished patients. This study illustrated the potential use of the MNA as an ongoing monitor of nutritional status and hence a measure of the impact of nutrition intervention.

The application of the continuum of care model in the re-configuration of nutrition and dietetics services

The continuum of health care model can be used to improve service delivery. Within a hospital setting, finite resources are available. Service gaps must be identified, priorities established and resources re-distributed to meet these gaps. Using Continuous Quality Improvement (CQI) tools, barriers to change were identified and a plan for improvement was formulated. Areas receiving disproportionate resources were identified and a more even resource allocation adopted. In an illustration of the success of strategic change, core services were not only maintained but also showed improved efficiency. The Department of Nutrition and Dietetics at Wollongong and Port Kembla Hospitals achieved an increase in dietetic services through a reorientation of current resources.

Cepstral distance measures of hormone concentration time series

In this paper we present a class of time series distance measures based on the difference of their cepstral transformations. We emphasise the convenience of the proposed distance measure in the cases when the time series can be treated as output of a linear system driven with a quasi-periodic stochastic signals. In order to illustrate the cepstral time series distance measure we applied them in cluster and multidimensional scaling analysis of daily hormonal secretion fluctuation series taken from a group of patients before and after surgery.

Three-dimensional optical storage inside transparent materials: errata

In our recent Letter1 a line of text was dropped in printing. On p. 2024 the beginning of the paragraph above Fig. 3 should read as follows: "Surprisingly, the 0.5-muJ pulse energy used in these microexplosions...".

Three-dimensional optical storage inside transparent materials

We present a novel method for three-dimensional optical data storage that has submicrometer size resolution, provides a large contrast in index of refraction, and is applicable to a wide range of transparent materials. Bits are recorded by use of a 0.65-N.A. objective to focus 100-fs laser pulses inside the material. The laser pulse produces a submicrometer-diameter structurally altered region with high contrast in index of refraction. We record binary information by writing such bits in multiple planes and read it out with a microscope objective with a short depth of field. We demonstrate data storage and retrieval with 2-microm in-plane bit spacing and 15-microm interplane spacing (17 Gbits/cm(3)). Scanning electron microscopy and atomic force microscopy show structural changes confined to an area 200 nm in diameter.

Developing mortality patterns: robust modified generalized likelihood ratio algorithm for infant mortality rate change detection

A new robust modified generalized likelihood ratio algorithm, which enables the changes of mortality rates to be detected automatically, is applied. The procedure is based on the calculation of discrimination function using robust least squares estimates of AR mortality rates residuals. The feasibility of the approach is demonstrated with experimental data concerning infant mortality rate in Serbia.

In situ localization of two prolactin-related messenger ribonucleic acids to binucleate cells of bovine placentomes

The bovine fetal placenta expresses a family of PRL-related genes, consisting of the gene encoding bovine placental lactogen (bPL), and a diverse group of related genes, exemplified by bovine PRL-related cDNA I (bPRCI). bPL and the protein encoded by bPRCI are quite distinct from one another, predicting proteins only about 36% similar in amino acid sequence. To identify the cells responsible for the expression of bPL and bPRCI, in situ hybridization experiments were performed. 35S-Labeled RNA probes were prepared from the 3' regions of bPL and bPRCI and allowed to hybridize to frozen sections of bovine placentomes. Transcripts corresponding to bPL and bPRCI colocalized to fetal binucleate cells, which is consistent with the immunocytochemical localization of bPL. Signal from radiolabeled antisense strand probe was blocked by pretreatment of the sections with a 150-fold excess of unlabeled probe, but not by an excess of unlabeled probe prepared using the other cDNA as a template. This demonstrated that the signals observed were specific for bPL and bPRCI and that the two probes did not cross-hybridize at the stringency of our conditions. Radiolabeled sense strand probes yielded no signal. We conclude that the binucleate cells of the bovine placenta transcribe at least two members of the PRL gene family that may influence fetal development and maternal adaptation to pregnancy.

