Preoperative Patient Expectation of Discharge Planning is an Essential Component in Total Knee Arthroplasty

Purpose

A better understanding of total knee arthroplasty (TKA) candidate expectations within the perioperative setting will enable clinicians to promote patient-centered practices, optimize recovery times, and enhance quality metrics. In the current study, TKA candidates were surveyed pre- and postoperatively to elucidate the relationship between patient expectations and length of stay (LOS).

Material and methods

This is a prospective study of patients undergoing TKA between December 2017 and August 2018. Patients were electronically administered surveys regarding their discharge plan 10 days pre-/postoperatively. All patients were categorized into three cohorts based on their LOS: 1, 2, and 3+ days. The effect of preoperative discharge education on patient postoperative satisfaction was evaluated.

Results

In total, 221 TKAs were included, of which 83 were discharged on postoperative day (POD) 1, 96 on POD-2, and 42 POD-3+. Female gender, increasing body mass index (BMI), and surgical time correlated with increased LOS. Preoperative discussions regarding LOS occurred in 84.62% (187/221) of patients but did correlate with differences in LOS. However, patients discharged on POD-1 were more inclined to same-day surgery preoperatively. Patients discharged on POD-3+ were found to be more uncomfortable regarding their discharge during the preoperative phase. Multivariable regressions demonstrated that preoperative discharge discussion was positively correlated with home discharge.

Conclusion

Physician-driven discussion regarding patient discharge did not alter patient satisfaction or length of stay but did correlate with improved odds of home discharge. These findings underscore the importance of patient education, shared decision-making, and managing patient expectations.

[Primary revision with replasty of the anterior cruciate ligament]

OBJECTIVE

Restoration of knee stability after rerupture of an anterior cruciate ligament (ACL) graft.

INDICATION

Acute and chronic functional instability with rerupture of an ACL graft with subjective instability with anatomical or non-anatomical bone tunnel without tunnel widening.

CONTRAINDICATIONS

Partial anatomical bone tunnels of the previous operation, significant tunnel widening of anatomical bone tunnels, local infection of the knee joint, local soft tissue damage.

SURGICAL TECHNIQUE

Graft choices are hamstring tendons (semitendinosus muscle, gracilis muscle), the quadriceps tendon, patellar tendon and a peroneus tendon split graft. In cases with anatomical tunnels, careful debridement is performed down to the tunnel wall. In non-anatomical tunnels, a new femoral tunnel is drilled over a deep anteromedial portal with the knee flexed more than 110° in the insertion area of the ACL. Using drills and dilators, a tunnel is prepared. At the tibia, the anterior horn of the lateral meniscus serves as a landmark in the absence of an ACL stump. The cortical tibial tunnel aperture is probed with a guide wire and the tunnel is drilled stepwise until the tunnel wall is reached, which is debrided with a spoon or synovial resector to remove graft residues and implants from the tunnel. The femoral fixation can either be done with a flip button, an interference screw or in the case of a bone block graft implant-free. At the tibial side, the graft is fixed with a resorbable interference screw and fixation button.

POSTOPERATIVE MANAGEMENT

The rehabilitation program comprises 4-5 phases. Inflammatory phase (weeks 1-2): control of pain and swelling (cooling, isometric tension exercises, 20 kg partial load). Phase 2 (weeks 2-6): increasing load and range of motion with closed chain exercises (target: extension/flexion 0-0-120°). Phase 3 (from week 6): strength and coordination exercises. Phase 4: balance, strength and jump exercises. Return to competitive sport not before postoperative month 6-10.

RESULTS

Included were 51 patients with recurrent instability after ACL surgery where primary ACL replacement was performed with ipsilateral bone quadriceps tendon graft or contralateral semitendinosus-gracilis graft. All patients had anatomical or non-anatomical tunnel locations without significant widening (>11 mm). After 2 years, the side-to-side difference for anterior tibial translation measured with the KT 1000 arthrometer was 2.0 ± 1.2 mm for the quadriceps group and 3.0 ± 2.9 mm for the semitendinosus-gracilis group (P = 0.461). No difference in the rate of positive pivot shift tests (P = 0.661); no significant difference in the individual Knee Injury and Osteoarthritis Outcome Score (KOOS) subscores or in the frequency of anterior knee pain.

