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PubMed1989

Ice crystal patterns in artificial gels of extracellular matrix macromolecules after quick-freezing and freeze-substitution.

Artificial gels, composed of collagen with or without hyaluronate (HA), a glycosaminoglycan (GAG), and chondroitin sulfate (CS), were prepared and quick-frozen for the purpose of studying the influence of composition and concentration on ice patterns. Dilute gels were spread on coverslips, plunged into a slush of 30% isopentane/70% propane (-185 degrees C), freeze-substituted, and examined by phase-contrast microscopy. Ice patterns were revealed as "ice cavities" in the gel after freeze-substitution. Ice morphology in the gels was gel-type-specific, suggesting that composition in dilute gels can influence ice pattern formation. Crystallization patterns reflecting high, intermediate, and low rates of freezing were observed in all gel types. Intermediate freezing in differentiating gel-type-specific ice patterns. Gels which included hyaluronate (HA) and chondroitin sulfate (CS) altered the ice crystal pattern commonly observed in collagen gels. Ice structure in collagen gels consisted predominantly of long, parallel crystals in the herringbone pattern. Ice crystals separated gel into thin, unbranched fibers with a primary spacing of approximately 2 microns. Ice morphology in HA gels formed a mosaic consisting of packets of ice crystals. Contiguous packets were often oriented at right angles to each other. Periodic crossbridges interconnect primary gel fibers of HA gels and interrupt the lengthwise growth of ice crystals. Smooth beads were visible on primary strands in HA gels frozen at intermediate velocities. The addition of CS to collagen gels resulted in formation of randomly oriented ice crystals in gels frozen at intermediate rates. CS has little influence on ice morphology at low freezing velocities. Primary strands in CS gels were decorated with rough-surfaced, osmiophilic aggregates.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Regenerating adult chicken skeletal muscle and satellite cell cultures express embryonic patterns of myosin and tropomyosin isoforms.

Regenerating areas of adult chicken fast muscle (pectoralis major) and slow muscle (anterior latissimus dorsi) were examined in order to determine synthesis patterns of myosin light chains, heavy chains and tropomyosin. In addition, these patterns were also examined in muscle cultures derived from satellite cells of adult fast and slow muscle. One week after cold-injury the regenerating fast muscle showed a pattern of synthesis that was predominately embryonic. These muscles synthesized the embryonic myosin heavy chain, beta-tropomyosin and reduced amounts of myosin fast light chain-3 which are characteristic of embryonic fast muscle but synthesized very little myosin slow light chains. The regenerating slow muscle, however, showed a nearly complete array of embryonic peptides including embryonic myosin heavy chain, fast and slow myosin light chains and both alpha-fast and slow tropomyosins. Peptide map analysis of the embryonic myosin heavy chains synthesized by regenerating fast and slow muscles showed them to be identical. Thus, in both muscles there is a return to embryonic patterns during regeneration but this return appears to be incomplete in the pectoralis major. By 4 weeks postinjury both regenerating fast and slow muscles had stopped synthesizing embryonic isoforms of myosin and tropomyosin and had returned to a normal adult pattern of synthesis. Adult fast and slow muscles yielded a satellite cell population that formed muscle fibers in culture. Fibers derived from either population synthesized the embryonic myosin heavy chain in addition to alpha-fast and beta-tropomyosin. Thus, muscle fibers derived in culture from satellite cells of fast and slow muscles synthesized a predominately embryonic pattern of myosin heavy chains and tropomyosin. In addition, however, the satellite cell-derived myotubes from fast muscle synthesized only fast myosin light chains while the myotubes derived from slow muscle satellite cells synthesized both fast and slow myosin light chains. Thus, while both kinds of satellite cells produced embryonic type myotubes in culture the overall patterns were not identical. Satellite cells of fast and slow muscle appear therefore to have diverged from each other in their commitment during maturation in vivo.

Animals↗
PubMed1986

Different protein synthetic patterns in scale-forming, feather-forming, and apteric embryonic chick dermis.

