Natural history of Streptococcus sanguinis in the oral cavity of infants: evidence for a discrete window of infectivity

The heterogeneous group of oral bacteria within the sanguinis (sanguis) streptococci comprise members of the indigenous biota of the human oral cavity. While the association of Streptococcus sanguinis with bacterial endocarditis is well described in the literature, S. sanguinis is thought to play a benign, if not a beneficial, role in the oral cavity. Little is known, however, about the natural history of S. sanguinis and its specific relationship with other oral bacteria. As part of a longitudinal study concerning the transmission and acquisition of oral bacteria within mother-infant pairs, we examined the initial acquisition of S. sanguinis and described its colonization relative to tooth emergence and its proportions in plaque and saliva as a function of other biological events, including subsequent colonization with mutans streptococci. A second cohort of infants was recruited to define the taxonomic affiliation of S. sanguinis. We found that the colonization of the S. sanguinis occurs during a discrete "window of infectivity" at a median age of 9 months in the infants. Its colonization is tooth dependent and correlated to the time of tooth emergence; its proportions in saliva increase as new teeth emerge. In addition, early colonization of S. sanguinis and its elevated levels in the oral cavity were correlated to a significant delay in the colonization of mutans streptococci. Underpinning this apparent antagonism between S. sanguinis and mutans streptococci is the observation that after mutans streptococci colonize the infant, the levels of S. sanguinis decrease. Children who do not harbor detectable levels of mutans streptococci have significantly higher levels of S. sanguinis in their saliva than do children colonized with mutans streptococci. Collectively, these findings suggest that the colonization of S. sanguinis may influence the subsequent colonization of mutans streptococci, and this in turn may suggest several ecological approaches toward controlling dental caries.

Pharmacokinetics of rapacuronium in infants and children with intravenous and intramuscular administration

BACKGROUND

A nondepolarizing muscle relaxant with an onset and offset profile similar to succinylcholine is desirable for pediatric anesthesia. The onset and offset of rapacuronium are rapid in children. In the current study, the authors determined its pharmacokinetic characteristics in children. In addition to administering rapacuronium by the usual intravenous route, the authors also gave rapacuronium intramuscularly to determine uptake characteristics and bioavailability.

METHODS

Forty unpremedicated patients aged 2 months to 3 yr were anesthetized with halothane, 0.82-1.0% end-tidal concentration. When anesthetic conditions were stable, rapacuronium was injected either into a peripheral vein (2 mg/kg for infants, 3 mg/kg for children) or a deltoid muscle (2.8 mg/kg for infants, 4.8 mg/kg for children). Four venous plasma samples were obtained from each subject 2-240 min after rapacuronium administration. A mixed-effects population pharmacokinetic analysis was applied to these values to determine bioavailability, absorption rate constant, and time to peak plasma concentration with intramuscular administration.

RESULTS

Plasma clearance was 4.77 ml x kg(-1) x min(-1) + 8.48 ml/min. Intramuscular bioavailability averaged 56%. Absorption from the intramuscular depot had two rate constants: 0.0491 min(-1) (72.4% of absorbed drug) and 0.0110 min(-1) (27.6% of the absorbed drug). Simulation indicated that plasma concentration peaks 4.0 and 5.0 min after intramuscular rapacuronium in infants and children, respectively, and that, at 30 min, less than 25% of the administered dose remains to be absorbed from the intramuscular depot.

CONCLUSIONS

In infants and children, rapacuronium's clearance and steady state distribution volume are less than in adults. After intramuscular administration, bioavailability is 56%, and plasma rapacuronium concentrations peak within 4 or 5 min.

Cost analysis of revision total hip arthroplasty. A 5-year followup study

A stratified, unselected sample of 30 patients who underwent revision total hip arthroplasty between 1990 and 1992 for whom complete clinical and financial data were available was studied. Clinical data included age, gender, diagnosis, length of stay, operative time and blood loss. Financial data included cost of implants, bone graft and accessories, hospital charge, and surgeon reimbursement. Results were compared with the results of an analogous group of 50 patients who underwent revision total hip arthroplasty at the same institution between 1995 and 1997. Cases were classified as simple (involving revision of only acetabular liner and/or femoral head), routine (revision of acetabular and/or femoral components), or complex (major structural graft, antiprotrusio cage, impacted grafting). For patients undergoing routine revision total hip arthroplasty, a dramatic decline of 52% occurred in length of stay during the 5-year span (10.7 days to 5.1 days). The average operative time also declined significantly (238 minutes to 199 minutes) as did the average implant cost ($4349 to $2827). Despite this, the average hospital charge increased 16% ($29,666 to $34,328). There was a significant and dramatic 35% decline in surgeon reimbursement ($3240 to $2178). There was no significant difference in surgeon reimbursement between simple, routine, and complex total hip arthroplasty. Patients who underwent complex procedures had a significantly greater length of stay (7.3 versus 5.1 days) and operative time (297 versus 199 minutes). The hospital charge was dramatically higher for patients undergoing complex procedures ($51,290 versus $34,328) but the surgeon reimbursement was lower on average, although not statistically significant ($1926 versus $2178). There was a significant increase in the number and complexity of revision total hip arthroplasties between the two periods. Significant decreases were achieved in length of stay, operating room time, and implant cost. Benefits from these changes were accrued to the hospital but not the surgeon because hospital costs decreased significantly whereas surgeon reimbursements declined dramatically.

Intramuscular rapacuronium in infants and children: dose-ranging and tracheal intubating conditions

BACKGROUND

Intravenous rapacuronium's rapid onset and short duration suggest that intramuscular rapacuronium might facilitate tracheal intubation without prolonged paralysis. Accordingly, the authors injected rapacuronium into the deltoid muscle to determine the optimal dose and time for intubation in pediatric patients.

METHODS

Unpremedicated patients (aged, 2 months to 3 yr) were studied. Part I: Spontaneous minute ventilation (V(E)) and twitch tension were measured during N2O/halothane anesthesia. Rapacuronium (2.2-5.5 mg/kg, given intramuscularly, n = 23), succinylcholine (4 mg/kg, given intramuscularly, n = 12), or vecuronium (0.1 mg/kg, given intravenously, n = 15) was given. Time to 50% depression of V(E) and 10% recovery of twitch were measured. Dose for each patient was changed 10-20% according to the previous patient's response. Part II: In 22 patients anesthetized with 0.82-1.0% halothane, the optimal rapacuronium dose determined in part I (infants, 2.8 mg/kg; children, 4.8 mg/kg) was given intramuscularly. Laryngoscopy was scored. Time to laryngoscopy was increased or decreased 0.5 min according to the previous patient's response.

