Influence of BMI percentile on craniofacial morphology and development in adolescents,Part II: elevated BMI is associated with larger final facial dimensions

BACKGROUND

Prevalence of adolescent obesity has markedly increased from 5.2% in 1974 to 19.7% in 2021. Understanding the impacts of obesity is important to orthodontists, as growth acceleration and greater pre-pubertal facial dimensions are seen in children with elevated body mass index (BMI).

METHODS

To identify whether adolescent obesity shifts the timing and rate of craniofacial growth resulting in larger post-treatment dimensions, we evaluated cephalometric outcomes in overweight/obese (BMI > 85%, n = 168) and normal weight (n = 158) adolescents (N = 326 total). Cephalometric measurements were obtained from pre- and post-treatment records to measure growth rates and final dimensions and were statistically evaluated with repeated measures analysis of variance and linear regression models.

RESULTS

Overweight and obese adolescents began and finished treatment with significantly larger, bimaxillary prognathic craniofacial dimensions, with elevated mandibular length [articulare-gnathion (Ar-Gn)], maxillary length [condylion-anterior nasal spine (Co-ANS), posterior nasal spine-ANS (PNS-ANS)], and anterior lower face height (ANS-Me), suggesting overweight children grow more overall. However, there was no difference between weight cohorts in the amount of cephalometric change during treatment, and regression analyses demonstrated no correlation between change in growth during treatment and BMI. BMI percentile was a significant linear predictor (P < 0.05) for cephalometric post-treatment outcomes, including Ar-Gn, Co-ANS, ANS-Me, upper face height percentage (UFH:total FH, inverse relationship), lower face height percentage (LFH:total FH), sella-nasion-A-point (SNA), and SN-B-point (SNB).

LIMITATIONS

The study is retrospective.

CONCLUSIONS

Growth begins earlier in overweight and obese adolescents and continues at a rate similar to normal-weight children during orthodontic treatment, resulting in larger final skeletal dimensions. Orthodontics could begin earlier in overweight patients to time care with growth, and clinicians can anticipate that overweight/obese patients will finish treatment with proportionally larger, bimaxillary-prognathic craniofacial dimensions.

Orthodontic loading activates cell-specific autophagy in a force-dependent manner

INTRODUCTION

Orthodontic tooth movement (OTM) relies on bone remodeling and controlled aseptic inflammation. Autophagy, a conserved homeostatic pathway, has been shown to play a role in bone turnover. We hypothesize that autophagy participates in regulating bone remodeling during OTM in a force-dependent and cell type-specific manner.

METHODS

A split-mouth design was used to load molars with 1 of 3 force levels (15, 30, or 45 g of force) in mice carrying a green fluorescent protein-LC3 transgene to detect cellular autophagy. Fluorescent microscopy and quantitative polymerase chain reaction analyses were used to evaluate autophagy activation and its correlation with force level. Cell type-specific antibodies were used to identify cells with green fluorescent protein-positive puncta (autophagosomes) in periodontal tissues.

RESULTS

Autophagic activity increased shortly after loading with moderate force and was associated with the expression of bone turnover, inflammatory, and autophagy markers. Different load levels resulted in altered degrees of autophagic activation, gene expression, and osteoclast recruitment. Autophagy was specifically induced by loading in macrophages and osteoclasts found in the periodontal ligament and alveolar bone. Data suggest autophagy participates in regulating bone turnover during OTM.

CONCLUSIONS

Autophagy is induced in macrophage lineage cells by orthodontic loading in a force-dependent manner and plays a role during OTM, possibly through modulation of osteoclast bone resorption. Exploring the roles of autophagy in OTM is medically relevant, given that autophagy is associated with oral and systemic inflammatory conditions.

