Understanding surgical attrition for "resectable" pancreatic cancer

OBJECTIVES

We used a novel combined analysis to evaluate various factors associated with failure to undergo surgery in non-metastatic pancreatic cancer.

METHODS

We identified rates of surgery and reasons for surgical attrition from clinical trials, which studied neoadjuvant therapy in resectable pancreatic cancer. Next, we queried the National Cancer Database (NCDB) for Stage I-III, T1-3 pancreatic adenocarcinoma patients. We investigated the rates and factors associated with the receipt of surgery. Finally, we evaluated variable importance predicting the receipt of surgery.

RESULTS

In clinical trials, 25-30 % of patients did not undergo surgery, mostly due to disease progression. In the NCDB, the overall surgical rate was only 49 %, but increased to 67 % in a curated cohort meant to mirror clinical trial patients. Patients treated at low-volume institutions (OR = 0.64, 95 % CI: 0.61-0.67) and who were uninsured (OR = 0.56, 95 % CI: 0.52-0.62) and Medicaid-insured (OR = 0.67, 95 % CI: 0.64-0.71) were less likely to receive potentially curative surgery.

CONCLUSION

We have identified a realistic target surgery rate of 70%-75 % in potentially-resectable pancreatic cancer. While attrition to pancreatic cancer surgery is mostly due to tumor biology, our study identified the most important non-medical barriers, such as facility volume and insurance, affecting pancreatic cancer surgery.

Preoperative therapy in melanoma: Evolving perspectives in clinical trials

We reviewed phase II and III trials beginning after 2010 studying preoperative therapy in melanoma (61 trials). Compared to standard adjuvant treatment, neoadjuvant immune checkpoint inhibitors (ICIs) show improved outcomes with approximately 70-80% recurrence free survival at 2 years. Several biomarkers demonstrate predictive value for pathological response (higher PD-L1 expression) and survival (IFN-γ signatures, CD8 + cell density). A number of 'non-standard' treatment mechanisms are being studied in combination with ICI therapies such as TLR-9 agonists, and anti-LAG3 checkpoint inhibitors, which show promise for alternative therapy options in the neoadjuvant setting. Finally, trials for advanced unresectable melanomas show improved survival compared to definitive systemic treatment when upfront systemic therapies lead to resectability. To conclude, in the preoperative setting for melanoma, ICIs have potential to improve outcomes for patients, and will likely change the standard treatment approach for advanced resectable disease.

Outcomes in elderly patients undergoing hepatic resection compared to liver transplant for hepatocellular carcinoma

BACKGROUND

Hepatic resection (HR) is an excellent option for patients with hepatocellular carcinoma (HCC). For patients meeting the Milan criteria, a liver transplant (LT) is also a viable option for patients with HCC, especially those with end-stage liver disease. With increasing rates of LTs amongst the elderly, we sought to determine long-term outcomes in patients who underwent HR compared to LTs in this patient population.

METHODS

We queried the national cancer database for elderly patients (≥70 years) diagnosed with HCC between 2004 and 2020. The primary outcome was overall survival (OS) computed using the Kaplan-Meier method and Cox proportional hazard regression. One-to-one propensity score matching was conducted on the basis of clinicodemographic features to account for baseline differences between patients undergoing each procedure.

RESULTS

Of the 5090 patients included, 4674 (91.8%) and 416 (8.2%) patients underwent HR and LT, respectively. Compared with HR patients, patients receiving LT had better OS (p < 0.001) and greater median survival time (65.6 months HR vs. 97.9 months LT, p < 0.001). On multivariable analysis, a LT was independently associated with improved survival (adjusted hazard ratio: 0.61, 95% confidence interval: 0.50-0.76, p < 0.001).

CONCLUSIONS

LT is associated with improved survival for well-selected elderly patients with HCC. Age alone should not be used as the sole parameter for the candidacy of LT in elderly patients.

