Oral Cavity Squamous Cell Carcinomas in Patients with a History of Oral Lichen Planus: Frequency and Outcomes

PURPOSE/OBJECTIVE(S)

Oral lichen planus (OLP) is an inflammatory condition which affects the mucous membranes of the oral cavity. While previous studies have described the association between OLP and development of oral cavity cancer, there is currently a paucity of literature examining the impact of this disease on treatment response and prognosis. As such, we present a retrospective cohort study of Oral cavity squamous cell carcinoma (OCSCC) patients with a history of OLP to explore the course of their disease.

MATERIALS/METHODS

Using an IRB approved tertiary care registry of head and neck cancer patients, we identified patients with OCSCC who had a prior diagnosis of OLP. The number of new primary tumors, rates of local (LF), regional (RF) and distant failure (DF), as well as overall survival (OS) were assessed using Cox proportional hazards and Kaplan Meier analysis for actuarial survival estimates.

RESULTS

Fifty-four patients with OCSCC and OLP were identified with 109 individual OCSCC diagnoses. Patients had a median age of 67 years, were predominantly female (n = 42, 77.8%) and never smokers (n = 29, 53.7%) with a median follow up after diagnosis of OCSCC of 46.5 months. Nine patients (16.7%) had a history of immunosuppression of whom 6 (11.1%) had chronic steroid use for treatment of OLP. Within the cohort, 33 (61.1%) of OLP patients had a single OCSCC, 11 (20.4%) had 2, and 10 (18.5%) had >3 separate tumors develop. The most common oral cavity subsites were oral tongue (n = 42, 38.5%), followed by alveolar ridge (n = 14, 12.8%) and gingiva (n = 13, 11.9%). Papillary SCC subtype was identified in 10.1%. 92.7% of tumors (n = 101) were treated with primary surgery, with 23 (21.1%) receiving adjuvant RT and 10 of those patients receiving concurrent chemotherapy. Among resected patients, pathologic stages were predominantly T1-2 (84.1%) and N0 (50% vs N1 15.6% and N2a-3 34.4%). The mean RT dose was 62 Gy in 32 fractions. Locoregional failure occurred in 24.8% of cancers (n = 27), with local and regional failure occurring in 13.8% (n = 15) and 11% (n = 12) of lesions, respectively. Recurrence free survival at 3 and 5 years was 75% and 70.3%, respectively, with overall survival at 3 and 5 years of 71.1% and 67%, respectively.

CONCLUSION

Patients with OCSCC and a history of OLP are predominantly female and never smokers. The tumors that develop in such patients are often early stage but a proportion of patients appear to be at higher risk of developing multiple malignancies and surveillance of this patient population to identify new tumors is crucial.

Dosimetric Analysis of Major Wound Complications Following Preoperative Ultra-Hypofractionated Radiation Therapy for Soft Tissue Sarcoma

PURPOSE/OBJECTIVE(S)

Preoperative radiation therapy (RT) for soft tissue sarcomas (STS), delivered with conventional fractionation, has been shown to reduce long-term toxicity at the expense of increased postoperative major wound complications (MWC). Ultra-hypofractionated RT has emerged as a potential alternative preoperative modality with early but comparable outcomes to conventional regimens. However, limited data are available evaluating dosimetric, patient, and treatment specific factors associated with development of MWC in this setting.

MATERIALS/METHODS

This IRB approved review included STS patients treated with preoperative 5 fraction daily RT followed by surgical resection within 7 days. Patients were evaluated for MWCs in association with patient and tumor characteristics, dosimetric parameters, and treatment techniques. MWCs were defined as a return to operating room, readmission for wound care or IV antibiotics, and persistent deep packing for >120 days. Prescription isodose line, PTV mean dose and the PTV volume exposed to 105% and 110% of prescribed dose were recorded. Dose to tissue likely to be involved in wound healing was assessed by creating a 1 cm thick superficial skin strip within 2 cm of the PTV which was then evaluated for volume, mean dose, V15, V21, V27, and V30. Secondary endpoints were locoregional control (LRC), metastasis free survival (MFS), and overall survival (OS).

