In vitro characterization of mesenchymal stem cell-seeded collagen scaffolds for tendon repair: effects of initial seeding density on contraction kinetics.

Mesenchymal stem cells (MSCs) were isolated from bone marrow, culture-expanded, and then seeded at 1, 4, and 8 million cells/mL onto collagen gel constructs designed to augment tendon repair in vivo. To investigate the effects of seeding density on the contraction kinetics and cellular morphology, the contraction of the cell/collagen constructs was monitored over time up to 72 h in culture conditions. Constructs seeded at 4 and 8 million cells/mL showed no significant differences in their gross appearance and dimensions throughout the contraction process. By contrast, constructs seeded at 1 million cells/mL initially contracted more slowly and their diameters at 72 h were 62 to 73% larger than those seeded at higher densities. During contraction, MSCs reoriented and elongated significantly with time. Implants prepared at higher seeding densities showed more well aligned and elongated cell nuclei after 72 h of contraction. Changes in nuclear morphology of the MSCs in response to physical constraints provided by the contracted collagen fibrils may trigger differentiation pathways toward the fibroblastic lineage and influence the cell synthetic activity. Controlling the contraction and organization of the cells and matrix will be critical for successfully creating tissue engineered grafts.

Prognostic significance of intraperitoneal free cancer cells obtained by laparoscopic peritoneal lavage in patients with gastric cancer.

Laparoscopy is a safe and useful method for examining the local extent and regional spread of disease in patients with gastric cancer. Peritoneal dissemination remains a frequent type of recurrence after surgical treatment. The aim of this study was to determine the prognostic value of intraperitoneal free cancer cells (IFCCs) detected by laparoscopic peritoneal lavage. Forty-nine patients with advanced gastric cancer underwent laparoscopy with cytologic examination for staging. Peritoneal lavage was performed when ascites was not present. Aspirated fluid from the peritoneal cavity was centrifuged and subjected to cytologic examination using Giemsa and Papanicolaou staining methods. Patients were surgically treated and followed for a minimum of 5 years. IFCCs were detected in 41% of the patients. In eight cases (16.3%) laparoscopy revealed carcinomatosis and/or multiple liver metastases, so laparotomy was not performed. Patterns of recurrence after curative resection included the following: peritoneal (n = 3), local (n = 4), liver (n = 1), and other (n = 1). All patients who tested positive for IFCCs had peritoneal recurrence. The absence of IFCCs was associated with improved overall survival (21 months for a 95% confidence interval of 7.4 to 34.6 vs. 4 months for a 95% confidence interval of 2.4 to 5.6). Overall survival adjusted for type of resection also demonstrated a favorable outcome for patients who were negative for IFCCs. The following conclusions were drawn: (1) laparoscopic peritoneal lavage cytology may be useful in identifying patients at high risk for peritoneal relapses and may alter treatment, and (2) lFCCs provide additional prognostic information in patients with gastric cancer.

Value of peritoneal lavage cytology during laparoscopic staging of patients with gastric carcinoma.

Forty-nine consecutive patients with advanced gastric carcinoma underwent preoperative staging by laparoscopy between June 1991 and June 1992. Peritoneal lavage with cytologic examination was performed when ascites was not present. In eight cases (16.3%), laparoscopy revealed carcinomatosis and/or multiple hepatic metastases, so laparotomy was not performed. Intraperitoneal free cancer cells (IFCCs) were detected in 41% of patients (65% in patients with ascites and 28% by peritoneal lavage). In the absence of macroscopic peritoneal dissemination, IFCCs were encountered in 29% of patients. IFCCs were present only when invasion of the gastric serosa was >3 cm2 or when adjacent organs and structures were already invaded. Mucinous adenocarcinoma, Borrmann class IV tumors, and Stage IV patients had higher incidence of IFCCs. Cytologic results were similar at laparoscopy and laparotomy (p > 0.05). Therefore, cytologic evaluation of peritoneal lavage added sensitivity to laparoscopy in assessing patients with advanced gastric carcinoma and may alter their therapeutic approach.

Chemotherapy with MECOP-B for intermediate-grade and high-grade non-Hodgkin's lymphoma in Saudi Arabia: clinical results and analysis of prognostic factors.

Between August 1985 and January 1994, 73 evaluable adult patients with bulky localized or advanced-stage, intermediate- and high-grade de novo non-Hodgkin's lymphoma (NHL) were treated with MECOP-B (methotrexate and leucovorin rescue, epirubicin, cyclophosphamide, vincristine, prednisone, and bleomycin). Over a median follow-up of 32 months (range, 4-98 months), 55 patients (75%) achieved complete remission (CR) (95% confidence interval, 81-69%) and 3 attained partial remission (PR) (4%) for an overall response rate of 79%. Using a multiple regression analysis where the dependent variable was response to therapy (CR vs. PR + treatment failure), poor performance status, and the presence of a bulky disease were negatively associated with the likelihood of achieving CR. Survival analysis showed that 49 (67%) patients (95% confidence interval, 74 and 60%) were alive, of whom 47 (64%) were disease-free. While the median survival has not been reached, the actuarial survival probability at 5 years +/- SE was 64 +/- 6%. Time to treatment failure for those attaining CR was also estimated. While the median survival has not been reached, probability of freedom from treatment failure at 5 years +/- SE was estimated as 74 +/- 7%. However, the long-term CR (CR rate times disease-free survival rate) was only 48%, and the 'measurement of efficacy' was 53%. These results were inferior to those from our earlier reports. The proportional hazards model of Cox identified poor performance status, older age, and high lactate dehydrogenase as factors with an adverse effect on survival. Using the results of the model, patients were categorized into three predefined risk groups with significant differences in outcome. Toxicity of the regimen was high, but comparable to that reported in the literature with a toxic death rate of 8%. We conclude that MECOP-B is an effective therapy for patients with aggressive NHL; however, based on the current results as compared with our earlier analysis, besides the emergence of prognostic factors, therapy of NHL should be individualized. Less expensive, less toxic regimens should be used for lower-risk patients, while the use of more intense, more toxic, more expensive programs should only be offered to those with a predicted poor outcome.