[Arthroscopic suprapectoral tenodesis of the long head of the biceps tendon]

OBJECTIVE

The aim of a tenotomy of the long biceps tendon is to remedy a painful pathology in the proximal region of the tendon. Tenodesis of the tendon can restore the motor and cosmetic function of the biceps brachii muscle.

INDICATIONS

Partial rupture or tendopathy of the long biceps tendon, injuries of the anchor of the long biceps tendon (SLAP lesions; SLAP: superior labrum anterior posterior), lesions of the pulley system.

CONTRAINDICATIONS

Infections or tumors, loss of the long head biceps tendon from the intertubercular groove.

SURGICAL TECHNIQUE

Shoulder arthroscopy via a posterior standard portal in beach chair position. Anteroinferior portal. Standard diagnostic arthroscopy. Checking the stability of the biceps anchor and the pulley system with a probe. Testing the extra-articular portion of the long biceps tendon with the hook. By pulling the tendon into the joint, the course of the tendon can be assessed. Anterolateral portal superior of the intertubercular groove. Pulling the tendon out of the anterolateral portal. Arming of the tendon with Krackow stitches. Fixation of the tendon in the intertubercle groove with a knotless suture anchor.

POSTOPERATIVE MANAGEMENT

Three weeks immobilization with an arm sling, 6 weeks no forced elbow flexion and forearm supination, 2 weeks active-assisted mobilization of the shoulder up to horizontal, 30° external rotation, internal rotation free.

RESULTS

The results published in the literature show that epiossal anchor tenodisis improves the clinical scores (preoperative vs. postoperative) and leads to a better cosmetic result and a lower rerupture rate than soft tissue tenodesis.

Experiences with Osteoligamentoplasty According to Weiss for the Treatment of Scapholunate Dissociation

BACKGROUND

In post-traumatic, dynamic, or static scapholunate (SL) instability, an SL ligament reconstruction is advisable to avoid long-term complications. However, a sufficient primary reconstruction is best achieved in acute injuries. For chronic SL dissociation, there is still no satisfying standard surgical technique. In this context, we evaluated the clinical outcome of Weiss's osteoligamentoplasty as a treatment option.

METHODS

Over a three-year period, 16 patients with chronic and symptomatic SL dissociation Grade-II and III, without the signs of osteoarthrosis were, surgically treated using a bone-retinaculum-bone autograft from the distal radius. All patients underwent prior wrist arthroscopy. The clinical outcome was measured using the Mayo-Wrist, Krimmer, and DASH score. In addition, radiological measurements were also performed.

RESULTS

The postoperative clinical outcome successfully increased the Mayo-Wrist score: 32 to 64 points, Krimmer score: 30 to 53 points and DASH score: 41 to 30 points. The radiological follow-up demonstrated no evidence of an SL gap or significant loss of reposition in the SL angle in 13 of the 16 cases. Till date, two patients had to be revised to an arthrodesis.

CONCLUSIONS

The autogenous osteoligamentary span from the distal radius improves a chronic SL dissociation and, therefore, presents a suitable option to anatomically reconstruct the SL ligament. It leads to a proper realignment of the carpus and could help to prevent arthritic changes of the wrist. Nevertheless, in patients with postoperative high occupational physical strain, the procedure should be performed with reservations. As long as there is no satisfying standard surgical treatment, Weiss's osteoligamentoplasty is a convincing technique.

Surgical treatment of acute acromioclavicular joint dislocations: hook plate versus minimally invasive reconstruction

PURPOSE

This study was performed to compare the clinical results of a minimally invasive technique for acute acromioclavicular (AC) joint dislocation repair with the traditional hook plate fixation.

METHODS

Forty-four patients with an acute (within 2 weeks after trauma) complete AC joint separation (35 male, nine female; median age 36.2 years, range 18-56) underwent surgical repair with either a minimally invasive AC joint repair or a conventional hook plate. Functional outcome was evaluated using the Constant-Murley Score (CMS), the TAFT score and the AC joint instability score (ACJI). Radiographic evaluation was performed with bilateral anterior-posterior (a.p.) stress and Alexander views.

RESULTS

All patients were available after a median follow-up of 32 months (range 24-51). There were no significant differences in the mean CMS, Taft score and the ACJI between the two groups. The radiological assessment revealed no significant difference in the coracoclavicular distance. In both groups, a slight loss of reduction was observed. Periarticular ossification was seen in 11 patients of the minimally invasive AC joint repair and eight patients of the hook plate group but this did not affect the final outcome. Hook plates were removed after a median interval of 11.9 weeks (range 10-13).