We have examined the protein synthetic profile of embryonic chick dermis from different regions of both wild-type and scaleless mutant embryos by two-dimensional polyacrylamide gel electrophoresis to determine if differences in inductive capability are associated with different patterns of gene expression. We have found proteins preferentially synthesized in dorsal dermis and anterior tarsometatarsal dermis at stages when these tissues are active in inducing feather or scale histogenesis, respectively, in the epidermis. Apteric dermis, which is unable to induce epidermal derivative formation, synthesizes a subset of the proteins specific to each region. Scaleless mutant dermis, which does not participate in feather or scale formation in vivo, synthesizes all of the dorsal dermis-specific or tarsometatarsal dermis-specific proteins appropriate to its regional origin. However, it lacks one protein common to all types of dermis tested, and synthesizes one protein inappropriate for its location. Examination of the protein synthetic profile of dorsal and anterior tarsometatarsal dermis at early stages of development reveals that young dorsal dermis, which can only form feathers, possesses the protein synthetic pattern specific to that region. Young tarsometatarsal dermis, which has the potential to form either feathers or scales, synthesizes the proteins we have identified as specific to dorsal and older tarsometatarsal dermis. These results suggest that different protein synthetic patterns are associated with different inductive potentials. However, combining young tarsometatarsal dermis with dorsal epidermis, which causes the formation of feathers, does not alter the pattern of proteins synthesized by the dermis. While this result may be due to an artifact of the culture system, an alternative explanation is that the protein synthesis pattern is not related to the type of epidermal derivative induced, but to the pattern in which the derivatives are induced. This is supported by the observation that the feathers formed in recombinants of tarsometatarsal dermis and dorsal epidermis are arranged in a scale pattern.

Animals↗
PubMed1988

Altered proteoglycan synthesis disrupts feather pattern formation in chick embryonic skin.

We have tested the role of proteoglycans in the development of feather pattern by culturing 7-day-old embryonic chick skins on medium containing para-nitrophenyl-beta-D-xyloside (2 mM). Xylosides compete with core proteins of proteoglycans by acting as exogenous acceptors for the synthesis of glycosaminoglycans leading to the synthesis of under- or unglycosylated core proteins and free glycosaminoglycans. We have demonstrated that xyloside treatment alters the structure of the proteoglycans synthesized by embryonic skin and disrupts the feather pattern. The altered pattern is seen as the fusion of individual feather rudiments. Fusion can occur diagonally, and in an anteroposterior and mediolateral direction. The effect induced by the disruption of proteoglycan structure takes place during the first 24 hr of culture during which time all the rows of feather rudiments are being established. The effect is reversible if the skins are returned to control medium after 24 hr but not after 48 hr of treatment with xyloside. Once established during the first 24 hr the feather pattern can only be slightly distorted by the xyloside treatment. The results are interpreted to mean that proteoglycans play a developmental role in the establishment of the feather pattern but not in its maintenance, suggesting that the two processes are under different developmental control. The altered feather pattern obtained by disrupting proteoglycan structure is highly similar to that obtained when skins are cultured in the presence of antibodies to L-CAM (W.J. Gallin, C.-M., Chuong, L.H. Finkel, and G.M. Edelman (1986), Proc. Natl. Acad. Sci. USA 83, 8235-8239). This observation suggests that there may be a functional relationship between the extracellular matrix and cell adhesion molecules in the establishment of feather pattern.

Animals↗
PubMed1991

Pigment patterns in neural crest chimeras constructed from quail and guinea fowl embryos.

The pattern of pigmentation in bird embryos is determined by the spatial organization of melanocyte differentiation. Some of the results from recent, neural crest transplantation experiments support a model based on a prepattern in the feathers; others could be interpreted in terms of a nonspecific pattern resulting from a failure of the crest cells to read the positional values in another species. To distinguish between these possibilities, the crucial test is to construct chimeras from two species with different pigment patterns. We have examined the wing plumage of quail and guinea fowl embryos. The quail has a characteristic pattern of pigmented and unpigmented feather papillae, whereas the guinea fowl shows uniform pigmentation. Chimeras were constructed by grafting wing buds isotopically between embryos. The wing buds were transplanted before they had become invaded by neural crest cells. Quail wing buds grafted to the guinea fowl developed, in most cases, a pigment pattern resembling that of the quail and not that of the guinea fowl. A few cases became uniformly pigmented and appeared to represent nonspecific patterns. The reciprocal grafts (guinea fowl wing buds grafted to the quail) became pigmented all over. We found evidence that the timing of melanocyte differentiation is controlled by cues in the feather papillae. Some cases developed a severe inflammatory response. The model which best accounts for these findings--and which can account for inconsistencies in previous reports--is the following. A prepattern is present in the feathers and this can control the differentiation of melanoblasts, even if they come from a different species. The local cues which constitute the prepattern are not positional values. In some chimeras melanoblasts fail to respond to the prepattern and so a nonspecific pattern of uniform pigmentation is produced.

