Free-energy-based framework for early forecasting of stem cell differentiation.

Commitment of stem cells to different lineages is inherently stochastic but regulated by a range of environmental bio/chemo/mechanical cues. Here, we develop an integrated stochastic modelling framework for predicting the differentiation of hMSCs in response to a range of environmental cues, including sizes of adhesive islands, stiffness of substrates and treatment with ROCK inhibitors in both growth and mixed media. The statistical framework analyses the fluctuations of cell morphologies over approximately a 24 h period after seeding the cells in the specific environment and uses the cytoskeletal free-energy distribution to forecast the lineage the hMSCs will commit to. The cytoskeletal free energy which succinctly parametrizes the biochemical state of the cell is shown to capture hMSC commitment over a range of environments while simple morphological factors such as cell shape, tractions on their own are unable to correlate with lineages hMSCs adopt.

The homeostatic ensemble for cells.

Cells are quintessential examples of out-of-equilibrium systems, but they maintain a homeostatic state over a timescale of hours to days. As a consequence, the statistics of all observables is remarkably consistent. Here, we develop a statistical mechanics framework for living cells by including the homeostatic constraint that exists over the interphase period of the cell cycle. The consequence is the introduction of the concept of a homeostatic ensemble and an associated homeostatic temperature, along with a formalism for the (dynamic) homeostatic equilibrium that intervenes to allow living cells to evade thermodynamic decay. As a first application, the framework is shown to accurately predict the observed effect of the mechanical environment on the in vitro response of smooth muscle cells. This includes predictions that both the mean values and diversity/variability in the measured values of observables such as cell area, shape and tractions decrease with decreasing stiffness of the environment. Thus, we argue that the observed variabilities are inherent to the entropic nature of the homeostatic equilibrium of cells and not a result of in vitro experimental errors.

A thermodynamically motivated model for stress-fiber reorganization.

We present a model for stress-fiber reorganization and the associated contractility that includes both the kinetics of stress-fiber formation and dissociation as well as the kinetics of stress-fiber remodeling. These kinetics are motivated by considering the enthalpies of the actin/myosin functional units that constitute the stress fibers. The stress, strain and strain rate dependence of the stress-fiber dynamics are natural outcomes of the approach. The model is presented in a general 3D framework and includes the transport of the unbound stress-fiber proteins. Predictions of the model for a range of cyclic loadings are illustrated to rationalize hitherto apparently contrasting observations. These observations include: (1) For strain amplitudes around 10 % and cyclic frequencies of about 1 Hz, stress fibers align perpendicular to the straining direction in cells subjected to cyclic straining on a 2D substrate while the stress fibers align parallel with the straining direction in cells constrained in a 3D tissue. (2) At lower applied cyclic frequencies, stress fibers in cells on 2D substrates display no sensitivity to symmetric applied strain versus time waveforms but realign in response to applied loadings with a fast lengthening rate and slow shortening. (3) At very low applied cyclic frequencies (on the order of mHz) with symmetric strain versus time waveforms, cells on 2D substrates orient perpendicular to the direction of cyclic straining above a critical strain amplitude.

Simulation of the cytoskeletal response of cells on grooved or patterned substrates.

We analyse the response of osteoblasts on grooved substrates via a model that accounts for the cooperative feedback between intracellular signalling, focal adhesion development and stress fibre contractility. The grooved substrate is modelled as a pattern of alternating strips on which the cell can adhere and strips on which adhesion is inhibited. The coupled modelling scheme is shown to capture some key experimental observations including (i) the observation that osteoblasts orient themselves randomly on substrates with groove pitches less than about 150 nm but they align themselves with the direction of the grooves on substrates with larger pitches and (ii) actin fibres bridge over the grooves on substrates with groove pitches less than about 150 nm but form a network of fibres aligned with the ridges, with nearly no fibres across the grooves, for substrates with groove pitches greater than about 300 nm. Using the model, we demonstrate that the degree of bridging of the stress fibres across the grooves, and consequently the cell orientation, is governed by the diffusion of signalling proteins activated at the focal adhesion sites on the ridges. For large groove pitches, the signalling proteins are dephosphorylated before they can reach the regions of the cell above the grooves and hence stress fibres cannot form in those parts of the cell. On the other hand, the stress fibre activation signal diffuses to a reasonably spatially homogeneous level on substrates with small groove pitches and hence stable stress fibres develop across the grooves in these cases. The model thus rationalizes the responsiveness of osteoblasts to the topography of substrates based on the complex feedback involving focal adhesion formation on the ridges, the triggering of signalling pathways by these adhesions and the activation of stress fibre networks by these signals.