Association of sociodemographic characteristics with utilization of sentinel lymph node biopsy for American Joint Committee on Cancer 8th edition T1b cutaneous melanoma

Sentinel lymph node biopsy (SLNB) is an important staging and prognostic tool for cutaneous melanoma (CM). However, there exists a knowledge gap regarding whether sociodemographic characteristics are associated with receipt of SLNB for T1b CMs, for which there are no definitive recommendations for SLNB per current National Comprehensive Cancer Network guidelines. We performed a retrospective analysis of the 2012-2018 National Cancer Database, identifying patients with American Joint Committee on Cancer staging manual 8th edition stage T1b CM, and used multivariable logistic regression to analyze associations between sociodemographic characteristics and receipt of SLNB. Among 40,458 patients with T1b CM, 23,813 (58.9%) received SLNB. Median age was 62 years, and most patients were male (57%) and non-Hispanic White (95%). In multivariable analyses, patients of Hispanic (aOR 0.67, 95%CI 0.48-0.94) and other (aOR 0.78, 95%CI 0.63-0.97) race/ethnicity, and patients aged > 75 (aOR 0.33, 95%CI 0.29-0.38), were less likely to receive SLNB. Conversely, patients in the highest of seven socioeconomic status levels (aOR 1.37, 95%CI 1.13-1.65) and those treated at higher-volume facilities (aOR 1.29, 95%CI 1.14-1.46) were more likely to receive SLNB. Understanding the underlying drivers of these associations may yield important insights for the management of patients with melanoma.

Outcomes in elderly patients undergoing hepatic resection compared to ablative therapy for hepatocellular carcinoma

BACKGROUND AND OBJECTIVES

Hepatic resection is an excellent option in the care of patients with hepatocellular carcinoma (HCC). Elderly patients often forego hepatic resection in favor of liver-directed ablative therapies due to the increased likelihood of adverse postoperative outcomes due to age. We sought to determine long-term outcomes in patients who underwent hepatic resection compared to liver-directed ablative therapy in this patient population.

METHODS

We queried the National Cancer Database for elderly patients (≥70 years) diagnosed with HCC between 2004 and 2018. The primary outcome was overall survival (OS) computed using the Kaplan-Meier method and Cox proportional hazard regression.

RESULTS

A total of 10 032 patients were included in this analysis. On unadjusted analysis (p < 0.001) as well as multivariable analysis (hazard ratio: 0.65, 95% confidence interval: 0.57-0.73), hepatic resection was associated with improved OS. The protective association between hepatic resection and OS persisted after 1:1 propensity score matching.

CONCLUSIONS

Hepatic resection is associated with improved survival for well-selected elderly patients with HCC. While age is often thought of as influencing the decision to offer surgery, our study, in combination with others, demonstrates that it should not. Instead, other objective indicators of performance and functional status may be considered.

Impact of Medicaid Expansion on the Treatment and Outcomes of Intrahepatic Cholangiocarcinoma

INTRODUCTION

The Affordable Care Act increased insurance coverage for patients residing in states that expanded Medicaid coverage, but its impact on the outcomes of intrahepatic cholangiocarcinoma (ICC) is not clear. Therefore, we examine the impact of Medicaid expansion (ME) on access to treatment and outcomes of ICC.

METHODS

We queried the National Cancer Database (NCDB) data for patients with a diagnosis of ICC (2010-2018). Difference-in-difference (DID) analysis was performed to assess the impact of January 2014 ME on curative-intent surgical resection, multimodal therapy, neoadjuvant chemotherapy, 30-day mortality, and overall survival (OS).

RESULTS

Of the 2150 patients included in the study,1574 (73.2%) and 576 (26.8%) patients lived in non-ME and ME states, respectively. On adjusted DID, ME was independently associated with receipt of curative-intent surgical resection (DID coefficient: 0.05, 95% confidence interval [95% CI]: 0.04-0.06, p = 0.002) and multimodal therapy (DID coefficient: 0.08, 95% CI: 0.06-0.10, p = 0.004). In addition, ME was associated with improved OS in ME states (hazard ratio [HR]: 0.73, 95% CI: 0.62-0.87, p = 0.001) but not in non-ME states (HR: 0.95, 95% CI: 0.80-1.12, p = 0.536).

CONCLUSION

ME status consistently predicted increased utilization of care processes that improved ICC outcomes, including greater rates of curative-intent surgery and multimodal therapy.

Trends and disparities in the utilization of systemic chemotherapy in patients with metastatic hepato-pancreato-biliary cancers

BACKGROUND

We described trends and disparities in utilization of systemic chemotherapy in metastatic hepato-pancreato-biliary (HPB) cancers.