Animals↗
PubMed1983

Temporo-spatial patterns of pre-ictal spike activity in human temporal lobe epilepsy.

The statistical properties of pre-ictal EEG spike activity in medial temporal lobe sites were analyzed in 6 patients with medically refractory complex partial seizures. A total of 24 1 h pre-ictal periods (2-6 periods per patient) were evaluated by quantifying the rate of occurrence of individual spatial patterns of spike activity derived from a subset (n = 6) of the recording channels. The channels chosen for analysis always included those medial temporal lobe sites which were documented to be most likely to initiate seizures, as well as their respective contralateral homologues. Each 1 h pre-ictal period was divided into 360 10 sec bins which were then visually classified into 1 of 64 possible spatial patterns of spike activity. These patterns, in turn, were grouped into 1 of 5 general spatial patterns and evaluated for trends across 3 20 min pre-ictal segments. Pooling these data across patients yielded the following results: (1) Focal patterns of spike activity tended to decline significantly in rate of occurrence several minutes prior to seizures, while the rate of independent contralateral patterns did not change. (2) The rate of occurrence of patterns of bilateral loosely coupled spike activity (involving focal and contralateral sites) increased significantly across the 20 min pre-ictal segments and was clearly augmented during the 20 min prior to seizures. These findings indicate that the degree of bilateral independence in medial temporal lobe spike activity tends to decrease several minutes prior to the localized onset of temporal lobe seizures; such changes may reflect the mechanisms responsible for the inter-ictal-ictal transition.

Action Potentials↗
PubMed1990

Human pepsinogen A isozymogen patterns in serum and gastric mucosa.

The pepsinogen A isozymogen pattern in gastric mucosa is genetically determined and can be visualized in nondenaturating polyacrylamide gel electrophoresis of supernatants of sonified gastric mucosal biopsies by demonstrating proteolytic activity after converting pepsinogen into pepsin by acid. Pepsinogen isozymogens are present in very low concentrations in the blood but can now be demonstrated in serum by a newly developed immunoblotting procedure. This study investigated whether the serum pepsinogen A isozymogen pattern adequately reflects the pepsinogen A phenotype. Serum and gastric mucosal pepsinogen A isozymogen patterns were compared in 72 subjects from the routine endoscopy program. A close correlation was found between the relative intensities of the pepsinogen A isozymogens in the serum and the gastric mucosal patterns. Increasing the pepsinogen A release into the circulation by oral omeprazole did not affect the pepsinogen A patterns in the blood. It is concluded that the serum pepsinogen A pattern reflects the pepsinogen A phenotype in humans. In addition, no preferential release of a pepsinogen A isozymogen into the circulation was observed. Thus, immunoblotting of serum provides a new and reliable tool to study pepsinogen genetics in humans. Because a relationship was previously shown between specific pepsinogen A phenotypes and gastric malignancies in humans, serum pepsinogen A patterns may provide a tool to detect subjects who are at risk of gastric cancers.

Adult↗
PubMed1982

Effects of drinking patterns on the relationship between alcohol an coronary occlusion.

Previous reports have described an inverse relationship between alcohol consumption and the prevalence of myocardial infarction or the extent of coronary artery occlusion. The study reported here explored the relationship between patterns of alcohol intake and coronary occlusion in 526 patients who have had coronary arteriography. Patients were characterized as regular drinkers, occasional drinkers and non-drinkers. Regular drinkers were further characterized as drinking relatively consistent amounts or variable amounts. The inverse correlation between amounts of alcohol consumed and coronary occlusion found in previous studies was reaffirmed. It was also observed that the pattern of alcohol intake was related to the degree of occlusion. Higher levels of occlusion were found among non-drinkers, occasional drinkers, and regular drinkers with patterns of variable intake, while significantly lower levels of occlusion were observed for regular drinkers who drank relatively consistent amounts (P = 0.014). Furthermore, while occlusion scores were inversely correlated with amounts consumed by regular drinkers with consistent intake (P = 0.019), drinkers with variable drinking patterns had higher occlusion scores regardless of amounts consumed. Analyses of serum lipids according to drinking patterns showed a significant association between the total/HDL cholesterol ratio and drinking patterns. These findings suggest that whatever attenuating effect alcohol consumption might exert on coronary occlusion, it appears to be reversed by a variable or sporadic pattern of alcohol intake.