Targeting resolution of neuroinflammation after ischemic stroke with a lipoxin A4 analog: Protective mechanisms and long-term effects on neurological recovery

BACKGROUND

Resolution of inflammation is an emerging new strategy to reduce damage following ischemic stroke. Lipoxin A₄ (LXA ₄) is an anti-inflammatory, pro-resolution lipid mediator that reduces neuroinflammation in stroke. Since LXA ₄ is rapidly inactivated, potent analogs have been synthesized, including BML-111. We hypothesized that post-ischemic, intravenous treatment with BML-111 for 1 week would provide neuroprotection and reduce neurobehavioral deficits at 4 weeks after ischemic stroke in rats. Additionally, we investigated the potential protective mechanisms of BML-111 on the post-stroke molecular and cellular profile.

METHODS

A total of 133 male Sprague-Dawley rats were subjected to 90 min of transient middle cerebral artery occlusion (MCAO) and BML-111 administration was started at the time of reperfusion. Two methods of week-long BML-111 intravenous administration were tested: continuous infusion via ALZET ^® osmotic pumps (1.25 and 3.75 μg μl^-1 hr^-1), or freshly prepared daily single injections (0.3, 1, and 3 mg/kg). We report for the first time on the stability of BML-111 and characterized an optimal dose and a dosing schedule for the administration of BML-111.

RESULTS

One week of BML-111 intravenous injections did not reduce infarct size or improve behavioral deficits 4 weeks after ischemic stroke. However, post-ischemic treatment with BML-111 did elicit early protective effects as demonstrated by a significant reduction in infarct volume and improved sensorimotor function at 1 week after stroke. This protection was associated with reduced pro-inflammatory cytokine and chemokine levels, decreased M1 CD40+ macrophages, and increased alternatively activated, anti-inflammatory M2 microglia/macrophage cell populations in the post-ischemic brain.

CONCLUSION

These data suggest that targeting the endogenous LXA ₄ pathway could be a promising therapeutic strategy for the treatment of ischemic stroke. More work is necessary to determine whether a different dosing regimen or more stable LXA ₄ analogs could confer long-term protection.

Stability of dissolved and soluble Fe(II) in shelf sediment pore waters and release to an oxic water column

Shelf sediments underlying temperate and oxic waters of the Celtic Sea (NW European Shelf) were found to have shallow oxygen penetrations depths from late spring to late summer (2.2-5.8 mm below seafloor) with the shallowest during/after the spring-bloom (mid-April to mid-May) when the organic carbon content was highest. Sediment porewater dissolved iron (dFe, <0.15 µm) mainly (>85%) consisted of Fe(II) and gradually increased from 0.4 to 15 μM at the sediment surface to ~100-170 µM at about 6 cm depth. During the late spring this Fe(II) was found to be mainly present as soluble Fe(II) (>85% sFe, <0.02 µm). Sub-surface dFe(II) maxima were enriched in light isotopes (δ56Fe -2.0 to -1.5‰), which is attributed to dissimilatory iron reduction (DIR) during the bacterial decomposition of organic matter. As porewater Fe(II) was oxidised to insoluble Fe(III) in the surface sediment layer, residual Fe(II) was further enriched in light isotopes (down to -3.0‰). Ferrozine-reactive Fe(II) was found in surface porewaters and in overlying core top waters, and was highest in the late spring period. Shipboard experiments showed that depletion of bottom water oxygen in late spring can lead to a substantial release of Fe(II). Reoxygenation of bottom water caused this Fe(II) to be rapidly lost from solution, but residual dFe(II) and dFe(III) remained (12 and 33 nM) after >7 h. Iron(II) oxidation experiments in core top and bottom waters also showed removal from solution but at rates up to 5-times slower than predicted from theoretical reaction kinetics. These data imply the presence of ligands capable of complexing Fe(II) and supressing oxidation. The lower oxidation rate allows more time for the diffusion of Fe(II) from the sediments into the overlying water column. Modelling indicates significant diffusive fluxes of Fe(II) (on the order of 23-31 µmol m-2 day-1) are possible during late spring when oxygen penetration depths are shallow, and pore water Fe(II) concentrations are highest. In the water column this stabilised Fe(II) will gradually be oxidised and become part of the dFe(III) pool. Thus oxic continental shelves can supply dFe to the water column, which is enhanced during a small period of the year after phytoplankton bloom events when organic matter is transferred to the seafloor. This input is based on conservative assumptions for solute exchange (diffusion-reaction), whereas (bio)physical advection and resuspension events are likely to accelerate these solute exchanges in shelf-seas.

