Infection of primary human gingival fibroblasts by Porphyromonas gingivalis and Prevotella intermedia

Adhesion and penetration of clinical isolates of Porphyromonas gingivalis and Prevotella intermedia in human gingival fibroblast monolayers were studied by transmission electron microscopy (TEM). Fibroblasts were cultured from biopsies of human healthy gingiva. Porphyromonas gingivalis and Prevotella intermedia were isolated from patients with periodontitis. Fibroblasts were incubated with microorganisms in an antibiotic-free medium for 24 h. Then cultures were washed to remove nonadherent bacteria. Consecutively, infected cultures were grown for another 24 h. Thereafter, the treated monolayers were prepared for TEM investigations. Internalized Porphyromonas gingivalis and Prevotella intermedia were visible after 24 h of incubation. Prevotella intermedia showed only division in cytoplasm of fibroblasts after 24 h and 48 h incubations. Infected fibroblasts revealed various morphological alterations such as extensive vacuolization and breakdown of mitochondria. These findings demonstrate that Porphyromonas gingivalis and Prevotella intermedia may invade human gingival fibroblasts and thus may damage these cells directly or due to the release of microbial cytotoxic components.

The micro-mitral operation comparing the Port-Access technique and the transthoracic clamp technique

BACKGROUND

Several minimally invasive approaches to the mitral valve have been described, including parasternal incision and right anterolateral thoracotomy.

MATERIAL AND METHODS

Since September 1996, 58 patients underwent minimally invasive mitral valve surgery at our institution through a right anterolateral minithoractomy. Two different techniques were used for institution of cardiopulmonary bypass (CPB) and aortic clamping: in the Port-Access group (group A) patients had femoro-femoral cannulation with a special arterial cannula to introduce an endoaortic balloon clamp (n = 23). The second group (group B) of patients underwent femoro-femoral CPB as well in combination with a specially designed transthoracic aortic clamp (Chitwood technique, n = 35). Patients were assigned to either technique in a nonrandomized fashion. Demographics were similar in both groups.

RESULTS

In group A, 4 valves were replaced, 19 patients had mitral valve repair. In group B, 7 patients had valve replacement and 28 patients underwent mitral repair. Four patients in group A were converted to Chitwood technique due to endoclamp dysfunction. Operating time, CPB time, cross-clamp time, and postoperative blood loss were lower in group B (operating time 295 +/- 83 min vs. 236 +/- 63.9 min; CPB min 167.6 = 64.9 min vs. 137.6 +/- 38.2 min; cross-clamp time 105.9 +/- 51.7 min vs. 78.9 +/- 25.2 min; postoperative blood loss 584 +/- 428 mL vs. 323 +/- 209 mL [p < 0.05]). Clinical outcome regarding postoperative mechanical ventilatilation time, hospital stay and hospital mortality was not different between groups.

CONCLUSIONS

Minimally invasive mitral valve procedures via right anterolateral minithoracotomy, including complex valve repair, can be performed successfully using either technique. However, the Chitwood technique provides better intraoperative handling with shorter operation time and less postoperative blood loss. Additionally, costs of a procedure are less using the Chitwood technique compared to the Port-Access technique.

Patient selection for Port-Access multi vessel revascularization

Minimally invasive multivessel revascularization is rarely performed due to the difficult exposure of the aorta as well as the complete coronary anatomy through a small thoracotomy. The Port-Access technique bears additional contraindications for this procedure, which limits its potential as compared with other approaches to 'less invasive surgery'. Our aim was to show the applicability of this surgical technique to a wide range of patients with coronary artery disease. In our initial experience with this method (31 patients), the quality of anastomoses, graft patency, and clinical outcome are good, and do not differ from standard multivessel coronary artery bypass grafting. Port-Access multivessel revascularization can be performed safely and is appropriate for a large patient population.

Complications of port-access cardiac surgery

Port-Access cardiac surgery is a recent technology that is undergoing rapid development. The learning curve associated with this technique is a challenge even for the skilled and experienced cardiac surgeon. Mainly because of femoral cannulation, the use of guidewires, and working through small incisions, Port-Access cardiac surgery contains certain pitfalls that are clearly associated with the technology involved. These pitfalls currently require troubleshooting, but as the technology progresses, this may become less of an issue. Communicating these pitfalls to others is important to help others to avoid or better manage complications and to contribute to improving the technology of Port-Access techniques.

