First sampled plasma troponin T is associated with one-year mortality in sepsis and septic shock, independent of age, gender, comorbidities, and clinically relevant biomarkers

Background

Patients with sepsis and septic shock often have elevated troponin T levels indicating acute myocardial injury. Studies investigating the relationship between troponin T levels as a predictor for mortality in sepsis have been contradictory.

Purpose

To investigate if the first in-hospital sampled plasma troponin T value is associated with one-year mortality in sepsis and septic shock independent of comorbidities, Sequential Organ Failure Assessment (SOFA)-score, Clinical Frailty Scale, Charlson Comorbidity Index (including age) and clinical biomarkers (e.g., serum lactate, creatinine, C-reactive protein).

Methods

Patients with sepsis and sepsis shock were included if they were admitted to the intermediate and intensive care units at our institution between 1st of March 2012 and 30th of September 2021, and if at least one troponin T value was recorded within the first two calendar days from symptom onset. Variables were collected from medical records. Normal troponin-T was defined as <15 ng/L. Elevated troponin T values were divided into quartiles (Q): Q1 15–35.9 ng/L, Q2 36–61.9 ng/L, Q3 62–125.9 ng/L and Q4 ≥126 ng/L. Kaplan-Meier stratified survival curves were plotted for normal levels and Qs of elevated troponin T. Multivariate Cox regression was used for multivariate analysis.

Results

586 patients were included and 529 (90%) had a first sampled troponin T ≥15 ng/L. 523 (89%) met the Sepsis-3 criteria for septic shock, the remainder met the criteria for sepsis. The mean age was 71 years and 220 (38%) were women. One-year mortality was 45% (n=264). Increasing levels of first sampled plasma troponin T were associated with higher hazard ratios (HR) for one-year mortality compared to normal levels (<15 ng/L): Q1 HR 5.29 (95% confidence interval [CI] 1.9–14.7); Q2 HR 7.47 (95% CI 2.71–20.6); Q3 HR 12.81 (95% CI 4.7–35.0); Q 4 HR 13.82 (95% CI 5.06–37.7) (Figure 1). Troponin T was independently associated with one-year mortality after adjustment for gender, plasma lactate, plasma CRP, prior atrial fibrillation, in-hospital onset atrial fibrillation, SOFA-score, CFS, and CCI (including age) (Table 1).

Conclusions

Elevated first sampled plasma troponin T in patients with sepsis and septic shock was associated with higher one-year mortality, independent of age, gender, comorbidities, and clinically relevant biomarkers. There was a risk gradient across the Qs of elevated troponin T with increasingly higher risk of death at one year per higher Q. Further studies are needed to ascertain whether elevated troponin T levels and clinical assessment scores can be used together in the clinical setting to identify patients for more aggressive treatment and cardiac work-up.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Region Stockholm

Astra Tech and Brånemark System Implants: A Prospective 5-Year Comparative Study. Results after One Year

BACKGROUND

Endosseous dental implants are used frequently, and many implant systems are available. The scientific documentation of the implant system presents a great variation, and it is often difficult to compare studies of different systems.

PURPOSE

The aim of this study was to compare two Swedish implant systems (Astra Tech and Brånemark System implants), in a prospective randomized study.

MATERIALS AND METHODS

Sixty-six patients were equally distributed between the two implant systems; 184 Astra Tech and 187 Brånemark System implants were used. The patients have been followed annually with clinical and radiographic examinations. The results after 1 year are reported.

RESULTS

The abutment procedure was found to be easier and less time-consuming with Astra Tech than with Brånemark implants. The operation times in minutes (mean +/- SEM) were for the respective implant 35 +/- 4.0 and 51 +/- 4.8 in the maxilla and 32 +/- 3.8 and 43 +/- 2.4 in the mandible. The differences in both cases were significant: p < .02 and p < .05, respectively. The failure rate for Astra Tech implants was 0.5% and for Brånemark implants 4.3%. The difference was significant (p < .05); however, taking into account that five of the eight implant losses in the Brånemark implant group occurred in one patient, an intraindividual correlation cannot be excluded. Therefore, this result should be interpreted with caution. The marginal bone level changes were examined already from the fixture installation. The major bone loss was found between fixture installation and baseline. This bone loss was several times greater than the bone loss between the baseline and the 1-year follow-up. The total bone loss during the observation period did not differ significantly between the systems, but they had different resorption patterns. The bone loss in the upper jaw between baseline and 1-year follow-up was 0.22 +/- 0.14 and 0.03 +/- 0.09 mm for the Astra Tech and Brånemark implants, respectively. In the lower jaw, the loss was -0.31 for both systems. The frequency of plaque accumulation and bleeding on probing did not differ between the implant systems.

CONCLUSIONS

Abutment connection with Astra Tech implants was simpler than the corresponding surgery with Brånemark System implants and the survival rate of Astra Tech implants was higher than that of Brånemark system implants.

