Growing tips of type I collagen fibrils formed in vitro are near-paraboloidal in shape, implying a reciprocal relationship between accretion and diameter

Collagen fibrils generated in vitro at 37 degrees C by enzymic removal of C-terminal propeptides from type I pC-collagen (an intermediate in the normal processing of type I procollagen to collagen containing the C-terminal propeptides but not the N-terminal propeptides) display shape polarity, with one tip fine tapered and the other coarse tapered. Mass measurements by scanning transmission electron microscopy show that the mass per unit length along both kinds of tip increases roughly linearly over distances of approximately 100 D periods from the fibril end [D (axial periodicity) = 67 nm]. The fine tips of fibrils of widely differing lengths exhibit near-identical mass distributions, the mass in all cases increasing at the rate of approximately 17 molecules per D period, irrespective of fibril length. Coarse tips display less regular behavior. These results show that (i) the shape of a fine tip is not conical but resembles more closely a paraboloid of revolution, and (ii) for this shape to be maintained throughout growth, accretion (rate of mass uptake per unit area) cannot everywhere be the same on the surface of the tip but must decrease as the diameter increases. To a first approximation, accretion alpha (diameter)-1.

A comparison of all-subset Cox and accelerated failure time models with Cox step-wise regression for node-positive breast cancer

Clinical studies usually employ Cox step-wise regression for multivariate investigations of prognostic factors. However, commercial packages now allow the consideration of accelerated failure time models (exponential, Weibull, log logistic, and log normal), if the underlying Cox assumption of proportional hazards is inappropriate. All-subset regressions are feasible for all these models. We studied a group of 378 node positive primary breast cancer patients accrued at the Henrietta Banting Breast Centre of Women's College Hospital, University of Toronto, between January 1, 1977, and December 31, 1986. 85% of these patients had complete prognostic factor data for multivariate analysis, and 96% of the patients were followed to 1990. There was evidence of marked departures from the proportional hazards assumption with two prognostic factors, number of positive nodes and adjuvant systemic therapy. The data strongly supported the log normal model. The all-subset regressions indicated that three models were similarly good. The variables 1) number of positive nodes, 2) tumour size, and 3) adjuvant systemic therapy were included in all three models along with one of three biochemical receptor variables 1) ER, 2) combined receptor (ER- PgR-; ER+PgR-; ER- PgR+; ER+PgR+; or 3) PgR. Better multivariate modeling was achieved by using quantitative prognostic factors, a check for appropriate underlying model-type, and all-subset variable selection. All-subset regressions should be considered for routine use with the many new prognostic factors currently under evaluation; it is very possible that there may not be a single model that is substantially better than others with the same number of variables.

The correlation of Ki67 growth factor and ERICA in breast cancer

Estrogen receptor (ER) status is an accepted prognostic indicator for breast cancer when measured by either the biochemical or immunohistochemical (ERICA) methods. Moreover, ERICA was found to be a better predictor of survival in human breast cancer than the biochemical assay for ER. The antibody to Ki67 recognizes the growth fraction of proliferating cells. We examined 100 primary breast cancers to investigate the relationship between ER status as measured by ERICA and Ki67 reactivity. Of the 56 ERICA positive cases, 47 (84%) were Ki67 negative whereas 30 of the 44 ERICA negative tumors were Ki67 positive (68%). There was evidence of a significant inverse relationship between ERICA and the growth fraction (77% of cases, p less than 0.001). In addition, a cluster of ERICA-positive Ki67-positive tumors that were larger and occurred in older patients was identified as a subset that might require aggressive therapy. Our results suggest that Ki67 may be an important additional criterion for predicting the biological behaviour of breast cancers.