Histopathological investigation of gingival tissue from patients with rapidly progressive periodontitis

In this study, fine structural features of the pocket walls in rapidly progressive periodontitis (RPP) and adult periodontitis (AP) in 20 cases were compared using light and transmission electron microscopy. Gingiva was also obtained from a control group of periodontally healthy teeth. Clinical parameters were assessed in both RPP and AP patients and in controls. Bone destruction and attachment loss were more marked in RPP than in AP. Light microscopical observations of inflamed RPP tissue as compared to AP showed gross histological distortions in the pocket walls. Micro-ridges within the epithelium and large intercellular spaces between the epithelial cells were observed in most RPP biopsies. Epithelial cells surrounding the microclefts and adjacent keratinocytes were found to produce interleukin-1beta (IL-1beta). Prevotella intermedia and Porphyromonas gingivalis were identified in the RPP biopsies using immunohistological methods. These microorganisms were localized outside the epithelium and inside intercellular spaces. Furthermore, the effect of inflammation on the distribution of collagen types I, III, IV, V, and VI in the human gingiva was studied after staining them with antibodies to these proteins. In RPP and AP tissues, the staining was sparse in areas of inflammation and leukocytic infiltration. Collagen type I and III were almost entirely lost at sites of inflammation. Type V and VI collagen antibodies were retained in inflamed areas. Type IV collagen was restricted to basement membrane structures. These observations demonstrated numerous structural features indicative of more pronounced degenerative changes in RPP than in AP.

Renal dysfunctions secondary to ifosfamide treatment in children

With the increasing use of ifosfamide in pediatric tumors, nephrotoxicity became the point of interest since it may cause chronic morbidity. In this study, the renal glomerular and tubular functions of 25 cases with solid tumors aged between 2-17 years (median 9) who were treated with ifosfamide, were investigated. For this purpose, routine blood urea, creatinine, calcium, phosphorus, electrolytes, urinary creatinine, phosphorus, glucose, protein and urinary retinol binding protein as well as microglobulin were evaluated. Except for two patients who had hypophosphatemia, phosphaturia, and proteinuria, all the cases had normal blood biochemistry, creatinine clearance, tubular phosphate reabsorption; and none had proteinuria, hematuria, or glycosuria. In spite of these findings, urine beta 2 microglobulin and retinol binding protein were found to be high in 11 patients and this elevation persisted during the following one year in 8 cases whose treatments were stopped and their levels increased in three patients who continued to receive fosfamide therapy. In correlation with the increasing cumulative dose of ifosfamide (32-126 g/m2), urinary retinol binding protein or beta 2 microglobulin of patients who are treated with ifosfamide may predict the existence of renal toxicity even if other routine renal function tests are normal. Thus, the periodic evaluation of urinary beta 2 microglobulin and retinol binding protein in patients receiving chemotherapy containing ifosfamide is recommended.

Skeletal and dental changes after orthognathic surgical treatment of mandibular prognathism

Ten patients with skeletal and dental Class III malocclusion with mandibular prognathism were treated orthodontically and surgically and the effects of the ramus sagittal split osteotomy technique on facial morphology and the dentofacial complex were investigated.

Thromboxane A2 receptor mediation of calcium and calcium transients in rat cardiomyocytes

We have examined the effect of the selective thromboxane A2 (TxA2) receptor agonist U46,619 on intracellular ionized Ca ([Ca2+]i) and the calcium transient rate (CATR) in cultured neonatal rat cardiomyocytes using the Ca-sensitive probe fura 2 and ratiometric microfluoroscopy. U46,619, 10(-6)-10(-8)M, increased basal diastolic Ca fluorescence and 10(-6) and 10(-7) M increased CATR. These effects were completely blocked by the highly selective TxA2 receptor antagonist SQ-29,548 (p > 0.5, n = 4 compared to baseline), confirming this response is a specific receptor-mediated event in the cardiomyocytes. TxA2 blockade did not diminish the Angiotensin (Ang II)-mediated [Ca2+]i and calcium transient rate response from that observed in non-blocked cells (p = 0.18 and 0.21 respectively, n = 4). The TxA2-mediated changes in Ca2+ fluorescence did not exhibit homologous desensitization as does Ang II, they did not exhibit heterologous desensitization, and maximally stimulating concentrations were additive in their effect on peak [Ca2+]i. These data support the hypothesis that TxA2 secretion or release following ischemia or other pathophysiologic events could alter cardiac calcium homeostasis. Although Ang II is reported to stimulate the release of TxA2 in a variety of tissues, including the heart, the Ca2+ and CATR response to Ang II are not diminished when TxA2 receptors are blocked. This study cannot rule out the possibility that Ang II-mediated increases in TxA2 may have an additive effect on Ca homeostasis.