Adult↗
PubMed1987

X-ray diffraction patterns from microtubules and neurofilaments in axoplasm.

Freshly extracted axoplasm from giant axons of the marine fan worm Myxicola infundibulum and the squid Loligo can be pulled into fibres that contain highly oriented cytoskeletal elements suitable for X-ray diffraction. A major advantage of studying axoplasmic components by this technique is that it allows essentially native structures and their interactions to be examined. We describe here the analyses of the X-ray diffraction patterns. We show that in Myxicola the pattern can be explained by diffraction from both neurofilaments and microtubules, whilst in Loligo the pattern arises solely from microtubules. At low resolution, X-ray patterns obtained from dehydrated axoplasmic microtubules resemble strongly the Fourier transforms generated from electron micrographs of negatively stained specimens. Hydration of axoplasmic fibres produced reversible changes in the X-ray pattern intensities, although the layer-line positions were unaltered. On the 4 nm layer-line, the intensity of the J3 reflection was dramatically reduced on hydration, though its position was unchanged. Hydration also affected the J10/J16 reflections, which increased in intensity, though here again the positions of the peaks were little altered. The X-ray patterns from our hydrated fibres resemble those produced by others from fibres of purified microtubules, though in our patterns contrast is generated towards the centre of the wall. We interpret our findings in the light of current ideas about microtubule structure as determined by X-ray diffraction and electron microscope techniques.

Animals↗
PubMed1990

A synergic approach to plant pattern generation.

The paper shows convergences between the results found in various models of phyllotaxis. It shows that a synergic approach is needed to deal with the problems of phyllotaxis. An algorithm, called the phi-model, based on the observation of the meaningful and symmetry-generating presence of the golden ratio phi in all types of spiral patterns, and consequently in all types of regular patterns in phyllotaxis, is proposed. The model is suggested by a property of the allometry-type model for pattern recognition in phyllotaxis. It extends recent morphological models developed around the idea of packing efficiency of plant primordia, models that yield the noble numbers, among which are the divergence angles of spiral patterns. The phi-model also gives the noble numbers and moreover orders them in a way that establishes connections with the morphogenetic principles used in models for pattern generation; the order has to do with the relative frequencies of the spiral patterns in nature. The phi-model is a link between the two entropy models in phyllotaxis and offers a nice correspondence with the minimal entropy model generated by a systemic and holistic approach. This latter type of approach is put forward as being able to give a general framework in which to organize the concepts, results, and models in phyllotaxis in a way that produces a synergy of efforts. The necessity of doing so is seen clearly when one considers that phyllotaxis-like patterns are encountered in other fields of research, so that the problem appears to transcend the strict botanical substratum.

Algorithms↗
PubMed1991

Spatial and temporal patterning distinguishes the locomotor activating effects of dizocilpine and phencyclidine in rats.

A behavioral pattern monitor was used to assess the effects of dizocilpine (MK-801) and phencyclidine on the spatial and temporal patterns of locomotion and investigatory behavior in rats. The monitor provided both quantitative measures of crossovers, rearings and holepokes and qualitative measurement of the spatial and temporal patterns of locomotion. Dizocilpine (0.004-0.5 mg/kg) and phencyclidine (0.25-5.0 mg/kg) produced similar, dose-dependent increases in locomotor activity. At small doses, dizocilpine and phencyclidine increased investigatory holepokes, while at larger doses, both drugs significantly decreased the number of holepokes. Rearings were reduced similarly by the larger doses of each drug. Both dizocilpine and phencyclidine produced perseverative spatial patterns of locomotion, especially at larger doses. However, the locomotor patterns produced by these drugs were found to be dissimilar in spatial quality. After phencyclidine, animals frequently circled the perimeter of the monitor chamber or moved repetitively in horseshoe or figure-8 patterns. By contrast, rats given dizocilpine completed small rotations about either end of the chamber. Pretreatment with a small dose (0.02 mg/kg) of haloperidol, prior to either dizocilpine (0.5 mg/kg) or phencyclidine (5.0 mg/kg) had no effect on the increase in locomotor activity or the decreases in investigatory holepokes produced by the drugs. However, haloperidol altered the effects of phencyclidine on the spatial and temporal patterns of locomotion, suggesting that sigma receptors or other haloperidol-sensitive binding sites, may influence the quality but not the quantity of phencyclidine-induced hyperactivity.