[Liver trauma due to penetrating lesions: miscellanea, personal case series, clinical and CT findings]. / Traumi epatici da lesioni penetranti. Miscellanea, casistica personale, aspetti clinici e con Tomografia Computerizzata.

PURPOSE: Penetrating liver wounds are related to many causes and rank second after blunt abdominal and liver trauma. We will report the clinical and radiological findings of our personal series of patients with penetrating trauma, especially by firearms and stab and cut wounds. We will also try to define the diagnostic workup of these traumas, which is especially based on CT signs of liver damage and associated changes and which is of basic importance for following treatment, both surgical or conservative. MATERIAL AND METHODS: In the last seven years we retrospectively reviewed 31 cases of penetrating liver trauma. The patients were 19 men and 12 women, ranging in age 18 to 73 (mean 42), with penetrating liver injuries from firearms (16 patients) and stab (9 cases) wounds; 6 patients had injuries from different causes. Abdominal CT was carried out in emergency with the CT Angiography (CTA) technique in all patients. In the patients with suspected chest and abdomen involvement CT was performed from the mid-chest for accurate assessment of diaphragm and lung bases and to exclude associated pleuropulmonary damage. RESULTS: Penetrating liver wounds were caused by firearms in 70% of cases, by stabbing in 12% and, in the extant 18%, by other causes such as home accidents, road and work traumas, and liver biopsy. In our series, the liver was most frequently involved, especially by firearms wounds; in our 16 cases the most frequent injuries were hemorrhagic tears. We found bullets in the liver in 6 cases. In one case of home accident the patient wounded himself while slicing bread with a long knife, which cut into the anterior abdominal wall and tore the anterior liver capsule, as seen at CTA. DISCUSSION AND CONCLUSIONS: Penetrating wounds to liver and abdomen are less frequent than those to the chest. In the past decade the use of CT has changed the diagnostic and therapeutic approach to such injuries completely, decreasing the resort to explorative laparotomy and hepatorrhaphy. Indeed, CT provides a clear picture of the extent and severity of damage, which permits to choose a conservative treatment in case of intraparenchymal hematomas and lacerocontusive foci without hemoperitoneum, which can be followed-up with physical and CT examinations. Moreover, Helical CT could provide the early diagnosis of active bleeding in the peritoneum and of focal bleeding in the liver, thus permitting prompt hepatorrhaphy or targeted hepatectomy. A diaphragm injury suspected at CT should always prompt the surgeon to intervention, especially when hemothorax, lung base pneumothorax, large liver hematoma or tear of the liver dome are associated. Finally, subdiaphragmatic free gas indicates gut perforation associated with liver damage, in which case surgery is necessary too.

Results of radical perineal prostatectomy with adjuvant brachytherapy.

Retrospective analysis of outcome in 137 patients who underwent radical perineal prostatectomy and bilateral injection of gold-198 implants into the periprostatic tissues and/or neurovascular pedicles as treatment for prostatic adenocarcinoma was performed. Patients had undergone treatment between 1975 and 1985. Local recurrence developed in 22 patients (16.1%) and distant metastases developed in 33 (24.1%). Clinical and surgical staging of disease and Gleason grading of pathologic specimens were performed retrospectively. Kaplan-Meier local recurrence, freedom from relapse (FFR), and survival rates decreased with increasing stage and pathologic grade. With clinical staging, these rates were not statistically different from previous rates achieved with external beam radiation therapy, and with pathologic staging, they were not statistically different from previous rates achieved with prostatectomy. The authors conclude that (a) 5-year follow-up is inadequate to determine local control rates after prostatectomy; (b) use of implants did not improve local control, FFR, or survival rates of 10 years; and (c) method of staging probably has more effect on local control, FFR, and survival rates than does treatment modality.

Extended field irradiation for carcinoma of the uterine cervix with positive periaortic nodes.

