Sphincter of oddi manometry: is it necessary to measure both biliary and pancreatic sphincter pressures?

BACKGROUND

Data are scant on the miss rate of sphincter of Oddi dysfunction if basal pressure in both biliary and pancreatic sphincter segments is not measured during manometry.

METHODS

Motility tracings with basal pressure measurements of both sphincter segments were retrospectively analyzed. Basal sphincter pressure greater than 40 mm Hg was considered abnormal in either sphincter segment.

RESULTS

The study population consisted of 73 subjects (64 women, 9 men; age 45.3 +/- 1.6 yr). The basal pressures in the 2 sphincter segments were highly discordant (correlation coefficient = 0.2, p = 0.04). Basal pressures were normal in both segments in 19%, abnormal in both segments in 40%, and abnormal in 1 segment but normal in the other in 41%. The negative predictive value of normal biliary sphincter pressure in excluding sphincter dysfunction was 0. 42; when the pancreatic sphincter pressure was normal, the negative predictive value was 0.58. The incidence of pancreatitis with dual duct manometry was comparable to the institutional experience with all sphincter studies.

CONCLUSIONS

Although the clinical relevance of individually elevated sphincter pressures remains uncertain, there is significant discordance of basal pressures between the biliary and pancreatic sphincter segments. If only the biliary sphincter pressure were to be measured, one fourth of abnormal sphincter pressures would be missed. Therefore, if the first sphincter segment has a normal basal pressure, the other segment should also be evaluated.

Endoscopic hemostasis in acute diverticular bleeding

BACKGROUND AND STUDY AIMS

Early reports of urgent colonoscopy in acute lower intestinal bleeding suggest a role for endoscopic therapy for bleeding colonic lesions, but scant data exist on bleeding diverticula. We report our experience with endoscopic hemostasis in acute diverticular bleeding.

PATIENTS AND METHODS

Bleeding diverticula were identified on urgent diagnostic endoscopy in five patients with acute gastrointestinal bleeding, two in the duodenum, and three in the colon. All patients had co-morbid conditions preventing more conventional therapeutic approaches. The five cases are described, including the technique of endoscopic hemostasis and outcome.

RESULTS

Endoscopic therapy using epinephrine injection, thermal cautery and/or laser therapy successfully induced hemostasis in all patients. One patient died of co-morbid illness during the hospital stay, while the remaining four patients had no recurrent bleeding over a mean follow-up period of 20.6 months.

CONCLUSION

Endoscopic therapy of bleeding diverticula is technically possible when the culprit diverticulum can be identified. This therapeutic modality may have a place in debilitated patients in whom other more invasive procedures are contraindicated, but further experience is needed to establish its safety.

Recurrent gastrointestinal bleeding: use of thrombolysis with anticoagulation in diagnosis

PURPOSE

To determine the safety and diagnostic accuracy of a provocative protocol with heparin and urokinase to induce bleeding and determine the source in patients with chronic gastrointestinal hemorrhage.

MATERIALS AND METHODS

Nine patients had gastrointestinal bleeding from an indeterminate source and had negative results from esophagogastroduodenoscopy, colonoscopy, small-bowel examination, and angiography. Ten provocative bleeding studies were performed prospectively. Patients had no clinical evidence of bleeding within 2 days before the study. Intravenous administration of heparin and urokinase was performed systemically during a 4-hour period while scintigraphy was performed continuously. Mesenteric angiography was performed immediately in patients in whom substantial gastrointestinal bleeding was detected at scintigraphy.

RESULTS

The provocative protocol was successful in inducing scintigraphically detectable hemorrhage in four (40%) studies within 4 hours. In two of these four studies, the source of hemorrhage was determined and treated with embolization or surgery. Three (30%) studies demonstrated scintigraphic evidence of hemorrhage only at delayed imaging (8-24 hours after initiation of the study). The remaining three (30%) studies did not show active bleeding. No complications occurred, including hemodynamic instability or uncontrollable decreases in hematocrit.

CONCLUSION

Since this protocol with heparin and urokinase enabled determination of the bleeding source in only two of 10 studies, protocol modifications are necessary before this intervention is used widely.