CONCLUSION

Good clinical results can be achieved with both minimally invasive AC joint repair and hook plate fixation. However, in the hook plate group a second operation is mandatory for plate removal.

LEVEL OF EVIDENCE

III.

Dasatinib suppression of medulloblastoma survival and migration is markedly enhanced by combining treatment with the aurora kinase inhibitor AT9283

Medulloblastoma (MB) expresses Src kinase, while aurora kinase A overexpression correlates with poor survival. We thus investigated novel combination treatment with dasatinib and AT9283, inhibitors of Src and aurora kinase, respectively, on MB growth in vitro and in vivo. Treatment with each drug significantly reduced cell viability and combined treatment markedly potentiated this response. AT9283 induced p53 expression, autophagy, and G2/M cell-cycle arrest, while combined treatment induced S phase arrest. Dasatinib treatment caused tumor regression in vivo. Activated Src was detected in 44% MB analyzed. We conclude that further evaluation of this combination therapy for MB is highly warranted.

[Anatomic reconstruction of the anterior cruciate ligament with the autologous quadriceps tendon. Primary and revision surgery]

OBJECTIVE

Restore function of the anterior cruciate ligament (ACL).

INDICATIONS

Chronic functional instability with rupture of the ACL, giving way phenomena, acute rupture of the ACL with concomitant meniscus repair, rerupture of ACL graft with anatomical tunnels.

CONTRAINDICATIONS

Local infection of the skin at the knee joint, local soft tissue damage, after rupture of the quadriceps tendon, enthesopathia of the quadriceps tendon, lack of patient compliance.

SURGICAL TECHNIQUE

Harvest quadriceps tendon graft with a bone block via a 4-5 cm long incision, starting from the middle third of the proximal patella pole without damaging the tendon fibers. Drill the femoral tunnel via a deep anteromedial portal with the knee flexed of more than 110° (tunnel diameter 0.5-1 mm smaller in diameter than bone block). Gentle tunnel preparation using dilators. In absence of an ACL stump the lateral meniscus anterior horn serves as tibial landmark. In case of revision surgery, remove graft material and implants from the tunnel. Graft fixation using press fit method in the femoral tunnel. Tibial graft fixation archieved with a resorbable interference screw and a button.

POSTOPERATIVE MANAGEMENT

Goal of the inflammatory phase (weeks 1-2) is pain and inflammation control (20 kg partial weight bearing). During the proliferative phase (weeks 2-6), load and mobility slowly increased (closed-chain exercises). During the remodeling phase (> 6 weeks), strength and coordination exercises are performed. In revision cases and in case of concomitant injuries, longer partial weight-bearing period might be necessary. Athletes should not return to competitive sports before 6-8 months.

RESULTS

In a prospective study, 33 patients (age 16-48 years) were examined after replacement of the ACL with a quadriceps tendon graft after a minimum follow-up (FU) of 2 years (12 revision; 21 primary surgery). No post- or perioperative complications. Postoperative radiographs showed an anatomical tunnel location and no dislocation of the bone block. After 2 years the difference of a-p translation compared to the other leg was assessed by the use of KT 1000. The revision group improved from an average of 7.2 mm (pre-op) to 2.2 mm (FU). The group with primary surgery improved from 6.4 mm (pre-op) to 1.7 mm (FU). A sliding pivot shift phenomenon was detected in 2 patients in the revision group and 1 patient in the primary surgery group.

[Arthroscopic arthrolysis of the elbow joint]

OBJECTIVE

Arthroscopic assisted improvement of range of motion in elbow stiffness. Detailed diagnostic evaluation including medical history and preoperative radiographs, CT and MRI scans are necessary for planning the operative treatment.

INDICATIONS

Restricted range of motion < 30° in extension and/or more than 100° in flexion related to intraarticular causes (loose bodies, osteophytes or contracture of the capsule).

CONTRAINDICATIONS

Extension deficit > 30°, extraarticular causes (e.g., heterotopic ossifications), nerve irritation, incongruity of joint surfaces, acute joint infection.