Implants in partially edentulous patients. A longitudinal study of bridges supported by both implants and natural teeth

The aim of the study was to compare the outcome of bridges supported by implants with bridges supported by a combination of implants and natural teeth abutments. The study comprised 23 patients with Applegate Kennedy Class I dentition in the mandible and a full upper denture. Implants ad modum Brånemark were inserted in the posterior areas of both mandibular quadrants. On one side, a bridge supported by 2 implants was constructed (Type I) and on the other side, a bridge supported by 1 tooth (mostly the canine or first premolar) and 1 implant was made (Type II). A total of 46 bridges were made and during the 3-year follow-up period, 4 Type I and 2 Type II bridges were lost. 8 out of 69 implants were lost during the 3-year follow-up, resulting in an implant survival rate of 88.4%. Marginal bone loss, one of several parameters, was evaluated on standardized intraoral radiographs. This was performed during the 1st and 2nd year of function and the total mean bone loss from loading was 0.46 mm and 0.56 mm, respectively. The bone loss during the 2nd year of function was significantly less, adjacent to implants supporting Type II bridges, than adjacent to implants supporting Type I bridges. Summarily, no disadvantages of combining of teeth and implants in the same bridge were found in this study. On the contrary, the slightly lower marginal bone loss adjacent to implants in Type II bridges may indicate that the bone reactions could be more favorable when bridges are connected to both implants and teeth.

Nonsubmerged implants in the treatment of the edentulous lower jaw: a 5-year prospective longitudinal study of ITI hollow screws

BACKGROUND

Although most implant systems have been designed for a two-stage surgical technique, a one-stage surgical technique has always been advocated for the ITI Dental Implant System (Straumann AG, Waldenburg, Switzerland). A new generation of ITI implants was presented in 1988 and included a hollow cylinder, a hollow screw, and a solid screw.

PURPOSE

The goal of this study was to evaluate the one-stage surgical technique in connection with the ITI hollow screw in a longitudinal study over 5 years.

MATERIALS AND METHODS

Forty-six patients with edentulous lower jaws were supplied with ITI hollow-screw implants. Patients who requested an overdenture (n = 18) had four implants inserted; those who requested a fixed bridge (n = 28) had five to six implants. The patients have been followed annually for 5 years. There was a dropout of three patients (6.5%); one patient did not want to cooperate, one moved from the area, and one was deceased. The clinical examinations included bridge removal for evaluation of the individual implant stability in connection with the 1-, 3-, and 5-year examinations. Radiographic examinations were performed with intraoral radiographs and the long-cone technique.

RESULTS

The survival rate after 5 years was 95.7%. The success rate (in which implants undergoing treatment of peri-implantitis were not counted as successes) was 91.4%. The mean marginal bone loss between the baseline and the 1-year examination was 0.1 mm and between the 1- and 5-year examinations was 0.1 mm. These changes in marginal bone level were not significant.

CONCLUSIONS

The success rate of ITI hollow-screw implants in the edentulous mandible was 91.4% after a 5-year observation period. There was no significant change in mean bone level between the loading of the implants and the 5-year examination. Peri-implantitis was diagnosed in three patients with poor oral hygiene, and it affected six implants. Five of these failed in spite of treatment.

Pain and orthopaedic and neurologic signs after lumbar discectomy: a 2-year followup

In a prospective study of 161 consecutive patients with lumbar discectomy, pain, lumbar mobility, and neurologic and root tension signs were followed up for at least 2 years. Sciatica and root tension signs decreased promptly after surgery and remained largely unchanged during followup, which was not the case for neurologic signs. Similarly, pain relief was not associated with neurologic signs but was associated with lumbar mobility and root tension signs. Patients without neurologic symptoms before surgery did not report more sciatica after 2 years than did those with positive neurologic signs before surgery. Positive crossed Lasegue sign and restricted lumbar mobility before surgery predicted better chances for postoperative pain relief. Patients with a ruptured anulus fibrosus at surgery had less sciatica and back pain after surgery than did patients with an intact anulus fibrosus.

Nonsubmerged Implants in the Treatment of the Edentulous Upper Jaw: A Prospective Clinical and Radiographic Study of ITI Implants?Results after 1 Year

BACKGROUND

A new generation of ITI implants, including a hollow cylinder, a hollow screw, and a solid screw, was described in 1988. Currently, the solid screw is the main alternative.

PURPOSE

The aim of this study was to gain further clinical documentation of ITI solid-screw implants used in the edentulous upper jaw. This is a report 1 year after loading.

MATERIALS AND METHODS

Twenty-eight patients with edentulous upper jaws (mean age, 57 yr) were supplied with four to eight ITI solid-screw implants in the upper jaw. In total, 167 implants (3.3 and 4.1 mm in diameter) were inserted. The implants were loaded about 7 months postoperatively. All patients were supplied with fixed screw-retained bridges.

RESULTS

Twelve implants failed: 10 prior to loading and 2 after. Overall implant survival rate was 92.8%. Three of the five patients with implant loss were smokers. Signs of peri-implantitis were found in seven patients, affecting 12 implants. Mean marginal bone level at the loading of the implants (7 months after insertion) was situated 4.7 mm from the reference point of the implant. There was no significant change between loading and the 1-year examination. However, at several implants, the bone level at baseline was situated far apical of the reference point, indicating a bone loss before loading.