METHODS

We queried the National Cancer Database for metastatic HPB cancers [hepatocellular carcinoma (HCC), biliary tract cancers (BTC), pancreatic adenocarcinoma (PDAC)]. We used multivariable analysis to examine the factors associated with utilization of systemic chemotherapy. We utilized marginal structural logistic models to estimate the effect of health insurance, facility type, or facility volume on utilization of systemic chemotherapy.

RESULTS

We identified 162,283 patients with metastatic HPB cancers: 23,923 (14.7%) had HCC, 26,766 (16.5%) had BTC, and 111,594 (68.8%) had PDAC. A total of 37.2% patients with HCC, 55.6% with BTC, and 56.4% with PDAC received chemotherapy. Age ≥70 years and Charlson-Deyo score ≥2 were associated with lower likelihood of receiving chemotherapy across all cancers. Patients with private health insurance had higher receipt of chemotherapy. Receiving treatment at academic facilities had no effect on the receipt of chemotherapy. Treatment of patients with HCC or PDAC at high-volume facilities resulted in higher receipt of chemotherapy.

CONCLUSION

A significant proportion of patients with metastatic HPB cancers do not receive systemic chemotherapy. Several disparities in administration of chemotherapy for metastatic HPB cancers exist.

Average treatment effect of facility hepatopancreatobiliary cancer volume on survival of non-resected pancreatic adenocarcinoma

BACKGROUND

To examine the average treatment effect of hepato-pancreato-biliary (HPB) cancer volume on survival outcomes of patients with non-resected pancreatic adenocarcinoma (PDAC).

METHODS

We queried the National Cancer Database (2004-2018) for patients with HPB malignancies (PDAC, pancreatic neuroendocrine neoplasms, hepatocellular carcinoma, biliary tract cancers). We determined the 25th, 50th, and 75th percentiles based on the total annual HPB volume. We then identified patients with non-resected PDAC. We utilized inverse probability (IP)-weighted Cox regression to estimate the effect of facility volume on overall survival (OS).

RESULTS

We identified 710,988 patients with HPB malignancies. The 25th, 50th, and 75th percentiles of total annual HPB volume were 32, 71, and 177 cases/year, respectively. We included a total of 196,150 patients with non-resected PDAC. Patients treated at ≥25th, ≥50th, and ≥75th percentile facilities had improved median OS compared to those treated at facilities below these thresholds (5.8 vs. 4.2months, 6.5 vs. 4.5months, 7.5 vs. 4.8months, respectively; p < 0.001 for all). Treatment at facilities ≥25th, ≥50th, and ≥75th percentile resulted in lower hazards of death than treatment at lower-percentile facilities (HR: 0.87, 95% CI: 0.84-0.90; HR: 0.87, 95% CI: 0.83-0.91; HR: 0.85, 95% CI: 0.79-0.91, respectively).

CONCLUSION

Our data suggest that consolidation of care of patients with PDAC to high-volume centers may be beneficial even in the nonoperative setting.

A Study on Outcome of Surgical Treatment of Chronic Retrocalcaneal Bursitis

Retrocalcaneal bursitis is one of the important causes of posterior heel pain which is due to repetitive friction of the retrocalcaneal bursa between the postero-superior calcaneal tuberosity (haglund deformity) and Achilles tendon. Most of the patients are treated by conservative methods. But when the condition becomes chronic and not responding to the conservative treatment, surgical treatment is an option of these cases. This prospective interventional study was conducted in the Department of Orthopaedic Surgery, BSMMU (Bangabandhu Sheikh Mujib Medical University), Dhaka, Bangladesh from September 2017 to August 2019. Within this period, total 40 cases of chronic retrocalcaneal bursitis were operated at BSMMU. The clinical and functional outcome was evaluated according to AOFAS (American Orthopedic Foot Ankle Society) scale. The results of this study showed significantly improvement of pain, functional status and deformity at the time of final follow-up period of 1 year, total mean score improved from 46/100 to 89/100. The outcome of the subjects was satisfactory 90% and unsatisfactory 10%. Surgical intervention is an effective option of treatment with satisfactory outcome, in the treatment of chronic retrocalcaneal bursitis.

Association of miR-146a rs57095329 with Behçet's disease and its complications

BACKGROUND

Behçet's disease is a chronic relapsing and remitting autoimmune multisystem inflammatory disease characterised by oral aphthae, genital ulcers, skin lesions, gastrointestinal involvement, arthritis, vascular lesions and neurological manifestations. We hypothesised a link between rs57095329 of miR-146a and Behçet's disease, with further links with common clinical features.

