Irregular Growth Pattern Research Articles

Transciliary Supraorbital Approach (Eyebrow Approach) for Resection of Retrochiasmatic Craniopharyngiomas: An Alternative Approach, Case Series, and Literature Review

Craniopharyngiomas are known for an irregular growth pattern and extension into the retrochiasmatic space with adherence to adjacent structures. We describe the use of the transciliary supraorbital approach (eyebrow approach) for resection of craniopharyngiomas with retrochiasmatic extension. Our clinical database was reviewed to identify operative cases of craniopharyngiomas between July 1998 and January 2011. Only patients who had retrochiasmatic extension and underwent an eyebrow approach were included in this analysis. Endoscopy was used to aid surgical resection at the discretion of the surgeon. Six patients were identified (three from a retrospective review and three during the course of prospective follow-up evaluation). The group included three men and three women (mean age: 41.2 years; range: 28-57 years). All patients had visual and hormonal deficits at presentation. Complete resection was achieved in four patients. Endoscopic assistance was used in three patients. Opening of the frontal sinus occurred in two cases during surgery; an additional surgical procedure was required for repair of a cerebrospinal fluid leak in one of these cases. The duration of clinical follow-up ranged from 18 to 97 months. All patients had excellent cosmetic results, visual improvement to a serviceable level, and a Karnofsky performance scale score ≥ 80. The eyebrow approach is safe for resection of craniopharyngiomas with retrochiasmatic extension. This approach offers a reasonable surgical corridor for resection of the retrochiasmatic tumor component and can be enhanced using endoscopic assistance.

Status and symptomatology of early blight (Alternaria solani) of potato (Solanum tuberosum L.) in Kashmir valley

Alternaria leaf blight is one of the most important diseases of potato (Solanum tuberosum L.) worldwide. The disease was prevalent in all the potato growing areas of Kashmir valley surveyed during 2009 and 2010. The overall mean disease incidence and intensity ranged from 24.54 to 28.23% and 13.84 to 15.98%, respectively. The highest disease incidence (39.09%) and intensity (22.54%) was recorded in district Budgam. The lowest level of disease was in district Shopian (14.89 and 8.05%, respectively). The pathogen associated with the disease was identified as Alternaria solani (Ellis and Martin) Jones and Grout. In early stages of disease development, small irregular to circular dark brown spots on lower leaves appear, measuring 0.5 mm in size. Upto fourth week of June concentric rings form as a result of irregular growth patterns by the organism in the leaf tissue giving the lesion a characteristic ‘target spot’ or ‘bulls eye’ appearance. The maximum lesion size 7.4 mm was recorded in the second week of August. Key words: Potato, Alternaria solani, survey, disease incidence, symtomatology.

Converging paths to progress for skull base chordoma: Review of current therapy and future molecular targets

Background:Chordomas of the skull base are rare locally aggressive neoplasms with a predilection for encapsulating critical neurovascular structures, bony destruction and irregular growth patterns, and from which patients succumb to recurrence and treatment failures.Methods:A review of the medical literature is performed, using standard search engines and identifying articles related to skull base chordomas, surgery, radiation therapy, chemotherapy, molecular genetics, and prospective trials.Results:A synthesis of the literature is presented, including sections on pathology, treatment, molecular genetics, challenges, and future directions.Conclusion:Beyond an understanding of the current treatment paradigms for skull base chordomas, the reader gains insight into the collaborative approach applied to orphan diseases, of which chordomas is a prime exemplar.

Growth Patterns of Dusky Pygmy Rattlesnakes (Sistrurus miliarius barbouri) from Central Florida

Abstract: We studied growth in snout–vent length (SVL) and body mass of Dusky Pygmy Rattlesnakes (Sistrurus miliarius barbouri) in Volusia County, Florida, with the use of mark–recapture techniques. Between February 1992 and December 2000, we PIT-tagged (Passive Integrated Transponder) 665 individuals of approximately 1 yr of age or greater that were subsequently recaptured at least once. Because snakes can be definitively aged at 1 yr, this resulted in a large sample of snakes of known age that were followed for up to 7 yr. Seventy-five of these individuals PIT tagged at 1 yr were identified from photographs of neonates born in captivity, allowing us to relate adult growth to neonate traits. Our data suggest that Pygmy Rattlesnakes in central Florida exhibit highly variable patterns of growth that are related to a mild climate that allows feeding and growth throughout the year, and to a fluctuating prey base that results in irregular growth patterns often unlike those predicted by typical growth equatio...