RESULTS

A total of 31 patients with a median age of 66 years (range 28-87) and a median follow up of 21 months (IQR 8-43) were included. All patients received 30 Gy in 5 fractions using IMRT/VMAT. There were 11 upper limb (36%) and 20 lower limb (65%) tumors included. Median time to resection following RT was 1 day (IQR 0-3). Median tumor size was 8 cm (IQR 5-13). MWC occurred in 13 patients (42%) with 10 patients (32%) requiring additional surgery. Dehiscence and infection requiring IV antibiotics occurred in 12 (39%) and 6 patients (19%), respectively. RT plans were predominately prescribed to the PTV mean (87%) with a median prescription isodose of 97% (IQR 96-97) and PTV mean dose of 3110 cGy (IQR 3089-3142). Median PTV volume, mean dose, and volume of PTV receiving 105% and 110% of the prescribed dose were higher in the MWC cohort although none reached significance. Similarly, for the 1 cm skin strip the median volume, mean dose, V30, V27, V21, and V15 were all higher in the MWC cohort without significant difference. Among patient, treatment, and tumor factors: tumor size, location, grade, margin status, type of wound closure, and prior non-oncologic resection were not associated with MWC. LRC, MFS, and OS at 3-years were 96%, 67%, and 76%, respectively.

CONCLUSION

Although not reaching significance, increased plan homogeneity and reduced dose/volume relationships in proximity to the skin trended to reduced MWC in this limited cohort. Multi-institutional collaboration may be warranted to better identify factors associated with MWC in patients treated with preoperative ultra-hypofractionated RT.

Liver Stereotactic Body Radiation Therapy (SBRT) to Downstage Patients with Hepatocellular Carcinoma prior to Liver Transplant

PURPOSE/OBJECTIVE(S)

Orthotopic liver transplantation (OLT) marks the most successful treatment for hepatocellular carcinoma (HCC) patients meeting Milan criteria. The process of reducing the disease burden of HCC patients not currently meeting criteria for OLT with local therapy is referred to as "downstaging" and has proven to be a feasible approach. RTOG 1112 recently demonstrated the efficacy and acceptable toxicity of liver SBRT for treating HCC. However, limited data currently exists describing the efficacy of SBRT for downstaging HCC patients and facilitating OLT.

MATERIALS/METHODS

A single institution IRB approved prospective liver SBRT registry was surveyed for all patients outside of Milan criteria (1 lesion >5 cm; 2-3 lesions >3 cm) without vascular invasion or extrahepatic disease. Patients felt least likely to become OLT candidates with downstaging (age >80, >4 lesions, lesion >12 cm) were excluded. The primary endpoints were downstaging and OLT. Secondary endpoints were time to transplant, local control (LC), recurrence free survival (RFS) and overall survival (OS).

RESULTS

A total of 38 HCC patients with a median age of 65 years (range 28 - 80) met inclusion criteria. Median follow up was 14 months (IQR 3 - 35). At baseline, median KPS was 80 (range 60 - 100) with 16 Child-Pugh (CP) A (42%), 13 CP B (34%), and 9 CP C patients (24%). All patients were outside of Milan criteria and 25 patients (66%) were outside of UCSF criteria at time of SBRT. No patients had extrahepatic disease or vascular invasion. Median number of lesions, largest tumor size, and total sum of lesions were 2 (range 1 - 4), 5.0 cm (IQR, 4.0 - 6.5), and 6.6 cm (IQR 5.9 - 9.2), respectively. Prior to SBRT, 22 patients (58%) had received non-SBRT local therapy. At time of SBRT a variety of dose fractionation schedules were selected with a median BED10 of 78 (IQR 62 - 100). Concurrent sorafenib was used in 2 patients (8%). Following completion of SBRT, 21 patients (55%) were successfully downstaged at a median 3.0 months (IQR 1.9 - 6.1) after treatment, most frequently secondary to decrease in size of the largest lesion (86%). Twelve patients (32%) proceeded to undergo OLT at a median 7 months (IQR 3 - 14) after SBRT and 105 days (IQR 18 - 344) following successful downstaging. Of the 25 patients initially exceeding UCSF criteria, 7 (28%) underwent OLT. Among those receiving OLT, 5 patients (42%) remain alive without evidence of disease, 3 patients (25%) have recurred, 3 patients (33%) died within 2 years from transplant complications, and 1 patient (8%) died from an unrelated cause. LC at 2 years was 83%. Median RFS and OS for the overall cohort were 7 months (95% CI 0 - 21) and 24 months (95% CI 11 - 36), respectively. Among the transplant recipients, the median OS was 37 months (95% CI 30 - 44) compared to 15 months (95% CI 6 - 23) among those not receiving transplant.