Forty-three patients were treated with extended field irradiation for periaortic metastasis from carcinoma of the uterine cervix (FIGO stages IB-IV). Twelve patients (28%) remained continuously free of disease to the time of analysis or death from intercurrent disease, 20 (46%) had persistent cancer within the pelvis, 11 (26%) had persistent periaortic disease, and 23 (53%) developed distant metastasis. The actuarial 5-year survival rate was 32%. The results correlated well with the periaortic tumor burden at the time of irradiation. None of 19 patients (0%) with microscopic or small (less than 2 cm) periaortic disease had periaortic failures, compared to 29% (4/14) of those with moderate-sized (2-5 cm) disease and 70% (7/10) of those with massive (greater than 5 cm) periaortic metastasis. Similarly, the 5-year survival rates were 50% (6/12) with microscopic disease, 33% (2/6) with small gross disease, 23% (3/13) with moderate-sized disease, and 0% (0/10) with massive periaortic metastases. Only 10% (1/10) of patients whose tumor extended to the L1-2 level survived 5 years, compared with 31% (9/29) of those whose disease extended no higher than the L3-4 level. The periaortic failure rates correlated to some extent with the dose delivered through extended fields, although the difference was not statistically significant. Only 8% (1/13) of those who had undergone extraperitoneal lymphadenectomies developed small bowel complications, compared with 25% (7/29) of those who had had transperitoneal lymphadenectomies. The incidence of small bowel obstruction was 8% (1/13) following periaortic doses of 4000-4500 cGy, 10% (1/10) after 5000 cGy, and 32% (6/19) after approximately 5500 cGy. From this, we concluded that the subset of patients who would benefit most from extended field irradiation are those in whom the residual disease in the periaortic area measures less than 2 cm in size at the time of treatment, whose disease extends no higher than L3, and whose cancer within the pelvis has a reasonable chance of control with standard radiation therapy techniques.

A comparison of the roles of surgery and radiation therapy in the management of carcinoma of the female urethra.

Between 1939 and 1986, 42 patients with carcinoma of the female urethra were treated with surgery and/or radiation therapy at the University of Iowa. Ten patients were treated with surgery alone, 28 with radiation therapy alone, and 4 with combined surgery and radiation therapy. Seventeen patients (40%) developed persistent or recurrent disease at the primary site and 15 (36%) had failures in the inguinal nodes. The actuarial 5-year survival rate was 33.5%. Only 36% (10/28) of patients treated with radiation therapy had local failures, compared to 60% (6/10) of those treated with surgery alone. The best results were achieved with combined interstitial and external beam irradiation. Whereas 57% (8/14) of patients who were treated with combined interstitial and external beam irradiation were alive NED at 3 years, none of 7 patients (0%) treated with interstitial implants only and 2 of 7 patients (29%) treated with external beam irradiation alone were alive NED at 3 years. There was a significantly lower inguinal failure rate in patients who received treatment to the inguinal nodes (10%) than in those who did not receive inguinal area treatment (52%), and this translated into a superior 5-year survival for those patients (60% vs 18%). Survival rates did not correlate with histopathologic type in this series, although there were differences in the patterns of failure. Survival rates did correlate well with clinical stage.

The role of radiation therapy in the management of ependymomas of the spinal cord.

Twenty patients with biopsy-proven ependymomas of the spinal cord were treated between 1960 and 1984-7 with surgery only, 3 with radiation therapy only, and 10 with surgery and postoperative radiation therapy. Of these, 2 patients developed recurrent tumor at the primary site, 3 developed a recurrent tumor in the thecal sac, and 1 developed distant metastasis. The absolute 5- and 10-year survival rates were 95% (19/20) and 86% (12/14), respectively. None of 13 patients who were treated with radiation therapy only or combined surgery and postoperative radiation therapy developed recurrent tumor at the primary site, and none of 7 patients who received thecal sac irradiation developed thecal sac recurrences. In contrast, 2 of 7 patients (29%) treated with surgery alone developed recurrent tumor at the primary site, and 3 of 13 patients (23%) who received no thecal sac irradiation developed a recurrent tumor in the thecal sac. The failure rates following surgery were greatest in patients who had tumor removed in a piecemeal fashion (43%, 6/14). The results show that radiation therapy is probably not necessary if the tumor has been removed completely in an en bloc fashion. However, radiation therapy is needed if the tumor has been incompletely removed or removed in a piecemeal fashion. If the tumor has been removed in a piecemeal fashion, the radiation portals should be extended to include the thecal sac. Histologic subtypes influenced the pattern of recurrence. Myxopapillary ependymomas and high grade cellular ependymomas appear to be more likely to recur in the thecal sac. However, no big difference could be detected in local recurrence.

