Civilian colon trauma: factors that predict success by primary repair

BACKGROUND

Primary repair has become the most common method of treatment for civilian injuries of the colon. However, colostomy may still be required in selected patients.

AIMS

This study was undertaken to identify factors for the performance of colostomy in patients with colon injuries.

METHODS

During a 60-month period, all penetrating injuries to the colon treated at Saint Louis University Hospital were evaluated. All patients underwent an operation within six hours of injury. Rectal injuries were excluded.

RESULTS

One hundred thirty consecutive patients with injuries to the colon were identified. Primary repair was performed in 81 patients (62 percent). Fecal diversion was used in 49 patients (38 percent). No deaths occurred related to colon injury. Complications related to colon injury included wound infections in 22 patients (17 percent) and intra-abdominal complications in 16 patients (abscess, 14; fecal fistula, 1). Wound complications were most closely related to whether the skin was closed primarily or left open (22 vs. 8 percent). Intra-abdominal complications occurred in 7 percent of patients in whom the colon injury was closed primarily and in 20 percent of patients in whom a stoma was created (P > 0.05). Patients chosen for colostomy had significantly greater blood loss, more associated injuries, and higher scores on the Abdominal Trauma Index (ATI) and Colon Injury Scale (CIS) and were more likely to have gross contamination (P < 0.05). Stepwise regression analysis of 13 factors revealed that only gross contamination and ATI predicted the occurrence of intra-abdominal complications and that CIS most closely predicted either wound or intra-abdominal complications. Stratification of patients based on an ATI of > or =30 and a CIS of > or =4 revealed no difference in outcome between primary repair and colostomy in either the low-risk or high-risk groups. However, severity of injury was greater in patients treated with colostomy.

CONCLUSIONS

Primary repair can be accomplished with low morbidity in the majority of civilians with penetrating injuries to the colon. Colostomy may be required in high-risk patients as defined by an ATI of > or =30 in association with a CIS of > or =4.

Transitions in infant feeding during the first year of life

OBJECTIVE

To document ages at which transitions in infant feeding occur, to compare these transitions to literature reports from the 1970s and 80s, and to identify maternal characteristics related to the age of the infant when solid food was first introduced.

METHODS

Ninety-eight mother/infant pairs (middle and upper socioeconomic status) participated in the longitudinal study. Using a randomized, incomplete block design, in-home interviews were conducted by trained personnel when infants were 2, 3, 4, 6, 8, 10, and 12 months of age; each mother/infant pair was seen four or five times. Information on food intake, including breast milk/formula, was collected at each interview. Means +/- SD and frequencies were calculated, and least squares analysis of variance was used to develop a predictive model related to the introduction of cereal.

RESULTS

Most mothers decided on the initial feeding mode (breastfeeding or formula) prior to pregnancy; 83% breastfed initially although most (76%) totally discontinued breastfeeding by 6 months. Infants' ages varied greatly when each of the seven categories of food was introduced, cereal was added to the infants' diets at a mean age of 3.8 +/- 1.4 (SD) months, juice 4.7 +/- 2.2, fruit 4.9 +/- 1.6, vegetables 5.2 +/- 1.3, mixed foods 7.8 +/- 2.1, table foods 8.2 +/- 2.1, and meat 8.2 +/- 2.1. The multivariate model explained 59% of the variability in ages of infants when cereal (generally the first solid food) was added. Significant variables (p < or = 0.05) were feeding mode, recommendation by the physician, and the interaction between feeding mode and education of the mother. Mother's employment and sibling rank of the infant contributed to the model (p = 0.06 and p = 0.09, respectively). Infants' age when cereal was added was not related to the variables of gender or birth weight.