CONCLUSION

With careful patient selection, liver SBRT serves as a feasible downstaging method to facilitate OLT in HCC patients.

Outcomes with Five Fraction Image-Guided Partial Breast Irradiation to Reduced Target Volumes

PURPOSE/OBJECTIVE(S)

The use of 5-fraction partial breast irradiation has been shown in a randomized trial to provide comparable rates of local control and reduced toxicities as compared to standard fractionation whole breast irradiation. The initial technique utilized a 2 cm expansion on the lumpectomy cavity (1 cm for clinical target volume [CTV], and 1 cm planning target volume [PTV]) without consistent image guidance (ex. cone beam computed tomography [CBCT]) or motion management recommendations. We present clinical outcomes using a 5-fraction image guided PBI technique (IG-PBI) to reduced target volumes for patients with early-stage breast cancer.

MATERIALS/METHODS

A retrospective review of an IRB approved institutional registry was performed to identify patients treated with IG-PBI. A total of 258 patients with early-stage breast cancer (Stage 0-IIA) receiving IG-PBI were identified. Patients received a dose of 30 Gy in 5 fractions delivered daily or every other day. An expansion of 1 cm on the lumpectomy cavity was used for those patients using deep inspiration breath hold (DIBH) while an expansion of 1.5 cm was utilized for those not using DIBH. All patients received daily CBCT. Plans were delivered using intensity-modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT) technique; while the prescription isodose line covered the PTV, the 26 Gy line was allowed to expand beyond the PTV. Kaplan-Meier analyses were used to assess rates of local control and survival. Patient demographics, stage, hormone therapy use, recurrence, mortality, and toxicity data were collected. Survival was analyzed with Kaplan-Meier curve.

RESULTS

Median age at diagnosis was 67 years (range 40-87) with a median follow-up of 29 months (IQR 22-40). Forty-six (18%) patients had in situ disease, 200 (78%) patients T1 tumors, and 12 (5%) patients had T2 tumors. Two hundred thirty-four (91%) patients were White, 15 (6%) were Black, and 9 (4%) were other races. One hundred ninety-six (76%) patients received endocrine therapy, and 16 (6%) patients received chemotherapy. Thirty-two (12%) patients developed grade 1 dermatitis and no grade 2 events were observed. One (0.4%) patient had a cardiac event (aortic stenosis) 19 months after breast radiotherapy. At last follow-up, one (0.4%) patient had a local recurrence and one (0.4%) developed a distant metastasis, with no regional nodal failures. Overall, 4 (1.5%) patients had died, all due to other causes. At 3 years, locoregional control was 99.4%.

CONCLUSION

Outcomes with IG-PBI demonstrate low rates of local recurrence and limited toxicity. The use of reduced target volumes is not associated with increased rates of local recurrence.

Meta-Analysis of Five Fraction Preoperative Radiotherapy for Soft Tissue Sarcoma

PURPOSE/OBJECTIVE(S)

There is increasing interest in shorter courses of radiation therapy (RT) in the management of soft tissue sarcoma (STS). Studies investigating preoperative ultra-hypofractionated 5-fraction RT for STS are few and often limited to single institution experiences with less than 50 patients. We therefore performed a meta-analysis to determine the efficacy and safety of preoperative 5-fraction RT for STS based on currently published literature, with an analysis evaluating effects of dose delivered.

