Coaggregation of black-pigmented Bacteroides species with other oral bacteria

Coaggregation of Bacteroides gingivalis and other black-pigmented bacteroides with several oral bacteria was studied with "reagent" strains specially prepared by methods that have been described previously. B. gingivalis coaggregated with Veillonella, Capnocytophaga and Actinomyces spp., but not with any Streptococcus spp. Coaggregation of B. gingivalis with other bacteria was inhibited and reversed by lactose. Of the asaccharolytic black-pigmented bacteroides, only B. gingivalis demonstrated any coaggregation with other bacteria, whereas within the saccharolytic species, B. loescheii showed a marked ability to coaggregate with several species of oral bacteria. This property of coaggregation by B. gingivalis may be an important factor in the pathogenesis of periodontal infections.     

Postoperative intussusception, causal or casual relationships?

Postoperative intussusception (POI) is a recognised but uncommon condition. Primary intussusception has been reported several times from Africa, but there are only two reports of postoperative intussusception. A literature review on POI was performed by searching the Medline between 1966 and 1998 together with relevant references in publications on the subject. Postoperative intussusception occurs within a month of an operation. It differs from primary intussusception. No specific aetiology has been found. Predisposing factors based on disorder of peristalsis have been proposed. At risk are patients with prolonged postoperative ileus after prolonged surgery with extensive dissection or after a postoperative regimen of radiation and/or chemotherapy. The diagnosis requires a high index of suspicion. Contrast radiology is not reliable in the diagnosis. The preferred treatment is operative reduction, but resection may be indicated. There are no reports of recurrence after surgical treatment. Preventive measures include gentle handling and avoidance of drying of intestines at operation. The paucity of reports from Africa may mean that the diagnosis is being overlooked.     

Update on Prevalence of Periodontitis in Adults in the United States: NHANES 2009 to 2012

Background: This report describes prevalence, severity, and extent of periodontitis in the US adult population using combined data from the 2009 to 2010 and 2011 to 2012 cycles of the National Health and Nutrition Examination Survey (NHANES). Methods: Estimates were derived for dentate adults, aged ≥30 years, from the US civilian non‐institutionalized population. Periodontitis was defined by combinations of clinical attachment loss (AL) and periodontal probing depth (PD) from six sites per tooth on all teeth, except third molars, using standard surveillance case definitions. For the first time in NHANES history, sufficient numbers of non‐Hispanic Asians were sampled in 2011 to 2012 to provide reliable estimates of their periodontitis prevalence. Results: In 2009 to 2012, 46% of US adults, representing 64.7 million people, had periodontitis, with 8.9% having severe periodontitis. Overall, 3.8% of all periodontal sites (10.6% of all teeth) had PD ≥4 mm, and 19.3% of sites (37.4% teeth) had AL ≥3 mm. Periodontitis prevalence was positively associated with increasing age and was higher among males. Periodontitis prevalence was highest in Hispanics (63.5%) and non‐Hispanic blacks (59.1%), followed by non‐Hispanic Asian Americans (50.0%), and lowest in non‐Hispanic whites (40.8%). Prevalence varied two‐fold between the lowest and highest levels of socioeconomic status, whether defined by poverty or education. Conclusions: This study confirms a high prevalence of periodontitis in US adults aged ≥30 years, with almost fifty‐percent affected. The prevalence was greater in non‐Hispanic Asians than non‐Hispanic whites, although lower than other minorities. The distribution provides valuable information for population‐based action to prevent or manage periodontitis in US adults.     

Stability of Oxygen Transmissibility During Ischemia

Abstract

Simultaneous measurements of oxygen availability (O₂a) and partial pressure (PO₂) were made by the double noble metal electrode system designed by Erdmann and Krell in an attempt to monitor the oxygen transmissibility (Dk) with respect to time before and after ischemic episodes in the brain cortex. Available current equations can appropriately describe the performance of the electrode in a homogeneous nonconsuming medium, and with some experimental error this electrode system can be used to estimate oxygen transmissibility changes in the brain based on the different chararcteristics of the O₂a (rod-type, flush-ended bare tip) and the PO₂ (rod-type, recessed tip) cathodes. Our method monitors the oxygen transmissibility within the diffusion sphere of the bare tip as the ratio of the currents related to O₂a and PO₂. We find with this system that even prolonged global cerebral ischemia does not alter the oxygen transmissibility of the brain tissue. Therefore, alteration of the oxygen transmissibility can not be a contributing factor to postischemic cerebral malfunction.     