CONCLUSIONS

The finding that the mothers' decision whether or not to breastfeed was made prior to conception supports the importance of population-based education aimed at women in the child-bearing years as well as patient instruction early in the pregnancy. However, the duration of breastfeeding was shorter than was reported in the 1980s. Infants varied greatly in ages when the seven categories of complementary foods were added to their diets. Although recommendations for delaying introduction of solid foods until the infant is 4 to 6 months of age have been in place for more than a decade, about half the mothers in this study did so earlier. Characteristics of mothers who introduced cereal earliest (i.e., mean age of infants < 4 months) were more likely to be formula feeding when cereal was added, to feed cereal via the bottle, to be primiparous, to be employed outside the home, and/or not to cite the physician as a source for guiding the infant's transition to supplemental food.

Motor-vehicle crash-injury risk factors among American Indians

The rates of motor-vehicle crash mortality are highest among American Indians and Alaska Natives, compared to other ethnic groups. The aim of this study was to compare risk factors for motor-vehicle crashes and occupant injuries between rural and urban American-Indian (AI) drivers, and between rural AI and non-AI rural drivers. A statewide traffic-accident database was linked to the Indian Health Service patient-registration database to identify crashes that involved American-Indian drivers. Using a cross-sectional design, crashes occurring in a two-county region during 1989 and 1990 were studied. A total of 9329 motor-vehicle crashes involving 16,234 drivers and 6431 passengers were studied. Two percent of drivers were American Indian. Compared to American-Indian drivers in urban crashes, rural crashes involving American-Indian drivers were more likely to result in injury or death (38% vs 64% p < 0.001). The difference in risk for crashes between urban and rural non-AI drivers was not as high (42% vs 33%). Only 44 percent of rural American-Indian motor-vehicle occupants reported wearing seat belts, compared to 70 percent of urban American-Indian occupants (p < 0.05). Rates of driver alcohol impairment, as assessed by the police, were much higher among AI drivers and highest among rural AI drivers. We conclude that, compared to non-American-Indian drivers, AI drivers are less likely to be restrained and more likely to be alcohol-impaired at the time of the crash. These risks are higher among rural AI drivers than urban AI drivers.

Focal glomerulosclerosis in the remnant kidney model--an inflammatory disease mediated by cytokines

BACKGROUND

The mechanism of progression of established renal disease remains unclear. While a low protein diet slows this progression, the role of cytokines in this process has been little investigated.

METHODS

We investigated cytokine expression by Northern blot and immunohistochemistry in two groups of 5/6 nephrectomized rats (5/6 Nx) fed a normal (24%) or low (6%) protein diet and compared them with sham operated controls.

RESULTS

The rats on 6% protein diet had significantly less focal glomerulosclerosis (FGS) (17.4 +/- 4.4 vs 27.4 +/- 8.8%, P < 0.05) and global sclerosis (GGS) after 7 weeks (0.4 +/- 0.8 vs 3.5 +/- 2.1% of glomeruli P < 0.05). Both experimental groups showed three times control levels of MCP-I expression after 2 weeks. However in the 5/6 Nx 6% protein group the expression decreased at 4 weeks (1.5 times controls) and reached control levels after 7 weeks. In contrast, the 5/6 Nx 24% protein group exhibited a further marked increase after 4 weeks (5.6 times controls) and was still two-fold higher after 7 weeks. TGF-beta expression was modestly but consistently increased at all time points (120-160% of controls), with no difference between the two study groups. Neither IL-1 beta or TNF-alpha was detectable at any time. Immunohistochemistry demonstrated TGF-beta intracellularly in distal tubular cells in both experimental and control animals, while MCP-1 protein was found in the area of FGS and in the apical pole of distal tubular cells in both experimental groups. Glomerular and interstitial ED1 positive cells were significantly increased after four weeks in the 5/6 Nx 24% protein group (P < 0.05).

CONCLUSIONS

A 'mechanical' injury to the kidney clearly results in an inflammatory response associated with the upregulation of MCP-1. A low protein diet modulates the expression of MCP-1 and improves the morphological sequelae seen after renal ablation.