A subfamily of bovine prolactin-related transcripts distinct from placental lactogen in the fetal placenta

The placentae of many species express genes homologous to the pituitary hormones. In the bovine, two transcripts distinct from the pituitary hormones have been previously described: bovine placental lactogen (bPL) and bovine prolactin-related cDNA I (bPRCI). Here we provide evidence for a subfamily of prolactin-related transcripts quite different from bPL and the rodent placental homologues, which include proliferin and rat prolactin-related proteins. Bovine prolactin-related cDNAs II and III (bPRCII and bPRCIII) are about 75% similar in nucleotide sequence to one another and bPRCI, but only 56% similar to bPL, and about 45% to the rodent placental transcripts. The deduced amino acid sequences follow a similar pattern: they are about 60% similar to one another, but only about 35% similar to bPL as well as the predicted rodent placental proteins. mRNA levels corresponding to bPL, bPRCI, and bPRCIII in the fetal placenta show distinct patterns. The role of these predicted hormones during pregnancy remains to be determined.

Function of the Y optic nerve fibres in the cat: do they contribute to acuity and ability to discriminate fast motion?

1. A controlled pressure block has been applied to the optic nerve of the cat, sufficient to bring about degeneration of the axons of the large (Y) nerve fibres caudal to the block site. This degeneration has been monitored by means of implanted electrodes in optic nerve and tract which have shown a loss of the short-latency (t1) response 4-6 days after the block, and also by histological examination of the optic nerve. 2. Cats with one optic nerve blocked in this way have been used in behavioural experiments, one or other eye being covered during the tests. Tested via the blocked nerve, all cats with loss of only Y fibres could perform certain tests: the visual placing reaction, the blink reflex, the pupillary (light) reflex and simple manoeuvres such as walking a plank and jumping from table to floor. 3. When acuity was tested by means of the Mitchell jumping apparatus, cats with loss of only Y fibres showed the same acuity using either eye. This was true also of one cat in which many X fibres had also degenerated, as evidenced by a 55% loss of the medium-latency (t2) response, but in another cat with 90% loss of the t2 response acuity was reduced to about half-normal. 4. Ability to discriminate fast motion was tested by a modification of the Mitchell apparatus. All cats were able to discriminate the motion of an 11.5 deg spot up to a velocity of 6260 deg/s, whether using their normal eye or their affected eye. However, the loss of the Y fibres reduced the ability to discriminate fast motion, so that for any given level of contrast the velocity which could be discriminated was about two-thirds of the velocity discriminated using the normal eye. The ability of the cat to discriminate fast motion seems to be similar to that of the human. 5. These results suggest that there is no sharp restriction of function between the Y and X systems but instead considerable overlap. However, each system possesses specialized features giving it superiority in certain conditions.

Vagal postganglionic innervation of the canine sinoatrial node

Differential, selective distribution of parasympathetic, postganglionic innervation to the atrioventricular nodal (AVN) region of the canine heart was recently described. Ablation of parasympathetic pathways to the AVN by disruption of the epicardial fat pad at the junction of the inferior vena cava and inferior left atrium did not interfere with normal vagal control of the sinoatrial node (SAN) function. In sharp contrast, surgical dissection of the fat pad overlying the right pulmonary vein-left atrial junction interrupted the major right and left vagal inputs to the SAN region. The pulmonary vein fat pad (PVFP) in the dog heart is triangular in shape with roughly equilateral dimensions of approximately 1 cm, its base extending from superior to inferior veins, and its apex extending nearly to the sinus nodal artery as it courses rostrally in the sulcus terminalis. Careful dissection of smaller fat pads around the circumference of the pulmonary veins and particularly over the rostral-dorsal surfaces of the right superior pulmonary vein and adjacent right atrium, completed SAN parasympathetic denervation. Care in making these dissections left the vagal supply to the AVN region essentially intact, and preserved the sympathetic supplies to both SAN and AVN regions. Autonomic ganglia, varying in size from 1 or 2 cells to 80-100 cells, were found scattered throughout the ventral PVFP (overlying and surrounding the right pulmonary vein-left atrial junction). The ganglia were generally imbedded in fatty connective tissue, although they commonly rested very close to, or were loosely surrounded by epicardial muscle. Ganglia were also found in smaller fat pads on the dorsal surfaces of the atrium between the azygos and the right superior pulmonary vein.