Sublingual nitrate plus 99Tcm-tetrofosmin infusion in the detection of severely ischaemic but viable myocardium: a comparative study with stress, redistribution, reinjection and late redistribution 201Tl imaging

To investigate the role of sublingual nitrate plus 99Tcm-tetrofosmin infusion in the detection of severely ischaemic but viable myocardium, we selected 25 patients with coronary artery disease who had at least one fixed segmental defect during conventional stress-redistribution (ST-RD) 201Tl single photon emission tomographic (SPET) imaging. Reinjection (RI) and 24 h late redistribution (LRD) imaging were also performed. Within a week of 201Tl imaging, one-day rest-stress (R-ST) 99Tcm-tetrofosmin SPET was performed with the same stress levels. The following day, 99Tcm-tetrofosmin was infused over 1 h immediately after sublingual nitrate administration and SPET images (N + Inf) were acquired. Of 100 fixed defects on R-ST 99Tcm-tetrofosmin imaging, 15 were reversible on N + Inf 99Tcm-tetrofosmin imaging. There was 91% concordance between ST-RD/RI/LRD 201Tl and R-ST/N + Inf 99Tcm-tetrofosmin imaging regarding reversibility. We conclude that N + Inf 99Tcm-tetrofosmin imaging may be clinically useful in the detection of severely ischaemic but viable myocardium.

Protein kinase C modulation of cardiomyocyte angiotensin II and vasopressin receptor desensitization

Angiotensin II (Ang II) and arginine vasopressin (AVP) increased intracellular free Ca2+ concentration [Ca2+]i and/or the [Ca2+]i transient rate (CaTR) in cultured neonatal rat cardiomyocytes. These agents increased membrane-bound protein kinase C (PKC) with peak activity at 5 and 10 minutes, respectively. Two-minute exposure to Ang II produced homologous desensitization to a repeated stimulation with Ang II and heterologous desensitization to AVP. Two-minute exposure to AVP also produced homologous desensitization to AVP but not heterologous desensitization to Ang II. When the AVP exposure time was increased from 2 to 10 minutes coincident with maximal AVP-mediated PKC activation, heterologous desensitization to Ang II was also observed. Acute activation (15 minutes) of PKC by phorbol 12-myristate 13-acetate (PMA) blocked responsiveness to both Ang II and AVP. When PKC activation was inhibited by 20 hours of prior exposure to PMA, as confirmed by PKC assay, homologous desensitization of Ang II still occurred, confirming an alternative mechanism(s) for homologous desensitization in the cardiomyocytes. In contrast, 20-hour PMA suppression of PKC markedly diminished the ability of the cardiomyocytes to exhibit AVP-mediated heterologous desensitization for Ang II. These data indicate that PKC activation plays a primary role in mediating vasopressin V1 receptor-induced heterologous desensitization of the Ang II receptor and participates in a hierarchy of two or more kinase systems mediating homologous desensitization of the Ang II receptor in cardiomyocytes.