Hyperplastic Luschka Ducts

Ducts of Luschka are a developmental abnormality found within the gallbladder fossa in up to 10% of cholecystectomy specimens. They are most often encountered by surgeons when injured during laparoscopic or open cholecystectomy, leading to bile leakage and subsequent peritonitis. Histologically, they are typically composed of lobular aggregates of small ductules lined by bland, cuboidal-to-columnar biliary-type epithelium, associated with centrally located, larger ductules surrounded by concentric fibrosis. We have identified 6 cases of florid Luschka duct proliferation in which the ductules demonstrated irregular growth pattern, loss of characteristic concentric fibrosis, and epithelial atypia that strongly suggested the diagnosis of invasive pancreatobiliary adenocarcinoma or metastatic adenocarcinoma involving the gallbladder serosa. Two of the cases were initially diagnosed as invasive adenocarcinoma, whereas the other 4 were sent for consultation to rule out adenocarcinoma. All cases were associated with marked acute and chronic cholecystitis with mucosal ulceration, cholelithiasis, and thickening of the gallbladder wall. The ducts of Luschka were located within the rim of adherent liver in all 6 cases and the gallbladder serosa in 5 cases. Limited follow-up information was available for all patients with no documentation of progressive disease. Awareness and proper recognition of the anatomic location and histologic features are imperative in distinguishing florid ducts of Luschka from both non-neoplastic conditions and most importantly adenocarcinoma.

Differential growth patterns and fitness may explain contrasted performances of the invasive Prunus serotina in its exotic range

This research investigates why the invasive American black cherry tends to dominate the forest canopy on well-drained, nutrient-poor soils, but usually hardly establishes on both waterlogged and calcareous soils in its exotic range. Prunus serotina was sampled from four soil types and two light conditions, to measure (1) radial growth; (2) height growth compared to the main native competitor, Fagus sylvatica; (3) leaf traits; (4) seed production; and (5) rate of fungal attack. We found that P. serotina invested a significant amount of energy in height growth and seed production on well-drained, nutrient-poor soils. These characteristics enabled it to rapidly capture canopy gaps and subsequently exert a mass effect on neighbouring stands. On moist soils, we found irregular growth patterns and high rates of fungal attack, while on calcareous soils, leaf traits suggested a low nitrogen assimilation rate, limiting the production of N-containing compounds. We conclude that P. serotina fails on waterlogged and calcareous soils because it is unable to allocate sufficient energy to fruiting and/or height growth. Conversely, it succeeds on well-drained, nutrient-poor soils because of high fitness which increases its invasiveness.

Loss of E-cadherin and MUC2 Expressions Correlated with Poor Survival in Patients with Stages II and III Colorectal Carcinoma

With the recent development of molecular markers, it has become possible to characterize colorectal carcinomas beyond clinical and histologic aspects. When considered together with tumor stage, molecular markers will allow us further insight into individual tumor biologies and prognoses. To investigate the expression and prognostic implications of the molecular markers, p53, bcl-2, Rb, hMLH1, hMSH2, β-catenin, E-cadherin, and MUC-2. We analyzed the clinical, histologic, and molecular factors for 229 patients with colorectal carcinoma of stage II and III and compared their prognoses. We used tissue microarrays to analyze the expressions of molecular markers and to assess their correlations with prognosis. Semiquantitative expressions of molecular markers and clinicopathologic parameters were analyzed with respect to prognosis. Among the clinicopathologic parameters, left-sided location, age older than 70years, higher preoperative serum carcinoembryonic antigen (CEA) level (≤5ng/mL), irregular growth pattern, and perineural invasion were significantly related to poor prognosis in stage II and III patients. For molecular factors, loss of expression of E-cadherin and MUC-2 showed significant correlation with poor overall survival in both cancer stages. Multivariate analysis showed that higher TNM stage, higher preoperative serum CEA level (≤5ng/mL), perineural tumor cell invasion, and loss of E-cadherin and MUC-2 expressions were independently correlated with poor overall survival. Our results indicated that of the analyzed molecular markers, MUC-2 and E-cadherin might be useful in predicting prognosis and planning for adjuvant therapy in patients with stage II and III colorectal carcinomas.