METHODS

We tested our hypothesis in 130 Behçet's disease patients and 131 age and sex-matched healthy controls. Behcet's disease current activity index (BDCAI) was used to assess patients' disease activity status. MiR-146a (rs57095329) was genotyped in all participants using RT-PCR and results in patients analysed according to clinical features.

RESULTS

The frequency of the GG and AG genotypes in rs57095329 were strongly associated with Behçet's disease (adjusted OR 8.05, 95% CI 3.63-17.82; P < 0.001 and OR 2.26, 95% CI 1.27-4.04; P = 0.006, respectively), and in dominant (GG+AG > AA) and recessive (GG > AA+AG) models (both P < 0.001). Additionally, G allele distribution was significantly greater in Behçet's disease compared with controls (OR 2.85, 95% CI 1.98-4.11, P < 0.001). The AA genotype and A allele were linked to oral ulcers, the GG genotype and G allele to neurological disease, and the GG genotype and G allele to ocular disease (all P < 0.01). There were no links with genital ulceration, skin lesions, vascular disease or the result of the pathergy test.

CONCLUSION

The miR-146a (rs57095329) is associated with Behçet's disease and certain genotypes and alleles with oral ulcers, and with ocular and neurological manifestations.

Molecular diagnosis and clinico-hemato-biochemical alterations and oxidant-antioxidant biomarkers in Babesia-infected dogs of Mizoram, India

BACKGROUND & OBJECTIVES

Babesiosis is a tick transmitted disease, infecting a wide variety of wild and domestic animals, as well as humans. This study was designed to investigate molecular diagnosis and clinic-hemato-biochemical and oxidant/antioxidant status in dogs of Mizoram, India.

METHODS

A total 1200 dogs screened for babesiosis during 2017-18 and 53 dogs suspected for babesiosis by clinical signs and were confirmed by molecular diagnosis. Clinical signs were recorded; also blood samples were taken to investigate hematologic changes, serum biochemical variations and oxidative stress biomarkers.

RESULTS

The overall incidence of babesiosis in dogs of Aizawl, Mizoram, India during the study period recorded was 1.25% (15/1200) and 28.3% cases confirmed from 53 suspected dogs (15/53). The most commonly observed clinical signs were fever, emaciation, depression and icterus and lymphadenopathy. Significant reduction in PCV, HB, RBCs, MCHC, total protein, and albumin along with significant increase in MCV, WBCs, monocytes and BUN were the most consistent hemato-biochemical changes. Oxidant/antioxidant assessment showed significant reduction in superoxide dismutase, catalase and total anti-oxidant (TAC) along with significant increase in lipid peroxidase (LPO) activities.

INTERPRETATION & CONCLUSION

The findings of this study demonstrated that the main causative agent of babesiosis in dogs in Mizoram Province is Babesia gibsoni which caused significant alteration of hemato-biochemical and oxidant-antioxidant status in dogs.

P1693 Mitral valve aneurysm complicating infective endocarditis

Funding Acknowledgements

Nothing to disclose

Background

Mitral valve aneurysm is an uncommon sequelae of infective endocarditis (IE), early diagnosis and timely intervention is of paramount importance to prevent aneurysm rupture and hemodynamic deterioration.

Clinical presentation

A 25-years old gentleman with no known past medical history, presented with a history of unexplained fever for the past month partially responding to antipyretics along with exertional dyspnea. On examination he had a blood pressure of 120/80 mmHg, a heart rate of 110 bpm, a temperature of 39oC, a harsh pansystolic murmur over the apex and early diastolic murmur over the second aortic area. Laboratory results revealed anaemia, leukocytosis elevated ESR and CRP and blood cultures were positive for streptococcus viridians. Electrocardiography showed sinus tachycardia.

Methods and results

Trans-Thoracic Echocardiography (TTE) revealed the presence of an echolucent cavity measured 1.6x1.6 cm overlying a perforation of the anterior mitral valve leaflet (AML) a long with two small vegetations attached to the AML at the perforation edge, largest measures 0.8cm. There was a severe mitral valve regurgitation. The aortic valve is thickened trileaflet with lack of diastolic cooptation and evidence of severe regurgitation. The left ventricle dimensions were dilated and function was reduced, estimated LVEF = 50%.