Cancer Clinical Trials Education Program: A Training Program to Reach Patients and the Public

Despite advances in cancer research, accrual of cancer patients or participants to clinical trials, as a treatment or prevention option, has remained low, hindering both research progress and patient access to potentially beneficial therapy. As one response, the National Cancer Institute (NCI) and the NCI-supported Cancer Information Service, partnered with the Oncology Nursing Society, the Association of Oncology Social Work, and Novartis Oncology, to implement the NCI’s Cancer Clinical Trials Education Program (CCTEP) for health professionals, using a “train-the-trainer” approach. From June 1997-June 1999, approximately 300 “charter” trainees completed the training program and presented programs for over 1,500 participants. Evaluation efforts are ongoing. The CCTEP was developed and is being implemented within a collaborative partnership model, insuring a broad reach to health professionals, patients and the public. The use of this partnership model for a far-reaching educational effort can be adapted by other program planners.

H2O2 production rate in Lactobacillus johnsonii is modulated via the interplay of a heterodimeric flavin oxidoreductase with a soluble 28 Kd PAS domain containing protein

Host and commensals crosstalk, mediated by reactive oxygen species (ROS), has triggered a growing scientific interest to understand the mechanisms governing such interaction. However, the majority of the scientific studies published do not evaluate the ROS production by commensals bacteria. In this context we recently showed that Lactobacillus johnsonii N6.2, a strain of probiotic value, modulates the activity of the critical enzymes 2,3-indoleamine dioxygenase via H₂O₂ production. L. johnsonii N6.2 by decreasing IDO activity, is able to modify the tryptophan/kynurenine ratio in the host blood with further systemic consequences. Understanding the mechanisms of H₂O₂ production is critical to predict the probiotic value of these strains and to optimize bacterial biomass production in industrial processes. We performed a transcriptome analysis to identify genes differentially expressed in L. johnsonii N6.2 cells collected from cultures grown under different aeration conditions. Herein we described the biochemical characteristics of a heterodimeric FMN reductase (FRedA/B) whose in vitro activity is controlled by LjPAS protein with a typical Per-Arnst-Sim (PAS) sensor domain. Interestingly, LjPAS is fused to the FMN reductase domains in other lactobacillaceae. In L. johnsonii, LjPAS is encoded by an independent gene which expression is repressed under anaerobic conditions (>3 fold). Purified LjPAS was able to slow down the FRedA/B initial activity rate when the holoenzyme precursors (FredA, FredB, and FMN) were mixed in vitro. Altogether the results obtained suggest that LjPAS module regulates the H₂O₂ production helping the cells to minimize oxidative stress in response to environmental conditions.

Intestinal epithelial cell mediated miscommunication in type 1 diabetes: a tipping point for disease? (MUC2P.933)

The host-environment dialogue at the intestinal interface has been strongly implicated in the development of inflammatory diseases. We are interested in understanding the role of this dialogue in autoinflammatory and autoimmune diseases such as type 1 diabetes (T1D). Although the gastrointestinal tract, a dynamic and highly regulated immunologic organ, has been demonstrated to be impaired in T1D, the mechanisms of any (mis)communications taking place remain unknown. Here we describe the global intestinal inflammatory environment and the phenotype of intestinal lymphocytes in human T1D. In addition, we evaluated the intestinal epithelial cell (IEC) innate immune responses using primary cell culture. Our data indicate a whole organ reduction in tolerogenic mediators concomitant with elevated IEC-induced pro-inflammatory mediators. Significant alterations in intestinal leukocyte populations were observed, whereby increased frequencies of pathogenic T cells and alterations in tolerogenic DCs were noted. Finally, T1D-derived primary IEC cultures demonstrated a lack of tolerogenic responses concomitant with induction of inflammatory response to microbial ligand stimulation as compared to non-T1D derived cultures. Together these data suggest a loss of gastrointestinal homeostasis in T1D potentially as a result of a dysfunctional IEC-mediated host-environment dialogue, though whether this is a cause of consequence of disease remains to be defined.