The mouse Spam1 maps to proximal chromosome 6 and is a candidate for the sperm dysfunction in Rb(6.16)24Lub and Rb(6.15)1Ald heterozygotes

We have determined the chromosomal localization of the murine gene encoding the 68-kDa sperm adhesion molecule 1, Spam1 or Ph-20. Using two independent approaches, fluorescence in situ hybridization (FISH) and interspecific backcross analysis we show the Spam1 maps to proximal mouse Chromosome (Chr) 6. This map position is within the conserved linkage group corresponding to human Chr 7q, where the human homolog, SPAM 1, has been shown to map previously. Genetic mapping shows the gene to be very closely linked to Met, one of the most proximal loci on MMU 6. It thus places the gene near the centromere and the junction of the Rb(6.16)24Lub and Rb(6.15)1Ald translocations. The essential role of the Spam1 sperm antigen in mouse sperm-egg interactions and its gene location provide strong support for its candidacy as the gene involved in the dysfunction of mouse sperm bearing the Rb(6.16)24Lub or Rb(6.15)1Ald translocation.

Characterization of microwell cultures of dissociated brain tissue for studies of cell-cell interactions

Microwell cultures of dissociated tissue from prenatal rat hippocampus and cerebral cortex as well as from early postnatal cerebellum were used for quantification of neuronal aggregation, process extension, and fasciculation. It was shown that the cells in culture from these different brain regions developed differently with regard to both architecture and rate of differentiation. The effect of a polyclonal antibody against the neural cell adhesion molecule (NCAM), the excitatory amino acid receptor agonist N-methyl-D-aspartate (NMDA), and the neurotoxin acrylamide on aggregation and fiber formation was investigated. Exposure to the NCAM antibody led to formation of fewer but larger aggregates and stimulated the morphological development of the cultures. Acrylamide affected aggregate formation, leading to smaller but more numerous aggregates, and it inhibited process extension and fasciculation. Treatment with NMDA affected process formation and led to formation of more numerous but smaller aggregates. Some of these effects were strongly tissue-dependent. Thus, large differences were seen regarding the effect of the NCAM antibody on aggregation and process extension in cultures from the different brain areas. The culture systems appear to represent convenient and reliable screening tools to study the influence of putative morphoregulatory substances on cell-cell interactions during early neuronal development.

Recommended clinical practices for maximizing peritoneal dialysis clearances

Data from the Canada-U.S.A. (CANUSA) Study have recently confirmed a long-suspected linkage between total clearance and patient survival in peritoneal dialysis (PD). Recognizing that what we have historically accepted as adequate PD simply is not, the Ad Hoc Committee on Peritoneal Dialysis Adequacy met in January, 1996. This committee of invited experts was convened by Baxter Healthcare Corporation to prepare a consensus statement that provides clinical recommendations for achieving clearance guidelines for peritoneal dialysis. Through an analysis of 806 PD patients, the group concluded that adequate clearance delivered with PD can be achieved in almost all patients if the prescription is individualized according to the patient's body surface area, amount of residual renal function, and peritoneal membrane transport characteristics. Use of 2.5 L to 3.0 L fill volumes, the addition of an extra exchange, and giving automated peritoneal dialysis patients a "wet" day are all options to consider when increasing weekly creatinine clearance and KT/V. Rather than specify a single clearance or KT/V target, the recommended clinical practice is to provide the most dialysis that can be delivered to the individual patient, within the constraints of social and clinical circumstances, quality of life, life-style, and cost. The challenge to PD practitioners is to make prescription management an integral part of everyday patient management. This includes assessment of peritoneal membrane permeability, measurement of dialysis and residual renal clearance, and adjustment of the dialysis prescription when indicated.