CONCLUSIONS

The ITI screw implants, used in the edentulous upper jaw, had a survival rate of 92.8%. Mean bone loss between loading and the 1-year examination was 0.1 mm. Some implants had a bone level indicating a significant bone loss before loading. Peri-implantitis was found at about 7.2% of the implants inserted and at 25% of the failing implants.

Tooth-implant and implant supported fixed partial dentures: a 10-year report

PURPOSE

The use of implants for prosthetic rehabilitation of partially edentulous patients is increasing. However, the possibilities of placing implants in the posterior part of the mandible are often limited. The purpose of this longitudinal study with 10 years of follow-up was to evaluate the use of short implants supporting fixed partial dentures (FPD) in the posterior part of the mandible, and to compare implant supported FPDs to tooth-implant supported FPDs.

MATERIALS AND METHODS

The patient material comprised 23 patients with residual mandibular anterior teeth, and each patient received FPDs unilaterally. On one side the FPD was supported by two implants, and on the other side by one implant and one tooth, thus permitting intraindividual comparison. The distribution of the two types of FPDs in each jaw was randomized. Implant success rates, marginal bone changes, and mechanical complications were studied.

RESULTS

The tooth-implant connection did not demonstrate any negative influences on the overall success rates for the 10-year period, nor were the shorter implants found to be less favorable.

CONCLUSION

It is suggested that a prosthetic construction supported by both a tooth and an implant may be recommended as a predictable and reliable treatment alternative in the posterior mandible.

Diagnosis and prognosis in lumbar disc herniation

In a prospective 2-year followup study of 160 consecutive patients undergoing primary surgery for suspected lumbar disc herniation, the authors studied the diagnostic and prognostic factors by using stepwise logistic regression analysis. When the different factors were entered in the same order as presented clinically, history and pain analysis contained most of the predictive information available. When all factors were entered simultaneously in the computations, the following factors (in order of relative importance) predicted relief of sciatica after 2 years: rupture of the anulus (as opposed to bulging disc or negative exploration), no preoperative comorbidity, and male gender. The following factors predicted return to work at 2 years: no preoperative comorbidity, duration of sciatica less than 7 months, education or vocational training in addition to compulsory school, age younger than 41 years, male gender, and no previous nonspinal surgery. Return to work does not seem to be a valid result parameter in lumbar disc surgery. The most important physical signs were root tension tests and lumbar range of motion, whereas neurologic signs were of secondary importance. Many people have asymptomatic herniations, and today supersensitive diagnostic imaging is widely available. Thus, the importance of clinical evaluation has increased, and most of the relevant information can be obtained by listening to the patient. A simple anamnesis apparently is a good alternative to psychologic tests in surgical triage.

Non-submerged implants in the treatment of the edentulous lower jar. A 2-year longitudinal study

Non-submerged ITI Bonefit implants (ITI Dental Implant System) were inserted in edentulous lower jaws of 46 patients. The patients were provided with either a fixed prosthesis or an overdenture, and has been followed during a 2-year-period. At the 1-year examination, the suprastructures were removed permitting test of the individual implant stability. Radiographic examinations were performed in connection with the loading of the implants and at the 1-year examination. In total 216 implants were inserted. 4 implants were lost before loading and 4 during the 2nd year of function, which gives a survival rate after 1 year 98% and after 2 years of 96%. The mean marginal bone loss during the first year of function was 0.1 mm. However, the marginal bone changes had a high degree of variation and four implants showed a severe bone loss. The intention is to follow this patient group with annual examinations during 5 years.

Immunological responses to maxillary on-lay allogeneic bone grafts

4 patients with severely resorbed maxillae underwent rehabilitation with on-lays of allogeneic femoral head bone grafts, titanium implants (Brånemark System) and fixed prostheses. Donors and recipients were matched according to blood groups (ABO/Rh). Potential immunological responses were monitored by determining autoantibodies in peripheral blood, and inflammatory reactions in the recipient site. Biopsies from the bone graft 6 months after grafting showed vital bone. After a mean observation period of 19.5 months, 22 of 23 implants were osseointegrated. None of the investigated autoantibodies were detected in peripheral blood, and there was no local inflammatory response. Allogeneic bone grafts in combination with titanium implants can be used in reconstruction of edentulous severely resorbed maxillae without immunological reactions directed against the graft.

Titanium implants and onlay bone graft to the atrophic edentulous maxilla: a 3-year longitudinal study

Treatment of the atrophic maxilla using an onlay bone-grafting technique in combination with simultaneous insertion of endosteal implants (Branemark System) was performed in 17 patients. They were followed during a 3-year period. At the end of this period, 14 patients had stable bridges in use and one patient had an overdenture. Two patients had had to return to conventional dentures due to implant losses. The survival rate of the implants after 3 years use was 75%. It is concluded that, in spite of the implant losses, onlay bone grafting to the maxilla is a valuable method in cases of severe maxillary atrophy.