Altered gastrointestinal environment and immune cellular plasticity during disease progression of type 1 diabetes (MUC2P.931)

The gastrointestinal (GI) tract is the largest environmental interface which is a barrier to environmental insults and a site of immune activation and tolerance induction. The initiating events leading to the loss of self-tolerance which results in the autoimmune process of type1 diabetes (T1D) have yet to be fully defined. Leakiness at the GI barrier has been observed preceding symptomatic onset of T1D. Using the non-obese diabetic (NOD) mouse, we assessed measures of barrier integrity, global intestinal inflammation, as well as the frequency of gastrointestinal and pancreatic innate lymphoid (ILC), regulatory and inflammatory cell subsets at key checkpoints of disease to determine kinetics associated with the loss of tolerance. Early in the disease process, NOD mice exhibited minor losses in barrier function along with elevated levels of duodenal TNFα and IFNɣ. Concomitant with an increased frequency of inflammatory T cells and reduced frequency of regulatory T cells, NOD mice also presented with an increased frequency of type 3 ILCs and a decreased frequency of type 1 ILCs within the mesenteric lymph node (MLN) at all stages of disease and in the pancreatic lymph node (PLN) at 8 wks of age. Overall, these data support a model wherein early in disease, minor changes in barrier function can result in intestinal inflammation shifting the balance of immunoregulation to that of inflammation potentially resulting in the loss of self-tolerance responsible for T1D.

Resonant Kα spectroscopy of solid-density aluminum plasmas

The x-ray intensities made available by x-ray free electron lasers (FEL) open up new x-ray matter interaction channels not accessible with previous sources. We report here on the resonant generation of Kα emission, that is to say the production of copious Kα radiation by tuning the x-ray FEL pulse to photon energies below that of the K edge of a solid aluminum sample. The sequential absorption of multiple photons in the same atom during the 80 fs pulse, with photons creating L-shell holes and then one resonantly exciting a K-shell electron into one of these holes, opens up a channel for the Kα production, as well as the absorption of further photons. We demonstrate rich spectra of such channels, and investigate the emission produced by tuning the FEL energy to the K-L transitions of those highly charged ions that have transition energies below the K edge of the cold material. The spectra are sensitive to x-ray intensity dependent opacity effects, with ions containing L-shell holes readily reabsorbing the Kα radiation.

Direct measurements of the ionization potential depression in a dense plasma

We have used the Linac Coherent Light Source to generate solid-density aluminum plasmas at temperatures of up to 180 eV. By varying the photon energy of the x rays that both create and probe the plasma, and observing the K-α fluorescence, we can directly measure the position of the K edge of the highly charged ions within the system. The results are found to disagree with the predictions of the extensively used Stewart-Pyatt model, but are consistent with the earlier model of Ecker and Kröll, which predicts significantly greater depression of the ionization potential.

Coherence properties of individual femtosecond pulses of an x-ray free-electron laser

Measurements of the spatial and temporal coherence of single, femtosecond x-ray pulses generated by the first hard x-ray free-electron laser, the Linac Coherent Light Source, are presented. Single-shot measurements were performed at 780 eV x-ray photon energy using apertures containing double pinholes in "diffract-and-destroy" mode. We determined a coherence length of 17  μm in the vertical direction, which is approximately the size of the focused Linac Coherent Light Source beam in the same direction. The analysis of the diffraction patterns produced by the pinholes with the largest separation yields an estimate of the temporal coherence time of 0.55 fs. We find that the total degree of transverse coherence is 56% and that the x-ray pulses are adequately described by two transverse coherent modes in each direction. This leads us to the conclusion that 78% of the total power is contained in the dominant mode.