Endoscopic intervention for biliary leaks after laparoscopic cholecystectomy: a multicenter review

BACKGROUND

Endoscopic therapy of biliary tract leaks was uncommon before laparoscopic cholecystectomy. Studies have demonstrated the efficacy of endoscopic drainage by endoscopic sphincterotomy or stent placement. Various endoscopic therapeutic modalities and long-term follow-up of this problem were studied.

METHODS

Members of the Midwest Pancreaticobiliary Group reviewed all patients referred for endoscopic therapy of biliary leaks after laparoscopic cholecystectomy from 1990 to 1994. Long-term follow-up was by direct patient contact.

RESULTS

Fifty patients were referred for endoscopic therapy of biliary leaks. Abdominal pain was present in 94%. The mean time from laparoscopic cholecystectomy to referral was 6.9 days. Therapy consisted of sphincterotomy only in 6 patients, stent only in 13, and sphincterotomy with stent in 31. Biliary leaks were healed in 44 patients at a mean of 5.4 weeks. A second or third endoscopic procedure was necessary to achieve healing in five patients. Two stent-related complications were noted. Percutaneous or surgical drainage of biliary fluid collections was required in 16 patients. The mean hospital stay for treatment of the leak was 11.1 days after endoscopic therapy. On follow-up (mean 17.5 months), all patients were well except two with mild abdominal discomfort.

CONCLUSIONS

Endoscopic sphincterotomy, stent placement, or sphincterotomy with stent are effective in healing biliary leaks after laparoscopic cholecystectomy. Despite prolonged treatment for the leak, patients did well on long-term follow-up.

Enteroscopy-enteroclysis: experience with a combined endoscopic-radiographic technique

BACKGROUND

Video enteroscopy provides high-quality diagnostic and therapeutic capabilities in the proximal small bowel. Enteroclysis remains an essential diagnostic technique in the distal small bowel. We report our experience with the combination of these techniques.

METHODS

Seventy-one patients with obscure gastrointestinal bleeding (group A, 54 patients) or abnormal radiologic studies (group B, 17 patients) were evaluated with enteroscopy. Enteroclysis via a tube inserted on withdrawal of the enteroscope was performed in all patients with nondiagnostic enteroscopy.

RESULTS

Enteroscopy identified bleeding sites in 29 of 54 (54%) group A patients (12 angiodysplasia, 10 ulcers, 7 gastric erosions, 1 vessel, 1 aortoenteric fistula), and lesions in 11 of 17 (65%) group B patients (7 ulcers, 3 benign strictures, 2 radiation enteritis, 1 mass). In group A, 13 (24%) patients had findings detectable by standard esophagogastroduodenoscopy. Enteroclysis identified masses in 2 of 24 (8%) group A patients, and lesions in 5 of 10 (50%) group B patients (3 strictures, 1 mass, 1 large diverticulum). No complications occurred.

CONCLUSIONS

The combination of enteroscopy and enteroclysis is safe and offers quality small bowel examinations in more comfortable and convenient single diagnostic sittings. This combination detected bleeding sources in 57% and lesions in 70% of patients. Though enteroclysis identified bleeding sources in only 8% of patients, this study excluded lesions other than angiodysplasia.

Enteroscopy with enteroclysis

The authors conclude that their experiences support the conclusion that the combination of enteroscopy and enterocysis is safe and offers quality small bowel examinations in a more comfortable and convenient single diagnostic setting. Although enteroclysis has identified bleeding sources in only 8% of patients who underwent this study, other lesions than angiodysplasia were confidently excluded in the remainder of patients. The combined procedure is well tolerated in the outpatient setting, more comfortable, and safer by decreasing radiation exposures than enteroclysis alone. Use of small bowel enteroscopy at an earlier stage in the evaluation of patients with obscure gastrointestinal bleeding increases cost effectiveness without compromising quality.