FRACTAL GROWTH AND MORPHOLOGICAL TRANSITIONS DURING CRYSTALLIZATION OF AMINO ACIDS IN PRESENCE OF GLUCOSE

Two-dimensional fractal and spherulitic patterns have been developed on microslides during the crystallization of amino acids in the absence and presence of glucose and agar-agar from their aqueous solutions. Lysine crystallized uniformly in the form of ringed spherulite, but in the presence of glucose it crystallized in the form of branched morphologies. Dependence of glucose concentrations on morphology of glutamic acid has also been studied. Morphology of glutamic acid was found to depend on glucose concentration. Due to interaction between glutamic acid and glucose, following morphological transitions were observed depending on glucose concentrations: spherulite → ringed spherulite → Fractal geometry → DLA-like pattern (D ≈ 1.725). Growth morphologies were characterized by measuring the location of bands (xn) as a function of band number n obeying the relation xn = mn + c, where m and n are slope and intercept respectively, and calculating the fractal dimension at different conditions. Influence of agar-agar on the morphology was also studied. Results showed that branched morphologies were more dominant in the presence of agar-agar. In case of glycine, irregular growth patterns were observed. Interaction between amino acids and glucose was studied by viscosity measurements. It has been inferred that interaction is maximum in case of interaction of glucose with glutamic acid (acidic) and minimum in case of glycine (neutral).

Visual and Pathologic Analyses of Keloid Growth Patterns

Keloids grow and spread not only vertically but also horizontally, although hypertrophic scars do not grow beyond the boundaries of the original injury. Clinically, we have encountered keloids with regular and irregular (untypical) shapes. As the characteristics of the irregular growth patterns of keloids have not been studied yet, we analyzed the irregular growth of keloids both visually and pathologically.A total of 220 keloid specimens, each from a different patient, were surgically removed and used in this study. Through visual analysis, the preoperative shapes of these 220 keloids were classified into those with a regular shape (R group) and those with an irregular shape (IR group). Moreover, we distinguished between cases that had received keloidectomy previously and those that had not. We also determined whether the keloids were recurrent keloids or not. In both the R and IR groups, keloid specimens were studied histologically to examine for infection.In the R group, there were 156 cases (70.9%; 55 males and 101 females with a mean age of 33.68 years). Three patients (1.9%) had infection and 2 patients (1.3%) had undergone keloidectomy previously. In the IR group, there were 64 cases (29.1%; 24 males and 40 females with a mean age of 45.27 years). Thirty patients (46.9%) had infection and 24 patients (37.5%) had undergone keloidectomy previously. Statistically, the rates of infection and keloidectomy were significantly different between the R group and the IR group.Severe infection or operative history may be the cause of irregularly shaped keloids. Thus, in the absence of significant infection or a surgical history, the shape of keloids may be determined uniquely by skin tension.

Maintenance metabolism and carbon fluxes in Bacillus species

BackgroundSelection of an appropriate host organism is crucial for the economic success of biotechnological processes. A generally important selection criterion is a low maintenance energy metabolism to reduce non-productive consumption of substrate. We here investigated, whether various bacilli that are closely related to Bacillus subtilis are potential riboflavin production hosts with low maintenance metabolism.ResultsWhile B. subtilis exhibited indeed the highest maintenance energy coefficient, B. licheniformis and B. amyloliquefaciens exhibited only statistically insignificantly reduced maintenance metabolism. Both B. pumilus and B. subtilis (natto) exhibited irregular growth patterns under glucose limitation such that the maintenance metabolism could not be determined. The sole exception with significantly reduced maintenance energy requirements was the B. licheniformis strain T380B. The frequently used spo0A mutation significantly increased the maintenance metabolism of B. subtilis.At the level of 13C-detected intracellular fluxes, all investigated bacilli exhibited a significant flux through the pentose phosphate pathway, a prerequisite for efficient riboflavin production. Different from all other species, B. subtilis featured high respiratory tricarboxylic acid cycle fluxes in batch and chemostat cultures. In particular under glucose-limited conditions, this led to significant excess formation of NADPH of B. subtilis, while anabolic consumption was rather balanced with catabolic NADPH formation in the other bacilli.ConclusionDespite its successful commercial production of riboflavin, B. subtilis does not seem to be the optimal cell factory from a bioenergetic point of view. The best choice of the investigated strains is the sporulation-deficient B. licheniformis T380B strain. Beside a low maintenance energy coefficient, this strain grows robustly under different conditions and exhibits only moderate acetate overflow, hence making it a promising production host for biochemicals and riboflavin in particular.