MATERIALS/METHODS

This study level meta-analysis was conducted using Bayesian methods. Statistical estimation for risk of outcome rates were conducted by posterior mean and 95% highest posterior density (HPD) intervals. Studies with two-year local control (LC) and description of major wound complications (MWC) per the CAN-NCIC-SR2 study were included in this meta-analysis, and these served as the primary endpoints. Secondary endpoints included rates of acute and late toxicity. A total of ten studies were identified; seven met inclusion criteria (Kalbasi 2020, Kubicek 2021, Leite 2021, Spalek 2021, Gobo Silva 2021, Bedi 2022, Mayo 2022). Three studies (Kosela-Paterczyk 2014, Kosela-Paterczyk 2021, Potkrajcic 2021) did not include adequate information to accurately determine 2-year LC or MWC. Subgroup analyses were performed for ≥30 Gy vs <30 Gy as the EQD2 of 30 Gy in 5 fractions for an α/β of 3-4 is 50-54 Gy, equivalent to standard preoperative RT fractionation.

RESULTS

A total of 208 patients were included from seven studies. Five studies used ≥30 Gy (n = 144) and 2 studies <30 Gy (n = 64). The median follow-up was 29 months (range: 21-57). Primary tumor location was lower extremity in 68%, upper extremity in 22%, and trunk in 10%. In studies with available information, most tumors were intermediate (27%, 46/169) or high grade (67%, 114/169) and 50% (79/158) were >10 cm. Two-year LC for the entire cohort was 96.9% (95% HPD: 0.9374-0.9889) and the rate of MWC was 30.6% (95% HPD: 0.2106-0.4149). Acute grade 2 and 3 dermatitis was seen in 12.7% and 2.2%, respectively. Late grade 2 toxicities included fibrosis (11.1%), stiffness (6.0%), and lymphedema (4.0%) and late grade 3 toxicities included fibrosis (1.8%) and stiffness (0.4%). Grade 4 toxicity was rare and included fibrosis (0.6%) and stiffness (0.6%). There was a trend toward improved LC with ≥ 30 Gy (95% HPD: 0.949-0.997 vs 0.838-0.986). There was no difference in MWC (95% HPD: 0.185-0.420 vs 0.172-0.553) or late toxicity between the two groups. Acute grade 3 dermatitis was seen less frequently with regimens <30 Gy (95% HPD: 0-0 vs 0.009-0.072), however rare overall.

CONCLUSION

Preoperative 5-fraction RT for STS demonstrates excellent 2-year LC with MWC and toxicity similar to standard fractionation preoperative RT. Multi-institutional trials with a universal RT protocol and larger sample size are warranted to assess this novel treatment paradigm.

Five Fraction Accelerated Partial Breast Irradiation vs. Intraoperative Radiation Therapy for Early-Stage Breast Cancer

PURPOSE/OBJECTIVE(S)

Accelerated partial breast irradiation (APBI) represents an alternative to whole breast irradiation (WBI), reducing the target volume and potentially treatment duration. APBI delivered in 5 fractions with intensity modulated radiation therapy (IMRT) has been shown to have comparable outcomes to WBI with reduced toxicity profiles. In contrast, intraoperative radiation therapy (IORT) offers patients the potential to complete adjuvant radiation therapy in a single treatment. While early data were initially promising, concerns regarding long-term rates of local recurrence exist. We present a comparison of 5 fraction APBI versus IORT.

MATERIALS/METHODS

We performed a retrospective review of 473 patients with early-stage breast cancer (Stage 0-IIA) treated at a single institution with 258 receiving APBI and 215 IORT from October 2011 to May 2021. APBI patients received 30 Gy in 5 fractions delivered with IMRT daily or every other day. IORT patients received 20 Gy in 1 fraction prescribed to the applicator surface delivered at the time of surgery. Kaplan-Meier analysis was used to estimate locoregional control rates and overall survival among the 2 groups.