SURGICAL TECHNIQUE

Prone position, filling of the joint with irrigation fluid, arthroscopic examination of the anterior and posterior compartment. Partial synovectomy, debridement and capsular release, removal of loose bodies and resection of osteophytes.

POSTOPERATIVE MANAGEMENT

Intensive physiotherapy, continuous passive motion. Plexus anesthesia and nonsteroidal antiphlogistic medication.

RESULTS

A total of 29 patients who underwent arthroscopic arthrolysis of the elbow joint were evaluated after a mean follow up of 15.4 months after surgery. Average preoperative extension deficit improved from 23° to 5°. Mean preoperative flexion improved from 115° to 131°. Improvement of range of motion was 34° on average. No vascular or neurologic complications were noted. Infection was not observed. In one case, stiffness persisted and early arthroscopic revision was needed. Postoperative patient satisfaction on the VAS Scale was 8.9. The Mayo Elbow Performance Index was 92.9 points on average.

[Translation errors in ophthalmology]

As global networks are built up, interlingual communication in ophthalmology becomes more and more important. Similar to any other specialised discipline, this raises the dilemma that on one hand precision is mandatory for an exact translation, but on the other hand translators often do not have the scientific and physicians the linguistic knowledge to fulfill this need. Furthermore, even within one language ophthalmological terminology is partially ill defined, and this problem multiplies when translating it into various other languages. However, translation errors can have serious consequences, particularly in medical disciplines. This case study casuistically demonstrates the most common basic mechanisms for translation errors in ophthalmology and shows a potential approach for solution.

Biomechanical investigation of the stabilization principle of the Latarjet procedure

PURPOSE

The purpose of the study was to determine the biomechanical status of the different components of the Latarjet procedure. The anterior capsule reconstruction with the transferred coracoacromial ligament (CAL) and the necessity of an intact subscapularis tendon were of particular interest. We hypothesized that the anterior capsule reconstruction will have a significant effect and that the Latarjet procedure will lose its stabilizing effect if the subscapularis tendon is torn.

METHODS

Stability testing of 12 human shoulder specimens was performed. After testing of the intact joint, a combined anterior glenoid and capsule defect was set arthroscopically. Then the Latarjet procedure was performed using an open approach and tested with and without loading of the conjoint tendons (10 N). Afterwards, the specimens were distributed into two groups and the Latarjet technique was reduced stepwise: dissection of the CAL, dissection of the conjoint tendons (group A); reduction of the coracoid segment, dissection of the subscapularis tendon (group B). Biomechanical testing was performed for each condition in two positions: 60° of glenohumeral abduction with neutral rotation and with 60° of external rotation; each with a passive humerus load of 30 N in the anterior, inferior and anteroinferior direction.

RESULTS

The Latarjet technique with load applied to the conjoint tendons significantly reduced translation compared with the defect condition for all tested positions in all directions. In group A, the CAL-dissection led to a significant increase of anterior translation (+5.0 mm, p = 0.003) and inferior translation (+7.3 mm, p = 0.025) in neutral rotation and of anterior translation in 60° of external rotation (+4.4 mm, p = 0.034). In group B, the reduction of the coracoid bone down to the coracoid tip resulted in a significant increase of only the anterior translation in abduction and 60° of external rotation (+4.5 mm, p = 0.05). In contrast, the detachment of the subscapularis tendon led to a significant increase of translation in all testing positions except the inferior direction in the neutral rotation.

CONCLUSIONS

We found the anterior capsule reconstruction to represent a significant contribution to the stabilizing effect of the Latarjet procedure, whereas a deficiency of the subscapularis tendon eliminates its effect.

CLINICAL RELEVANCE

We recommend to perform the Latarjet technique with an anterior capsule reconstruction (e.g. CAL transfer) and with a transfer of the coracoid bone block rather than a transposition of the coracoid tip. Furthermore, we were able to show that an intact subscapularis tendon is a necessary prerequisite for a reliable stabilization.

Structural properties of a new device for graft fixation in cruciate ligament reconstruction: the shim technique

INTRODUCTION

In ACL reconstruction using a soft tissue graft, aperture fixation with interference screws (IFS) can lacerate and rotate the graft and cause primary tunnel widening. To overcome these downsides, a new wedge-shaped implant (MegaShim, Karl Storz, Germany) was developed. We hypothesized that aperture fixation of hamstring ACL reconstruction using the MegaShim technique shows comparable structural properties when compared to interference screw fixation.