Human estrogen receptor beta-specific monoclonal antibodies: characterization and use in studies of estrogen receptor beta protein expression in reproductive tissues

Investigation of the role of the second, more recently described estrogen receptor, denoted ERbeta, will be critical in understanding the molecular mechanisms underlying tissue-specific gene regulation by estrogens. Expression of ERbeta in a variety of tissues has been examined predominantly at the mRNA level, and there is little information regarding the cellular localization and size of the endogenous ERbeta protein, due, in part, to the limited availability of human ERbeta-specific antibodies. Thus, our aim was to generate specific antibodies to human ERbeta and use them to determine the tissue-specific distribution and size(s) of the ERbeta protein. To this end, we have cloned three different hybridoma cell lines that produce monoclonal antibodies specific for the hormone-binding domain of human ERbeta. The antibodies, made in mice against human ERbeta amino acids 256-505 (hormone binding domain lacking the F domain), are designated CFK-E12 (E12), CMK-A9 (A9) and CWK-F12 (F12) and were determined to be the IgG gamma1 isotype for E12, and IgG gamma2b for A9 and F12. All three monoclonal antibodies could be used to detect in vitro translated, baculovirus expressed, and cell transfected and expressed ERbeta protein by Western blot analyses, and all failed to detect ERalpha. A9 and F12 were able to immunoprecipitate efficiently the native form of ERbeta protein in the presence and absence of estradiol. Epitope mapping studies indicate that the E12 and F12 antibodies recognize overlapping peptide sequences in the N-terminal region of the hormone-binding domain, a region that is highly conserved among species. Immunocytochemical studies with these antibodies reveal nuclear-specific localization of the ERbeta protein in granulosa cells of the rat ovary. Nuclear ERbeta is also specifically localized in epithelial and some stromal cells of mouse and rat epididymis. Western blot analysis with protein extracts from ovarian granulosa cells of human, rat, mouse, and pig showed a ca. 52 kDa and an additional ca. 62-64 kDa band in these species. These results indicate the presence of two predominant molecular size forms of the ERbeta protein in ovarian granulosa cells and demonstrate the utility of these antibodies for detection of ERbeta in the human and in several other mammalian species.

Quit Today! A targeted communications campaign to increase use of the cancer information service by African American smokers

BACKGROUND

African Americans have traditionally made little use of the Cancer Information Service (CIS), an information and education program of the National Cancer Institute, for smoking cessation assistance. This study evaluated whether a targeted communications campaign utilizing strategically placed radio and television advertisements in combination with community outreach could lead more adult African American smokers to call the CIS for smoking cessation information and materials.

METHODS

Fourteen communities, served by four CIS regional offices, were carefully matched on demographic variables and then randomly assigned to either an experimental or a control group. Six radio advertisements targeting African American smokers to call the CIS for help in quitting smoking were developed and pretested for three different black-oriented formats. One television spot also was produced and pretested. The audio portion of the television ad was utilized as a seventh radio spot for the general programming formats. These advertisements were placed on selected radio and television stations reaching predominantly African American adult audiences. Also, copies of a videotape designed to motivate African American smokers to quit and to call the CIS for help in quitting were widely disseminated through community-based organizations in each experimental market. The aim was to increase the number and proportion of quitting-related calls to the CIS from African Americans within experimental communities.

RESULTS

The call volume from African American smokers was significantly higher in the experimental communities than in the control communities (P < 0.008). The call rate from African American men was higher than typically observed. Overall, African Americans in the experimental communities reported radio more often than television as the way they heard about the CIS.

CONCLUSION

The results suggest that paid targeted advertising, using radio as a primary channel, is an effective method of reaching an underserved population at risk. Future research directions are discussed.

A self-help intervention for African American smokers: tailoring cancer information service counseling for a special population

BACKGROUND

African Americans remain a critically underserved group for smoking cessation interventions. This study tested the effectiveness of a tailored, culturally sensitive intervention for African American smokers who called the NCI Cancer Information Service (CIS) for help to quit smoking.