Preliminary results of a pilot study of pentoxifylline in the treatment of late radiation soft tissue necrosis.

Between September 1988 and August 1989, 12 patients with 15 sites of late radiation necrosis of the soft tissues were treated with pentoxifylline, a hemorrheologic agent that has been used to treat a variety of vasculo-occlusive disorders. Four of these necroses were located in the oromucosa, four in the mucosa of the female genitalia, and seven in the skin. At the time of analysis, 87% (13/15) of the necroses had healed completely, and one was partially healed. Furthermore, the time-course of healing with pentoxifylline was significantly less than the duration of nonhealing prior to pentoxifylline (average: 9 weeks vs 30 1/2 weeks). All patients had pain relief. These results indicate that pentoxifylline can contribute to the healing of soft tissue radiation necrosis. They also support the concept that late radiation injury in skin and mucosa is at least partly due to vascular injury.

The role of radiation therapy in the treatment of solitary plasmacytomas.

Between 1960 and 1985, 30 patients with solitary plasmacytomas were treated with radiotherapy at the University of Iowa: 13 patients with extramedullary plasmacytomas (EMP) and 17 with solitary plasmacytomas of bone (SPB). The local control rates were 92% for patients with EMP and 88% for those with SPB. Two of nine patients (22%) with EMP treated to the primary tumor only developed regional lymph node metastasis, indicating the need for elective irradiation of this area. The most common pattern of failure in both groups was progression to multiple myeloma. This occurred in 23% of the patients with EMP and 53% of those with SPB. The time course of progression to multiple myeloma differed for the two groups. All of those who progressed to multiple myeloma in the EMP group did so within 2 years, whereas a significant number of those in the SPB group progressed more than 5 years after initial therapy. None of five patients who received adjuvant chemotherapy in the SPB group progressed to multiple myeloma, compared to 75% (9/12) of the patients who did not receive chemotherapy.

The prevalence and severity of late effects in normal rat duodenum following intraoperative irradiation.

In humans, a portion of the duodenum is often at risk for radiation-induced complications following intraoperative radiation therapy for pancreatic carcinoma. To determine experimentally the prevalence and severity of late effects in the normal mammalian duodenum, 190 rats received single doses of 0, 15, 20, 25, 30, or 40 Gy orthovoltage X rays to temporarily exteriorized 3 cm circumferential segments of duodenum. The animals were killed 2, 6, 8, or 10 months later. Actuarial survival, change in body weight, and a radiation injury score based on eight histopathologic alterations were used as endpoints. Epithelial atypia, intestinal wall fibrosis, serosal thickening, and vascular sclerosis were the dominant histopathologic alterations at all dose levels throughout the 10-month observation period. The prevalence and severity of histologic radiation injury showed sigmoidal dose-response relationships with the plateaus starting at 20 Gy. Doses of 20 Gy or greater also resulted in a substantial loss of body weight and a high level of early deaths (20-80 days). All endpoints indicate that intraoperative doses of 20 Gy or greater are associated with unacceptable risks of late and irreversible complications.

The role of kilovoltage irradiation in the treatment of keloids.

This is a retrospective analysis of the results of kilovoltage irradiation given to prevent the regrowth of 203 keloids excised at the University of Iowa Hospitals and Clinics, Iowa City, Iowa, Lutheran Hospital in Moline, Illinois, and Mercy Hospital in Cedar Rapids, Iowa. We found that a minimum follow-up of 1 year is needed to evaluate the results of post-excisional kilovoltage x-ray therapy. A dose versus response effect was also observed. Although it is desirable to use the lowest possible dose of radiation that is likely to be effective, the likelihood of failure is too great to justify the routine use of doses of less than 900 cGy regardless of how they are fractionated or when they are given. It appears that the total dose of irradiation that is given to prevent the regrowth of an excised keloid is more important than when irradiation is started, the size of the largest fraction given, whether the irradiation is completed in 1 week or 3, or where the keloid has grown. When a small number of keloids were irradiated less than 1 year after they first appeared greater than or equal to 1500 cGy were sufficient to control 90% of them without re-excision.

A comparison of the roles of surgery and radiation therapy in the management of craniopharyngiomas.