Solute clearance approach to adequacy of peritoneal dialysis

To investigate the effect of dialysis prescription on patient outcome for peritoneal dialysis patients, the relationship between total solute clearance and the relative risk of death has been investigated. Preliminary studies have suggested that more clearance is better and that patient outcome is predicted by total solute clearance. The recently published Canada-U.S.A. (CANUSA) multicenter study, evaluating adequacy of dialysis and nutrition in peritoneal dialysis patients, has further defined this relationship. Although these publications allow us to establish guidelines for the treatment of peritoneal dialysis patients, they also define the limitation of our knowledge and raise new questions. In this article we review our current knowledge regarding the predicted value of total solute clearance with patient outcome and nutritional status. Furthermore, we attempt to outline a practical approach for optimizing total solute clearance in peritoneal dialysis patients. Based on a review of the published literature and clinical recommendations, we feel that the minimal target total solute clearance for continuous forms of peritoneal dialysis is a weekly total KT/V > 2.0 and/or a weekly total creatinine clearance > 60 L/week/1.73 m2. For intermittent therapies, a weekly total KT/V > 2.2 and/or a weekly total creatinine clearance > 70 L/week/1.73 m2 is recommended.

Supplementation with L-2-oxothiazolidine-4-carboxylic acid, a cysteine precursor, does not protect against lipid peroxidation in puromycin aminonucleoside-induced nephropathy

Lipid peroxidation in the kidney has been shown to precede proteinuria in puromycin aminonucleoside (PAN)-induced nephropathy. The aim of this study was to determine if L-2-oxothiazolidine-4-carboxylic acid (procysteine) would protect rats against PAN-induced nephrotoxicity. Male Sprague-Dawley rats were treated with procysteine (16 mg/100 g body weight i.p.) 24 h and 30 min prior to receiving a single injection of PAN (15 mg/100 g body weight i.v.) followed by procysteine in the drinking water (4 g/l). Control rats received procysteine alone (intraperitoneally and in drinking water) or PAN alone and then plain water. Proteinuria was not significantly different between PAN/ procysteine and PAN groups, reaching a maximum at day 14 and persisting at day 28. Lipid peroxidation was more severe in PAN/procysteine rats reaching a maximum at day 3 (253 +/- 30 ng/mg protein) compared to day 5 in PAN rats (196 +/- 20 ng/mg protein). Procysteine alone did not modulate proteinuria over 28 days or lipid peroxidation over 7 days. GSH levels over 7 days were not elevated by procysteine and were virtually zero in PAN and PAN/procysteine rats. Focal glomerulosclerosis (FGS) was worse at day 28 in PAN/procysteine rats than in PAN rats (39 +/- 8.2 vs. 23 +/- 4.5%; p < 0.05). This study shows that procysteine as a potential source of reducing equivalents does not protect against renal lipid peroxidation and FGS in this model. On the contrary, PAN/procysteine rats developed significantly more FGS through yet unknown mechanisms.

A comparison of chlorhexidine, cetylpyridinium chloride, triclosan, and C31G mouthrinse products for plaque inhibition

There are a large number of mouthrinse products available to the general public for use as adjuncts to oral hygiene. Many have not been evaluated and relatively few comparisons of products have been made. This study compared 4 mouthrinse products containing cetylpyridinium chloride (CPC), chlorhexidine, C31G, or triclosan with saline rinse included as a placebo control. Twenty dentate volunteers took part in this 4-day plaque regrowth study which had a single blind, randomized cross-over design balanced for residual effects. On day 1 of each study period, volunteers were rendered plaque free by a professional prophylaxis, suspended normal oral hygiene measures, and rinsed twice daily for 1 minute with 15 mL of the allocated rinse. On day 5, subjects were scored for disclosed plaque by plaque index and plaque area. By both measures the order of decreasing product efficacy was chlorhexidine, CPC and triclosan, C31G, and saline. All the differences in favor of the chlorhexidine product were highly significant as were those in favor of the other rinses compared to saline. It is concluded that the findings of this study reflect the actual chemical benefits of the products divorced from the indeterminate variable of toothbrushing.