3DTrans-esophageal Echocardiography(TEE) was done for better visualization of the mitral valve. The cavity involved A2 scallop, it was perforated and communicating with the LA with an additional regurgitation jet. The aortic valve showed no detectable masses or abscesses.

Accordingly, patient was diagnosed with infective enfocarditis complicated with AML perforation and aneurysm formation, anti-biotics were commenced and patient was referred for double valve replacement.

Discussion

Mitral valve aneurysm most commonly occurs secondary to infective endocarditis of the aortic valve, while our patient does not demonstrate evidence of vegetations at the aortic valve but he had an unhealthy valve with severe regurgitation jet that hits AML and might by a cause of hit lesion at the AML and eventually complicated by aneurysm formation.

Discussion

Echocardiography is a crucial imaging modality in patient with long standing fever and underlying valvular heart disease to rule out infective endocarditis. 3D-TEE is of added value along with TTE in better definition of vegetations, detection of infective endocarditis complication and it has a crucial role in proper diagnosis and surgical planning for better clinical outcomes.

Abstract P1693 Figure. Mitral valve aneurysm

Pattern of induced estrus and conception rate following Ovsynch and Ovsynch based gonadotropin-releasing hormone treatments initiated on day 6 of estrous cycle in repeat breeding crossbred cows

Aim:

The aim was to evaluate the estrus response, incidence of accessory corpus luteum formation and fertility following different hormonal protocols in repeat breeding crossbred cows.

Materials and Methods:

This study was carried out on 24 repeat breeding crossbred cows allotted into four groups. Cows of Group I was not given any treatment, Group II was treated with gonadotropin-releasing hormone (GnRH) injection on day 6 post-estrus, Group III was treated with Ovsynch protocol, and Group IV was treated with Ovsynch based GnRH treatment. Estrus responses such as duration, onset, percentage, and intensity of estrus were recorded during the study. The incidence of accessory corpus luteum was recorded per rectally on day 7 after first and additional GnRH of Ovsynch treatment. The conception rate for all groups was calculated by the absence of estrus and on day 45 after artificial insemination (AI) per rectum. Serum samples were collected at AI and day 12 post-AI in Group I and II. Serum samples were also collected at GnRH, Prostaglandin F_2α (PGF_2α), timed AI (TAI) and day 12 post-TAI in Group III and IV.

Results:

Ovsynch and Ovsynch based GnRH treatments are resulted in 100.00% induction of estrus after the PGF_2α injection. Onset of induced estrus after the PGF_2α injection for Group III and IV was recorded as 48.750±0.713 and 51.472±1.989 h, respectively, and it was not significant. There was no significant difference in duration of estrus among the groups. The incidence of intermediate estrus intensity was found to be highest. All the cows showed the incidence of formation of accessory corpus luteum subsequent to GnRH treatment on day 6 of the estrous cycle in Group II, III, and IV. The conception rate was 0.00%, 16.67%, 50.00%, and 50.00% in Group I, II, III, and IV, respectively.

Conclusion:

Ovsynch and Ovsynch based GnRH treatments initiated on day 6 of estrous cycle capable of responding with a higher percentage of ovulation and formation of accessory corpus luteum which helped in higher conception rate over single post-AI GnRH treatment in repeat breeders. These treatments responded with better estrus response but did not significantly improve estrus intensity.

Efficacy of Heatsynch protocol for induction of estrus, synchronization of ovulation and timed artificial insemination in yaks (Poephagus grunniens L.)

The objective of this study was to test the efficacy of induction of estrus, synchronization of ovulation and timed artificial insemination in anestrous yaks using the Heatsynch protocol. In Experiment 1, 10 anestrous yaks were administered an analogue of gonadotropin releasing hormone (GnRH) followed by prostaglandin (PG)F2alpha 7 days later and then estradiol cyponate (ECP) 24 h after that. Ovulation was detected by rectal palpation at 2h intervals beginning at the initial signs of estrus. Blood samples were collected at 2h intervals beginning at the time of ECP injection up to 2h after the occurrence of ovulation for the determination of LH and progesterone. All the animals responded to the Heatsynch protocol with expression of estrus and synchronization of ovulation. The mean time interval from the ECP injection to ovulation was 59.4+/-2.62 h (range 50-72 h). The interval from the LH peak to ovulation was 30.2+/-2.3 h. The high degree of synchrony in ovulation could be attributed to the synchrony in the timing of LH peaks. In Experiment 2, 10 anestrous yaks were treated with the Heatsynch protocol (as in Experiment 1) and TAI was performed at 48 and 60 h after the ECP treatment. Concurrently, 16 cycling yaks were inseminated approximately 12 h after detection of spontaneous estrus. Pregnancy rates were similar in both groups, 40% for TAI and 43.75% for yaks inseminated following spontaneous estrus (p>0.05). From this study, two conclusions can be drawn. First, the Heatsynch protocol can be successfully used to induce and synchronize estrus in anestrous yaks and, second, ovulation following the Heatsynch protocol is synchronized adequately to permit the use of fixed time AI in this species.