METHODS

This paper presents results of a 2-year study of tailored counseling strategies among African American smokers (n = 1,422) who called four regional CIS offices in response to a radio-based media campaign in 14 communities. Callers were randomly assigned to receive either the standard CIS quit smoking counseling and guide (Clearing the Air) or counseling and a guide (Pathways to Freedom) tailored to the quitting needs and barriers of African American smokers. Callers were predominantly female (63.6%). ages 20-49 (88%), with a high school education or more (84%). Median smoking history was 17 years; median smoking rate was 20 cigarettes/day. Standard (n = 689) and Tailored (n = 733) group subjects did not differ on most baseline measures.

RESULTS

On most measures, Standard and Tailored counseling/guides received similar ratings, but the Tailored guide was rated as having more appealing photos (P = 0.001) and as being more appropriate for family members (P = 0.003). Six-month follow-up with 893 subjects (response rates were 63% Standard, 62% Tailored, ns) showed significantly more quit attempts (P = 0.002) and greater use of prequitting strategies (P < 0.05) among Tailored than among Standard subjects, but no differences in self-reported 1-week abstinence (14.4% Standard, 16.2% Tailored) (ns). An opportunistic 12-month follow-up of subjects recruited in the last year of the study (n = 445) (response rates were 57% Standard, 60% Tailored, ns) showed a significantly higher quit rate (15.4% Standard, 25.0% Tailored) for Tailored subjects (P = 0.034).

CONCLUSIONS

Results show promise for tailored approaches to boost quit attempts and success rates among African American smokers.

Awareness of cancer-related programs and services among rural African Americans

African Americans are at increased risk for cancer and represent an important target population for programs such as Healthy People 2000, the Cancer Information Service (CIS), and the 5 a Day for Better Health Initiative. Yet, awareness of such programs among rural blacks is unknown. This study assessed awareness of these programs and determined related knowledge and beliefs among rural African Americans. It was undertaken as part of the baseline survey for the Black Churches United for Better Health project, a National Cancer Institute-funded initiative. A minority of respondents (n = 3737) demonstrated name recognition of Healthy People 2000 (23.4%), the CIS (42.4%), and the 5 a Day Program (40.7%). Far fewer (7.4%) were able to correctly identify the recommended daily number of servings of fruits and vegetables. Reported family history of cancer was associated with a greater tendency believe that eating more fruits and vegetables can prevent disease. These findings underscore the need for efforts to reach the rural black community with culturally sensitive and stage appropriate cancer prevention messages. Knowledge of family history of cancer may play an important role in targeting subgroups and delivering effective cancer prevention messages.

Do nurses and parents of children with chronic conditions agree on parental needs?

Nurses who work in partnership with parents in pediatric settings are encouraged to base nursing intervention decisions on mutually defined priorities and goals. In this study, 38 parents and 13 nurses affiliated with 10 ambulatory programs in one children's hospital were surveyed using modified versions of the Bailey and Simeonsson (1988a) Family Needs Survey to compare their assessments of parental needs. Although nurses and parents identified many of the same needs related to information, support, and community services, there were some differences particularly in prioritization. Only nurses identified needs related to family functioning. Parents generally scored items lower than their nurses did and expressed fewer actual needs for themselves, suggesting that nurses may concentrate more on parents' deficits than on their strengths. Strengthening parents in their roles of primary care givers occurs when nurses, in collaboration with parents, accurately assess parental needs and negotiate appropriate interventions.

Collodion baby dehydration: the danger of high transepidermal water loss

We describe transepidermal water loss (TEWL) measurements in a collodion baby suffering from severe hypernatraemic dehydration and hypothermia, who required intravenous fluid therapy in a special incubator. The TEWL values 4 days after birth were abnormally high compared with normal infants of the same age. The TEWL measurements returned towards normal within the first month, in parallel with the improvement of both the skin signs and the electrolyte and fluid balance.

Pheochromocytoma associated with prior carotid body tumors (chemodectomas). Detection with I-131 MIBG

Chemodectomas (carotid body tumors) were surgically removed on two occasions, first 10 years and then 3 months prior to detection with I-131 MIBG of an adrenal pheochromocytoma in a 32-year-old man with a family history of chemodectoma. Recent reports suggest patients with multiple and/or familial instances of chemodectoma frequently have associated catecholamine-secreting tumors detectable with I-131 or I-123 MIBG. This case documents the above association and suggests that any patient with proven carotid body tumor(s) be screened for catecholamine-secreting tumors via urinary/plasma catecholamine determinations.