Endoscopic management of bile duct leaks after attempted laparoscopic cholecystectomy

Fourteen patients with symptomatic bile duct leaks following laparoscopic cholecystectomy were treated using endotherapeutic techniques. Patients presented with abdominal pain, liver test abnormalities, jaundice, leukocytosis, and fever. Twelve leaks originated from cystic duct stumps and two from right posterior hepatic ducts. Distal biliary obstruction, which may have promoted leakage, was present in five patients. Treatment methods included stent insertion with endoscopic sphincterotomy (ES), stent insertion without ES, and nasobiliary tube (NBT) placement without ES. Eleven of 14 patients had prompt resolution of their bile leaks following initial endotherapy. Three patients with continued leakage underwent successful repeat endoscopic retrograde cholangiopancreatography 4-5 days after the initial examination. Cholangiographic evidence of leak closure was documented in all patients, and all remained asymptomatic during an average follow-up period of 18.5 months. Endoscopic therapy is safe and effective treatment for clinically significant bile leaks following laparoscopic cholecystectomy. In our small group of patients, NBT alone did not appear to be as effective as endoprostheses with or without ES. The ideal endoscopic treatment method has not yet been established but will likely vary depending on the site and specific nature of the injury and any concomitant biliary ductal pathology.

Complications related to diagnostic and therapeutic endoscopic retrograde cholangiopancreatography

Endoscopic retrograde cholangiopancreatography (ERCP) is examined from a variety of viewpoints in this article, including physician experience with ERCP and the environment in which the procedure is performed, the initial intent to treat, and complications, including their severity. Specific complications discussed include pancreatic hemorrhage, perforation, septic complications, complications related to stents, rare complications, and late complications following sphincterotomy.

Percutaneous gallstone removal: long-term follow-up

PURPOSE

To evaluate gallstone and symptom recurrence rates, long-term complications, and life expectancy after percutaneous gallstone removal.

PATIENTS AND METHODS

Medical records of 87 patients (mean age, 69 years +/- 14 [standard deviation]) undergoing percutaneous gallstone removal between 1987 and 1992 were reviewed. Physicians and patients (or their families) were contacted for clinical follow-up. Thirty-one patients returned for follow-up ultrasound (US).

RESULTS

The final study group consisted of 65 patients. Mean survival from the time of initial gallbladder drainage was 33 months +/- 19. Over a mean clinical follow-up period of 33 months, eight of 65 patients (12%) developed recurrent symptoms; six of these eight had recurrent gallstones shown at US. Of 30 patients with technically adequate US images (mean follow-up, 14 months +/- 12), 12 (40%) had recurrent gallstones. Six of these 12 patients had recurrent symptoms. No long-term complications were identified.

CONCLUSION

The risk of gallstone recurrence after percutaneous removal is notable, but the symptom recurrence rate is much lower. Percutaneous gallstone removal is beneficial for patients at prohibitive surgical or general anesthetic risk.

Washington University experience with extracorporeal shock-wave lithotripsy of pancreatic duct calculi

OBJECTIVES

To ascertain the effectiveness and safety of extracorporeal shock-wave lithotripsy (ESWL) for pancreatic calculi.

METHODS

Fourteen ESWL treatments were performed in 12 patients with chronic pancreatitis.

RESULTS

Fragmentation was perceptible after 13 of 14 treatments. Subsequent endoscopic manipulation resulted in complete extraction, partial extraction, and failed extraction of the fragments after 7, 4, and 2 of the ESWL treatments, respectively. No complications occurred and no patient had pancreatitis following ESWL. At a median follow-up of 19 to 22 months, 4 patients have had complete relief of symptoms, 4 have had a decrease in both severity and frequency of pain, and 4 have had no improvement.

CONCLUSIONS

ESWL is a safe and useful noninvasive adjunct in the treatment of patients with pancreatic duct calculi.

MR imaging of annular pancreas

The appearance of annular pancreas on magnetic resonance (MR) images is described in a 14-year-old with pancreatitis and incomplete pancreas divisum. The presence of the coexisting abnormalities complicated the interpretation of an upper gastrointestinal series and computed tomographic (CT) study. MR imaging was useful as a problem-solving technique to supplement the conventional imaging tests.