Macromolecular organization of chicken type X collagen in vitro

The macromolecular structure of type X collagen in the matrices of primary cultures of chick hypertrophic chondrocytes was initially investigated using immunoelectron microscopy. Type X collagen was observed to assemble into a matlike structure with-in the matrix elaborated by hypertrophic chondrocytes. The process of self assembly was investigated at the molecular level using purified chick type X collagen and rotary-shadowing EM. It was shown that under neutral conditions at 34 degrees C, individual type X collagen molecules associate rapidly into multimeric clusters via their carboxy-terminal globular domains forming structures with a central nodule of carboxy-terminal domains and the triple helices radiating outwards. Prolonged incubation resulted in the formation of a regular hexagonal lattice by lateral association of the juxtaposed triple-helical domains from adjacent multimeric clusters. This extended lattice may play an important role in modifying the cartilage matrix for subsequent events occurring in endochondral bone formation.

Morphology of sheet-like assemblies of pN-collagen, pC-collagen and procollagen studied by scanning transmission electron microscopy mass measurements

At high concentrations, type I pN-collagen, pC-collagen and procollagen (the first 2 generated from procollagen by enzymic cleavage of C-propeptides and N-propeptides, respectively) can all be made to assemble in vitro into thin D-periodic sheets or tapes. Scanning transmission electron microscopy mass measurements show that the pN-collagen sheets and procollagen tapes have a mass per unit area corresponding to that of approximately 6.8 monolayers of close-packed molecules. pN-collagen sheets are extensive and remarkably uniform in mass thickness (fractional S.D. 0.035); procollagen tapes are neither as extensive nor as uniform in thickness. The mean thickness of pC-collagen tapes is less and the variability is greater. In pN-collagen sheets, the overlap: gap mass contrast in a D-period is increased from 5:4 (the ratio in a native collagen fibril) to 6:4, showing that the N-propeptides do not project into the gap but are folded back over the overlap zone. Assuming all N-propeptides to be constrained to the two surfaces of a sheet, their surface density can be found from the mass thickness of the sheet. In a lateral direction (i.e. normal to the axial direction where the spacing is D-periodic), the N-propeptide domains are calculated to be spaced, centre to centre, by 2.23 (+/- 0.1) nm on both surfaces. This value (approx. 1.5 x the triple-helix diameter) implies close-packing laterally with adjacent domains in contact. Sheet formation and the "surface-seeking" behaviour of propeptides can be understood in terms of the dual character of the molecules, evident from solubility data, with propeptides possessing interaction properties very different from those displayed by the rest of the molecule. The form and stability of sheets (and of first-formed fibrils assembling in vivo) could, it is suggested, depend on the partially fluid-like nature of lateral contacts between collagen molecules.

Heterogeneity in responses to cancer. Part II: Sexual responses

Heterogeneity in psychosexual responses to disease-specific diagnosis is demonstrated for two groups of cancer patients with testis cancer and Hodgkin's disease who are comparable in prognosis and treatment intensity. The two groups of patients and their partners are shown to differ in their ability to recover from psychiatric problems associated with the diagnosis and/or treatment of cancer.

Heterogeneity in responses to cancer. Part I: Psychiatric symptoms

Heterogeneity in psychiatric responses to disease specific diagnosis is demonstrated for two groups of cancer patients who are comparable in prognosis and treatment intensity. Implications of this heterogeneity are drawn for etiological study and for planning psychiatric interventions.

D-periodic assemblies of type I procollagen

The solubility limit of purified chick type I procollagen, incubated at 37 degrees C in phosphate-buffered saline, was found to be in the range 1 to 1.5 mg/ml. At higher concentrations large aggregates formed. These comprised: (1) D-periodic assemblies; (2) narrow filaments with no apparent periodicity; and (3) segment-long-spacing-like aggregates. The D-periodic assemblies, which predominated at high concentrations, were separated from the other types of aggregate and found to be ribbon-like. Ribbons were uniform in thickness (approximately 8 nm) and up to 1 micron wide. Staining patterns showed features similar to those in native-type collagen fibrils. Immunolabelling indicated that the carboxyl-terminal propeptide domains were close to the carboxyl-terminal gap-overlap junction, and that the amino-terminal propeptide domains were folded over into the amino-terminal side of the overlap zone. Both propeptide domains appeared to be located on the surface of the assemblies. These observations show that intact propeptide domains hinder, but do not prevent, the formation of D-periodic assemblies. The presence of the propeptide domains on the surface of a growing assembly could restrict its lateral growth and limit its final thickness.