Single-tooth replacement by osseointegrated Brånemark implants. A retrospective study of 82 implants

The aim of the study was to evaluate the outcome of single-tooth restorations on Brånemark implants performed during the period 1984-1989. The material comprised 58 consecutive patients with 82 implants. The observation period varied from 1 to 5 years. Two implants were lost, both of them before loading. The overall survival rate was 97.6%. Radiographic follow-up was performed for 72 implants after 1 year and for 51 implants after 2 years. The bone loss during the first year was on average 9.6 +/- 0.1 mm and during the second year 0.1 +/- 0.1 mm. Although the observation time for most of the patients was only 2 years, the results indicate that the outcome of single-tooth restorations may be as favorable as for implants in edentulous jaws.

Bridges supported by free-standing implants versus bridges supported by tooth and implant. A five-year prospective study

The clinical question at issue, whether it is possible to combine implants and natural teeth via fixed bridges, is of current interest. The treatment of the subjects of this prospective study was performed between June 1984 and December 1986. This article presents the 5-year results of the study. The consecutive patient material comprised 23 patients with Applegate Kennedy Class I residual dentition in the mandible and a complete maxillary denture. All 23 patients were provided with implants ad modum Brånemark in each mandibular quadrant. One side was randomized to rehabilitation with fixed bridge between the distal tooth of the residual dentition and an implant; the other side received a free-standang bridge on 2 implants. The fixture survival rate was 88%. No difference was found between the two sides. Bridge stability was 89% for the implant bridges and 91% for the combination bridges. The change in marginal bone level at the implants was small during the 5-year follow up period (on average 0.1-0.3 mm) and with no difference between the two sides. In conclusion, it was not possible to demonstrate any higher risk of implant or prosthetic failure for tooth-implant fixed bridges compared with implant-supported bridges.

Spatiotemporal pattern of quantal release of ATP and noradrenaline from sympathetic nerves: consequences for neuromuscular transmission

The recent explosive development in research concerning the fundamental mechanisms of synaptic transmission helps put the present paper in context. It is now evident that not all transmitter vesicles in a nerve terminal, not even all those docked at its active zones, are immediately available for release (36). We watch, fascinated, the unraveling of the amazingly complex cellular mechanisms and molecular machinery that determine whether or not a vesicle is "exocytosis-competent" (77,78,39,79). Studies on quantal release in different systems show that neurons are fundamentally similar in one respect: that transmitter release from individual active zones is monoquantal (2). But they also show that active zones in different neurons differ drastically in the probability of monoquantal release and in the number of quanta immediately available for release (3). This implies that one should not extrapolate directly from transmitter release in one set of presynaptic terminals (e.g., in neuromuscular endplate or squid giant synapse) to that in other nerve terminals, especially if they have a very different morphology. As shown here, one should not even extrapolate from transmitter release in sympathetic nerves in one tissue (e.g., rat tail artery) to that in other tissues or species (e.g., mouse vas deferens). It is noteworthy that most studies of quantal release are based on electrophysiological analysis and therefore deal with release of fast, ionotropic transmitters from small synaptic vesicles at the active zones, especially in neurons in which these events may be examined with high resolution (49,48,46,33,32). Such data are useful as general models of the release of both fast and slow transmitters from small synaptic vesicles at active zones in other systems, provided that these transmitters are released in parallel, as are apparently ATP and NA in sympathetic nerves. They tell us little or nothing, however, about the release of transmitters (e.g., neuropeptides) from the large vesicles, nor about the spatiotemporal pattern of monoquantal release from small synaptic vesicles in the many neurons that have boutons-en-passent terminals. They show that the time course of effector responses to fast, rapidly inactivated transmitters such as ACh or ATP is necessarily release related. But they do not even address the possibility that the effector responses to slow transmitters such as NA, co-released from the same terminals, may obey completely different rules and perhaps rather be clearance related (7).(ABSTRACT TRUNCATED AT 400 WORDS)

Histologic investigations on 33 retrieved Nobelpharma implants

Thirty Nobelpharma implants were retrieved from 17 patients despite a remaining clinical stability, after between 1 and 16 years of clinical function. The reasons for implant removal were bone resorption in combination with soft tissue disorders, psychological causes, implant fracture and post mortem cases. When measured at the cortical passage, there was an average of 84.9% direct bone-to-implant contact and 81.8% average surface bone area in individual threads as evaluated in a computerized morphometric system at the light microscopic level.