A new synthesis of oxadiazole, thiazolidinone, N-phthalimidoamino carbonyl and arylidene derivatives with potential antimicrobial activity

Condensation of carbohydrazide derivatives Ia, b with dimethyl acetylenedicarboxylate and acetylenedicarboxylic acid yielded benzofuran derivatives II a-d. Reaction of Ib with aromatic aldehydes formed products III a-d. Treatment of compounds III a-d with mercaptoacetic acid yielded the cyclocondensation products (IVa-d). Phthalic anhydride reacted with compounds (Ia, b)to form products (Va, b). It has been found that both khellin and visnagin (VIa, b)react with aromatic aldehydes to give arylidene derivatives (VIIa-e). Condensation of diphenyl nitrilamine with 2-arylidene furochromones VII derivatives afforded cyclo-adducts (VIII a-i). The antibacterial activities of the selected compounds were tested against Staphylococcus aureus, B. subtilis, E. coli, Pseudomonas, Salmonella and Erwinia with good results.

Neuroprotective effect of alpha(2) agonist (brimonidine) on adult rat retinal ganglion cells after increased intraocular pressure

Brimonidine, a selective alpha(2)-adrenoceptor agonist, has recently been shown to be neuroprotective as it significantly improves survival of retinal ganglion cells (RGCs) after calibrated optic nerve injury in rats. In the present study, we examined the effect of brimonidine (alpha(2)-adrenoceptor agonist) on RGC survival after increased intraocular pressure (IOP) in adult rats. RGCs were prelabeled by bilateral tectal injection of 5% Fluoro-Gold (FG). Two days later, unilaterally IOP was increased 2.2-2.5 times (28-30.5 mmHg) that of the normal pressure (12.5-14.5 mmHg) by cauterization of three episcleral veins. The elevated IOP was maintained throughout the duration of the experiment. Rats were treated intraperitoneally with brimonidine (1 mg/kg) or phosphate-buffered saline (PBS) once per week beginning either before (group A) or after (group B) increasing the IOP. Another group of rats was left as the control with elevated IOP but without any brimonidine/PBS treatment. Rats were euthanized at 3, 4 and 5 weeks after IOP elevation. Identifiable RGCs were counted and compared between control and experimental groups. Brimonidine significantly protected RGCs from elevated IOP-induced cell death. In control rats with three-vein cauterization, there was 5-6% cell death per week. Almost all RGCs were protected following brimonidine treatment for 3 weeks both in groups A and B. At 4 weeks, there was 4.5% cell death in group A and 6.5% in group B. At 5 weeks, cell death was 5.9% in group A and 6.2% in group B. The difference in cell death in groups A and B was insignificant. No significant differences were observed between PBS-treated and control groups. No significant changes in elevated IOP was found after brimonidine or PBS treatment when compared with the nontreated control group. Although pressure remained elevated throughout the length of the experiment, 3 weeks later the amount of cell death gradually increased in brimonidine-treated animals.