Experimental glomerulosclerosis: Defektheilung of the kidney

Research in the role of cytokines in experimental glomerulonephritis has increased our understanding of the mechanisms that may be involved in the development of progressive renal disease. Glomerulosclerosis, the final common pathway in a variety of underlying kidney diseases, is characterized by increased extracellular matrix formation and cell proliferation. Transforming growth factor-beta (TGF-beta) and monocyte chemoattractant protein-1 (MCP-1) have been identified in animal models as mediators in the processes that follow renal injury. There is evidence of similar events occurring in other fibrotic disorders, suggesting that there is a common generic pathway of fibrosis. This review summarizes our knowledge of TGF-beta and MCP-1 in experimental kidney disease and compares these results with mechanisms described in other organs. We propose that glomerulosclerosis represents Defektheilung (healing by secondary intention) of the kidney after various injuries. The growing knowledge of the mechanisms involved will help advance future therapeutic interventions by directing the healing process toward primary healing.

Multiple organ failure: is it disappearing?

The incidence of multiple organ failure (MOF) during the last decade has been reported variously as 2% to 25%, depending on the patient population examined. The mortality rate from this devastating complication ranges from 40% to 80%. Although the incidence has not changed during the last decade, it does not mean that there has been no progress. Tertiary centers are now seeing trauma and nontrauma patients who have more significant underlying disease and injuries. Likewise, a higher percentage of our trauma patients are now referred from outside institutions where there may not be the facilities to administer the complex, rapid resuscitation these patients require. Prevention of MOF remains its best treatment. Rapid, adequate volume resuscitation, adequate nutrition, appropriate antibiotic usage, and aggressive pulmonary management are important for preventing the downward physiologic spiral that leads to MOF and death. Once MOF has occurred, it is not clear that these same measures are as effective in altering outcome.

A 6-month home-usage trial of 0.1% and 0.2% delmopinol mouthwashes (I). Effects on plaque, gingivitis, supragingival calculus and tooth staining

Delmopinol is a morpholinoethanol derivative which, in mouthrinses used in the absence of normal oral hygiene, has been shown effective in the inhibition of plaque and gingivitis. The aim of this study was to determine the adjunctive oral hygiene benefits and safety of delmopinol rinses when used alongside normal toothcleaning. This 6-month home use study was a placebo-controlled, double-blind, randomised parallel design evaluating 0.1% and 0.2% delmopinol rinses and structured to conform with the ADA Council of Dental Therapeutics guidelines. A total of 450 dentate male and female subjects were recruited who had no relevant medical or pharmacotherapy histories determined from a full medical examination, including haematological and biochemical tests. Subjects had moderate levels of plaque and gingivitis. At baseline, 3 and 6 months subjects were scored for plaque, gingivitis, tooth stain and supragingival calculus, with plaque sampled for microbiological analysis. Additionally, oral mucosal examinations were performed and subjects questioned for adverse symptoms. Baseline special tests were repeated at the end of the study. After baseline examinations, the subjects received a professional prophylaxis, provided with the allocated mouthwash and instructed to use 10-ml volumes for 60 s 2 x daily and where appropriate after toothbrushing and meals. Demographic features of the 3 groups were similar and losses to trial were small. Adverse signs and symptoms included transitory numbness of the tongue, tooth and tongue staining, taste disturbance and rarely mucosal soreness and erosion. All local side-effects were less commonly reported at 6 compared to 3 months and only 6 subjects were withdrawn because of adverse event. No systemic effects attributable to the agent were observed and no significant shifts in haematological or biochemical parameters occurred. All groups showed considerable improvements in oral hygiene and gingival health with some significant differences in favour of 0.2% delmopinol compared to placebo for gingivitis and more particularly plaque. Staining was also significantly increased in the delmopinol groups but not calculus. In the present study, a considerable Hawthorne effect occurred, which must in part explain why only a modestly significant effect was achieved.

Diaphragm fatigue following maximal ventilation in man

When highly motivated normal subjects perform maximal isocapnic ventilation, a substantial fall in ventilation is observed during the first minute associated with slowing of the maximum relaxation rate (MRR) of the inspiratory muscles. This suggests that these muscles are excessively loaded, raising the possibility that overt contractile failure of the diaphragm contributes to the fall in ventilation. We therefore investigated the effect of maximal isocapnic ventilation (MIV) on twitch transdiaphragmatic pressure (Pdi,Tw) elicited by cervical magnetic stimulation. We measured Pdi,Tw before and after 2 min MIV in nine normal subjects. Initial mean (SD) ventilation for the nine subjects was 196 (15) L.min-1 falling by 35% at 1 min. Pdi,Tw fell following MIV, at 10 min was reduced by 24%, and remained substantially reduced 90 min after MIV. No change in Pdi,Tw was observed during control studies in which subjects were studied with the same protocol but omitting MIV. We conclude that diaphragmatic contractility is reduced after 2 min maximal isocapnic ventilation and diaphragmatic fatigue may be a limiting factor in maximal ventilation in man.