RESULTS

Part I: Rapacuronium typically depressed ventilation in < or = 2 min with 10% twitch recovery in 20-60 min. With succinylcholine, median time to ventilatory depression was 1.3 and 1.1 min for infants and children, respectively; for vecuronium, 0.7 and 0.6 min. Part I: Intubating conditions were good-excellent at 3.0 and 2.5 min in infants and children, respectively; time to 10% twitch recovery (mean +/- SD) was 31 +/- 14 and 36 +/- 14 min in the two groups.

CONCLUSIONS

This pilot study indicates that deltoid injection of rapacuronium, 2.8 mg/kg in infants and 4.8 mg/kg in children, permits tracheal intubation within 2.5-3.0 min, despite a light plane of anesthesia. Duration of action is intermediate.

Metastable Equilibrium Solubility Distribution of Carbonated Apatite as a Function of Solution Composition

Previous studies have shown that carbonated apatites (CAPs) exhibit the phenomenon of metastable equilibrium solubility (MES) in weak acid media. The purpose of the present investigation was to examine two questions: first, whether the MES concept is applicable to a broader range of solution conditions and, second, whether a driving force function associated with a surface complex having a constant stoichiometry governs the dissolution of CAP and, if so, what is this stoichiometry. CAP preparations with carbonate contents of 1.8-5.7 wt% (synthesized by hydrolysis of dicalcium phosphate anhydrate in solutions of varying bicarbonate levels or by direct precipitation from supersaturated calcium/phosphate/carbonate solutions) were studied as follows. MES distributions for each of the CAP preparations were determined by equilibrating the CAP under stirred conditions in a series of acetate buffers (0.10 M) containing various levels of calcium and phosphate in the pH range 4.5-6.5 and a solution calcium/phosphate ratio in the range 0.1-10. The amount dissolved in each instance was regarded as the fraction of the CAP possessing an MES value greater than that corresponding to the ion activity product (IAP) of the equilibrating solution. The solution IAPs were calculated from the solution compositions using plausible calcium phosphate stoichiometries, viz., dicalcium phosphate dihydrate, octacalcium phosphate, tricalcium phosphate, hydroxyapatite, carbonated apatite (based on the bulk composition of the particular CAP involved in the experiment), and tetracalcium phosphate. The fraction of CAP dissolved was plotted against the solution IAPs for each experimental set using each of the six assumed stoichiometries for the surface complex. The results demonstrated that the MES concept was applicable to all of the CAP preparations in media of various solution compositions and different pH levels. The most important new outcome of this study was that MES profiles for each of the CAP preparations in all of the experiments were found to be superimposable when solution IAPs were calculated using the hydroxyapatite stoichiometry, while such was not the case when other stoichiometries were used to calculate the solution IAPs. Copyright 1999 Academic Press.

The influence of renal function on the pharmacokinetics and pharmacodynamics and simulated time course of doxacurium

Doxacurium's clearance (C1) is markedly decreased in patients with renal failure undergoing kidney transplantation. However, no studies have determined the influence of renal function (as assessed by creatinine clearance [CrCl]) on its pharmacokinetics in patients without renal failure. We studied 53 patients aged 19-59 yr. During N2O/isoflurane anesthesia, doxacurium was infused over 10 min, plasma was sampled for up to 6 h, and twitch tension was measured. A three-compartment model was fit to plasma concentration data and an effect compartment model to twitch data. Mixed-effects modeling was used to determine the influence of covariates, including CrC1, on doxacurium's pharmacokinetic/pharmacodynamic parameters. Obesity decreased both doxacurium's Cl (1.1% per percent above ideal body weight [IBW]) and its neuromuscular junction sensitivity (0.4% per percent above IBW). Cl increased 0.6% per mL/min increase in CrCl. In addition, the rate constant for equilibration between plasma concentration and effect decreased 46% per 1% increase in isoflurane, central compartment volume decreased 86% per 1% increase in isoflurane concentration, and slow distributional Cl decreased 69% per mg/ 100 mL increase in serum albumin. Simulations showed that the latter two covariates influence the time course of bolus doxacurium administration minimally. Both obesity and renal dysfunction prolong doxacurium's recovery markedly. When dosing is based on IBW, effects of CrCl on neuromuscular recovery are smaller compared with dosing based on actual weight. Therefore, obese patients should be dosed based on IBW. No further dosage adjustment is necessary for patients with renal dysfunction; however, recovery will take longer in patients with moderate-to-severe renal dysfunction.

IMPLICATIONS

We examined the factors influencing doxacurium's pharmacokinetic and pharmacodynamic characteristics. Both creatinine clearance and obesity significantly influence its time course. The effect of obesity is minimized if patients are dosed based on ideal body weight.

Impact of patient acuity on preference for information and autonomy in decision making

OBJECTIVES

To test the hypotheses that ED patients' desires for medical information and for autonomy in decision making are inversely related to increasing acuity of illness, increasing age, and lower level of formal education.

METHODS

The authors conducted a prospective study of ED patients who presented for care during seven nonconsecutive 24-hour periods. Of 804 patients approached, 665 completed a questionnaire that was administered by a trained research assistant. Patients rated their desire for medical information, and for participation in medical decision making, on two 10-cm visual analog scales. Patient acuity level was determined in routine fashion by trained triage nurses, who were unaware of the nature of this study.

RESULTS

Desire for information was uniformly high, and did not vary statistically between triage groups (p = 0.41). The most acutely ill patients (level I) were more likely to be excluded by the research interviewer (p < 0.001). Of included level I patients, desire to participate was not decreased (p < 0.01). Higher level of formal education (p = 0.036) and younger age (p < 0.001) were associated with greater desire for autonomy in decision making.

CONCLUSION

Among ED patients able to participate, higher acuity of illness was not associated with a decreased desire for medical information. Many very acutely ill patients preferred autonomy in medical decision making. Older patients and those with less formal education expressed a lesser desire for decision-making autonomy.

Pelvic reconstruction for severe periacetabular metastatic disease

The functional outcome of acetabular reconstruction in 21 patients with severe acetabular deficiency was examined. The surgical indications were pain, immobility, and loss of indepedence. Surgical reconstruction included curettage, placement of an acetabular roof ring with screws crossing the defect, cementation of the defect, and cemented hip arthroplasty. Although three patients died within the first month, the mean postoperative survival was 14.5 +/- 4.0 months, with a 10.4 +/- 3.0-month period of independent living. Statistically significant postoperative improvements were seen in pain and mobility scores. Using the Musculoskeletal Tumor Society score for the lower extremity, a mean postoperative score of 14.2 of a total 30 was calculated. Low scores were attributed to the patients' overall disease, including the requirement of continued narcotic pain control, occupational restriction, and the presence of Trendelenburg limp. Surgical complications occurred in six patients and included three early postoperative deaths, two related to poor preoperative pulmonary function; two dislocations, one related to a late infection; one femoral nerve palsy; and one foot drop. Although associated with a high complication rate, acetabular reconstruction for metastatic disease can lead to marked improvement in pain control, function, independence, and quality of life in carefully selected patients.