Animals↗
PubMed1988

The meal pattern of rats shifts from postprandial regulation to preprandial regulation when only five meals per day are scheduled.

In order to investigate whether an observed difference in the meal patterns of rats and human may be due to constraints that humans have on the timing of meals and their large but infrequent meal pattern, rats had similar constraints imposed on their meal intake. Fifteen male Long-Evans rats were monitored in five individual enclosed chambers equipped with pellet sensing eatometers for three fourteen-day data collection periods. Both groups were monitored in a baseline ad lib condition, then one group (n = 7) was allowed access to food only once every two hours, while the second group (n = 8) was allowed to access only five times per day. Both groups were then monitored for a second ad lib baseline period. The imposition of both schedules reduced meal frequencies and estimated premeal stomach contents, and increased meal sizes and estimated postmeal stomach contents. The imposition of the five meal per day, but not the twelve meal per day schedule of meal access, eliminated the significant relationships between meal size and the postmeal interval evident during baseline conditions and produced significant relationships between meal size and the premeal interval and estimated premeal stomach content, not seen during baseline conditions. The rats under the five meal per day access schedule showed a preprandial pattern of intake very similar to that previously observed in humans eating ad lib. It was concluded that the preprandial pattern, typical of humans, is characteristic of intake involving large infrequent meals which produce stomach filling to an upper limiting threshold. The postprandial pattern, typical of rats, is characteristic of intake involving small frequent meals that are initiated when the stomach empties to a lower threshold. A peripheral, stomach capacity, model then, can be used to explain both the preprandial and the postprandial patterns. Which pattern is used depends upon environmental conditions.

Animals↗
PubMed1995

Underwater refraction-polarization patterns of skylight perceived by aquatic animals through Snell's window of the flat water surface.

The grass shrimp (Palaemonetes vulgaris) orients itself by means of the polarization pattern of the sky visible through Snell's window of the water surface. The celestial polarization pattern viewed from water is distorted and modified because of refraction and repolarization of skylight at the air-water interface. This work provides a quantitative account of the repolarization of skylight transmitted through a flat water surface. The degree and direction of linear polarization, the transmissivity and the shape of the refraction-polarization oval are calculated at the air-water interface as functions of the polarization characteristics and the incident angle of partially linearly polarized incoming light. Two-dimensional patterns of linear polarization ellipses and of the degree and direction of polarization of skylight are presented for different zenith distances of the sun. The corresponding underwater refraction-polarization patterns are computed. Transmissivity patterns of a flat water surface are calculated for unpolarized light of an overcast sky and for partially polarized light of clear skies as a function of the zenith distance of the sun. The role of these refraction-polarization patterns in orientation and polarization vision of the grass shrimp (P. vulgaris) and rainbow trout (Oncorhyncus mykiss) is reviewed. The effects of cloud cover, surface waves and water turbidity on the refraction-polarization patterns are briefly discussed.

Animals↗
PubMed1993

Containment and growth of neuroblastoma cells on chemically patterned substrates.

Patterned substrates offer the promise of controlled positioning and directional guidance of growing neurites. Therefore, they could be useful for constructing small neuronal networks with defined geometry in vitro. We have fabricated chemically patterned substrates using self-assembled monolayer films with a lithographic mask technique and demonstrated the feasibility for geometrically patterning neuroblastoma cells in culture. N-octadecyltrichlorosilane (OTS) was chemically bonded to glass and fused silica substrates, rendering the surface hydrophobic and non-adhesive to cells. Using surface analysis techniques, we have confirmed that OTS films were true monolayers and can be photocleaved from the surface by deep UV irradiation. An adhesive pattern of n-(2-aminoethyl-3-aminopropyl)trimethoxysilane was formed on a selectively irradiated OTS surface via a deep UV lithographic procedure. The chemically patterned surface was then seeded with SK-N-SH human neuroblastoma cells, and cellular attachment and growth were monitored by optical microscopy. The use of 2-dimensional substrates supported the containment and growth of neuroblastoma cells within the pattern for at least 15 days in culture. These chemical patterns may also be useful in controlled arrangements of hearts cells or muscle cells on prosthetic implant devices.