Effects of osmotic solutes on fibronectin mRNA expression in rat peritoneal mesothelial cells

Hypertonic glucose in a peritoneal dialysate may modulate cell metabolism in the peritoneal cavity during continuous ambulatory peritoneal dialysis (CAPD). To examine the effects of high glucose concentration and hyperosmolarity, rat mesothelial cells were cultured for 3 or 6 days in media containing either 5, 25 or 50 mM glucose containing 20 or 45 mM mannitol. Fibronectin gene expression was investigated by Northern blot analysis. By day 6, fibronectin mRNA levels increased compared to 5 mM glucose controls with increasing glucose concentration (25 mM, 193%, 50 mM, 314%); high osmolarity due to mannitol did not increase mRNA levels (20 mM and 45 mM mannitol yielded 75 and 104%, respectively). Thus, hypertonic glucose augments fibronectin gene expression in peritoneal mesothelial cells due to the higher concentrations of glucose and not to hyperosmolarity. The glucose-driven increase in fibronectin expression may contribute to the peritoneal fibrosis in CAPD patients.

The efficacy of an anti-gingivitis chewing gum

Chlorhexidine is a well-established agent used for the control of supragingival plaque but is not without disadvantages, such as tooth staining, which limits its clinical applications to short-term use. This clinical trial studied the clinical effectiveness and stain-forming potential of chlorhexidine in a chewing gum base. Subjects (151) were screened for baseline plaque and gingival indices before receiving a dental prophylaxis and randomized into 3 treatment groups: group 1 chewed 2 pieces of chlorhexidine diacetate gum for 10 min 2x a day (total daily chlorhexidine = 20 mg), group 2 chewed 2 pieces of placebo gum for 10 min 2x a day and group 3 rinsed with 10 ml of 0.2% chlorhexidine gluconate mouthwash for 1 min 2x per day (total daily chlorhexidine = 40 mg). Plaque, gingivitis and stain evaluations were made at 4 and 8 weeks. Plaque and bleeding scores were significantly lower at 4 and 8 weeks in the chlorhexidine gum group compared to the placebo gum group and similar at 8 weeks to the rinse group. Stain intensity at week 8 was significantly less for the chlorhexidine gum than rinse. The staining measured by extent was also less with the chlorhexidine gum than the rinse, but the difference was not significant at week 4. At week 8, stain extent was significantly lower in the chlorhexidine gum group than chlorhexidine rinse. In conclusion, the results of this study demonstrate that this chlorhexidine chewing gum used with normal tooth cleaning provides similar adjunctive benefits to oral hygiene and gingival health as a 0.2% chlorhexidine rinse.