Parasympathetic ganglia innervating the canine atrioventricular nodal region

Surgical disruption of the small (approximately 0.7 x 1.0 cm) epicardial fat pad situated at the junction of the inferior vena cava (IVC) and inferior surface of the left atrium (ILA) interrupts both right and left vagal input to the atrioventricular nodal (AVN) region of the canine heart. This intervention eliminates AV block during supramaximal stimulation of both cervical vagi, without interfering with sinus bradycardia normally associated with sinoatrial nodal (SAN) suppression. Independent modulation of SAN and AVN activities by the parasympathetic system is thereby revealed. Histology of the excised IVC-ILA fat pad reveals multiple well organized autonomic ganglia. These ganglia range from 2 to 80 cells per cluster and are associated with numerous nerve trunks. Individual ganglia are commonly surrounded by fatty connective tissue closely adjacent to epicardial muscle. They have not been found imbedded within atrial muscle and have been been found in or close to endocardial muscle layers. Other ganglia, imbedded in the fat pad overlying the posterior surface of the left atrium or in the atrioventricular groove, do not directly modulate A-V conduction. Surgical dissection around the extreme left or middle segments of the great cardiac vein and the coronary sinus failed to interrupt either left or right vagal input to the AVN region. Parasympathetic, preganglionic pathways to these AVN synapses do not, therefore, course from left to right along the atrioventricular groove. However, dissection around the extreme right portion of the coronary sinus at its penetration of the inferior interatrial septum, did interrupt vagal influences upon A-V conduction. Thus, numerous autonomic ganglia have been localized in the canine heart which serve as synaptic stations mediating both right and left vagal regulation of A-V conduction.

Selective vagal innervation of the heart

Parasympathetic ganglia are imbedded (1) in the epicardial fat pad located on the posterior surface of the dog's heart and (2) immediately overlying the point of penetration by the coronary sinus into the interatrial septum. The fat pad is situated between the inferior vena cava and the inferior left atrium. It contains multiple encapsulated ganglia, each consisting of two to 80 separate cells, richly intermingled with neural elements. Destruction of these ganglia by surgical excision and/or phenol painting interrupts both right and left vagal inhibition of atrio-ventricular (A-V) conduction, without obviously altering vagal modulation of sinoatrial function. Excision or phenol destruction of the fat pad overlying the right pulmonary vein inlets to the left atrium interrupts both right and left vagal inhibition of sinoatrial function, again without interfering with vagal control of atrioventricular nodal function. Well organized, encapsulated autonomic ganglia are also found throughout this fat pad. These experiments thus identify and localize separate concentrations of ganglion cells which differentially modulate automaticity and A-V conduction in the canine heart.

Overlap of segmental populations and axon collaterals in the thoracic sympathetic system of the cat

Sympathetic preganglionic axons are known to branch in the sympathetic chain, i.e. extraspinally. The possibility that the axons may branch within the spinal cord (intraspinally) and exit through different roots has not been well examined. The purpose of this study was to determine if intraspinal collaterals exist in the distribution of preganglionic neurons innervating the stellate ganglion of the cat using the double-labeled retrograde fluorescent dye technique (Diamidino Yellow and Fast Blue). The right stellate ganglion of pentobarbital-anesthetized cats was isolated; the sympathetic chain was ligated in two places just caudal to the T2 white ramus and then sectioned between the ligatures. One fluorescent tracer was injected into the stellate ganglion; the complementary-colored tracer was injected into the sympathetic chain below the cut. After a 6-day survival time, frozen serial 40-micron sections of spinal cord segments T1-T4 were cut and mounted. The longitudinal distribution of dyes: indicated a segmental preganglionic organization and overlapped approximately 700 micron. However, no sympathetic preganglionic neurons were double-labeled with both dyes. Additional experiments demonstrated a small number of extraspinal preganglionic axon collaterals.