The collagen fibril--a model system for studying the staining and fixation of a protein

A collagen fibril is made up of long rod-like molecules regularly D-staggered with respect to one another. This means that (i) its axially projected fine structure, resolvable to approximately 2 nm in electron micrographs, repeats D-periodically (D = 67 nm), and (ii) the amino acid residues contributing to each element of the fine structure can be inferred from sequence data. Electron-optical data from a fibril D-period can can therefore be correlated directly with chemical data. Such correlations confirm the electrostatic nature of the staining reaction when a fibril is positively stained. After negative staining, the principal factor determining the small-scale distribution of stain is local exclusion by 'bulky' amino acid side-chains. ('Bulkiness' is the average cross-sectional area, or 'plumpness', of a side-chain.) A small superimposed positive staining contribution can also be detected. Fixation of collagen by aldehydes and diimidoesters occurs via an initial reaction with lysyl (and hydroxylsyl) side-chains and alpha-amino groups, followed by secondary cross-linking reactions that differ from fixative to fixative. These secondary reactions determine the nature and abundance of the cross-links and the extent to which they influence subsequent staining behaviour.

Pleomorphism in type I collagen fibrils produced by persistence of the procollagen N-propeptide

The assembly of type I collagen and type I pN-collagen was studied in vitro using a system for generating these molecules enzymatically from their immediate biosynthetic precursors. Collagen generated by C-proteinase digestion of pC-collagen formed D-periodically banded fibrils that were essentially cylindrical (i.e. circular in cross-section). In contrast, pN-collagen generated by C-proteinase digestion of procollagen formed thin, sheet-like structures that were axially D-periodic in longitudinal section, of varying lateral widths (up to several microns) and uniform in thickness (approximately 8 nm). Mixtures of collagen and pN-collagen assembled to form a variety of pleomorphic fibrils. With increasing pN-collagen content, fibril cross-sections were progressively distorted from circular to lobulated to thin and branched structures. Some of these structures were similar to fibrils observed in certain heritable disorders of connective tissue where N-terminal procollagen processing is defective. The observations are considered in terms of the hypothesis that the N-propeptides are preferentially located on the surface of a growing assembly. The implications for normal diameter control of collagen fibrils in vivo are discussed.

The regulation of size and form in the assembly of collagen fibrils in vivo

A possible mechanism for regulating the lateral growth of collagen fibrils in vivo is considered. A growth inhibitor associated with a particular part of the long semiflexible collagen molecule restricts that part of the molecule to the surface of the growing assembly. Lateral accretion ceases when these inhibitors form a complete circumferential layer around the fibril surface. Cell-mediated removal of the inhibitors allows lateral growth to proceed to a second limiting layer, and so on to subsequent limiting layers. In this way, cycles of inhibitor removal and limited lateral accretion permit growth to be synchronized over large populations of fibrils. Observed diameter distributions in bundles of embryonic and neonatal fibrils are those expected from a mechanism of this kind. The mechanism depends on the existence of axial order (D-periodicity) in fibrils, but not on any specific lateral packing of molecules. Rather, contacts between newly assembled molecules are presumed to be partly fluid-like in lateral directions (except where covalent cross-links have formed). Some initial fluidity in lateral packing prior to cross-linking does not preclude the subsequent emergence of quasi-crystalline packing as cross-links form. The cylindrical shape of fibrils in vivo may also be attributable in part to fluidity of intermolecular contacts at the growing surface.

Stimulation of protein phosphorylation in mixed glial cell primary cultures and subcultures by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate

Glial cell primary cultures consisting of protoplasmic and fibrous astrocytes, oligodendrocytes and progenitor glial cells incubated in medium containing 0.5% foetal calf serum and treated with 25 nM 12-o-tetradecanoylphorbol-13-acetate (TPA) for periods between 15 and 60 min showed a stimulation of protein phosphorylation which was most prominent in a polypeptide with a molecular weight of about 80,000 Da. Glial subcultures consisting mainly of Type 2 astrocytes, oligodendrocytes and progenitor glia showed a similar TPA stimulation of 80,000 Da protein phosphorylation detectable within 1 min of phorbol ester addition. TPA treatment of primary glial cultures led to an enhancement of phospholipid turnover but exposure of primary glial cultures to concentrations of TPA up to 250 nM caused no morphological change in protoplasmic astrocytes. 4-Phorbol (4-PH) or dimethylsulfoxide (DMSO) was without effect on protein phosphorylation or lipid turnover in glial cultures.