METHODS

In a porcine knee model, ACL reconstructions with a tunnel diameter of 6, 7, 8 and 9 mm were performed and human hamstring grafts were fixed using the MegaShim technique (group I). In group 2, grafts were fixed in a hybrid fixation using a MegaShim and cortical flip button (FlippTack, Karl Storz, Germany). Interference screw graft fixation served as a control group (group III). Maximum load, yield load and stiffness were recorded using material testing machine. Grafts were cyclically preconditioned between 0 and 20 N for 10 cycles before the graft-bone complex was loaded to failure. Statistical evaluation was performed using SPSS Version 11.0.

RESULTS

Mean maximum load to failure for the hybrid fixation was significantly higher than after interference screw or MegaShim fixation. The difference between MegaShim and interference screw fixation showed no significant difference for 6 and 7 mm sizes. An 8 and 9 mm MegaShim fixation resulted in significantly lower ultimate failure load compared to interference screw fixation. Stiffness of grafts fixed using 6 mm MegaShim was significantly lower than grafts fixed with hybrid or interference screw fixation, whereas no significant differences were found in the 7, 8, and 9 mm fixations.

CONCLUSION

Aperture fixation using the MegaShim technique provides comparable structural properties compared to interference screw fixation. Hybrid fixation using MegaShim and cortical flip button results in significantly higher ultimate failure loads than both aperture fixation approaches. Smaller grafts (6 mm) showed significantly lower ultimate failure load and stiffness than interference screw fixation. The "MegaShim technique" is an alternative to interference screw fixation concerning initial fixation strength.

Quantitative detection of gold nanoparticles on individual, unstained cancer cells by scanning electron microscopy

Gold nanoparticles are rapidly emerging for use in biomedical applications. Characterization of the interaction and delivery of nanoparticles to cells through microscopy is important. Scanning electron microscopes have the intrinsic resolution to visualize gold nanoparticles on cells. A novel sample preparation protocol was developed to enable imaging of cells and gold nanoparticles with a conventional below lens scanning electron microscopes. The negative influence of 'charging' on the quality of scanning electron microscopes' images could be limited by deposition of biological cells on a conductive (gold) surface. The novel protocol enabled high-resolution scanning electron microscopes' imaging of small clusters and individual gold nanoparticles on uncoated cell surfaces. Gold nanoparticles could be counted on cancer cells with automated routines.

SERUM PROTEASES AND THE MECHANISM OF THE ABDERHALDEN REACTION : STUDIES ON FERMENT ACTION. XX

1. Normal serum protease is not specific; it is active in both dilute acid as well as alkaline media. It is destroyed by heating to 70° C. for thirty minutes. It is markedly impaired when heated at 56° C. for thirty minutes. It is inhibited by the unsaturated soaps and lipoids. 2. Guinea pig and rabbit serum contain relatively much protease; the leucocytes are without proteolytic ferments. 3. Normal human and dog serum contain little or no protease; the leucocytes are strongly proteolytic. 4. Serum complement and protease are not identical. 5. During various pathological conditions the non-specific protease is increased in both human and dog serum. 6. An increase in antiferment is in many instances coincident. 7. During the Abderhalden reaction the placental tissue becomes more resistant to enzyme action, because of the adsorption of the antiferment from the serum. 8. The dialyzed serum loses antiferment because of adsorption by the placental tissue or other adsorbing substances, including probably the dialyzing membrane. 9. The digestive substrate is the serum protein made available for protease action by the adsorption of the antiferment. 10. The proteases in pathological conditions investigated by us (pregnancy, tuberculosis, and pneumonia) are non-specific.

THE SERUM FERMENTS AND ANTIFERMENT DURING PNEUMONIA : STUDIES ON FERMENT ACTION. XXIV

1. The crisis in pneumonia is usually accompanied by (a) decrease in the serum antiferment; (b) the mobilization of a non-specific protease in the serum; (c) an increase in serum lipase; (d) a decrease in the non-coagulable nitrogen, and of the proteoses in the serum. 2. The crisis is associated with the beginning of an active autolysis, the latter depending on an altered relation between the ferment-antiferment balance. 3. The fibrin and leucocytic debris must be considered as one of the potential sources of toxic substances. With rapid autolysis proceeding, only non-toxic materials are absorbed.