Flow cytometric surface light chain analysis of lymphocyte-rich effusions. A useful adjunct to cytologic diagnosis.

The cytologic diagnoses in 49 body cavity fluids from 46 patients, of whom 30 had a clinical diagnosis of lymphoma or lymphatic leukemia, and 16 patients with benign inflammatory or reactive conditions, were compared to flow cytometric surface immunoglobulin light chain analysis (kappa-lambda analysis [KLA]). The results of both tests were correlated with clinical outcome and all available information from biopsy, autopsy, and additional cell marker studies. When the diagnoses by both cytologic analysis and KLA were in agreement (57.1% of cases), there were no false-negative or false-positive results. Overall, false-positive and false-negative rates were, respectively, 6.1% and 12.2% with cytologic study, and 4.1% and 4.1% with KLA. Sixteen samples were from patients with small lymphocytic lymphoma (CLL) and small cleaved lymphoma, which had a false-negative rate of 37.5% by cytologic study, and only 6.2% by KLA. There was one false-positive result by KLA among the benign effusions. These findings indicate that KLA is a powerful adjunct to the cytologic evaluation of lymphocyte-rich effusions, especially in cases of lymphoproliferative disorders characterized by small lymphocytes, in which the cytologic diagnosis is frequently difficult.

Pseudoangiomatous hyperplasia of mammary stroma. Some observations regarding its clinicopathologic spectrum.

Pseudoangiomatous hyperplasia of mammary stroma (PHMS) is a benign proliferation of keloid-like fibrosis, containing slit-like pseudovascular spaces. Its main importance is its distinction from angiosarcoma; however, the clinicopathologic spectrum of PHMS remains incompletely described. We report two new cases and describe our findings in 200 consecutive breast specimens evaluated for the presence of PHMS. The first patient presented with peau-de-orange change in the overlying breast skin, thus mimicking inflammatory breast carcinoma. Furthermore, this patient's PHMS lesion had been diagnosed and treated inappropriately as a low-grade angiosarcoma. The second case showed the more typical, fibroadenoma-like presentation of PHMS. In addition, PHMS changes occur commonly in routine breast biopsy specimens. In fact, our review of 200 consecutive breast specimens showed PHMS in at least one microscopic focus in 23% of cases. The PHMS changes occurred in younger patients than the control population and were associated with fibrocystic changes, in fibroadenomas, in gynecomastia, in normal breast tissue, and in sclerosing lobular hyperplasia. Ultrastructural and immunohistochemical studies of one case showed that the capillary-like spaces were either acellular or lined by fibroblasts. Pseudoangiomatous hyperplasia of mammary stroma represents a clinicopathologic spectrum, extending from focal, insignificant microscopic changes to cases where PHMS produces a breast mass. Increased awareness of PHMS and its clinicopathologic spectrum will allow its differentiation from other vascular tumors of the breast, especially low-grade angiosarcoma.

Atypical cysts and carcinomas of the kidneys in the phacomatoses. A quantitative DNA study using static and flow cytometry.

Reported are the pathologic features of atypical cysts and/or renal cell carcinomas found in the kidneys of four patients having either tuberous sclerosis or Hippel-Lindau disease. In addition, cellular DNA contents of the cells lining the atypical cysts and comprising the carcinomas were quantitated using both static and flow cytometric techniques. These studies showed that cysts lined by atypical epithelial cells are frequently present in renal parenchyma adjacent to the renal carcinomas, and that the cytologic features of atypical cells lining the cysts were essentially the same as the cytologic features found in the adjacent well-differentiated, renal cell carcinomas. DNA quantitative studies revealed that both the renal cell carcinomas and the atypical cyst lining cells had the same DNA indices and were essentially DNA euploid. In this patient group these findings are consistent with the hypothesis that the atypical cyst lining cells evolve into the renal cell carcinomas; however, they do not prove this proposed but likely sequence.

The effect of altered thyroid status on lipid metabolism in Nubian goats.

The effects of triiodothyronine (T3)-induced hyperthyroidism and of carbimazole (CZ)-produced hypothyroidism on lipid metabolism were studied in Nubian goats (Capra hircus). T3 treatment decreased the serum, liver and heart triglyceride, cholesterol and phospholipid concentrations. These changes were accompanied by an increase in the activity of lipoprotein lipase (LPL) in the heart and skeletal muscles. CZ treatment at a dose of 90 mg/goat significantly increased the serum triglyceride, liver cholesterol and heart phospholipid. CZ treatment significantly increased the liver and heart triglyceride concentration but the activity of LPL was not affected.