Cell Adhesion↗
PubMed1994

Pattern formation in the vertebrate neural plate.

Recent advances have been made in the understanding of the cellular and molecular mechanisms involved in the formation and patterning of the neural plate of vertebrate embryos. Both planar and vertical signaling pathways appear to be involved in the neural induction and axial patterning of the neural plate. The neural plate, behaving as a developmental field, might be patterned by signals emanating from boundary regions: the organizer region and the midline and edges of the neural plate. Here, A. Ruiz i Altaba describes a possible model for anteroposterior patterning involving ;lanar signals for amphibian, avian and mammalian embryos, compares the axial patterning of the neural plate with the patterning of insect epithelia, and discussed possible roles of noggin, follistatin and hedgehog-related genes in neural induction and patterning.

Animals↗
PubMed1988

Effect of intracaudate haloperidol and apomorphine on switching motor patterns upon current behaviour of cats.

Previous studies using various experimental set-ups, have shown that the dopaminergic activity in the caudate nucleus (CN) is involved in the organism's ability to switch from one motor or behavioural program to another without the help of external stimuli (switching arbitrarily). The main purpose of the present study was to investigate how arbitrarily switching motor patterns manifests itself in an 'open field situation'. Therefore, the effects of CN application of haloperidol (12.5 micrograms/5 microliter) and apomorphine (0.6 micrograms/5 microliter) were analyzed on the ability to switch from one motor program to any other program in cats habituated to an observation cage. Application of haloperidol decreased switching. In addition the number of distinct motor patterns declined after injecting haloperidol into the CN. The haloperidol-induced effect, however, was not selectively restricted to any particular motor pattern. Switching from one motor pattern to another increased after CN injection of apomorphine. Moreover, the number of distinct motor patterns increased after CN injection of apomorphine. However, the effect of CN application of apomorphine was not selectively restricted to any particular motor pattern. Since previous studies have demonstrated that various expressions of dopaminergic CN activity are funnelled through the deeper layers of the superior colliculus (dl-SC), it was hypothesized that switching induced by CN application of apomorphine may also be channelled through the dl-SC. Therefore the effect of dl-SC-injected muscimol (75 ng/1 microliter) was analyzed on the ability to switch motor programs in cats pretreated with apomorphine. Injection of muscimol into the dl-SC reduced both the number of distinct motor patterns and the number of switchings in cats pretreated with apomorphine.

Animals↗
PubMed1987

The effect of blur and contrast on VEP latency: comparison between check and sinusoidal and grating patterns.

Pattern defocusing was used to evaluate the contribution of different spatial frequency components in checks to VEP latency. Latency shifts with increasing blur (-2.5 to +2.5 diopters) were determined for sinusoidal grating and check patterns equated in fundamental spatial frequency. With both check and grating patterns, the effect of blur was greater the higher the spatial frequency. Given an equal fundamental spatial frequency, however, the latency of checks was more effected. This latency difference between check and sine patterns was pronounced at low fundamental spatial frequencies (large pattern) and decreased with higher spatial frequencies (small pattern). Latencies were then compared for patterns which were defocused vs. simply reduced in contrast. Results show that the increase in latency with defocused large checks is due to both fundamental and higher harmonic spatial components but with small checks, to the fundamental spatial frequency alone.

Adolescent↗
PubMed1990

Histologic pattern analysis of basal cell carcinoma. Study of a series of 1039 consecutive neoplasms.

This study attempts to define histologic patterns in 1039 consecutive cases of basal cell carcinoma and to correlate these patterns with adequacy of margins of surgical excision. Five major histologic patterns were identified: nodular, 218 cases (21%); superficial, 181 cases (17%); micronodular, 151 cases (15%); infiltrative, 77 cases (7%); and morpheic, 11 cases (1%). A mixed pattern (two or more major histologic patterns) was present in 401 cases (38.5%). Our study indicates that nodular and superficial basal cell carcinomas can be completely removed by simple surgical excision in a high percentage of cases (93.6% and 96.4%, respectively) whereas the micronodular, infiltrative, and morpheic basal cell carcinomas have a higher incidence of positive tumor margins (18.6%, 26.5%, and 33.3%, respectively) after excision. Mixed patterns that consisted of combinations of the nodular, micronodular, or infiltrative types exhibited a behavior similar to the pattern that resulted in a greater chance of incomplete surgical removal.

Basal Cell Carcinoma↗