Effects of increased intraocular pressure on rat retinal ganglion cells

The effects of elevated intraocular pressure (IOP) on the morphology of rat retinal ganglion cells (RGCs) was analyzed in this study. After cauterizing two limbal derived episcleral veins, IOP in experimental eyes was elevated 1.5--1.8 times that of control. RGCs of experimental and control eyes were analyzed after: bilateral tectal injections of Fluoro-Gold, and application of fluorescent dye crystals, 4-Di-10-ASP to the proximal stump of the cut optic nerve, at different time intervals after IOP elevation. The RGCs in control and experimental eyes were evaluated at 4, 6, 8, and 10 weeks by counting, as well as by determining the soma diameter. The dendritic field of three types (I, II, III) of RGCs between control and experimental eyes were also studied at 4,6,10 weeks after IOP elevation. At every time point, the number of cells in experimental eyes were significantly less than those of the control eyes. The average retinal ganglion cell death was 3--4% per week in the eyes with elevated IOP. The soma and dendritic field diameter of the RGCs in the experimental eyes were significantly larger in all cell types. However, types I and III cells expanded their dendritic fields more rapidly than type II cells. Furthermore, dendritic fields of surviving RGCs in experimental eyes occupied about the same extent of the retina as the controls. The increase in soma diameter and expansion of dendritic fields in the remaining RGCs in eyes with elevated IOP suggests the existence of plasticity in adult retina.

Differentially expressed DNA sequences following recovery from unilateral testicular torsion in rat

The molecular response during recovery from torsion-induced stress in the testis is diverse with a variety of mechanisms. In this study, using unilateral testicular torsion in rat as a model, we used subtractive hybridisation to identify differentially expressed DNA sequences in the torsioned and control testes. Three genes were identified as being down regulated in the torsioned testis compared with controls: Control Testis genes 1, 2 and 3 (CT1, CT2 and CT3). Two genes were up regulated in the torsioned testes: Torsioned Testes genes 1 and 2 (TT1 and TT2). Differential expression was confirmed by Reverse Northern blot analysis. An homology search revealed that CT1 had 88% homology with rat metallothionein cDNA; CT2 had 81% homology with rat cell surface antigen in MHC class I, but no homology could be found for CT3. TT1 had 92% identity with rat Rieske iron-sulphur protein mRNA whereas TT2 had 73% identity with a human clone of unknown function (RP 11-252D22). These results indicate that changes in gene expression occur following torsion induced stress, and that identification of differentially expressed genes may provide insights into the mechanisms of cellular tissue damage in this model.

Axon resealing following transection takes longer in central axons than in peripheral axons: implications for axonal regeneration

Injury to axons in the CNS leads to little regenerative repair and loss of function. Conversely, injury to axons in the PNS results in vigorous regrowth of severed axons, usually with restoration of function. This difference is generally attributed to a CNS environment that either cannot support or actively inhibits regeneration and/or a failure of CNS neurons to survive axotomy. One of the earliest responses of neurons to axotomy is the resealing of cut axons. A delay in resealing could affect a neuron's ability to survive axotomy and to regenerate a new axon. In the present experiments, using a dye exclusion technique, we demonstrate that following transection of a peripheral sensory nerve, axons reseal within 8--10 h, whereas following optic nerve transection complete resealing does not occur for more than 20 h. These results show that resealing of cut axons in a CNS environment is significantly delayed compared with axons in the PNS and suggest that this could contribute to the failure of CNS neurons to regenerate following injury.

Torsion-induced injury in rat testes does not affect mitochondrial respiration or the accumulation of mitochondrial mutations

Male rats were subjected to 1 h testicular torsion of the spermatic cord or 1 h torsion followed by detorsion and recovery up to 4 weeks. The extent of tissue damage was evaluated by a testicular biopsy score count and mitochondrial function. Torsion for 1 h followed by detorsion induced significant morphological damage, which became more severe with longer periods of recovery. This morphological damage could not be correlated with mitochondrial damage as assessed by measuring the 4834 bp mitochondrial DNA 'common deletion' using a quantitative competitive polymerase chain reaction (PCR) assay. Mitochondrial respiratory chain activity, as measured by mitochondrial oxygen consumption using an oxygen electrode, did not vary between the treated animals and the controls. We conclude that the common mitochondrial DNA deletion and oxygen consumption are not good indicators of testicular damage induced by torsion.

The termination of optic nerve fibers in the albino mouse

To establish the terminal sites of the optic nerve fibers in the albino mouse, the immunohistochemical method using cholera toxin, subunit B (CTB), as well as three kinds of selective silver impregnation methods for degenerating nerve fibers were used. Termination was confirmed in the following nuclei: bilateral dorsal nuclei of the lateral geniculate body (LGB), ventral nuclei of LGB, preoptic areas, posterolateral nuclei, superior colliculi, suprachiasmatic nuclei, medial terminal nuclei of the accessory optic tract (AOT), and dorsal terminal nuclei of AOT. The percentage of the optic nerve fibers crossing at the optic chiasm was estimated at 90 to 95. Fibers from the unilateral retina were observed to terminate more in the contralateral nucleus. With regard to the suprachiasmatic nucleus, however, the terminations were observed to be distributed evenly and bilaterally.