Physiological time series: distinguishing fractal noises from motions

Many physiological signals appear fractal, in having self-similarity over a large range of their power spectral densities. They are analogous to one of two classes of discretely sampled pure fractal time signals, fractional Gaussian noise (fGn) or fractional Brownian motion (fBm). The fGn series are the successive differences between elements of a fBm series; they are stationary and are completely characterized by two parameters, sigma2, the variance, and H, the Hurst coefficient. Such efficient characterization of physiological signals is valuable since H defines the autocorrelation and the fractal dimension of the time series. Estimation of H from Fourier analysis is inaccurate, so more robust methods are needed. Dispersional analysis (Disp) is good for noise signals while bridge detrended scaled windowed variance analysis (bdSWV) is good for motion signals. Signals whose slopes of their power spectral densities lie near the border between fGn and fBm are difficult to classify. A new method using signal summation conversion (SSC), wherein an fGn is converted to an fBm or an fBm to a summed fBm and bdSWV then applied, greatly improves the classification and the reliability of H, the estimates of H, for the times series. Applying these methods to laser-Doppler blood cell perfusion signals obtained from the brain cortex of anesthetized rats gave H of 0.24+/-0.02 (SD, n=8) and defined the signal as a fractional Brownian motion. The implication is that the flow signal is the summation (motion) of a set of local velocities from neighboring vessels that are negatively correlated, as if induced by local resistance fluctuations.     

Effects of cigarette smoke with different tar contents on hepatic and pulmonary xenobiotic metabolizing enzymes in rats

The effects of smoke from cigarettes with two different tar contents (32 mg/cigarette, high tar, and 15 mg/cigarette, low tar) on hepatic and pulmonary monooxygenase (MO) activities (aniline 4-hydroxylase [AH]; aminopyrine N-demethylase [AMND]; 7-ethoxyresorufin O-deethylase [EROD]; p-nitroanisole O-demethylase [p-NAOD]), lipid peroxidation (LP) and reduced glutathione (GSH) levels and glutathione S-transferase (GST) activities toward several substrates (1-chloro-2,4-dinitrobenzene [CDNBI; 1,2-dichloro-4-nitrobenzene [DCNB]; ethacrynic acid [EAA]; 1,2-epoxy-3-(p-nitrophenoxy)-propane [ENPP]) were determined in adult male rats. Adult male rats were exposed to smoke of high- or low-tar cigarettes five times a day, with 1-hour intervals, for 3 days in a chamber where smoke and fresh air lead alternatively and were killed 16 hours after the last treatment. Smoke of both high- and low-tar cigarettes (SHTCC and SLTCC) significantly increased hepatic and pulmonary EROD and p-NAOD activities compared to controls. However, the increase noted by SHTCC on pulmonary EROD activity was higher than that of SLTCC. Hepatic AMND and pulmonary AH activities were significantly increased only by SHTCC. LP level was significantly decreased and increased by SHTCC in liver and lung, respectively, whereas it remained unaltered by SLTCC. Only SHTCC significantly increased GSH level in liver. In the lungs, both SHTCC and SLTCC significantly increased GSH level to the same extent. Hepatic GST activity toward EAA was significantly increased by SHTCC but was significantly decreased by SLTCC. ENPP GST activity was significantly decreased by SHTCC and SLTCC in the livers. In the lungs, all the GST activities examined were significantly depressed by SHTCC whereas only GST activity toward DCNB was reduced significantly by SLTCC. These results reveal that the hepatic and pulmonary MOs and GSTs are differentially influenced by SHTCC and SLTCC in rats.     

Collaboration in urological practice in the new millennium

The aim of this paper is to highlight areas in which urologists collaborate with other healthcare practitioners and to identify further areas of beneficial collaboration. A review of the literature using Medline search and the authors clinical experience. There is close collaboration with the radiologists in urological investigations and embolization of tumours, aspiration of cysts and abscesses as well as obtaining biopsy specimens. Cross referral of patients occurs between urologists, gynaecologists, oncologists and radiotherapists. Technological advances enabling different specialist to master certain procedures like ultrasonography and laser surgery should make collaboration obligatory and mandatory. Collaboration also occurs with orthopaedic, paediatric and plastic surgeons, proctologists and specialist nurses involved in urological treatments. Sometimes, there have been competition and conflicts with the above specialists, especially the gynaecologist in the treatment of urogenital fistulae. Close co-operation among healthcare practitioners will improve the standard of practice to the benefit of the patient as well as to promote healthier work atmosphere in health care delivery. Conflict and competition are diversionary, costly and unnecessary. The urologist appears best placed to lead the way in collaborative clinical practice in this millennium.