Relationships among carbonated apatite solubility, crystallite size, and microstrain parameters

The use of the metastable equilibrium solubility (MES) concept to describe the solubility properties of carbonated apatites (CAPs) and human dental enamel (HE) has been well established in previous studies using a range of CAPs with varying carbonate contents and crystallinities. It was shown in these studies that the mean value of the CAP MES is directly related to the broadening parameter full width at half maximum (FWHM) of the 002 reflection of the X-ray diffraction profile. The apparent solubility of the CAPs increased monotonically with an increase in the broadening of the diffraction peaks, and when this peak broadening was taken into account, carbonate had no additional effect upon the MES. The broadening of the diffraction peaks has been used as an indicator of crystallinity, and is generally influenced by both crystallite size and microstrain. The purpose of the present study was to extract the crystallite size and microstrain parameters separately from the X-ray diffraction peaks and then to determine their relationships to the corresponding MES values. The samples studied were CAPs synthesized by precipitation from Ca(NO3)2 and NaH2PO4 solutions in carbonate containing media at temperatures of 95, 80, and 70 degrees C, and powdered HE. The crystallite size and microstrain parameters were determined simultaneously with the refinement of the structural parameters with the Rietveld method of whole-pattern-fitting structure-refinement. A modified pseudo-Voigt function was used to model the observed peak profiles. The MES distributions for the CAPs and HE were determined by a previously described method. The results of this study showed that the CAPs possessed an MES distribution and therefore provided further support that MES distribution is a common phenomenon, regardless of the method of CAP synthesis. The crystallite size decreased and the microstrain increased with increasing carbonate content and decreasing temperature of synthesis of the CAPs. A plot of the mean of the MES distribution versus the microstrain parameter showed that the apparent solubility of the CAPs and HE correlated very well with the microstrain parameter. On the other hand, a plot of the mean of the MES distribution versus the crystallite size parameter showed a poor correlation between MES and crystallite size. These findings support a view that microstrain, rather than crystallite size, is the dominant factor governing the effective solubility of the CAPs and dental enamel.

p53 function influences the effect of fractionated radiotherapy on glioblastoma tumors

PURPOSE

Glioblastoma multiforme brain tumors (GM) are treated with a spectrum of fractionation regimens based on the clinical and anatomical characteristics of the tumor but rarely based on the molecular characteristics of the individual neoplasm. This study tests the hypothesis that the response of cell lines derived from GM to fractionated radiotherapy depends on the function of wild-type p53 (wt p53), a tumor suppressor gene frequently mutated in GM tumors.

METHODS & MATERIALS

Isogenic derivatives of glioblastoma cells differing only in p53 function were prepared using a retroviral vector expressing a dominant negative mutant of p53 (mt p53). Radiation survival in vitro was quantitated using linear quadratic and repair-saturation mathematical models. Apoptosis was assayed by a terminal deoxynucleotide transferase-labeling technique and chromatin morphology.

RESULTS

We have previously reported the generation of isogenic GM cell lines differing only in p53 function. U87-175.4, lacking wt p53 function, had a significantly lower alpha/beta value than U87-LUX.8, expressing functional wt p53, leading us to hypothesize that fractionated irradiation would preferentially spare GM cells harboring mt p53 compared with those expressing functional, wt p53. Survival curves following either 2.0 Gy or 3.5 Gy/fraction demonstrated that lack of functional wt p53 was associated with resistance to fractionated irradiation. Radiation-induced apoptosis could not account for the observed differences in clonogenic survival. Rather, our data suggested that a deficit in the G1-checkpoint contributed to increased resistance to fractionated irradiation of cells expressing mutant p53.

CONCLUSIONS

The effect of fractionated radiotherapy in GM may depend on the function of the tumor suppressor gene p53. A potential clinical consequence of these findings is that hyperfractionation regimens may provide a therapeutic advantage specifically for tumors expressing wt p53 whereas a radiotherapy course of fewer, larger fractions may be appropriate for the treatment of tumors carrying p53 mutations. Further studies are needed to confirm our proposal that the p53 status of GM tumors can be used to guide our choice of fractionation schemes.

Interleukin-10 inhibits cytokine synthesis in monocytes stimulated by titanium particles: evidence of an anti-inflammatory regulatory pathway

The anti-inflammatory mediator interleukin-10 was investigated as a potential inhibitor of proinflammatory cytokine release in human peripheral blood monocytes activated with titanium particles. It inhibited the secretion of both tumor necrosis factor-alpha and interleukin-6 in a dose-dependent manner, with complete inhibition observed at 2 ng/ml. Co-culture experiments were performed to determine whether this cytokine may have functional importance as an inhibitor of the inflammatory response. When unstimulated lymphocytes and monocytes were co-cultured with titanium-stimulated monocytes, they significantly suppressed the secretion of both interleukin-6 and tumor necrosis factor-alpha. The inhibitory effect of these co-cultured cells could be partially blocked with the addition of an interleukin-10 neutralizing antibody. Interleukin-10 levels were measured in monocyte cultures treated with titanium particles as well as in fresh monocyte cultures treated with conditioned medium from titanium-stimulated monocytes. The latter experiments demonstrated marked stimulation of interleukin-10 secretion in conditioned medium-treated cultures, an effect that was related to the presence of tumor necrosis factor-alpha in the conditioned medium. The addition of titanium to conditioned medium-treated cultures markedly reduced the secretion of interleukin-10, suggesting that the most responsive cells are unstimulated monocytes exposed to agents released from activated monocytes. Altogether, the expression and responsiveness to interleukin-10 suggest a potential role for anti-inflammatory cytokines in regulation of the inflammatory response to wear debris.