Fluoro-Green and Fluoro-Red: two new fluorescent retrograde tracers with a number of unique properties

As a means of improving nerve tract-tracing in the peripheral and central nervous systems we experimented with two (retrograde) fluorescent emulsions, which we have tentatively named Fluoro-Green (FGr) and Fluoro-Red (FRe), and which we believe possess the following seven advantages: (1) they show little diffusion beyond the injection site; (2) their excitation/emission characteristics allow their use in double-tracing experiments; (3) they do not 'leak' from labeled cells; (4) their fluorescence is presented as large granules in the cytoplasm and its processes; (5) the fluorescence lasts for a sufficiently long time to permit repeated observation; (6) they may be used in combination with a wide variety of other neuroanatomical tracing methods; (7) they are economical, non-toxic and easy to utilize.

Esophageal cancer in Qatar

There were 41 cases of esophageal cancer over a 7 years period in the State of Qatar. Qataris accounted for 30 (73.17%) of these cases while representing about 38% of the entire population. Also there is a slight preponderance of female cases especially among Qataris. Nutritional factors, dietary preferences, environmental factors, social status and habits as well as genetic factors may constitute important etiologic factors in the genesis of esophageal cancer in Qatar.

Growth effects, uptake and metabolism of trifluralin in tissue cultures

Growth effects, uptake and metabolism of trifluralin (alpha, alpha, alpha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) in carrot (Daucus carota L.) and tobacco (Nicotiana tabaccum L.) callus tissue were determined. Carrot callus was initiated from tap root tissue on Murashige and Skoog medium with kinetin and 2,4-dichlorophenoxy acetic acid (2,4-D). Tobacco callus was initiated from pith tissue on Murashige and Skoog medium with indole-3-acetic acid (IAA) and kinetin.

Effect of yohimbine on xylazine-induced diuresis in rats

Intraperitoneal (ip) administration of xylazine (1-6 mg/kg) in male rats significantly increased urine flow over a 2-hr period in a dose-dependent manner, while urine osmolality was significantly decreased. Xylazine at 4.5 and 6 mg/kg significantly increased sodium excretion, whereas the 3 and 6 mg/kg doses of xylazine significantly increased potassium excretion. Yohimbine injected ip at 0.5 or 1 mg/kg 15 min before xylazine (6 mg/kg, ip) significantly decreased urine flow by 44% and 64% respectively. Yohimbine also prevented the increase in sodium and potassium excretion induced by xylazine. The data indicate that yohimbine is of value in controlling the diuretic effect of xylazine in rats.

Abortion rate and mortality among exotic pregnant heifers imported to the Gezira in the central region of the Sudan

Despite the intensive management and husbandry precautions, exotic pregnant heifers imported to the Gezira, Sudan, suffered excessive stress. Four of five heifers aborted due to stress. Death was due to pasteurellosis, babesiosis and heart water.

Binge stroke. A case report

Cerebral infarction developed in a 33-year-old normotensive coloured male after an alcoholic binge. This sequence of events has been described in Scandinavia and may occur in southern Africa more often than is realized.

Intake and digestibility of berseem (Medicago sativa) and Sorghum Abu 70 (Sorghum vulgare) forages by Sudan zebu cattle and desert sheep

Two experiments were carried out with Sudan zebu cattle and desert sheep to study the voluntary intake and digestibility of berseem (Medicago sativa) and Abu 70 (Sorghum vulgare) forages when offered ad lib. alone and with supplements of molasses to the cattle and dura grain to the sheep. In both experiments the intake of berseem was significantly higher than Abu 70. Supplementation increased Abu 70 intake and while molasses significantly increased berseem intake by cattle, dura decreased its intake by sheep. On the basis of metabolic body size sheep showed a higher intake of these forages than cattle. There was no significant difference in DM digestibility between berseem and Abu 70 by cattle. Sheep digested berseem significantly better than Abu 70. Molasses and dura significantly increased the digestibility of Abu 70 by cattle and sheep but had no significant effect on the DM digestibility of berseem.