Promoting bicycle helmets: a new focus for injury prevention

Bicycle accidents cause many serious injuries and deaths in the United States, often as a result of head injury in riders not wearing helmets. Helmets reduce the incidence of head injury, and an aggressive safety education campaign has been shown to increase the number of children wearing helmets while riding. Such a campaign has been initiated in the Central Indiana area. The campaign is designed to educate families and to promote bicycle helmet use among children and their parents. Suggestions are given on how physicians can help educate, distribute information and encourage bicycle helmet use through their contact with families. A resource list is included so these materials can be easily obtained. Ultimately, we hope such a program will increase helmet use and consequently reduce morbidity and mortality from head injury in Indiana's children.

Root surface caries subsequent to gingivectomy in rats inoculated with Streptococcus sobrinus (mutans) and Actinomyces viscosus

We studied the effect of oral infection with cariogenic micro-organisms on alveolar bone loss and root surface caries subsequent to gingivectomy in rats. Thirty-six rats were fed diet MIT 200 (67% sucrose); one-half, the controls, had antibiotics added to the diet. At ages 18, 19, and 21 days, the experimental group was orally infected with streptomycin-resistant Streptococcus sobrinus (mutans) 6715 and Actinomyces viscosus M-100. At age 30 days, all animals were subjected to a gingivectomy on maxillary and mandibular left quadrants. The experimental group was re-inoculated at age 36 days. Animals were killed seven weeks after surgery. Jaws were stained, and planimetric measurements of exposed root surface area and caries on lingual/palatal surfaces of 1st and 2nd molars were made from video images with a computer/digitizer. Compared with the non-operated contralateral quadrants, gingivectomy significantly increased exposed root surface area in the maxilla and in the mandible in both the control and experimental groups. Oral inoculation significantly increased exposed root surface in mandibular (but not maxillary) quadrants which had received a gingivectomy, but had no effect on non-gingivectomized quadrants. There was no caries in the control group, whereas ten rats in the experimental group had root surface caries lesions, all in quadrants which had received a gingivectomy. This rat model should prove useful in further studies of root surface caries.

Respiratory phase locking during mechanical ventilation in anesthetized human subjects

The coupling patterns between the rhythm of a mechanical ventilator and the rhythm of spontaneous breathing were studied in enflurane-anesthetized adult human subjects. The spontaneous breathing pattern was altered in response to different frequencies and amplitudes of forced lung inflations. A 1:1 phase locking (the frequency of the mechanical ventilator is matched by the frequency of spontaneous breathing with a fixed phase between the 2 rhythms) was observed in a range of up to +/- 40% of some of the subject's spontaneous breathing frequencies. During 1:1 phase locking, there were marked changes in the expiratory duration as measured from the electromyogram of the diaphragm. The phase relationship between onset of inflation and onset of inspiration depended on the frequency and amplitude of mechanical inflation. At ventilator settings that did not give 1:1 phase locking, other simple phase-locked patterns, such as 1:2 and 2:1, or irregular non-phase-locked patterns were observed. Reflexes arising from lung inflation, which may underlie the entrainment, are discussed in the context of these results.

Quantitation of corneal endothelial potentials using a carbocyanine dye

The carbocyanine dye, diS-C3-(5) was used to quantitate the plasma membrane potential of the bullfrog corneal endothelium. It was shown that valinomycin hyperpolarized the endothelial cell and that in the presence of the ionophore the membrane potential largely reflected the K+ equilibrium potential. Using calibration curves constructed by changing medium K+ concentration in the presence of valinomycin, and nigericin and ouabain to abolish ion gradients and electrogenic pump activity, the cell membrane potential was calculated to be 28.6 +/- 4.2 mV. The major source of this potential was a K+ diffusion potential, and the membrane Na+ conductance reduced the cell potential to less than the apparent K+ equilibrium potential of 51.5 +/- 5.1 mV. About 20% of the cell potential could be ascribed to the rheogenic (Na+ + K+)-ATPase.