Fifty-two patients with craniopharyngioma were seen between January 1961 and July 1986. Of these, 40 were treated with surgery alone, 8 with surgery and postoperative radiotherapy, and 3 with radiotherapy alone. One patient received no treatment. For the group treated with surgery alone, 33% (13/40) had local tumor control, 42.5% (17/40) developed major complications, and 71% (25/35) survived 5 years. With surgery and postoperative radiotherapy, 100% (8/8) had local tumor control, 25% (2/8) developed major complications, and 100% (7/7) survived 5 years. Two of the three patients treated with radiotherapy alone had local tumor control and the third was salvaged with surgery. The "complete resection" rate for 32 patients treated with radical surgery was 63% (20/32). Tumor control was achieved in 50% (10/20) of the patients treated with "complete resection" without radiotherapy, in 15% (3/20) of the patients treated with "incomplete resection" without radiotherapy, and in 100% (8/8) of the patients treated with "incomplete resection" and postoperative radiotherapy. In this series, doses of 5000-5500 cGy were as effective in achieving control as 5500-6000 or 6000-7000 cGy.

Primary malignant lymphoma of the mandible.

From 1945 through 1985, 32 cases of primary lymphoma of bone were treated at the University of Iowa Hospitals and Clinics. Sixteen cases (50%) demonstrated the lesion in the long tubular bones with a predilection for the lower and upper extremities. The frequently involved flat bones (six cases) were the bones of the pelvis. There were only three cases (9%) where the mandible was the primary site. In this report, the literature is reviewed and three cases with primary lymphoma of the mandible are presented.

Intraoperative irradiation in a rat model: histopathological changes in irradiated segments of duodenum.

During intraoperative radiation therapy for carcinoma of the head of the pancreas in humans, a portion of duodenum is often at risk for radiation-induced complications because of its fixed anatomical position within the treatment field. This study was undertaken to determine the feasibility of using the rat as a model to determine the radiotolerance of normal mammalian duodenum. The procedures used to exteriorize and irradiate a selected segment of duodenum are described. Histopathologic changes in 5-cm segments of midduodenum were studied 14 and 28 days after 0, 30, 40, or 50 Gy X-radiation. Complete denudation of the epithelium and thickening of the muscularis and serosal layers occurred in all irradiated segments by day 14. By day 28, even though crypt and villus architectures were atypical, large areas of epithelial regeneration were seen in rats receiving 30 Gy. In contrast, complete denudation of the epithelium were still evident along most of the length of the irradiated segments in rats receiving 40 or 50 Gy. Serosal fibrosis was prominent in all irradiated animals, regardless of dose. These results indicate that radiation doses above 30 Gy carry high risks of complications. The rat is considered a suitable animal model.

Chemodectoma of the temporal bone: a comparison of surgical and radiotherapeutic results.

Between January 1950 and December 1981, 32 patients with chemodectomas of the temporal bone were treated at the University of Iowa Hospitals and Clinics. Thirteen patients were treated with surgery alone, 15 with radiation therapy alone, one with preoperative radiation therapy and surgery, and three with surgery and postoperative radiation therapy. In general, the patients treated with radiotherapy alone or combined therapy (radiotherapy group) had more advanced tumors than those treated with surgery alone (surgery group). For the surgery group, the initial local control rate was 46% and the ultimate local control rate 84% following salvage with additional surgery, 31% developed complications, and 78% survived 10 years. For the radiotherapy group, 84% had local tumor control, 11% developed complications, and 77% survived 10 years. These results demonstrate that radiation therapy is an effective treatment modality for chemodectomas of the temporal bone.

Inoperable adenocarcinoma of endometrium: radiation therapy.

Between 1960 and 1979, 41 patients with adenocarcinoma of the endometrium who were poor surgical risks were treated with radiation therapy at the University of Iowa. Local tumor control was achieved in 78% of the patients, 5% manifested complications, and 46% survived 5 years ("uncorrected" 5-year survival rate). Intercurrent disease was the major cause of death (54%), and intrauterine recurrence (22%) was the most frequent recurrence. Intraperitoneal spread (12%) occurred as commonly as hematogenous metastases (12%). Three of nine local failures occurred after 5 years. Local control rates correlated well with clinical stage, and the survival rates correlated well with the stage and grade of the tumor. Local tumor control was achieved in 95% of patients who received greater than 7,000 mg-h intracavitary radium, compared with 63% of patients treated with less than 7,000 mg-h.