LIPOIDS AS INHIBITORS OF ANAPHYLACTIC SHOCK : STUDIES ON FERMENT ACTION. XVIII

1. The antitryptic titer of the serum can be increased by subcutaneous injections of serum lipoids (antitrypsin) and of the lipoids from egg yolk. 2. Animals so injected show a relative immunity to acute anaphylactic shock (two minimum lethal doses). 3. Extraction of lipoids contained in antigens increases the toxicity of the antigen when injected into a sensitized animal. 4. Sublethal doses of soap solutions injected simultaneously with the antigen (purified horse serum albumen) prevent anaphylactic shock. 5. The refractory state following anaphylactic shock is related in part to an increase in the antitryptic titer of the serum.

SEROTOXIN : STUDIES ON FERMENT ACTION. XIV

1. Sera from which the protective lipoids (unsaturated fatty acids) have been removed are toxic for the homologous animal. 2. The toxicity is due to three factors: (a) an alteration in the mechanism of coagulation, with resulting intravascular coagulation; (b) the exposure of the native serum proteins; (c) the formation of toxic split products (primary proteoses) by autolysis. 3. A definite maximum of toxicity can be determined, with a final stage of atoxicity due to continued autolysis. 4. Hirudin and sodium citrate do not protect animals. 5. Heating to 70° C. destroys, or greatly lessens, the toxicity of the serotoxin, although the isolated proteoses are toxic after boiling. 6. The return of the extracted lipoids (saponified) neutralizes the toxicity. 7. Unsaturated soaps also neutralize the toxicity. 8. Sublethal doses produce extreme prostration, marked fall in body temperature, no eosinophilia, and an increase of antitrypsin. 9. Sublethal doses of rapidly prepared chloroform sera cause a decrease in coagulation time; sublethal doses of autolyzed sera cause an increase in coagulation time. 10. Previously injected animals are more resistant (increased antiferments). 11. Iodized animals are less resistant (decreased antiferments).

SOAPS AS FERMENT-INHIBITING AGENTS : STUDIES ON FERMENT ACTION. X

1. Sodium soaps prepared from olive oil, croton oil, cod-liver oil, linseed oil, etc., have the property of inhibiting the action of trypsin and leucoprotease. 2. The activity of these soaps is dependent upon the degree of unsaturation of the fatty acids and is in proportion to their iodin value. 3. Saturation of the acids with a halogen (iodin) causes a loss of this property. 4. Soaps of the saturated fatty acids tested do not have this influence on ferments.

THE MECHANISM OF ANAPHYLACTIC SHOCK : STUDIES ON FERMENT ACTION. XXIII

1. The serum ferments are practically unaltered by a primary injection of foreign protein. 2. During the course of sensitization the injection of the antigen is followed by the mobilization of a non-specific protease which increases in rapidity and intensity as the maximum period of sensitization is reached. 3. Acute shock is accompanied by: (a) The instantaneous mobilization of a large amount of non-specific protease; (b) a decrease in antiferment; (c) an increase in non-coagulable nitrogen of the serum; (d) an increase in amino-acids; (e) a primary decrease in serum proteoses. 4. Later there is a progressive increase in the non-coagulable nitrogen, in proteoses, and in serum lipase. 5. The acute intoxication is brought about by the cleavage of serum proteins (and proteoses) through the peptone stage by a non-specific protease. 6. The specific elements lie in the rapid, mobilization of this ferment and the colloidal serum changes which bring about the change in antiferment titer.

A STUDY OF THE FERMENTS AND FERMENT-INHIBITING SUBSTANCES IN TUBERCULOUS CASEOUS MATERIAL : STUDIES ON FERMENT ACTION. XII

1. Caseous matter obtained from lymph glands which have not become secondarily infected contains substances which inhibit enzyme activity. These substances consist chiefly of soaps of the unsaturated fatty acids. 2. The inhibiting substances are present in relatively smaller amounts when the caseous matter has become secondarily infected. This is probably due to the dilution and washing out of the soaps. 3. Ferments are either entirely absent or present in very small amounts, unless the caseous matter has become secondarily infected. 4. Caseous material from the lungs contains smaller amounts of the inhibiting substances. This may be due to the acuteness of the process, which does not permit an accumulation of the soaps, or to the binding of the soaps with the ferments. 5. Ferments are present in caseous pneumonia. In the whole emulsion the ferments are less active in an alkaline than in an acid reaction; but removal of the soaps shows that those active in an alkaline reaction are also present in considerable amounts. 6. The previous treatment with iodin of caseous matter from both lymph glands and lungs increases the action of the trypsin.