Clinical findings and HER-2/neu gene amplification status of breast carcinoma patients

The study group was derived from the archival materials of 48 invasive intraductal breast cancer patients who had undergone partial mastectomy/ axillary dissection. All patients included in the study had clinically T1-2N0M0 invasive ductal carcinoma. To detect HER-2/neu status, fluorescent in situ hybridization was performed using a HER-2/neu locus-specific probe. Signals were counted and patients were classified in three groups according to signal ratios: signal ratio <2, group 1 (n=31); signal ratio 2-4, group 2 (n=11); signal ratio >4, group 3 (n=6). Ratios of axillary metastatic lymph nodes to dissected total lymph nodes were 17%, 23% and 83% in groups 1, 2 and 3 respectively (P=0.003). The number of metastatic axillary lymph nodes, and the ratio of microscopic metastatic lymph nodes were highest in group 3 (P=0.001 and P=0.008, respectively). No significant difference was observed between groups for distant metastasis in a 5-year follow-up period. Signal ratios decreased with estrogen receptor expression (P=0.03). Histopathologically, an irregular growth pattern of the tumor was observed in 100% of the patients in group 3, and in 54% and 60% in groups 1 and 2, respectively (P=0.04). Lymphovascular invasion of the tumor was significantly higher in group 3 compared to the other two groups (P=0.01). The extensive intraductal component ratio was the highest in group 3 (P=0.04). The appearance of desmoplastic reaction and lymphocyte infiltration did not show significant difference between the groups. Our results show that HER-2/neu signal ratio increases with lymphovascular invasion, an extensive intraductal component, irregular growth pattern and axillary metastasis in clinically T1-2N0M0 invasive ductal carcinoma of the breast.

Modelling dominant height growth and site index curves for rebollo oak (Quercus pyrenaicaWilld.)

A dominant height growth model and a site index model were developed for rebollo oak (Quercus pyrenaica Willd.) in northwest Spain. Data from 147 stem analysis in 90 permanent plots, where rebollo oak was the main species, were used for modelling. The plots were selected from the National Forest Inventory at random in proportion to four biogeoclimatic stratums. Different traditional and generalized algebraic difference equations were tested. The evaluation criteria included qualitative and quantitative examinations and a testing with independent data from another region. The generalized algebraic difference equation of Cieszewski based on Bailey equation showed the best results for the four stratums. An analysis of the height growth patterns among ecological stratums was made in order to study the necessity of different site index curves. Results indicated the validity of a common height growth model for the four stratums. In spite of the irregular height growth pattern observed in rebollo oak, probably due to past management, the model obtained allows us to classify and compare correctly rebollo oak stands growing at different sites.

Deployment of Self-expanding Stents for Recanalization of Acute Cerebrovascular Occlusions