Protein kinase C activity in soluble fractions from glial cells in primary culture and subcultures

Protein kinase C (calcium + phospholipid-dependent kinase) activity has been measured in soluble 100,000 g fractions from mixed glial cells in primary culture; in 12 day cultures the specific activity (mean +/- S.D.) was 184 +/- 10 pmol 32P incorporated/10 min/mg protein. In glial cell subcultures lacking protoplasmic astrocytes protein kinase C specific activity was lower. An inhibitor of protein kinase C in 100,000 g supernatants was removed by chromatography through DE-52 anion exchange resin increasing the specific activity of the calcium + phospholipid-dependent kinase about 20 times. Protein kinase C was also associated with membrane fractions from glial cells; the membrane-associated enzyme had a higher specific activity than in the cytoplasm.

Collagen self-assembly in vitro: electron microscopy of initial aggregates formed during the lag phase

Initial aggregates formed in collagen self-assembly were visualized by electron microscopy, using formaldehyde to fix the state of aggregation at various points in the turbidimetric lag phase. Measurements of the length distributions of monomers and small oligomers show that the first-formed aggregates are dimeric, with the most prevalent dimer having a maximal (approximately equal to 4D; D = 67 nm) stagger between constituent molecules.

An unusual nitrofurantoin-induced drug reaction

A case of drug-induced lupus erythematosus associated with erythema multiforme due to nitrofurantoin is presented. This case differs from those previously reported in that no pulmonary infiltrate was found. In 21 months, there was a complete clinical and serologic remission after nitrofurantoin was withdrawn from the therapeutic regimen.

Gastrointestinal obstruction associated with multiple-dose activated charcoal

The development of a gastrointestinal obstruction associated with multiple doses of activated charcoal is described. A carbamazepine-intoxicated patient received 240 g of activated charcoal and a total of 600 mL magnesium citrate with the development of an ileus and a small-bowel obstruction. The patient also had episodes of emesis associated with charcoal administration. This case suggests that the use of multiple doses of activated charcoal may be associated with gastrointestinal obstruction, a previously unreported adverse effect. Further evaluation of the incidence of adverse effects associated with activated charcoal is needed to determine optimal therapeutic regimens.

Cholera in children at Eshowe Hospital

During a 2-week period in May 1983 Eshowe Hospital inpatients were screened for cholera and positive cases were found on all the wards that were investigated. The high incidence among paediatric patients suggested the possibility of an epidemic in the community and/or cross-infection within the ward. At this time 9 paediatric nurses were found to have cholera-positive stools and subsequently 8 children contracted cholera after admission to hospital. The possibility of cross-infection by person-to-person transmission is suggested. In the second part of this study, our clinical experience of cholera among inpatients during the period January 1983 - March 1984 is reviewed. The number of children in hospital with cholera-positive stools decreased sharply during the winter months; this was possibly related to variations in both temperature and rainfall. The full range of symptomatology was seen and several children had repeated episodes of proven cholera. The mortality was highest in bottlefed babies who were malnourished or under 1 year of age. Between 30 May and 15 June 1983, 293 consecutive children attending the paediatric outpatients department were screened for cholera; 99 cases were confirmed. Thus cholera was shown to be present in the paediatric community outside Eshowe Hospital. Diagnosis based on the history and clinical findings proved unreliable and laboratory investigation was essential. Rivers were the most common and dangerous source of domestic water. The majority of accompanying adults questioned were using untreated water or failing to treat the water adequately.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunocytochemical demonstration of glial-neuronal interactions and myelinogenesis in subcultures of rat brain cells