Canine intersegmental hip joint forces and moments before and after cemented total hip replacement

Intersegmental forces and moments (i.e. resultant free body forces and moments computed at the joint centers) were studied in canine hindlimbs before and after cemented total hip replacement (THR). Five large, adult, mixed-breed dogs were selected. Their gait was recorded (while leash-walked) before surgery using high-speed cinematography and a force plate. Cemented total hip replacement was unilaterally performed on each dog. Gait was again recorded at one and four months after surgery. Segmental properties (mass, center of mass, and mass moment of inertia) of the hindlimbs were experimentally determined, and an inverse dynamics approach was used to compute intersegmental forces and moments in the sagittal plane. Significant reductions in intersegmental joint forces and moments were observed in the operated hindlimb one month after surgery, although kinematic gait parameters were unaltered. Decreases of 77.0% for vertical forces, 61.9% for craniocaudal forces, and 66.2% for extension moments were determined. Four months after surgery, the joint forces and moments had returned to their preoperative values. This experiment demonstrates that the dynamics of normal walking can be restored in a canine model by four months after THR. It also shows that kinetic (rather than kinematic) parameters are more descriptive of antalgic gait in the canine.

Ground reaction force comparison of canine cemented and cementless total hip replacement

Ground reaction forces were studied in the hindlimbs of ten dogs after cemented and cementless total hip replacement. The femoral components in five dogs were surgically press fitted into the medullary canal for porous ingrowth fixation (cementless) while the remaining five dogs had their femoral component cemented in place. Gait analysis was performed monthly for four postoperative months. Reductions in vertical ground reaction forces were observed in both cemented and cementless implanted hindlimbs one and two months after surgery. By three months postoperative, both groups had effectively returned to their preoperative vertical ground reaction force levels on the implanted hindlimb. At three and four months post implantation, the cemented group demonstrated equal load distribution between the operated and unoperated hindlimbs, whereas the cementless group showed a disparity in load distribution between the operated and unoperated hindlimbs which persisted for the four-month test period. We believe that the paired comparisons between operated and unoperated limbs are more descriptive of antalgic gait than comparisons with preoperative control values.

Centronuclear myopathy with type I fibre hypotrophy and "fingerprint" inclusions associated with Marfan's syndrome

The authors present results of histological and electron-microscopical investigations of muscular tissue obtained by biopsy from a 20-year-old man, who showed typical features of Marfan's syndrome associated with slowly progressive muscular weakness. The muscle showed a peculiar combination of centronuclear myopathy with hypotrophy of type I fibres and the so called "fingerprint myopathy". The combination of such myopathic phenomena with Marfan's syndrome presents a unique and hitherto undescribed condition.

Determination of total tin in environmental biological and water samples by atomic absorption spectrometry with graphite furnace

Analysis of traces of tin using several analytical techniques (X-ray fluorescence, neutron activation, polarographic techniques and atomic absorption) have been tested. Parameters such as simplicity, rapidity, sensitivity and interferences are compared in order to choose the most useful method for practical purpose. Finally, flameless atomic absorption was chosen for the determination of total tin concentration in different natural samples. Digestion of biological samples (plant, plankton, fish, etc.) was achieved by using Lumatom (a trade organic chemical). Thus, the digested sample is directly injected into the graphite furnace. This digestion technique is suitable and rapid with a minimum of error (contamination and losses). For tin analysis in water samples, a preconcentration of tin is carried out by coprecipitation with 1, 10-phenanthroline and tetraphenyl boron. The precipitate is separated and dissolved in alcohol or in Lumatom. The sensitivity of this method is 0.1 ng absolute tin.

Hereditary persistent distal cramps

A disease consisting of persistent muscle cramps involving distal muscle groups that occurred in 12 members of the same family is described. The cramps appeared on exertion and in full relaxation or during sleep. In the third generation they appeared in the second decade; in the fourth and fifth generations in childhood with higher frequency and intensity of cramps. The disease is not sex linked and seems to be dominantly inherited. Electromyography showed no myotonic response on insertion. Motor unit potentials were normal. Continual waxing and waning electrical discharges corresponding to clinically visible contractions of parts of the muscles were present. Repetitive nerve stimulation caused no change in the amplitude of evoked muscle potentials. On spinal anaesthesia or nerve block the muscle contractions continued but became painless. The movements were only stopped with local infiltration of anaesthetic into the muscle. There were no cramps on ischaemic work. Drug studies revealed no benefit on carbamazepine, slight relief with meprobamate, and complete disappearance with potassium chloride. The remission outlasted the treatment for three months and then cramps of milder degree reappeared. Repeated potassium chloride treatment was not effective. The cramps increased on hydrochlorothiazide, and 12 hours after spinal anaesthesia. In the authors' opinion the disease should be considered as not belonging to any known nosological entity.