Effects of coronary artery bypass surgery on hemodynamic parameters and derived indices of myocardial function

Pre- and postoperative hemodynamic indices were compared in 116 patients subjected to aorto-coronary bypass after an average interval of 128 days. The patients were separated into three different groups according to graft status: Group 1 (n = 77), all grafts patent; Group 2 (n = 27), one occluded graft out of two or three implanted; Group 3 (n = 12), all grafts occluded. There were no significant major changes of values so obtained in the three groups. Those subjects with initially depressed cardiac indices or elevated left ventricular end-diastolic pressures manifested a significant trend toward improvement when at least one bypass graft was patent. A reduction of cardiac index was noted in patients with occluded left anterior descending coronary grafts only in association with closure of other grafts. Deterioration of cardiac index or left ventricular end-diastolic pressure into the abnormal range was unusual in the study group, even when all grafts were occluded. It is concluded that data relating to the influence of aorto-coronary bypass on standard indices of left ventricular function can be properly interpreted only when certain subsets of patients are studied.

Mitral valve prolapse in patients with coronary artery disease. Echocardiographic-angiographic correlation

Echocardiography was performed in 25 consecutive patients with angina pectoris and angiographically demonstrable coronary artery disease. Left ventricular echograms detected late or pansystolic mitral valve bowing suggesting of mitral valve proplapse in 6/25 (24%). Left ventricular angiography showed prolapse of the posterior mitral leaflet in 15/25 (60%), including 5 detected by echocardiography. Significant triple vessel coronary disease was present in 11 of 15 patients with prolapsed mitralvalve. In each of the latter a greater than 90 per cent obstructive lesion was noted in at least one coronary artery: right coronary artery, 9 subjects (82%); left circumflex coronary artery, 5 patients (33%); and left anterior descending coronary artery, 4 patients (27%). Of 15 subjects with angiographic evidence of mitral valve prolapse, 13 had left ventricular asynergy-inferior or inferoposterior in 8 subjects (62%) and anterior or anteroapical in 5 subjects (38%). Eleven subjects had vectorcardiographic evidence of transmural myocardial infarction-inferior or inferoposterior in 9 (82%) and anteroseptal in 2 (18%). A single subject with mitral valve prolapse had mild mitral regurgitation. It is concluded that: (1) coexisting prolapse of the posterior mitral valve leaflet and coronary artery disease is usually associated with triple vessel obstructive lesions, (2) severe right coronary disease, inferior left ventricular wall asynergy, and inferior myocardial infarction are important angiographic and vectorcardiographic correlates, and (3) echocardiography will detect such mitral valve prolapse in only one-third of affected cases.

Correlation of electrocardiogram and vectorcardiogram with coronary occlusion and myocardial contraction abnormality

Electrocardiograms and Frank vectorcardiograms were recorded in 156 consecutive patients with total occlusion of at least one coronary artery (on arteriography) and associated left ventricular contraction abnormality (on ventriculography). The angiograms and cardiograms were independently reviewed. In the presence of single vessel occlusion, appropriate vectorcardiographic diagnosis of myocardial infarction was determined in 118 of 156 cases (76 percent) compared with a lower electrocardiographic detection rate in 77 of 156 cases (49 percent). Findings diagnostic of two coexisting infarctions were observed in 71 percent of vectorcardiograms and 37 percent of electrocardiograms in 51 patients with double vessel occlusion and two areas of left ventricular dyskinesia. The vectorcardiographic detection rate was similarly superior to the electrocardiographic rate in the presence of subtotal coronary occlusion and myocardial asynergy in single (73 percent versus 53 percent) and double (53 percent versus 28 percent) vessel disease. The incidence rate of false positive diagnoses was 3 percent for electrocardiography and 4 percent for vectorcardiography. It is concluded that the vectorcardiogram is superior to the electrocardiogram in the diagnosis of obstructive coronary artery disease and left ventricular contraction abnormality.