CD40-mediated signal transduction in human airway smooth muscle

CD40 is a member of the TNF receptor family that was initially described on the surface of B cells. Recently, CD40 has also been described on mesenchymal cells, such as endothelial cells and fibroblasts, where engagement by its ligand CD40 ligand can lead to up-regulation of costimulatory and cell adhesion molecules, as well as secretion of proinflammatory cytokines. Since airway inflammation potentially involves cell-cell interactions of T cells and eosinophils (which express CD40 ligand) with airway smooth muscle (ASM) cells, we postulated that ASM may express CD40 and that engagement of ASM CD40 may modulate smooth muscle cell function. We demonstrate that CD40 is expressed on cultured human ASM and that expression can be increased by treatment with TNF-alpha or IFN-gamma. Cross-linking CD40 on ASM resulted in enhanced IL-6 secretion and an increase in intracellular calcium concentrations, which were dependent on calcium influx. We show that CD40-mediated signaling events include protein tyrosine phosphorylation and activation of NF-kappaB. Pretreatment of ASM with the tyrosine kinase inhibitors genistein or herbimycin inhibited the rapid mobilization of calcium induced via CD40, suggesting that calcium mobilization was coupled to activation of protein tyrosine kinases. In addition, inhibition of calcium influx inhibited both CD40-mediated NF-kappaB activation and enhancement of IL-6 secretion. These results delineate a potentially important CD40-mediated signal-transduction pathway in ASM, involving protein tyrosine kinase-dependent calcium mobilization, NF-kappaB activation, and IL-6 production. Together, these results suggest a mechanism whereby T cell/smooth muscle cell interactions may potentiate airway inflammation.

Flux enhancement effects of ionic surfactants upon passive and electroosmotic transdermal transport

This study focused upon the enhancement effects of ionic surfactants upon passive and electroosmotic transdermal flux. The first phase of the study involved validating theories relating surface properties of a membrane to electroosmotic solvent flow under appropriate experimental conditions using a synthetic model membrane (stack of 50 Nuclepore membranes). Numerical solutions to the Poisson-Boltzmann equation and the equations of fluid motion served as the theoretical basis for the experimental studies. Important outcomes of the model membrane studies were that electroosmotic solvent flow velocity was enhanced by the addition of an anionic surfactant, sodium dodecyl sulfate, and reversed by the addition of a cationic surfactant, dodecyltrimethylammonium bromide. The effective membrane pore wall surface charge densities were determined under a variety of experimental conditions. Adsorption of dodecyl sulfate to the pore wall increased the net negative charge on the pore wall. A reversal of the net pore wall surface charge density resulted from the adsorption of dodecyltrimethylammonium. The interrelationship between electroosmosis, surfactant adsorption, and ionic strength was also evaluated. The second phase of the study was an investigation of the effects of sodium dodecyl sulfate upon the transport of neutral polar permeants through human epidermal membrane (HEM). Fluxes of [14C]urea and [3H]sucrose were simultaneously measured across HEM samples under passive and 250 mV conditions; flux measurements were made before, during, and after HEM exposure to sodium dodecyl sulfate. A systematic analysis of the experimental data made it possible to elucidate the specific contributions of sodium dodecyl sulfate and the applied electric potential to the overall flux enhancement. Sodium dodecyl sulfate enhanced the intrinsic passive permeability of the HEM, and it also enhanced the contribution of electroosmosis to the flux during iontophoresis.

Antimicrobial resistance in bacterial chronic sinusitis

Recent reports describe the emergence of antimicrobial resistant bacteria in acute sinusitis and an increased incidence of enteric gram negative bacilli in chronic sinusitis. The objective of this cross sectional study is to identify the emergent resistance patterns in bacterial chronic sinusitis. Specifically, this article seeks to characterize the bacteriology of outpatient chronic sinusitis, then to compare the antimicrobial susceptibilities of the bacterial isolates with standard culture data from a tertiary care center. Between March and August, 1994, 113 new outpatients presented with chronic sinusitis at a major teaching institution. Of these patients 34 underwent endoscopically guided aerobic culture of the paranasal sinuses and nasal cavities. Of the 48 total cultures, there were 43 positive cultures yielding 72 isolates. Thirty-eight cultures had two or fewer isolates; four cultures had three plus isolates, and one culture grew out normal flora. The most frequently isolated organisms were coagulase negative Staphylococcus (SCN), 20 (28%); Pseudomonas aeruginosa, 12 (17%); and Staphylococcus aureus, 9 (13%). Within the limited sample size for each isolate, Staphylococcus coagulase negative, Pseudomonas, and Pneumococcus demonstrated higher antimicrobial resistance compared to the medical center's corresponding nonurinary isolates. Additionally, three of six patients with Pseudomonal aeruginosa (50%) had a quinolone resistant strain. These preliminary data suggest that both an increased incidence of antimicrobial resistance and of enteric gram negative bacilli may exist in these outpatient, tertiary care center patients with chronic bacterial sinusitis.

Combined effects of laser irradiation/solution fluoride ion on enamel demineralization

OBJECTIVE

The effects of CO2 laser irradiation of dental enamel were evaluated in enamel demineralization experiments in partially saturated solutions (i.e., solutions containing both calcium and phosphate ions) with and without fluoride ions.

SUMMARY BACKGROUND DATA

Previous studies had shown that a continuous-wave CO2 laser at an energy density of around 130 J/cm2 may induce an increased acid resistance in human dental enamel as assessed by exposure to severe demineralization conditions (0.1 mol/L acetate buffer, pH 4.5 and ionic strength 0.5 mol/L).

METHODS

Enamel blocks were irradiated with a continuous-wave CO2 laser at a wavelength of 10.6 microns using energy densities of from 42.5 to 170.0 J/cm2. The blocks were then exposed to a partially saturated demineralizing solution with or without 0.2 ppm fluoride at a temperature of 30 degrees C for 24 hours. The demineralization was examined both qualitatively by light microscopy and quantitatively by microradiography.

RESULTS

A comparison between the lased and the unlased portions of enamel showed increased acid-resistance with increasing laser energy density and, at the highest energy density of 170.0 J/cm2, there was little or no lesion development in the fluoride-free dissolution medium. The demineralization of enamel was reduced dramatically in the presence of 0.2 ppm fluoride for both lased and unlased enamel; there was only modest lesion development observed for unlased enamel and, at an energy density as low as 85.0 J/cm2, the surface of enamel was found to be completely protected.

CONCLUSIONS

These findings are consistent with the mechanism that laser irradiation of dental enamel results in significant reduction of the effective solubility of enamel mineral and that there is a significant synergism between laser irradiation and solution fluoride with regard to this effect.