RESULTS

Mean age was 70.7 years old (IQR:67-74) for the IORT patients and 66.6 years old (IQR:62-72) for the APBI patients (p<0.001). Median follow up was 5.7 years for IORT patients and 2.4 years for APBI patients (p<0.001). For IORT patients, 11%/83.5%/5.5% of patients and for APBI 17.8%/77.5%/4.7% of patients had Tis/T1/T2 disease (p = 0.005). With regards to adjuvant therapies, 79%/76% of IORT/APBI patients were offered endocrine therapy (p = 0.50) and 1.4%/6.2% chemotherapy (p = 0.008). Recurrence at any time was seen in 7.9% (n = 17) of patients receiving IORT as compared to 0.8% (n = 2) of patients receiving APBI. APBI was however no differences in recurrence free survival (92.6% vs. 98.5%, p = .079) or overall survival were noted (92.8% vs. 95.1%, p = 0.99).

CONCLUSION

In a series of almost 500 patients with stage 0-IIA breast cancer, IORT was associated with higher rates of locoregional recurrence compared to APBI with no survival difference at 5 years. These outcomes, consistent with other series and current guidelines, suggest a limited role for IORT as monotherapy following breast conserving surgery.

Epithelial to mesenchymal transition (EMT) and airway remodelling after human lung transplantation

BACKGROUND

Aberrant epithelial repair is a key event in the airway remodelling which characterises obliterative bronchiolitis (OB) in the transplanted lung. The potential for airway epithelium from lung transplant recipients to undergo epithelial to mesenchymal cell transition (EMT) was assessed in culture and in vivo in lung allograft tissue.

METHODS

Change in epithelial and mesenchymal marker expression was assessed after stimulation with transforming growth factor beta(1) (TGF-beta(1)) alone or in combination with tumour necrosis factor alpha (TNFalpha) and compared with untreated controls. The ability of cells to deposit extracellular matrix, secrete matrix metalloproteinases (MMPs) and invade collagen was investigated. Immunolocalisation of epithelial and mesenchymal markers was compared in airway tissue from stable recipients and those with OB.

RESULTS

Untreated cells maintained epithelial morphology and phenotype. TGF-beta(1) reduced expression of epithelial markers, increased expression of vimentin and fibronectin, promoted collagen I and fibronectin deposition and increased MMP-9 production. Co-treatment with TNFalpha dramatically accentuated phenotypic and some functional features of EMT. Airway epithelial biopsies from recipients with OB demonstrated significantly increased staining for mesenchymal markers and significantly reduced E-cadherin staining compared with stable recipients.

CONCLUSIONS

These observations demonstrate the ability of human airway epithelium to undergo EMT and suggest this phenomenon may be a potential link between inflammatory injury and TGF-beta(1)-driven airway remodelling in the development of OB.

Airway epithelial cell senescence in the lung allograft

Chronic lung allograft dysfunction, manifesting as bronchiolitis obliterans syndrome (BOS), is characterized by airway epithelial injury, impaired epithelial regeneration and subsequent airway remodeling. Increased cellular senescence has been reported in renal and liver allografts affected by chronic allograft dysfunction but the significance of cellular senescence in the airway epithelium of the transplanted lung is unknown. Thirty-four lung transplant recipients, 20 with stable graft function and 14 with BOS, underwent transbronchial lung biopsy and histochemical studies for senescence markers in small airways. Compared to nontransplant control lung tissue (n = 9), lung allografts demonstrate significantly increased airway epithelial staining for senescence-associated beta galactosidase (SA beta-gal) (p = 0.0215), p16(ink4a) (p = 0.0002) and p21(waf1/cip) (p = 0.0138) but there was no difference in expression of these markers between stable and BOS affected recipients (p > 0.05). This preliminary cross-sectional study demonstrates that cellular senescence occurs with increased frequency in the airway epithelium of the lung allograft but does not establish any association between airway epithelial senescence and BOS. A prospective longitudinal study is required to better address any potential causal association between airway epithelial senescence in stable allograft recipients and the subsequent development of BOS.