Structure of the bone-titanium interface in retrieved clinical oral implants

7 clinically stable, "osseointegrated", titanium implants, inserted in human jaws for 1-16 years, were retrieved for morphological analysis of the bone-titanium interface, using 3 different preparation techniques. The bone-titanium interface varied as judged from light microscopy of ground sections. The threads of the implants were well filled (79-95%) with dense lamellar bone as quantified with morphometry. A large fraction of the implant surface (56-85%) appeared to be in direct contact with the mineralized bone. In general, the non-bone areas consisted of pockets with osteocytes, bone marrow tissue and/or vessels. Sections were prepared for light microscopy and transmission electron microscopy using a fracture technique, where the implant was separated from the embedded tissue before sectioning, and an electropolishing technique, where the bulk part of the implant was electrochemically removed. In areas judged as direct mineralized bone-titanium contact in the light microscope, the interfacial structure varied at the ultrastructural level. In areas along the interface, unmineralized tissue was present either as a narrow 0.5-1 micron wide zone containing collagen fibril or as deeper pockets containing osteocytes or vessels. In areas with mineralized bone contact, an amorphous granular layer (100-400 nm wide) with no mineral was observed in the innermost interface bordering the mineralized bone, with an electron-dense lamina limitans-like line (approximately 50 nm thick). It is concluded that the bone-titanium interface of the 7 clinically retrieved titanium oral implants examined in the present study bone was heterogenous. In areas of a direct mineralized bone-titanium contact at the ultrastructural level, mineralized bone reached close to the implant surface, but was separated by an amorphous layer, being 100-400 nm thick.

A calcium-dependent component of the action potential in sympathetic nerve terminals in rat tail artery

A pharmacological approach was employed in order to visualize a Ca2(+)-dependent component of the extracellularly recorded nerve terminal impulse in the secretory regions of the sympathetic postganglionic nerves in the rat tail artery. Application of potassium-channel-blocking agents within the recording electrode caused the nerve terminal impulse to acquire a delayed negative deflection, which we have termed the late negative component (LNC) of the nerve terminal impulse. The time course and the latency of the LNC differed from that of the postjunctional transmitter-induced excitatory junction current, and the LNC persisted when the excitatory junction current was blocked by adenosine [alpha,beta-methylene]triphosphate, and was resistant to the alpha 1-antagonist prazosin and the alpha 2-antagonist yohimbine. Probably, therefore, the LNC was exclusively prejunctional in origin. For the following reasons it seems likely that the LNC, at least in part, was caused by influx of Ca2+ into the secretory regions of these nerves: (a) the LNC occurred only when potassium-blocking agents were present within the recording electrode; (b) the LNC amplitude increased with the Ca2+ concentration inside the recording electrode and was reduced by the removal of Ca2+; (c) the LNC was enhanced by replacing Ca2+ in the medium inside the recording electrode with Ba2+; (d) the LNC was depressed by the inorganic Ca2(+)-channel blocker cadmium or the Ca2(+)-channel-blocking peptide omega-conotoxin added within the recording electrode only, or by addition of cadmium or cobalt (but not the organic Ca2(+)-channel blocker nifedipine) inside and outside the recording electrode.(ABSTRACT TRUNCATED AT 250 WORDS)

Presynaptic receptors and modulation of noradrenaline and ATP secretion from sympathetic nerve varicosities

Our results in the model tissues examined show (1) that alpha 2 agonist(s) depressed the secretion of NA and ATP caused by nerve stimulation at low frequency, (2) that the secretion of both NA and ATP was moderately autoinhibited, under conditions when endogenous NA was shown to accumulate extracellularly, (3) that a K+ channel blocking agent increased much more strongly than alpha 2-adrenoceptors block the secretion of both NA and ATP, and also amplified enormously the NA-mediated neurogenic contraction, (4) that, therefore, a high K+ efflux is likely to be much more important than alpha 2-adrenoceptor-mediated autoinhibition for maintaining a low release probability in sympathetic nerve varicosities, and (5) that the alpha 2-adrenoceptor agonist, clonidine, or the Ca2+ channel blocking agent, Cd2+, inhibited transmitter secretion, at least in part, via targets "upstream" of the varicosity.

Planning and control of vertical dimension in Le Fort I osteotomies

Depending on the different anatomy of the soft and hard tissues, concavity or convexity of the face, measurements of inferior or superior repositioning of the maxilla may be less predictable when using only the osteotomy site for this calculation. A more reliable method would be to measure the distance from a bone mark in the forehead to the incisor edges. This method has been practiced by our clinic during the past five years. The method is thought to offer a more accurate estimation of the position of the upper anterior teeth in relation to the lip, although one must anticipate a certain degree of postoperative relapse especially concerning inferior repositioning. In order to evaluate the accuracy of our method, a comparison has been made of the calculated vertical repositioning and the surgical results in two groups. In group I (12 individuals) conventional estimation of maxillary repositioning in the osteotomy line was made; in group II (12 individuals) measurements were made from a bone mark on the forehead to the incisor edges. A satisfying correlation was found between calculated and achieved results in both groups. In comparison between calculated and immediate postoperative measurements the results showed no statistically significant difference between the two methods.