Gangliogenesis in leech: morphogenetic processes leading to segmentation in the central nervous system

Using intracellular lineage tracers to study the main neurogenic lineage (N lineage) of the glossiphoniid leech embryo, we have characterized events leading from continuous columns of segmental founder cells (nf and ns primary blast cells) to discrete, segmentally iterated ganglia. The separation between prospective ganglia was first evident as a fissure between the posterior boundary of nf- and the anterior boundary of ns-derived progeny. We also identified the sublineages of nf-derived cells that contribute parallel stripes of cells to each segment. These stripes of cells project ventrolaterally from the dorsolateral margin of each nascent ganglion to the ventral body wall. The position and orientation of the stripes suggests that they play a role in forming the posterior segmental nerve; they are not coincident with the ganglionic boundary, and they form well after the separation of ganglionic primordia. Previous work has shown that cells in the anterior stripe express the leech engrailed-class gene. Thus, in contrast to the role of cells expressing engrailed in Drosophila, the stripes of N-derived cells expressing an engrailed-class gene in leech do not seem to play a direct role in segmentation or segment polarity.

Decreased citrate improves iron availability from infant formula: application of an in vitro digestion/Caco-2 cell culture model

We have applied an in vitro digestion/Caco-2 cell culture model to the assessment of iron availability from human milk and a generic cow's milk-based infant formula. Experiments were designed to determine the availability of iron from human milk relative to infant formula and whether known promoters of iron absorption would increase Caco-2 cell iron uptake and availability from the infant formula. In addition, we sought to determine if decreasing the citrate concentration in the infant formula would increase the iron uptake. Although approximately twice as much iron was in solution from digests of the infant formula relative to that of human milk, smaller or equal amounts of iron were taken up from the infant formula relative to the human milk digest. These results are qualitatively similar to in vivo studies. Addition of known iron uptake promoters to infant formula did not enhance Caco-2 cell iron uptake from the infant formula digest, indicating that the iron in the infant formula existed predominantly in a tightly bound unavailable form(s). Enzymatic pretreatment of the infant formula with citrate lyase and oxalacetate decarboxylase decreased the citrate concentration by 67% and resulted in a 64% increase of iron in solution, which corresponded to a 46% increase in the cell iron uptake. Iron uptake from the "low citrate" formula plus cysteine was 102% greater relative to the nontreated formula. The results indicate that too much citrate can reduce iron uptake, particularly if it is present at concentrations greater than promoters such as ascorbic acid and cysteine.

Regulation of vascular endothelial growth factor expression by insulin-like growth factor I

Insulin-like growth factor I (IGF-I) and vascular endothelial growth factor (VEGF) levels are correlated with retinal ischemia-associated intraocular neovascularization in humans. Since VEGF is required for iris and retinal neovascularization in animal models of retinal ischemia, we tested whether IGF-I could act as an indirect angiogenic factor by increasing VEGF gene expression. IGF-I increased retinal pigment epithelial (RPE) cell VEGF mRNA in a concentration-dependent manner with an EC50 of 7 nmol/1 (53.6 ng/ml). RPE and bovine smooth muscle cells exposed to 50 nmol/l (383 ng/m1) IGF-I achieved peak VEGF mRNA expression within 2 h. IGF-I-treated RPE cells increased VEGF protein levels in conditioned media and stimulated capillary endothelial cell proliferation. Blockade of the IGF-I receptor with a neutralizing antibody abrogated the VEGF increases in RPE cells. Further, hypoxia-mediated and IGF-I-mediated increases in VEGF mRNA and protein levels were additive in RPE cells, and the hypoxia-induced VEGF increases were independent of endogenous IGF-I. VEGF promoter activity was enhanced by IGF-I in RPE cells, but VEGF transcript half-life was unaltered. In summary, the supplementation of RPE and smooth muscle cell cultures with IGF-I at 5-100 nmol/l increased VEGF mRNA and secreted protein levels. The VEGF increases in RPE cells occurred primarily through enhanced transcription of the VEGF gene and via the IGF-I receptor. Elevated IGF-I levels may promote neovascularization through increased retinal VEGF gene expression.

Chronic treatment with dexmedetomidine desensitizes alpha 2-adrenergic signal transduction

Tolerance to the hypnotic response was induced in rats by chronically infusing dexmedetomidine, a novel alpha 2-adrenergic agonist. The alpha 2-adrenoceptor affinity for dexmedtomidine and para-iodoclonidine was significantly reduced in tolerant rats, while Bmax was uncharged. The ability of pertussis toxin (PTX) to ribosylate guanine nucleotide regulatory proteins (G proteins) ex vivo was reduced in tolerant rats; the quantity of PTX-sensitive G proteins was unchanged. Forskolin-stimulated adenylyl cyclase was less sensitive to inhibition by dexmedetomidine in the tolerant rats; however, acute intraperitoneal injection of dexmedetomidine still reduced cyclic adenosine monophosphate levels in tolerant rats. Both the decrease in ribosylation and the lower alpha 2-adrenoceptor binding affinity may reflect a decrease in the ability of the G protein to couple to the alpha 2-adrenoceptors in the locus coeruleus of tolerant rats. In this state, the alpha 2 adrenoceptors are less capable of transducing the effector response (inhibition of adenylyl cyclase).

Technology evaluation report: obtaining pulse oximeter signals when the usual probe cannot be used

We studied the function of four different monitoring probes used with the Satlite pulse oximeter (Datex, Helsinki). The aim was to evaluate ease of use and compare the function of the probes and their attachment methods in different locations (finger, toe, ear, thumb web, instep, wrist, and ankle). Two similar pulse wave oximeters were used in the study. To select the best signal we determined the absolute height of the plethysmographic waveform for each probe. Probes were compared on awake normal adult volunteers (N = 13), in anesthetized adult patients (N = 12), and in neonates weighting 500-1000 g (N = 8). In all the adult trials, the clip-on finger probe was used as a reference, and probes taped or clipped onto the finger provided adequate signal from the ear or from the thumb web, however. In the neonates, taped-on probes were most satisfactory.

Prolonged ciprofloxacin administration does not accelerate neutrophil recovery after autologous bone marrow transplantation

STUDY OBJECTIVE

To determine whether prolonged ciprofloxacin administration following autologous bone marrow transplantation (ABMT) accelerates neutrophil recovery.

DESIGN

Retrospective analysis of 40 consecutive patients undergoing ABMT.

SETTING

Tertiary care bone marrow transplant program.

PATIENTS

Two sequential arms of 20 consecutive patients with Hodgkin's disease or non-Hodgkin's lymphoma undergoing ABMT.

INTERVENTIONS

The first arm received ciprofloxacin from the day of transplantation until initiation of broad-spectrum antibiotic therapy (median 5 days) while the second arm continued ciprofloxacin until recovery of the neutrophil count (median 15 days).