The elucidation of the molecular mechanisms of brain tumor biology requires accurate and relevant models. Important new research demonstrates that multi-passaged tumor cell lines, used for years for both in vitro assays and for xenograft transplants in vivo, exhibit significant variation in gene expression and phenotypic characteristics when compared with the parent tumor from which they were originally derived. This progressive divergence of tumor cell lines from primary phenotype and genotype has profound implications for the application of both basic and preclinical studies. A candidate cell to replace these traditional lines is the proposed “cancer initiating cell,” or “cancer stem cell” a precursor cell isolated from solid brain tumors which appears capable both of self-perpetuation and differentiation in permissive conditions. In a recent study by Lee et al. in Cancer Cell (9:5, 391–403, 2006), CD133+ tumor stem cells were isolated from GBMs and compared with existing cell lines. These stem cells were found to resemble neural stem cells and primary tumor more closely than traditional GBM cell lines. Tumor cells grown in the presence of EGF and bFGF, without serum, expressed neural stem cell markers, maintained proliferative capacity, and demonstrated neural and glial differentiation upon transfer to serum culture. In contrast, tumor cells grown in serum did not possess NSC markers, did not maintain the capacity for differentiation, and demonstrated irregular growth patterns. With respect to tumorigenicity, these tumor stem cells produced brain tumors in neonatal SCID mice even after several passages, with histology, growth pattern, and genetic expression all mimicking human GBM (Figure). Cells cultured with serum were only tumorigenic following late passage, and harbored gene mutations that progressively diverged from the parent GBM.Figure: Phenotypic characterization of tumors derived from tumor stem cell compared with late passage serum-cultured GBM cells A–C: Representative microphotographs of intracranial xenograft tumor (A), serum-cultured cell-derived tumor (B), tumor generated from U87MG glioma cell lines (C). Note the extensive infiltration into the surrounding cerebral cortex in A only. Tu indicates central tumor mass. D–F: Infiltrative/migratory nature of xenograft tumors diffusely infiltrate adjacent cortex (D) and migrated along the corpus callosum (E) and olfactory bulb (F). Inset in F is a hematoxylin/eosin (H/E)-stained section depicting normal olfactory bulbs. LV in D indicates lateral ventricle. G–I: Immunohistochemical staining of tumors by antibodies for Nestin (G), Sox2 (H), and G FA P (I).The results of this study indicate that TSCs can be isolated from primary brain tumors and that these TSCs maintain stem cell characteristics in vitro, possess the ability to recapitulate the parent tumor xenographically, and exhibit a gene expression profile similar to that of human GBM. The use of TSCs as a more appropriate clinical model of study as compared to current tumor cell lines is an important and exciting new prospect in the field of neurosurgery as the origins and therapeutic approach to brain tumors continue to be explored. JEFFREY P. G REENFIELD M.D., Ph.D. CAITLIN HOFFMAN, B.S. JOHN A BOOCKVAR, M.D. STEM CELL RESEARCH

Fallibility of Glioblastoma Multiforme Cell Lines Overcome by Use of Tumor-Derived Stem

The elucidation of the molecular mechanisms of brain tumor biology requires accurate and relevant models. Important new research demonstrates that multi-passaged tumor cell lines, used for years for both in vitro assays and for xenograft transplants in vivo, exhibit significant variation in gene expression and phenotypic characteristics when compared with the parent tumor from which they were originally derived. This progressive divergence of tumor cell lines from primary phenotype and genotype has profound implications for the application of both basic and preclinical studies. A candidate cell to replace these traditional lines is the proposed “cancer initiating cell,” or “cancer stem cell” a precursor cell isolated from solid brain tumors which appears capable both of self-perpetuation and differentiation in permissive conditions. In a recent study by Lee et al. in Cancer Cell (9:5, 391–403, 2006), CD133+ tumor stem cells were isolated from GBMs and compared with existing cell lines. These stem cells were found to resemble neural stem cells and primary tumor more closely than traditional GBM cell lines. Tumor cells grown in the presence of EGF and bFGF, without serum, expressed neural stem cell markers, maintained proliferative capacity, and demonstrated neural and glial differentiation upon transfer to serum culture. In contrast, tumor cells grown in serum did not possess NSC markers, did not maintain the capacity for differentiation, and demonstrated irregular growth patterns. With respect to tumorigenicity, these tumor stem cells produced brain tumors in neonatal SCID mice even after several passages, with histology, growth pattern, and genetic expression all mimicking human GBM (Figure). Cells cultured with serum were only tumorigenic following late passage, and harbored gene mutations that progressively diverged from the parent GBM.Figure: Phenotypic characterization of tumors derived from tumor stem cell compared with late passage serum-cultured GBM cells A–C: Representative microphotographs of intracranial xenograft tumor (A), serum-cultured cell-derived tumor (B), tumor generated from U87MG glioma cell lines (C). Note the extensive infiltration into the surrounding cerebral cortex in A only. Tu indicates central tumor mass. D–F: Infiltrative/migratory nature of xenograft tumors diffusely infiltrate adjacent cortex (D) and migrated along the corpus callosum (E) and olfactory bulb (F). Inset in F is a hematoxylin/eosin (H/E)-stained section depicting normal olfactory bulbs. LV in D indicates lateral ventricle. G–I: Immunohistochemical staining of tumors by antibodies for Nestin (G), Sox2 (H), and G FA P (I).The results of this study indicate that TSCs can be isolated from primary brain tumors and that these TSCs maintain stem cell characteristics in vitro, possess the ability to recapitulate the parent tumor xenographically, and exhibit a gene expression profile similar to that of human GBM. The use of TSCs as a more appropriate clinical model of study as compared to current tumor cell lines is an important and exciting new prospect in the field of neurosurgery as the origins and therapeutic approach to brain tumors continue to be explored. JEFFREY P. G REENFIELD M.D., Ph.D. CAITLIN HOFFMAN, B.S. JOHN A BOOCKVAR, M.D. STEM CELL RESEARCH