ATP as a sympathetic co-transmitter in rat vasomotor nerves--further evidence that individual release sites respond to nerve impulses by intermittent release of single quanta

A combination of intra- and extracellular recording was used to study neurotransmitter release in sympathetic vasomotor fibres in rat femoral and mesenteric arteries. The results show that neurotransmission in these preparations is similar to that in the 'short' sympathetic nerves in guinea-pig vas deferens and the 'long' sympathetic nerves in rat tail artery in the following respects: (1) The intracellularly recorded excitatory junction potentials (EJPs) and the extracellularly recorded junction currents (EJCs) presumably are caused by ATP secreted as a sympathetic co-transmitter. (2) The stimulus-evoked and spontaneous EJCs share the same brief time-course, which is similar to that of spontaneous EJPs, but much briefer than that of stimulus-evoked EJPs. (3) 'Successful' nerve impulses appear to release single transmitter quanta. (4) The probability of activation of individual release sites is low (0.002-0.02). (5) The low release probability cannot be accounted for by failure of the nerve impulse to invade the terminals. Moreover, it is also shown that application of tetrodotoxin to the medium within the recording electrode effectively abolishes transmitter secretion in the area enclosed by the tip of the electrode, indicating that the effective length constant for a passively propagating nerve action potential is probably very small and that activation of the release mechanisms in 'long' sympathetic nerve fibres seems to require that the varicosities are actively invaded.

On the secretory activity of single varicosities in the sympathetic nerves innervating the rat tail artery

1. Nerve terminal impulses (NTIs) and spontaneous or stimulus-evoked excitatory junction currents (SEJCs or EJCs), reflecting secretion of transmitter quanta from release sites in the sympathetic nerves of rat tail artery, were recorded by extracellular electrodes. 2. The release of transmitter quanta from single varicosities was analysed on a pulse-by-pulse basis. 3. Since the SEJCs were tetrodotoxin-resistant, and hence probably caused by single quanta, they were employed to analyse the quantal content of EJCs. 4. In the majority of recordings, EJCs were large compared to SEJCs from the same attachment, and preceded by prominent NTIs. This type of activity appeared to reflect simultaneous activation of several nerve fibres and numerous varicosities. 5. By focal stimulation, it was usually possible to improve the resolution by examining spots in which a large proportion of the suprathreshold stimuli failed to cause EJCs. Here, averaged NTIs preceding large EJCs were indistinguishable from averaged NTIs not followed by EJCs. Thus, failure of invasion by the nerve impulse was not a cause of the frequent secretory failure. 6. In these attachments the amplitude distribution of nerve stimulus-evoked EJCs was similar to that of the SEJCs and many individual EJCs could be matched in amplitude and time course by SEJCs. Thus, transmitter secretion from these sympathetic nerve varicosities seems to be basically monoquantal. 7. Under conditions when all EJCs were smaller than or equal to the largest SEJCs some characteristic EJC profiles appeared only a few times in response to several hundred suprathreshold stimuli at low frequency (0.5-1 Hz). Using tentatively these EJCs as 'fingerprints' of single quanta from particular release sites, the probability for activation of individual release sites ranges from 0.002 to 0.02.

Time course of transmitter action at the sympathetic neuroeffector junction in rodent vascular and non-vascular smooth muscle

1. Transmitter release from sympathetic postganglionic nerve terminals innervating the guinea-pig and mouse vas deferens and the rat tail artery has been studied in vitro by focal extracellular recording with particular emphasis on the time course of transmitter action underlying the intracellular potential changes. 2. In the absence of stimulation, spontaneous excitatory junction currents (SEJCs) were recorded with amplitudes up to 500 microV and durations between 40 and 100 ms. SEJCs were unaffected by the competitive alpha-adrenoceptor antagonist prazosin but blocked by alpha, beta-methylene ATP which desensitizes P2-purinoceptors. 3. During trains of supramaximal stimuli at 0.1-4 Hz stimulus locked excitatory junction currents (EJCs) were evoked intermittently from the population of varicosities located under the suction electrode. 4. SEJCs were similar in amplitude and time course to EJCs evoked by low-frequency stimulation in the same attachment in all three tissues. 5. SEJCs recorded using either a conventional AC amplifier or a patch clamp amplifier had the same time course. 6. These studies show that the time course of the current underlying the excitatory junction potential is brief and essentially the same in three different tissues. The prolonged time course of the excitatory junction potential in different tissues can be accounted for by the passive membrane properties.

Intermediate bone grafting of alveolar clefts

During the five year period 1980 to 1985 bone grafting was performed in 37 cleft patients before the eruption of the canine tooth (group IBG) and in 30 patients after the eruption of the canine tooth (group SGB). The initial healing was more favourable in the IBG group. In 72.5% of the clefts oro-nasal fistulae were present preoperatively. In all cases the fistulae were successfully closed. In the IBG group with orthodontic closure of the gap in the dental arch the interdental bone height in the grafted area was more than 75% of normal bone height in all clefts. In group SBG this situation was found in only 66% of the bone-grafted areas. There seems to be a clear relation between the age or the developmental stage of the canine tooth on the one hand and the possibility of orthodontic closure of the gap in the dental arch and good interdental bone height on the other hand. This also leads to the suggestion that if bone grafting to the alveolar cleft is required the operation should be performed before the eruption of the canine tooth on the cleft side.