THE NATURE OF SERUM ANTITRYPSIN : STUDIES ON FERMENT ACTION. XIII

1. The ferment-inhibiting action of the serum is due to the presence of compounds of the unsaturated fatty acids. 2. These fatty acid compounds may be removed from the serum by means of chloroform or ether. 3. Soaps prepared by saponifying the chloroform or ether extracts inhibit the action of trypsin. 4. The anti-enzyme action of the serum can be removed by filtering acid serum through kaolin, and can in part be restored by extracting the kaolin. 5. The decrease in strength of anti-enzyme in old sera is probably due to the action of the serum lipase. 6. Iodin, potassium iodide, or hydrogen peroxide remove the inhibiting action of the serum. 7. Soaps of the unsaturated fatty acids lose their ferment-inhibiting action when heated with serum at 70 degrees C.

SERUM CHANGES FOLLOWING KAOLIN INJECTIONS : STUDIES ON FERMENT ACTION. XXV

1. The intoxication produced by the intravenous injection of inert substances such as kaolin is due to protein split products derived from the serum proteins. 2. The kaolin acts as an adsorbing medium for the serum antiferment, bringing about an alteration in the ferment-antiferment balance. 3. The intoxication is accompanied by an increase in serum protease, and of proteoses. 4. The serum lipase, the amino-acids, and the total non-coagulable nitrogen show relatively little change. 5. The antiferment shows an initial increase, followed by a loss.

BACTERIAL ANTIFERMENTS : STUDIES ON FERMENT ACTION. XVII

1. Intact bacteria probably resist tryptic digestion because of the absence of an exposed protein substrate. 2. Dried organisms resist digestion in a degree proportional to their content of unsaturated lipoids. 3. Lipoidal extractives reduce the resistance to tryptic digestion. 4. The extracted lipoids (saponified) are antitryptic in a degree proportional to their unsaturation. 5. The inactivation of the antiferment in Gram-negative organisms is probably due to changes in the degree of lipoidal dispersion. 6. Bacteria adsorb lipoids from the serum when incubated at 37° C. Such organisms when dried are found to be more resistant to tryptic digestion than untreated organisms.

FERMENT-INHIBITING SUBSTANCES IN TUBERCLE BACILLI : STUDIES ON FERMENT ACTION. XI

1. Tubercle bacilli contain unsaturated fatty acids which, when saponified, have the property of inhibiting the action of trypsin and leucoprotease. 2. In proportion to their iodin value these soaps are more active as inhibiting agents than the soaps prepared from linseed, olive, and cod-liver oils. 3. The activity of the soaps is dependent on the presence of unsaturated carbon bonds. 4. Saturation of the soaps with iodin destroys their inhibiting action. 5. Soaps probably play an important part in the production of the condition known as caseation in tuberculosis.

THE RELATION OF BACTERIOLYSIS TO PROTEOLYSIS : STUDIES ON FERMENT ACTION. XVI

1. There is no demonstrable increase in non-coagulable nitrogen during bacteriolysis. 2. Bacteria treated with immune serum and complement are so altered that they are more readily digested by trypsin. 3. Bacteria treated with complement alone become more resistant to proteolysis. 4. Bacteria treated with an excess of immune serum and complement become more resistant to proteolysis.

SERUM FERMENTS AND ANTIFERMENT AFTER FEEDING : STUDIES ON FERMENT ACTION. XXI

1. After feeding, an increase in non-coagulable nitrogen of the serum can be determined, reaching a maximum in about six hours. 2. This increase is greatest in the portal blood and is partially due to an increase in amino-acids. There is no increase in proteoses. 3. There is usually a progressive decrease in serum protease, reaching a minimum after from five to seven hours. 4. The portal blood may show an unaltered or an increased amount of protease. 5. The serum antiferment shows a slight increase, but is subject to considerable fluctuation. 6. The serum lipase (esterase) shows a slight increase, reaching a maximum after three hours. The hepatic blood usually contains the lowest concentration of lipase.