Evaluation of a transcutaneous carbon dioxide monitor (“TOSCA”) in adult patients in routine respiratory practice

BACKGROUND

Non-invasive measurement of oxygenation is routine in adult clinical practice but transcutaneous monitoring of PCO(2) (PtcCO(2)) is used much less due to technical difficulties with earlier transcutaneous electrodes.

OBJECTIVE

Our aim was to determine the reliability of estimating arterial PCO(2) (PaCO(2)) using a recently introduced combined SaO(2)/PtcCO(2) monitor ("TOSCA", Linde Medical Systems) in adult patients in routine clinical respiratory practice.

METHODS

PtcCO(2) was measured in patients requiring arterial blood gases for clinical reasons. Ten minutes after the probe had been attached to an earlobe PtcCO(2) was recorded, immediately before arterial blood sampling. The PCO(2) values obtained were compared by Bland-Altman analysis.

RESULTS

Samples were taken from 48 unselected patients with varied pathology. There were no technical problems. Median age was 56 years (range 20-86 years). The mean difference between PaCO(2) and PtcCO(2) was -0.04kPa, sd of the difference 0.67kPa. Bland-Altman analysis showed generally good agreement between the two measurements across the range of PaCO(2) values (4-10.9kPa). Four of 48 measurements showed a PCO(2) difference >1kPa with no technical or clinical explanations apparent.

CONCLUSIONS

The accuracy of estimation of PaCO(2) by the TOSCA transcutaneous electrode was generally good and the device appears promising for use in routine clinical respiratory practice.

Palmitate potentiation of glucose-induced insulin release: a study using 2-bromopalmitate

The mechanisms whereby fatty acids (FA) potentiate glucose-induced insulin secretion from the pancreatic beta cell are incompletely understood. In this study, the effects of palmitate on insulin secretion were investigated in isolated rat islets. Palmitate did not initiate insulin secretion at nonstimulatory glucose concentrations, but markedly stimulated insulin release at concentrations of glucose > or = 5.6 mmol/L. At concentrations of palmitate > or =0.5 mmol/L, the important determinant of the potency of the FA was its unbound concentration. At total concentrations < or = 0.5 mmol/L, both the total and unbound concentrations appeared important. Surprisingly, 2-bromopalmitate did not affect palmitate oxidation, but significantly diminished palmitate esterification into cellular lipids. Neither methyl palmitate, which is not activated into a long-chain acyl-CoA ester, nor 2-bromopalmitate affected glucose-stimulated insulin release. Further, 2-bromopalmitate partly inhibited the potentiating effect of palmitate. These results support the concept that FA potentiation of insulin release is mediated by FA-derived signals generated in the esterification pathway.

Extramammary Paget's disease with diffuse involvement of the lower female genito-urinary system

Extramammary Paget's disease of the lower female genito-urinary system is an uncommon neoplasm with a high rate of recurrence. A 52-year-old white female with a history of extramammary Paget's disease, originally excised in 1985 by skinning vulvectomy and who had multiple recurrences, including two in a vaginal graft and with extension to the urethra and the uterine cervix, in 1992 underwent an anterior pelvic exenteration for control of the disease process. Standard surgical management for extramammary Paget's disease without invasion or without an underlying adenocarcinoma is simple or skinning vulvectomy. However, because the disease commonly recurs, diffuse involvement may require more extensive surgery including pelvic exenteration in extraordinary cases.

Successful transplantation of a kidney with early membranous nephropathy

This report describes a patient with end-stage renal disease secondary to long-standing type II diabetes mellitus who received a cadaveric renal transplant from a 37-year-old woman who died of massive cerebral infarction. An autopsy performed on the donor following organ procurement revealed no obvious contraindications to transplantation. A renal biopsy of the donor kidney performed at the time of transplantation, however, subsequently showed early membranous nephropathy by electron microscopy. There was immediate graft function and the recipient continues to have good renal function 3 years post-transplantation.