Probing active galactic nuclei with H2O megamasers

We describe the characteristics of the rapidly rotating molecular disk in the nucleus of the mildly active galaxy NGC4258. The morphology and kinematics of the disk are delineated by the point-like watervapor emission sources at 1.35-cm wavelength. High angular resolution [200 microas where as is arcsec, corresponding to 0.006 parsec (pc) at 6.4 million pc] and high spectral resolution (0.2 km.s-1 or nu/Deltanu = 1.4 x 10(6)) with the Very-Long-Baseline Array allow precise definition of the disk. The disk is very thin, but slightly warped, and is viewed nearly edge-on. The masers show that the disk is in nearly perfect Keplerian rotation within the observable range of radii of 0.13-0.26 pc. The approximately random deviations from the Keplerian rotation curve among the high-velocity masers are approximately 3.5 km.s-1 (rms). These deviations may be due to the masers lying off the midline by about +/-4 degrees or variations in the inclination of the disk by +/-4 degrees. Lack of systematic deviations indicates that the disk has a mass of <4 x 10(6) solar mass (M[symbol: see text]). The gravitational binding mass is 3.5 x 10(7) M[symbol: see text], which must lie within the inner radius of the disk and requires that the mass density be >4 x 10(9) M[symbol: see text].pc-3. If the central mass were in the form of a star cluster with a density distribution such as a Plummer model, then the central mass density would be 4 x 10(12) M[symbol: see text].pc-3. The lifetime of such a cluster would be short with respect to the age of the galaxy [Maoz, E. (1995) Astrophys. J. Lett. 447, L91-L94]. Therefore, the central mass may be a black hole. The disk as traced by the systemic velocity features is unresolved in the vertical direction, indicating that its scale height is <0.0003 pc (hence the ratio of thickness to radius, H/R, is <0.0025). For a disk in hydrostatic equilibrium the quadrature sum of the sound speed and Alfven velocity is <2.5 km.s-1, so that the temperature of the disk must be <1000 K and the toroidal magnetic field component must be <250 mG. If the molecular mass density in the disk is 10(10) cm-3, then the disk mass is approximately 10(4) M[symbol: see text], and the disk is marginally stable as defined by the Toomre stability parameter Q (Q = 6 at the inner edge and 1 at the outer edge). The inward drift velocity is predicted to be <0.007 km.s-1, for a viscosity parameter of 0.1, and the accretion rate is <7 x 10(-5) M[symbol: see text].yr-1. At this value the accretion would be sufficient to power the nuclear x-ray source of 4 x 10(40) ergs-1 (1 erg = 0.1 microJ). The volume of individual maser components may be as large as 10(46) cm3, based on the velocity gradients, which is sufficient to supply the observed luminosity. The pump power undoubtedly comes from the nucleus, perhaps in the form of x-rays. The warp may allow the pump radiation to penetrate the disk obliquely [Neufeld, D. A. & Maloney, P. R. (1995) Astrophys. J. Lett. 447, L17-L19]. A total of 15 H2O megamasers have been identified out of >250 galaxies searched. Galaxy NGC4258 may be the only case where conditions are optimal to reveal a well-defined nuclear disk. Future measurement of proper motions and accelerations for NGC4258 will yield an accurate distance and a more precise definition of the dynamics of the disk

The comparative tea staining potential of phenolic, chlorhexidine and anti-adhesive mouthrinses

Staining of teeth and mucous membranes is a well-known side-effect with chlorhexidine mouthrinses in which dietary chromogens play an important rôle. The purpose of this study was to determine whether a co-polymer anti-adhesive agent would prevent staining by a low concentration chlorhexidine solution. Additionally, the possibility that an essential oil/phenolic rinse product may cause staining was investigated. The rinses studied were the anti-adhesive alone and combined with 0.02% chlorhexidine and the essential oil/phenolic rinse. These were positioned against a positive control rise, 0.2% chlorhexidine, and a negative control rinse, water. The study was a single blind 5-treatment, randomised Latin square cross-over design, incorporating balance for carry-over effects. 15 volunteers participated and on Day 1 of each study period were rendered stain free by scaling and polishing of the teeth. Oral hygiene was suspended and 8 x per day subjects rinsed under supervision, firstly with the allocated formulation and then with 10 ml of warm black tea. On Day 4, tooth and tongue staining was scored by area and intensity (colour). A washout period of at least 3 1/2 days was permitted between treatment periods when oral hygiene was resumed. Before the study and during washouts, volunteers practised tongue brushing. Tooth and tongue staining was significantly increased with 0.2% chlorhexidine compared to the essential oil/phenolic rinse which in turn was significantly increased compared to the other 3 rinses. The antiadhesive/chlorhexidine rinse produced no more staining than the anti-adhesive or water rise. However, the parallel plaque regrowth study suggests this inhibition of staining resulted from the vitiation of the chlorhexidine activity by the antiadhesive. The methodology would appear a simple and quick way of assessing the propensity of mouthrinses to cause extrinsic staining.