Subcultures have been established from primary rat brain cell cultures and have been characterised with a range of cell-specific immunocytochemical markers. The subcultures are mainly composed of fibrous astrocytes, oligodendrocytes and neurones. The cells do not divide to any great extent giving a system where it is possible to follow culture development at the cellular level for a number of weeks. During this time oligodendrocytes colonise subpopulations of neurones, differentiate further showing the presence of myelin basic protein and elaborate myelin-like membrane; the fibrous astrocytes remain scattered uniformly throughout the cultures. Radially oriented processes emerge from the oligodendrocyte-neurone aggregates which subsequently coalesce to form fascicles that link the clusters of cells together. These fascicles react with antibodies for both neurofilament protein and myelin basic protein. The subcultures provide a straightforward system that is composed of cells derived entirely from the CNS, is free from mitotic inhibitors and yet retains a sufficiently low cell density to allow immunocytochemical identification of the cell types present. The subcultures should be useful for the study of trophic interactions between oligodendrocytes and neurones as well as the early events associated with myelinogenesis.

Popliteal artery damage in closed injuries of the knee

Injury to the popliteal artery is reported in two patients with closed ligament injuries of the knee, and no fracture or dislocation. The importance of careful assessment of the circulation in this type of patient is emphasised.

Mica sandwich technique for preparing macromolecules for rotary shadowing

The sandwich technique, in which a drop of sample solution is spread into a thin layer between two pieces of freshly cleaved mica, is a simple-to-use alternative to spraying for depositing macromolecules onto mica. Test specimens of collagen molecules and actin filaments were found to suffer less shear-induced damage, they were more uniformly distributed, and only very small sample volumes were needed. Either drying from a glycerol solution (40-70% v/v) or freeze-drying can be employed. Glycerol-drying is simpler, but freeze-drying may offer better preservation of supra-molecular assemblies.

The development of a method for assessing the quality of life of cancer patients

Although the need for a method of measuring the quality of life of patients undergoing therapy for cancer has been widely recognised, no adequately evaluated or feasible method has been established. We describe a method in which 31 items were assessed by patient self report using linear analogue scales. Eighteen items inquiring about general health problems were derived from the Sickness Impact Profile, an established method of assessing the effect of health upon behaviour and function. Thirteen items inquiring about major problems associated with breast cancer were derived from clinical experience and the opinions of patients with this disease. Each item of the measurement method (instrument) has been evaluated for content, feasibility, reliability and validity by methods that are widely used in psychometry but less familiar in medicine. It appeared easy to use, acceptable and reliable in these assessment. Validity was evaluated indirectly since no standard measurements of quality of life exist for comparison. Most items appeared valid when compared to alternative measurement methods including the Sickness Impact Profile and evaluation by a physician in a structured interview. The correlations between items in the instrument were analysed by factor analysis and seemed to fit with the clinical features of breast cancer. The method distinguished between clinically distinct groups of patients and detected changes with time. The study illustrates the possible approaches to the scientific evaluation of methods for measuring subjective features of patients lives. This method appears suitable for some purposes to measure quality of life in breast cancer and is intended to be flexible enough to be modified for other diseases. However, further evaluation, development and refinement will be needed before routine clinical application can be recommended.

Computed tomography of the anterior cruciate ligament

The anterior cruciate ligaments of 20 patients with suspected pathology in one ligament were studied by thin-section computed tomography (CT) and reformating techniques. In 19 patients, the suspect anterior cruciate ligament was abnormal and this was confirmed by subsequent arthroscopy or arthrotomy in thirteen. Thin-section CT and reformatting techniques provide a useful means of non-invasively imaging the anterior cruciate ligament.

Aeroallergens of the southeast Missouri area: a report of skin test frequencies and air sampling data

Aeroallergens in the Southeast Missouri area were identified by analyzing the positive skin tests of eight hundred seventeen patients and five years of air sampling. The important trees, grasses and weeds are enumerated. Reactivity levels of house dust, feathers and Dermatophagoides farinae exceeded all others. First among the fungi was Epicoccum purpurascens .