MEASUREMENTS AND MAIN RESULTS

Neutrophil recovery was similar in the two groups (16 vs 14 days; p = 0.41). There were no differences in platelet recovery, bacteremia, or treatment-related mortality.

CONCLUSION

Prolonged ciprofloxacin administration does not significantly accelerate neutrophil recovery following ABMT.

Cerebral ocular Whipple's disease: a 62-year odyssey from death to diagnosis

A 47-year-old white man with dementia, supranuclear ophthalmoplegia, and myoclonic ocular and facial jerks died in 1931. The case report in 1936 by Ford and Walsh diagnosed encephalitis. In 1993, we made a clinical diagnosis of Whipple's disease on the basis of the 1936 publication. We restudied the pathologic material and found, in addition to extensive encephalitis, PAS-positive material in only the eye, brain, spinal cord, and pituitary. Electron microscopy demonstrated free and intracytoplasmic microorganisms in the eye and brain. We review the history of cerebral ocular Whipple's disease and the implications from this case, which occurred before the development of antibiotics.

Coronary artery aneurysms after angioplasty and atherectomy

Coronary artery aneurysm formation after percutaneous transluminal coronary angioplasty and directional coronary atherectomy is unusual. We report the case of a left anterior descending coronary artery aneurysm that formed in such a patient. The left anterior descending coronary artery was bypassed and the aneurysm was plicated with the aid of coronary angioscopy. The English-language medical literature on the topic of coronary artery aneurysms is reviewed.

Preclinical ROC studies of digital stereomammography

Reports the diagnostic performance of observers in detecting abnormalities in computer-generated mammogram-like images. A mathematical model of the human breast is defined in which breast tissues are simulated by spheres of different sizes and densities. Images are generated by casting rays from a specified source, through the model, and onto an image plane. Observer performance when using two viewing modalities (stereo versus mono) is compared. In the stereo viewing mode, images are presented to the observer (wearing liquid-crystal display glasses), such that the left eye sees the left image only and the right eye sees the right image only. In this way, the images can be fused by the observer to obtain a sense of depth. In the mono viewing mode, identical images are presented to the left and right eyes so that no binocular disparities will be produced by the images. Observer response data are evaluated using receiver operating characteristic (ROC) analysis to characterize any difference in detectability of abnormalities (in either the density or the arrangement of simulated tissue densities) using the two viewing modes. The authors' experimental results indicate the clear superiority of stereo viewing for detection of arrangement abnormalities. For detection of density abnormalities, the performance of the two viewing modes is similar. These preliminary results suggest that stereomammography may permit easier detection of certain tissue abnormalities, perhaps providing a route to earlier tumor detection in cases of breast cancer.

Heat-treatment-induced reduction in the apparent solubility of human dental enamel

Holcomb and Young (1980) have shown a significant increase in human dental enamel (HE) structural order resulting from heat treatment in the temperature range of from 275 to 400 degrees C. Also, previous work in our laboratory had shown dramatic decreases in the initial dissolution rates (IDRs) of both carbonated apatite (CAP) heated at similar temperatures (from 300 to 500 degrees C) and HE exposed to CO2 laser irradiation for which calculated surface temperatures were in this same range. We hypothesize that thermal treatment shifts the apparent solubility distribution profile of HE toward lower apparent solubilities, paralleling the observed increased in crystal structural order and the decrease in IDRs. Powdered HE was heated in a furnace at temperatures ranging from 150 to 500 degrees C for 24 hours. The apparent solubility distributions of both heated and unheated HE powders were measured by equilibration for 24 hours in a series of partially saturated solutions simulating various amounts of HE dissolved in a pH 4.5 dissolution medium. The apparent solubility distribution for the unheated HE showed a peak at KHAP [the ion activity product based on the Ca10(PO4)6(OH)2 stoichiometry] of 10(121.0). Heat treatment shifted the apparent solubility distribution to lower solubilities. The peak KHAP values were approximately 10(124.8) at 200 degrees C; approximately 10(127.8) at 300 degrees C; and approximately 10(-129.1) from 400 to 500 degrees C. This approximately 8 orders of magnitude decrease in KHAP for HE heated at from 400 to 500 degrees C correlates with the previously observed reduction in the IDR driving force for laser-treated HE experiencing a similar surface temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

The helix-loop-helix protein Id-2 enhances cell proliferation and binds to the retinoblastoma protein

Cell growth and differentiation are usually antagonistic. Proteins of the basic helix-loop-helix (bHLH) family bind DNA and play important roles in the differentiation of specific cell types. Id proteins heterodimerize with bHLH transcription factors, blocking their activation of lineage-specific gene expression and thereby inhibiting cellular differentiation. To examine the effect of Id-2 on cell proliferation, we overexpressed Id-2 in the human osteosarcoma cell line U2OS. Id-2 expression in U2OS reduced the serum requirement for growth and stimulated cellular proliferation by shortening the doubling time and increasing the percentage of cells in S phase. We demonstrated that Id-2 expression was able to reverse the inhibition of cellular proliferation and the block in cell cycle progression mediated by the product of the retinoblastoma tumor suppressor gene pRB. This effect was not associated with changes in the state of pRb phosphorylation in transfected cells. In vitro, unphosphorylated pRb from cell lysates specifically bound Id-2 but was not able to bind a mutated form of Id-2 lacking the HLH domain that also did not antagonize the growth arrest by pRb. In vitro-synthesized pRb containing mutations within the E1A/large T-binding pocket did not bind Id-2. However, wild-type pRb was able to bind to a region of Id-2 corresponding to only the HLH domain. In vivo, a physical association between Id-2 and pRb was seen in cross-linked extracts from SAOS-2 cells transfected with Id-2 and pRb. Our data identify a role for Id-2 in the regulation of cellular proliferation and suggest that the interaction between Id-2 and pRB is a molecular pathway over which synchronous changes in growth and differentiation are mediated in vivo.

Open complex formation by DnaA initiation protein at the Escherichia coli chromosomal origin requires the 13-mers precisely spaced relative to the 9-mers

The 245 bp chromosomal origin, oriC, of Escherichia coli contains two iterated motifs. Three 13-mers tandemly repeated at one end of the origin and four 9-mers in a nearby segment of oriC are highly conserved in enteric bacteria, as is the distance separating these two sequence clusters. Mutant origins were constructed with altered spacing of the 9-mers relative to the 13-mers. Loss or addition of even a single base drastically reduced replication, both in vivo and in vitro. Spacing mutant origins bound effectively to DnaA protein but failed to support efficient open complex formation. These results suggest that interaction with the 9-mers positions at least one subunit of DnaA to recognize directly the nearest 13-mer for DNA melting.