Laparoscopic duodenal diverticulectomy following hemorrhage

A 53-year-old man on warfarin therapy for an aortic valve prosthesis suffered a massive upper gastrointestinal hemorrhage. Urgent endoscopy revealed active bleeding from the apex of a large duodenal diverticulum. Bleeding was successfully controlled with heater-probe applications, and the patient recovered uneventfully. Because of the patient's lifelong need for anticoagulation therapy, elective laparoscopic duodenal diverticulectomy was subsequently done using intraoperative endoscopic guidance. The patient returned to full activity and diet within 3 days and has remained stable during the postoperative interval. We describe here a new minimal access approach to a complicated duodenal diverticulum combining laparoscopic and endoscopic techniques.

Role of laparoscopic cholecystectomy in the management of acute gallstone pancreatitis

Laparoscopic cholecystectomy has rapidly become the prime modality for removal of the gallbladder. However, as laparoscopic techniques for treating choledocholithiasis are evolving, we reviewed our experience with acute gallstone pancreatitis since the inception of laparoscopic cholecystectomy. Between November 1989 and March 1993, we treated 57 patients with acute gallstone pancreatitis. Cholecystectomy was performed during the initial admission in 46 patients (81%, group I), while 11 (19%) underwent delayed cholecystectomy at a second admission 2 to 9 weeks later (group II). Within group I, eight patients (17%) were thought to have contraindications to laparoscopic cholecystectomy and underwent open cholecystectomy. In the remaining 38 patients of group I, laparoscopic cholecystectomy was completed successfully. Preoperative endoscopic retrograde cholangiopancreatography (ERCP) was performed in 23 of these patients (61%) and endoscopic sphincterotomy was performed in 6 patients (26%). In four other patients, the intraoperative cholangiogram revealed common bile duct stones that were removed using laparoscopic techniques. The 11 patients in group II were all treated by laparoscopic cholecystectomy; of these patients, 3 underwent preoperative endoscopic stone removal and 1 had choledocholithiasis managed laparoscopically. Postoperative hospitalization averaged 4 +/- 1 days (mean +/- SEM), and there was no major morbidity or 30-day mortality. This is the first large series of acute gallstone pancreatitis in the era of laparoscopic cholecystectomy. Our experience suggests that laparoscopic cholecystectomy with or without ERCP should be the primary approach for treating acute gallstone pancreatitis in the 1990s.

Diagnosis and management of biliary complications of laparoscopic cholecystectomy

Laparoscopic cholecystectomy has become the operation of choice for symptomatic cholelithiasis. However, this operation may result in serious biliary complications. Our aims were to review our experience with biliary complications of laparoscopic cholecystectomy and to document the mechanisms of the injuries and the techniques of managing these complications. We treated 20 patients with biliary complications of laparoscopic cholecystectomy. Symptomatic collections of bile (bilomas) were present in five patients. One of these patients underwent operative ligation of an accessory bile duct in the gallbladder bed, whereas the others had percutaneous or endoscopic therapy. In the remaining 15 patients (of whom 13 were referred from other hospitals), injuries to the major bile ducts were managed by combined radiologic, endoscopic, and operative therapies. In 10 of these patients (67%), the mechanism of injury was the misidentification of the common bile duct as the cystic duct. In 3 of 15 patients, a noncircumferential injury to the lateral aspect of the common bile duct occurred. The Bismuth levels of the remaining bile duct injuries were type I in 3, type II in 4, type III in 3, and type IV in 2. Early outcome of therapy for these bile duct injuries has been favorable. One patient was lost to follow-up, and 2 died of nonbiliary causes, whereas 12 patients are alive and well with normal serum liver enzyme levels at 4 to 19 months postoperatively (mean: 14 months). The most common cause of major bile duct injury during laparoscopic cholecystectomy is mistaking the common bile duct for the cystic duct. Most bilomas can be managed successfully with noninvasive methods. Coordinated efforts by radiologists, endoscopists, and surgeons are necessary to optimize the management of patients with major bile duct injury, suggesting that patients with biliary complications of laparoscopic cholecystectomy should be referred to specialty centers for optimal care.