Fractal Analysis of Surface Growth Patterns in Endometrioid Endometrial Adenocarcinoma

Objective: A fractal is a shape made of parts similar to the whole in some way. The objective of this study was to determine whether surface growth patterns in endometrioid endometrial adenocarcinoma are fractal, and the mean fractal dimension differs according to histologic grades and depth of myometrial invasion. Methods: After the images of photographs of 120 resected uteri with endometrial cancers were digitized, the fractal dimensions of surface of tumors were measured using a fractal analysis software. Results: The mean fractal dimensions of surface growth patterns in G1, G2, and G3 adenocarcinoma were 2.318, 2.303, and 2.383, respectively. These values were significantly greater than the topological dimension of a surface (= 2). The value was significantly higher in G3 than in G2 (p = 0.03). And although not statistically significant, the value of G3 was greater than G1 (p = 0.10) and than (G1 and G2) group (p = 0.06). No significant difference nor tendency was found in the fractal dimension of the surface of the tumor according to depth of invasion. Conclusion: This study shows that the surface of endometrioid endometrial adenocarcinoma has a fractal structure, and the mean fractal dimension may differ according to histologic grades. Our report proposes a new way of looking at endometrial cancer pathology. We believe that fractal geometry gives insights into tumor morphology and becomes a useful tool for analyzing complex and irregular tumor growth patterns mathematically.

Thermophilic bacteria colony growth and its consequences in the food industry

The growth kinetics of thermophilic bacteria &amp;lt;i&amp;gt;Bacillus acidocaldarius&amp;lt;/i&amp;gt; (CCM 3497), &amp;lt;i&amp;gt;Bacillus stearothermophilus&amp;lt;/i&amp;gt; (CCMI&amp;nbsp;237), &amp;lt;i&amp;gt;Thermus aquaticus&amp;lt;/i&amp;gt; (CCM 3488), &amp;lt;i&amp;gt;Thermus ruber&amp;lt;/i&amp;gt; (CCM 4212), and &amp;lt;i&amp;gt;Thermus species&amp;lt;/i&amp;gt; (CCM 4199) on solid media were studied in the temperature range of 40&amp;ndash;60&amp;deg;C. The behaviour of bacterial colonies on agar plates was recorded with a digital camera during 160 hours of experiment. The growth of colony diameter was found to be linear with time at lower temperatures and an acceleration of the growth with time at suboptimal growth temperature 60&amp;deg;C was observed. A simple mathematical model describing the effect of irregular colony growth pattern on its rim can elucidate this unusual phenomenon. &amp;nbsp;

Growth interruptions in silicified conifer woods from the Upper Cretaceous Two Medicine Formation, Montana, USA: implications for palaeoclimate and dinosaur palaeoecology

Taphonomic studies suggest that most dinosaur bone assemblages in the Upper Cretaceous (Campanian) Two Medicine Formation of Montana originated from drought-induced mass mortalities on the floodplain. This hypothesis is tested further by studying intra-annual growth patterns in silicified woods of cupressaceous/taxodiaceous conifers found in association with dinosaur bone material at a palaeolatitude of 48°N. True growth rings are completely absent, but growth interruptions characterised by concentric, variably persistent zones, 1–8 latewood cells wide are common. Interruptions are irregularly spaced so that, for example, four interruptions may occur along a radius of only 25 cells in one specimen, whilst in another specimen a radius more than 650 cells wide may completely lack interruptions. Irregular growth patterns like this occur in Upper Cretaceous woods across a broad latitudinal belt in the US Western Interior demonstrating that they resulted from regional climatic forcing rather than localised phenomena. Growth interruptions record the occurrence of short-term, aperiodic disturbances to tree growth, under an equable, megathermal climate that was otherwise favourable for continuous, year-round cambial activity. The only probable cause of growth interruption formation were drought-induced fluctuations in the water table and resultant water stress. Growth patterns suggest that sufficient water for uninhibited growth was continuously available for years at a time, but when water stress did occur, it did so repeatedly over a very few months. Comparison with present-day East Africa, where trees show very similar growth patterns, implies that the equable, but erratically humid, environment of the Late Cretaceous Western Interior was exactly the kind of setting where mass mortalities amongst megafauna might be expected. Like East Africa, this environment would have had sufficient carrying capacity to permit large herds of megafauna to develop under normal conditions, but when repeated phases of droughts struck, such populations would have been highly vulnerable.