The bovine papillomavirus type 1 genome contains multiple loci of static DNA bending, but bends are absent from the functional origin of replication

Twenty-four overlapping restriction fragments spanning the entire bovine papillomavirus type 1 (BPV-1) genome were analyzed by electrophoresis to determine the extent of static DNA bending in the BPV-1 genome. Thirteen of 24 fragments contained static bends. Based on known locations of previously mapped bend loci and the overlapping pattern of these 13 fragments, we estimate that there are 8-11 distinct static bend loci in the BPV-1 genome. The bend loci were not uniformly distributed on the genome and with one exception, were clustered from nucleotides 5816 to 2621 on the BPV-1 map. This portion of the BPV-1 genome contains most of the transcriptional regulatory sequences as well as the origin of replication. The concordance between the genomic distribution of DNA bends and cis-active elements is consistent with the possibility that bent sequences may contribute to the function of at least some of these elements. However, unlike SV40, there was no static bend at that functional origin of replication for BPV-1. The nearest bends to the origin were approximately 120 bp to the 5' side and 300 bp to the 3' side. As both of these bends were outside of the sequences required for origin function, it is unlikely that static bending plays a critical role in BPV-1 replication.

SPLATT combined with tendo achilles lengthening for spastic equinovarus in adults: results and predictors of surgical outcome

During a 4-year period, split anterior tibial tendon transfer (SPLATT) was performed on 42 adults with cerebrospastic equinovarus deformity. Twenty-one patients (24 feet) had a minimum 1-year follow-up, which included detailed documentation of foot appearance position and function as well as ambulatory status. Thirteen patients were male and 8 were female. Average age of the patients was 41 years. Seventeen patients were independent ambulators with orthoses, one was a maximally assisted ambulator. Three patients with spastic quadriparesis were nonambulatory. All patients had uniform surgical technique and postoperative management. This paper presents the results of SPLATT and identifies risk factors for poor surgical outcomes. After an average follow-up of 39 months, 83% of the feet were rated as having good or excellent results. All ambulatory patients had improved gait and 35% of them were able to discontinue their orthoses. Poor surgical outcomes were associated with nonambulatory status in brain injured patients (P = .018). Salvage of failed SPLATT is discussed.

Psychiatric complications of family reunion after four decades of separation

OBJECTIVE

After four decades of separation due to civil war, many people who had migrated to Taiwan from mainland China had the unexpected opportunity to briefly visit their families in mainland China. A study was conducted to examine psychiatric complications associated with these family reunions following long involuntary separation.

METHOD

Eighty subjects who made the journey were given semistructured interviews investigating their psychological experiences relating to the family reunion. The variables investigated were sociodemographic characteristics, the subject's previsit emotional condition, factors related to the family reunion experience, and stress encountered during the visit.

RESULTS

The survey indicated that more than one-fifth of the subjects (22.5%) developed psychiatric complications, mainly depression, immediately after the visit. Determinants found to contribute significantly to the occurrence of emotional disorders were previous ways of expressing homesickness, family members seen during the reunion, family misfortunes that the subjects discovered, family conflict encountered at the reunion, and tactics for coping with such stressors.

CONCLUSIONS

The study results suggest that family reunions after long-term separation can be trauma-repairing experiences for some but for others can lead to trauma reexperiencing and psychiatric complications requiring mental health intervention.

Hydroubiquinone-cytochrome c2 oxidoreductase from Rhodobacter capsulatus: definition of a minimal, functional isolated preparation

The hydroubiquinone-cytochrome c2 oxidoreductase (cyt bc1) from Rhodobacter capsulatus has been solubilized according to the dodecyl maltoside method and isolated, and its minimal functional composition has been characterized. We find the complex to be composed of three protein subunits corresponding to polypeptides of cyt b (44 kDa), cyt c1 (33 kDa), and 2Fe2S cluster (24 kDa). A fourth band sometimes discernable at 22 kDa appears to be an artifact of the polyacrylamide gel electrophoresis procedure. Its appearance is shown to be derived from the 2Fe2S cluster subunit by the similarity of the binding of subunit-specific monoclonal antibodies and the identical N-terminal sequence of the 24- and 22-kDa bands. The cofactors of cyt bc1, namely, cyt bH, cyt bL, cyt c1, and the 2Fe2S center, the Qos and Qow domains of the Qo site, and the Qi site appear intact as indicated by their optical and EPR spectral signatures, redox properties, and inhibitor binding. The electron paramagnetic resonance spectrum of the cyt bH heme is altered by antimycin, consistent with a change in the dihedral angle between the ligating histidine imidazoles, while the spectrum of the cyt bL heme is broadened by stigmatellin. The ubiquinone-10 content is variable, ranging from 0.8 to 3 molecules/cyt bc1. Activity studies define this three-subunit cyt bc1 complex as a minimal structure, equipped as the enzyme in the native state and capable of full catalytic activity.

Strategies in the surgical treatment of malignant ventricular arrhythmias. An 8-year experience

Introduction of the automatic implantable cardioverter defibrillator (AICD) has dramatically affected the surgical treatment of malignant ventricular tachyarrhythmias. The authors continue to perform electrophysiologically directed subendocardial resection (SER) of left ventricular (LV) scars in selected patients, and we revascularize (CABG) those patients undergoing AICD implantation who have significant myocardial ischemia. In an attempt to define the optimal role of each procedure, this report analyzes our 8-year experience with 348 consecutive patients treated surgically for these arrhythmias (SER since 1983 and AICD since 1986). All patients undergoing SER had organized ventricular tachycardia (VT) as a result of myocardial infarction, and most had LV aneurysms; of those undergoing AICD or AICD/CABG, 60% had VT, 15% had ventricular fibrillation, and 25% had both or were noninducible. The thirty-day mortality rate was 1.5% (3/197) for AICD, 5.4% (5/93) for AICD/CABG, and 8.6% (5/58) for SER; these mortality figures are not significant different. Late deaths in all groups were predominantly due to congestive heart failure, and actuarial survival as well as freedom from sudden death was similar between the groups at 4 years. Recurrent VT occurred in 167 of 282 (59%) of long-term survivors of AICD or AICD/CABG during follow-up and in nine of 53 (17%) of those with SER. Forty-eight per cent of survivors of AICD or AICD/CABG required antiarrhythmic medications, whereas only 11% of those with SER required antiarrhythmics. Long-term survival in each group is much higher than that reported for comparable patients with severe LV dysfunction treated medically. In those patients with organized VT and LV aneurysm who are judged able to survive the procedure, SER offers a high likelihood of cure rather than simple prevention of sudden death.