Extraoral or intraoral approach in the oblique sliding osteotomy of the mandibular rami? Clinical experience and results

The clinical results of oblique sliding (subcondylar) osteotomy of the mandibular rami performed by the extraoral or intraoral approach were compared. The patient material comprised 40 patients with mandibular prognathism. Twenty patients were operated upon using the extraoral approach and 20 patients were operated on using the intraoral approach. All patients had intermaxillary fixation for 7 weeks. The patients in both groups were followed up for 18 months. The experience of the operations was that the intraoral approach gave a shorter operation time than the extraoral approach. The extraoral approach, however, gave better visibility in the operation field and greater possibilities of manipulating the proximal fragment into an optimal position. In the follow-up evaluation, there were no significant differences between the two surgical techniques with regard to dental relapse, post-operative occlusion and mandibular function.

Skeletal remodelling in the temporomandibular joint after oblique sliding osteotomy of the mandibular rami

Skeletal remodelling of the temporomandibular joints took place in 80% of cases after oblique sliding osteotomies of the rami. The new bone formation was found in both the condylar and temporal parts of the joint. It was mostly located on the posterior surface of the condyle and in the roof of the temporal part of the joint. No differences in skeletal remodelling were found between wiring and nonwiring cases.

Neuropeptide Y--a cotransmitter with noradrenaline and adenosine 5'-triphosphate in the sympathetic nerves of the mouse vas deferens? A biochemical, physiological and electropharmacological study

A combination of biochemical, physiological and electropharmacological methods was employed to examine the occurrence of neuropeptide Y and the pre- and postjunctional effects of this peptide on sympathetic neuromuscular transmission in the mouse vas deferens. This tissue had a high content of neuropeptide Y-like immunoreactive material, suggesting a dense innervation by neuropeptide Y-containing nerve fibres. Addition of neuropeptide Y at concentrations from 5 X 10(-9) to 5 X 10(-7) M induced both pre- and postjunctional effects in vitro. Neuropeptide Y per se induced a rise in the resting tension, and "instantly" potentiated the contractile effects of exogenous noradrenaline and of the stable adenosine 5'-triphosphate (ATP) analogue, alpha,beta-methylene ATP. Neuropeptide Y reduced the secretion of [3H]noradrenaline evoked by electrical nerve stimulation, and selectively depressed the stimulus-evoked, but not the spontaneously occurring excitatory junction potentials in smooth muscle cells. Further, neuropeptide Y reduced the amplitudes of the twitch contractions evoked by electrical field stimulation with short stimulus trains at 10 Hz, and also (although to a smaller extent) the delayed contractile response to longer trains of nerve stimuli. The pre- and postjunctional effects of neuropeptide Y were not changed by alpha- or beta-adrenoceptor blocking agents, or by tachyphylaxis to the effects of ATP, or by the calcium channel blocker nifedipine.

IN CONCLUSION

sympathetic neuromuscular transmission in the mouse vas deferens may be mediated not only by noradrenaline and ATP, but also by neuropeptide Y.(ABSTRACT TRUNCATED AT 250 WORDS)

Relative pre- and postjunctional roles of noradrenaline and adenosine 5'-triphosphate as neurotransmitters of the sympathetic nerves of guinea-pig and mouse vas deferens

Experiments were designed to examine the relative roles of noradrenaline and adenosine 5'-triphosphate (ATP) as mediators of the contractile responses of the guinea-pig and the mouse vas deferens to electrical nerve stimulation. To study possible prejunctional actions of the agents used, in some experiments their effects on the secretion of [3H]noradrenaline were determined. The contractile responses were recorded with force displacement transducers. Pharmacological techniques were employed to examine the pre- and/or postjunctional effects mediated by noradrenaline and ATP, respectively. Noradrenaline-mediated components were "removed" by depleting the neuronal stores of noradrenaline (by pretreatment with reserpine), or by addition of adrenoceptor-blocking agents. ATP-mediated components were "removed" by desensitizing ATP receptors (with the stable analogue alpha, beta-methylene ATP). The results permit three major conclusions: (1) In both species noradrenaline and ATP "auto-inhibit" mechanisms responsible for transmitter secretion; the prejunctional effects of ATP are less marked in the mouse vas deferens, and in both species much weaker than those mediated by noradrenaline, acting via alpha 2-adrenoceptors. (2) In these species, both noradrenaline and ATP participate in the generation of both phases of the contractile responses to nerve stimulation. The relative roles of each vary with the frequency and train length of stimulation, and also with the species. The main transmitter of "phase I" contractions in guinea-pig vas deferens is ATP, and in the mouse vas deferens, noradrenaline. "Phase II" contractions are triggered mainly by noradrenaline, in both species. Sympathetic neuroeffector transmission in these tissues can be accounted for almost entirely in terms of dynamic interplay between pre- and postjunctional actions of noradrenaline and ATP. (3) The results are compatible with the hypothesis that ATP is a co-transmitter with noradrenaline in these sympathetic nerves.