Release of Transforming Growth Factor Beta-1 in a Vestibular Schwannoma Cell Line

Vestibular schwannoma (VS) often displays an irregular growth pattern due to factors which remain unknown. In this study, VS cell lines from tissue removed during surgery were cultured in order to assess the presence of transforming growth factor beta-1 (TGFbeta-1) a multifunctional polypeptide that has different pleiotropic effects on various tissues. The antibody-binding inhibition assay technique was used. The proliferation rate of VS cell lines in vitro was assessed by [3H]thymidine incorporation, with determinations carried out on days 0, 1, 2 and 4 after removal of fetal calf serum (FCS) from the medium. After 48 h of FCS deprivation, cell growth decreased. TGFbeta-1 release also decreased progressively 24 h after removing FCS from the medium, reaching an overall decrease of 50% after 3 days. The cell culturing procedure appeared suitable for VS cells, in that VS cultures were viable for at least 4 months. TGFbeta-1 was initially shown to be released in significant amounts, but also to decrease progressively to values five times lower after 4 days. These data thus support the possibility of a significant association between TGFbeta-1 release and VS cell replication.

Growth patterns of dipterocarps in treated and untreated plots

This study investigated the irregular growth pattern of dipterocarps in response to competition and possibly other factors, a phenomenon known as ‘Umsetzen’ in German silvicultural terminology. The analysis was carried out based on growth data from three experimental sites in the Bintulu-Miri region, Sarawak, Malaysia. The individual plots laid down in the experimental sites were logged and received liberation thinning of potential crop trees (PCTs) 1 year after timber harvest. For comparison, growth data in control plots were analysed. The observation period was 13–14 years. Liberation thinning focused on species of the Red meranti group ( Shorea spp.) but also some well-formed individuals of the Heavy hardwood group ( Shorea spp., some Hopea spp.) were selected. Liberation thinning could significantly increase the periodic annual diameter increment (PAI) of selected trees in both groups over the whole period observed. However, growth rates declined in later periods. In the Red meranti group, larger individuals (>20 cm DBH) benefited slightly more from treatment than smaller trees (10–20 cm DBH), while in the Heavy hardwood group a reversed pattern was found. Autocorrelation analysis of PAI between three successive periods demonstrated the ‘Umsetz’ phenomenon. Growth rates of the first and second period, 1–2 and 4–5 years after treatment or logging, were significantly correlated in both species groups and size-classes (<60 cm DBH), indicating that the growth of trees in the second period was influenced by the previous period. Growth autocorrelation declined in later periods, suggesting that at least some PCTs have lost their dominant position. PCTs of 15–25 cm DBH in the Red meranti group showed the most stable growth over the observation period. Further long-term studies are required to investigate whether a second treatment after 10 years or so may sustain the fast growth of PCTs over another decade.

Release of Transforming Growth Factor Beta-1 in a Vestibular Schwannoma Cell Line

Vestibular schwannoma (VS) often displays an irregular growth pattern due to factors which remain unknown. In this study, VS cell lines from tissue removed during surgery were cultured in order to assess the presence of transforming growth factor beta-1 (TGF g -1) a multifunctional polypeptide that has different pleiotropic effects on various tissues. The antibody-binding inhibition assay technique was used. The proliferation rate of VS cell lines in vitro was assessed by [ 3 H]thymidine incorporation, with determinations carried out on days 0, 1, 2 and 4 after removal of fetal calf serum (FCS) from the medium. After 48 h of FCS deprivation, cell growth decreased. TGF g -1 release also decreased progressively 24 h after removing FCS from the medium, reaching an overall decrease of 50% after 3 days. The cell culturing procedure appeared suitable for VS cells, in that VS cultures were viable for at least 4 months. TGF g -1 was initially shown to be released in significant amounts, but also to decrease progressively to values five times lower after 4 days. These data thus support the possibility of a significant association between TGF g -1 release and VS cell replication.