Preliminary experience using endoscopic ultrasonography in the diagnosis of choledocholithiasis

Twenty patients with symptomatic cholelithiasis and suspected choledocholithiasis were evaluated in an ongoing prospective trial using endoscopic ultrasonography (EUS), standard abdominal ultrasonography (US) and ERCP for the detection of choledocholithiasis prior to laparoscopic cholecystectomy. EUS was used successfully to image the extrahepatic bile duct in all patients. EUS detected three of four proven bile duct stones and correctly identified 16 bile ducts as stone free, thus being more accurate than standard abdominal US. The preliminary results of this ongoing prospective trial and the experience reported by other authors suggest that EUS may be as sensitive as ERCP in the detection of choledocholithiasis.

Percutaneous cholecystolithotomy: analysis of results and complications in 58 consecutive patients

Percutaneous cholecystolithotomy was attempted in 58 consecutive patients. Patients were considered for percutaneous cholecystolithotomy only if they had symptomatic gallstones and a strong contraindication to surgical cholecystectomy. The procedure consisted of three parts: (a) initial percutaneous cholecystostomy, (b) tract dilation and stone removal, and (c) tract evaluation and tube removal. Local anaesthesia and intravenously administered analgesia were used in all procedures. Percutaneous cholecystolithotomy was successful in removing all of the stones in 56 patients (97%), including cystic duct calculi in 15 patients and common duct calculi in 10 patients. Major complications occurred in five patients (9%); in four cases, they were related to bile leakage after the cholecystostomy tube was removed. Thirty-day mortality was 3% (two patients). Advantages of percutaneous cholecystolithotomy include avoidance of general anesthesia and the ability to treat patients in any disease setting, including acute cholecystitis. Percutaneous cholecystolithotomy, although technically demanding, is an effective alternative to surgical cholecystectomy in elderly and debilitated patients.

Small intestinal lesion resembling graft-vs-host disease. A case report in immunodeficiency and review of the literature

We report graft-vs-host disease-like histology in a small intestinal biopsy specimen that was obtained from a patient with common variable immunodeficiency and related T-cell defect. We include findings from immunohistochemical studies and follow-up information. Review of the literature yielded only a small number of histologically documented cases of this lesion without previous bone marrow transplantation. Awareness of this clinicopathologic entity is important in the interpretation of gastrointestinal biopsy specimens.

Incomplete lower esophageal sphincter relaxation in subjects with peristalsis: prevalence and clinical outcome

Incomplete lower esophageal sphincter relaxation is recognized in achalasia and has been reported in subjects with esophageal spasm. We reviewed 500 consecutive manometric studies from a 3-yr period to determine the prevalence of this manometric finding, its association with other motility abnormalities, and the clinical outcome of subjects without associated aperistalsis (i.e., without achalasia). We identified 60 subjects with incomplete lower sphincter relaxation, 17 of whom had at least some normal peristalsis (3.4% of the total). Mean lower sphincter residual pressure for these 17 subjects (4.5 +/- 2.8 mm Hg) was intermediate between those with achalasia (11.7 +/- 6.8 mm Hg) and those with normal relaxation (0.1 +/- 0.2 mm Hg). Both peristaltic and contraction abnormalities in the esophageal body were prevalent in the 17 subjects compared with those who had normal relaxation. Outcome with conservative medical therapy after a mean follow-up of 3.3 yr was not significantly related to presence of peristaltic or contraction abnormalities at presentation, and 71% of subjects with or without these concomitant findings had improvement or complete resolution of symptoms. Only one subject worsened and was treated with pneumatic dilation. We conclude that incomplete relaxation of the lower esophageal sphincter without aperistalsis is uncommon, symptom regression occurs with conservative therapy, and pneumatic dilation appears rarely required over a modest follow-up period.

Reevaluation of manometric criteria for vigorous achalasia. Is this a distinct clinical disorder?