Intraoral or extraoral approach in oblique sliding osteotomy of the mandibular ramus. A cephalometric study

Positional changes of the mandible after oblique sliding osteotomy of the mandibular rami were investigated by means of cephalometric analysis. The patient material comprised 40 patients. Twenty patients were operated upon using an extraoral approach and 20 were operated on using an intraoral approach. The patients were followed up with lateral cephalograms for 18 months after operation. In both groups, a posterior rotation of the mandible took place during the fixation period. This rotation gave a further retro-displacement of gnathion and a shortening of posterior facial height. The incidence of patients with considerable posterior rotation of the mandible was higher in the intraoral than in the extraoral group. The difference between the means of the changes in the mandibular plane angle (dEO = 4.9 degrees, dIO = 6.3 degrees) of the groups was, however, not statistically significant. Nor was there any significant difference in relapse between the two groups after release of the fixation.

Discrete events measure single quanta of adenosine 5'-triphosphate secreted from sympathetic nerves of guinea-pig and mouse vas deferens

Intracellularly recorded excitatory junction potentials in smooth muscle cells, and the first time differentials of their rising phases ("discrete events") were used to analyse transmitter secretion from the postganglionic sympathetic nerves of guinea-pig and mouse vas deferens. The aim was to determine whether the transmitter causing these responses is noradrenaline or adenosine 5'-triphosphate (ATP). Depletion of the noradrenaline stores following treatment with reserpine reduced the frequency of occurrence, but not the amplitude, of spontaneous junction potentials and discrete events. Nerve stimulation could still evoke "fast" junction potentials and discrete events, normal in appearance, but "slow" junction potentials were reduced in amplitude and had shorter times to peak. In contrast, desensitization of ATP receptors by alpha, beta-methylene ATP abolished spontaneous and stimulus-induced "fast" (but not "slow") junction potentials and discrete events, reversibly. It is concluded that it is not noradrenaline, but ATP or some related compound which causes spontaneous and "fast" stimulus-induced junction potentials, and discrete events. The present and earlier data show that discrete events reflect the secretion of individual quanta of ATP (or quanta of "ATP + noradrenaline", if both are secreted in parallel from the same vesicle) from postganglionic sympathetic nerve terminals in guinea-pig and mouse vas deferens.

Intraosseous wiring in ramus osteotomy

The value of intraosseous wiring of the fragments after oblique osteotomy of the mandibular rami was studied. A wired group (14 patients) and a nonwired group (15 patients) were compared cephalometrically. There were only small differences between the groups but there was a tendency toward a smaller postoperative posterior rotation of the mandible in the wired group. It was concluded that in routine cases of mandibular prognathism wiring is not necessary.

Changes in the temporomandibular joint after oblique sliding osteotomy of the mandibular rami. A longitudinal radiological study

Changes in the temporomandibular joint following oblique sliding osteotomy of the mandibular rami were studied using axial, frontal and lateral radiographs. The condyle/fossa relationship was also studied with regard to the effect of intraosseous wiring of the proximal fragment. Antero-inferior displacements of the condyles were regularly seen after the osteotomies. The use of intraosseous wiring had no adverse effects on the temporomandibular joint.

Mandibular reconstruction with bone grafts

A total of 23 patients with partly resected mandible were repaired with autogenous bone grafts from the iliac crest and ribs. The reasons for reconstruction are presented in Table 1. The grafts healed without complications in 21 cases. With the exception of two of the cases with gunshot wounds, all patients recovered good mobility of the jaw and satisfactory mandibular contours. The patients had been folloed up for 6 months to 11 years. Radiographic examination at the last examination showed that resorption of the graft had been only slight or moderate. Through marrow-spongious bone grafts are regarded as best from an osteogenetic point of view, our cases showed that good results can be achieved also with solid block grafts. The authors discuss the use of plate osteosynthesis without IMF instead of other types of graft fixation and IMF. In six cases where the area of the graft was loaded with a prosthesis, resorption was not more extensive than in the other cases.

Periapical condition of anterior teeth after surgical correction of mandibular prognathism. A radiographic study

Extrusion and root resorption of the mandibular anterior teeth have been reported after surgical correction of mandibular prognathism by horizontal osteotomy of the rami. The aim of the present study was to find out whether oblique sliding osteotomy also has such side effects. Intraoral radiographs of the maxillary and mandibular anterior teeth of 61 patients were studied. Enlargement of the periodontal space and signs of root resorption were estimated postoperatively and at a later review 1 1/2-5 years after the operation. Enlargement of periodontal space occurred postoperatively in 16.2% of the maxillary incisors and 52.2% of the mandibular incisors. The enlargements were mostly reversible and at the final review only 1.1 and 8.5% of the maxillary and mandibular incisors, respectively, showed such enlargements. Root resorption was rarely found in radiographs from the postoperative control. At the final review, however, there were signs of root resorption of 1.6 and 20.8% of the maxillary and mandibular incisors, respectively. It appears warranted to conclude that the anterior teeth, especially the mandibular incisors, are exposed to strong forces also after oblique sliding osteotomy of the mandibular rami.