The comparative effects on plaque regrowth of phenolic chlorhexidine and anti-adhesive mouthrinses

The inhibition of bacterial attachment to the tooth surface is one possible approach to plaque control. This study evaluated in vivo the plaque inhibitory action of a novel copolymer reported to have considerable antiadhesive properties in vitro. The study was a single blind, 5-treatment, randomised Latin square crossover design, incorporating balance for carry-over effects. The rinses were the antiadhesive (1%), the antiadhesive with 0.02% chlorhexidine, a 0.2% chlorhexidine rinse product, an essential oil/phenolic rinse product and water. 15 volunteers participated and on day 1 of each study period were rendered plaque-free, ceased toothcleaning and rinsed 2 x daily, under supervision, with the allocated formulation. On day 5, plaque was scored by index and area. Washout periods were 2 1/2 days. Alone or combined with chlorhexidine, the antiadhesive agent showed no effects greater than water. The chlorhexidine rinse was significantly more effective than the essential oil/phenolic rinse which in turn was significantly more effective than the other rinses.

A proposed glossary for dialysis kinetics

Quantification of the dialysis dose and assessment of nutritional status and response to nutritional therapy have become standard parts of the management of the chronic dialysis patient. Although advances in these areas have led to a more rational basis for therapy, certain misconceptions and points of confusion appear to have occurred. Recognizing the importance of a standard nomenclature to the development of concepts and the communication of research findings, we have attempted to compile a list of terms that are commonly used in the field of dialysis. New terms have been proposed for current ones that do not seem adequate. In addition, we have discussed potential methodologies for obtaining more accurate data for dialysis kinetics and for precise monitoring of nutritional intake and status. It is hoped that this glossary will stimulate discussion that will lead to refinements in terminology and concepts that will, in turn, improve research and practice in nephrology. It is anticipated that many of these definitions and recommendations will be modified or superseded as the management of patients with renal failure continues to advance.

Localized granuloma annulare and autoimmune thyroid disease. Are they associated?

This case report identifies a temporal relationship between the diagnosis of localized granuloma annulare and the subsequent development of primary hypothyroidism in a previously healthy 10-year-old girl. We suspect these disorders are associated, but any association between them requires further study.

The effect of oxidising mouthrinses compared with chlorhexidine on salivary bacterial counts and plaque regrowth

For various clinical indications, oxidising agents have been used in dentistry for many years. Little is known, however, of their antibacterial activity and their ability to inhibit plaque formation. In this study, 2 mouthrinses containing peroxyborate (Bocasan) and peroxycarbonate (Kavosan) were compared alongside a negative control saline rinse and a positive control chlorhexidine rinse (Corsodyl) for their ability to inhibit plaque reformation. Employing a randomised four replicate 4 x 4 latin square cross over design and, whilst omitting all other oral hygiene, plaque was measured by area and index after rinsing for 4 days. In a second study, in vivo antibacterial effects of the rinses were assessed by measuring salivary bacterial counts following single rinses with the preparations at various time intervals over 7 h. Plaque inhibition by chlorhexidine was significantly greater than the other rinses. All rinses were significantly better than the saline rinse at inhibiting plaque. For plaque area, the peroxycarbonate rinse was significantly better than the peroxyborate rinse at inhibiting plaque. Salivary bacterial count reductions were significantly greater compared to saline with chlorhexidine at all time intervals up to 7 h. Whilst both peroxyborate and peroxycarbonate rinses produced greater reductions in bacterial counts than saline up to 3 h, at no time interval were the differences significant. The findings of these studies would suggest oxidising mouthrinses may inhibit plaque formation not by a direct antibacterial effect, but by some other mechanism. The magnitude of plaque reductions obtained with the peroxyborate and more so peroxycarbonate rinses would suggest a need for further study of these preparations when used as adjuncts to normal toothbrushing.