CRAHCA (Center for Research in Ambulatory Health Care Administration): member involvement leads to practical applications

The research undertaken by CRAHCA results in many new techniques and ideas being adopted by medical practice managers. However, it is not merely a one-way street. In this article, six group practice managers respond to questions about how they have used and been involved with research activities the Center has developed.

Making room in the marketplace: a special initiative for the poor

Faced with increased concern over the role of the voluntary healthcare sector, specifically Catholic providers, in the care of the poor, Mercy Health Services (MHS), a healthcare system, established a two-year, three-phase planning and development effort known as the Special Initiative for the Poor (SIP). Established in March 1986, SIP was designed to find out: Who are the poor? What are their needs? What is MHS's responsibility in meeting these needs? Among its objectives, SIP was charged with: 1. Educating and raising awareness of governance and management staffs. 2. Developing a way to assess human needs. 3. Determining the financial implications of the organization's commitment to the poor. 4. Recommending ways to enhance the understanding, energy, and commitment to the poor throughout the system. During the first six months, SIP staffers traveled to hospitals and subsidiaries throughout the system, meeting with management and staff, explaining the project, laying the groundwork, and gaining support. In the development phase, SIP created the Community Assessment of Human Needs, a systematic approach to identify and understand the unmet human needs of the poor. It also developed a simple inventory formula to help hospitals determine which of their programs were specifically for the poor and determine what these programs cost. Finally, in the implementation stage, several of SIP's recommendations are challenging the organization to move beyond its current commitments.

Forward locomotion elicited by electrical stimulation in the diencephalon and mesencephalon of the awake rat

Stimulation electrodes were implanted in 63 rats at a total of 208 sites in the diencephalon and midbrain. The sites were tested for elicited forward locomotion, i.e., alternate stepping of the forelimbs and/or hindlimbs, while the rats stood on a treadmill belt in a 27 X 9 X 24-cm chamber. Current levels of 50-300 microA and pulse frequencies of 50, 100 and 154 Hz were presented as single 5-sec trains and as 20 repetitive trains of 1-sec duration with a 3-sec intertrain interval. Locomotion was elicited with low current (50 or 100 microA) single trains at 28% of the sites. Of the regions sufficiently well sampled to warrent comparisons, two showed high densities of locomotion-positive sites with single low current trains. They were the medial hypothalamus (the dorsomedial and the posterior nuclei) and the ventral tegmental area. The medial forebrain bundle and the zona incerta were generally positive but many sites in these regions required repetitive trains. Among the regions with few locomotion-positive sites were the subthalamic nucleus, the fields of Forel and the habenular complex. In the dorsal midbrain, in and around the central gray, low current single trains elicited leaping. The results are discussed in terms of the existence of a delimited subthalamic locomotor region and a ventral midbrain locomotor system independent of a dorsal midbrain system.

Unilateral lesions of the anteromedial cortex in the rat impair approach to contralateral visual cues

This experiment determined the effects of large unilateral lesions of the anteromedial cortex (AMC) on visually guided performance of rats in a cross maze. Deficits were found in the approach to only visual cues that were located in the arm contralateral to the lesion. The deficit appeared in three testing conditions: when the cue was continuously visible throughout the trial; when it was visible only at the choice point; and when it was seen only at the start of the trial but not at the choice point. The failure to approach a contralateral cue was not due to a simple ipsilateral turning bias; rats with lesions could approach cues in the anterior arm as efficiently as controls. The deficit was most apparent on the initial sessions and recovery occurred for all conditions. The findings indicate that the AMC participates in the visual guidance of approach behavior.

Protrusio acetabuli in rheumatoid arthritis

Protrusio acetabuli is common is rheumatoid arthritis. Progression of this deformity can be measured by serial roentgenograms. The inward progression of the femoral head is the result of upward migration of the acetabular roof and collapse of the femoral head which appears to occur in a ratio of approximately two to one. Adrenal cortical steroids may play a significant role in the etiology of this condition in rheumatoid arthritis. This complication of intrapelvic protrusion of the prosthetic acetabulum following total hip replacement has been presented and suggestions made to overcome this problem. Early operation on those patients showing rapid development of protrusio may prevent complications.