Autophosphorylation of skeletal muscle myosin light chain kinase

Ca2+/calmodulin-dependent myosin light chain kinase phosphorylates the regulatory light chain of myosin. Rabbit skeletal muscle myosin light chain kinase also catalyzes a Ca2+/calmodulin-dependent autophosphorylation with a rapid rate of incorporation of 1 mol of 32P/mol of kinase and a slower rate of incorporation up to 1.52 mol of 32P/mol. Autophosphorylation was inhibited by a peptide substrate that has a low Km value for myosin light chain kinase. Autophosphorylation at both rates was concentration-independent, indicating an intramolecular mechanism. There were no significant changes in catalytic properties toward light chain and MgATP substrates or in calmodulin activation properties upon autophosphorylation. After digestion with V8 protease, phosphopeptides were purified and sequenced. Two phosphorylation sites were identified, Ser 160 and Ser 234, with the former associated with the rapid rate of phosphorylation. Both sites are located amino terminal of the catalytic domain. These results indicate that the extended "tail" region of the enzyme can fold into the active site of the kinase.

Characterization of the pet operon of Rhodospirillum rubrum

The three genes of the pet operon, coding, respectively, for the Rieske iron-sulfur protein, cytochrome b and cytochrome c 1 components of the cytochrome bc 1 complex in the photosynthetic bacterium Rhodospirillum rubrum have been sequenced. The amino acid sequences deduced for these three peptides from the nucleotide sequences of the genes have been confirmed, in part, by direct sequencing of portions of the three peptides separated from a sample of the purified, detergent-solubilized complex. These sequences show considerable homology with those previously obtained for the pet operons of other photosynthetic bacteria. Northern blots of R. rubrum mRNA have established that the operon is transcribed as a single polycistronic message, the start site of which has been determined by both primer extension and nuclease protection. Photosynthetic growth of R. rubrum was shown to be inhibited by antimycin A, a specific inhibitor of cytochrome bc 1 complexes, and antimycin A-resistant mutants of R. rubrum have been isolated. Preliminary results suggest that it may be possible to express the R. rubrum pet operon in a strain of the photosynthetic bacterium Rhodobacter capsulatus from which the native pet operon has been deleted.

Selective stimulation of parasympathetic nerve fibers to the human sinoatrial node

BACKGROUND

In animals, parasympathetic nerve fibers that innervate the sinoatrial node can be selectively stimulated to increase atrial cycle length. These nerve fibers course through an epicardial fat pad at the margin of the right superior pulmonary vein, the superior vena cava, and the right atrium. We hypothesized that similar nerves exist and can be selectively stimulated in humans.

METHODS AND RESULTS

Microscopic examination of fat pads excised from the margin of the right superior pulmonary vein, the superior vena cava, and the right atrium during two human autopsies revealed the presence of nerve fibers and ganglia. We electrically stimulated this epicardial fat pad in 16 patients during cardiac surgery. The fat pads were stimulated with continuous-pulse trains for 15 seconds via a hand-held bipolar electrode using constant current (10-15 mA), constant pulse width (0.02-0.05 msec), and at 6.6, 10, 20, 25, and 30 Hz. The mean atrial cycle length +/- 1 SEM increased from 734 +/- 34 msec at baseline to a maximum of 823 +/- 61 msec at 6.6 Hz, 1,167 +/- 125 msec at 10 Hz, 1,734 +/- 281 msec at 20 Hz, 2,993 +/- 661 msec at 25 Hz, and 2,461 +/- 668 msec at 30 Hz during nerve stimulation. Linear regression analysis showed that the response of atrial cycle length to sinoatrial parasympathetic nerve stimulation was frequency dependent. The maximum response and complete decay of the response occurred within 4-8 seconds of initiation or termination of sinoatrial parasympathetic nerve stimulation. Atrioventricular conduction time and the PR interval did not change during sinoatrial parasympathetic nerve stimulation, even when the atria were paced at the baseline heart rate.

CONCLUSIONS

Electrical stimulation of parasympathetic nerve fibers in a fat pad near the sinoatrial node increased atrial cycle length without affecting atrioventricular nodal conduction. This is the first study in which such nerve fibers that innervate the sinoatrial node have been selectively stimulated in humans.

The vineberg procedure revisited: Angiographic evaluation and coronary artery bypass surgery in a patient 21 years following bilateral internal mammary artery implantation

A patient receiving bilateral internal mammary implantation (Vineberg's operation) in 1969 was symptom free for a period of 21 years. In 1990 he developed acute myocardial infarction followed by post-infarction angina. Cardiac catheterization revealed severe left main and three vessel disease and patency of both mammary implants which filled the left anterior descending and circumflex coronary arteries via collaterals. Coronary artery bypass surgery was indicated due to the native coronary artery disease and inability of the internal mammary grafts' blood flow to alleviate symptoms. The patient underwent direct coronary artery bypass grafting utilizing femoral vessels for cannulation and saphenous veins for grafting, while preserving the mammary implants. This unique case attests to the longevity of the internal mammary artery grafts. These grafts, even if directly implanted, can serve as a crucial source of blood to an otherwise severely underperfused myocardium. Strategy and technical aspects of surgical redo in patients who underwent Vineberg's operation are discussed.

Purification of casein kinase I and isolation of cDNAs encoding multiple casein kinase I-like enzymes

We have purified casein kinase I (CKI) over 6000-fold from bovine thymus and have sequenced seven tryptic peptides that account for nearly 25% of the primary sequence of the enzyme. By using PCR, partial cDNAs encoding CKI and a related enzyme (CKI-delta) were isolated. A product that may correspond to an alternatively spliced form of CKI was also detected. The CKI PCR product was used to probe a bovine brain cDNA library from which cDNAs corresponding to CKI (CKI-alpha) and two homologous enzymes (CKI-beta and CKI-gamma) were identified. The finding that there are at least four CKI-like enzymes suggests that CKI activity in tissues or cell extracts may be composed of multiple related but distinct protein kinases. This group of enzymes is not similar to any other known protein kinases and may, therefore, represent an additional branch of the protein kinase family.

Comparative study of Filshie clip and Pomeroy method for postpartum sterilization

A prospective randomized comparison of the peri-operative complications and long-term sequelae between the Filshie clip and Pomeroy methods was undertaken in 200 postpartum women at Tri-Service General Hospital, Taipei, Taiwan. The peri-operative complications in either group were mild and infrequent. One pregnancy in the Pomeroy group was reported after follow-up for 24 months. No significant difference between the two groups was found in respect to long-term sequelae.