Clinical and manometric data from 97 consecutive patients with idiopathic achalasia were analyzed to see if a distinct subset with vigorous achalasia could be identified. Statistical analyses failed to detect a unique group of subjects based on the distribution of contraction wave amplitudes alone. Because of this, patients falling above the 95th percentile (N = 4, mean wave amplitude greater than 100 mm Hg for each) were compared with those having mean amplitudes above the conventional threshold for the diagnosis of vigorous achalasia (mean amplitude 60-100 mm Hg, N = 4), and with the remainder (N = 89, mean amplitude less than 60 mm Hg). Subjects with mean amplitudes less than 60 mm Hg and with mean amplitudes 60-100 mm Hg closely resembled each other in all measured clinical features, whereas subjects with mean amplitudes greater than 100 mm Hg were all male, were older (67 +/- 4 years vs 47 +/- 2 years; P less than 0.01), and appeared to have somewhat longer duration of symptoms when compared with the remainder (82 +/- 41 vs 44 +/- 10 months; P = 0.4). Chest pain and other esophageal symptoms, basal and residual lower sphincter pressures, and response to first treatment did not differ among the three groups. These data indicate that high-fidelity manometry techniques identify a rare subset of achalasia patients with mean contraction amplitudes exceeding 100 mm Hg that, although older and possibly with greater duration of symptoms, presents similarly to others with idiopathic achalasia. Outcome from conventional treatment is also similar for the "vigorous" and "nonvigorous" patients, making the distinction of questionable value.

Effects of total parenteral nutrition enriched with branched chain amino acid infusion on liver function and serum amino acid pattern in dogs undergoing hepatectomy

In order to study effects of different total parenteral nutritional regimens on the recovery of liver function and on plasma amino acid pattern after major hepatectomy, twelve healthy mongrel dogs were submitted to 70% liver resection and randomly divided into three different groups: group I (control group) received only 10% glucose; group II received 10% glucose plus 8.5% Freamine; group III received 10% glucose plus 100% branched chain amino acid (BCAA) solution. Blood samples were analyzed for determining biochemical parameters, including plasma amino acid levels, before surgery and on 3rd and 7th postoperative day. The 'BCAA group', compared to other groups, showed higher values of plasma proteins (p less than 0.01) and prothrombin activity (p less than 0.05) on the 3rd postoperative day. The total concentration of plasma amino acids decreased after hepatectomy. Gluconeogenetic amino acids alanine and glutamine were markedly decreased in groups II and III, likely due to their increased consumption during gluconeogenesis. Aromatic amino acids were increased in all groups, due to the transient liver insufficiency. BCAA markedly increased in group III on 3rd postoperative day and returned to basal values on 7th postoperative day; possible explanations of such alterations are discussed. Our findings suggest that BCAA may represent a first choice substrate in the early phase after hepatectomy.

Hepatico-jejuno-duodenoplasty for biliary stricture

The authors present the results of their experience in the therapy of biliary strictures, using a jejunal loop interposed between the biliary tract and duodenum. This procedure allows extensive biliary discharge and aims to prevent the pathophysiologic disturbances of gastroduodenal functions, which result from Roux-en-Y anastomosis, and has the advantages of both Roux-en-Y and choledochoduodenostomy procedures. The authors report nine years positive experience with this technique. No gastroduodenal postoperative complaints are reported in their series, whereas an 8% incidence of duodenal ulcers is reported after Roux-en-Y anastomoses.

A chicken repetitive DNA sequence that is highly sensitive to single-strand specific endonucleases

A DNA sequence consisting of the 5-mer AGAGG repeated tandemly 32 times has been detected in a chicken genomic clone and found to be present in about 2000 copies per chicken genome. This sequence was highly susceptible to single-strand specific endonucleases isolated from Aspergillus oryzae (S1) and mung bean, but cleavage by a single-strand specific endonuclease isolated from Neurospora crassa occurred only at a pH below 5.5. Endonucleolytic cutting of the AGAGG sequence by the single-strand specific enzymes required a supercoiled substrate and was independent of ionic strength.

[Comparative experimental physiopathological evaluation of Roux-en-Y biliary shunt and choledocho-duodenal anastomosis with an interposed jejunal loop in dogs]

The authors compare in an experimental study two biliary tract reconstructive procedures in dogs: Roux-en-Y hepatico-jejuno-stomy and hepatico-jejunoduodenoplasty. The former causes in increase of plasma gastrin and insulin and moreover a decrease of duodenal pH after alimentary stimules, whereas the latter, preserving biliary flux through the duodenum doesn't alter such parameters, and therefore should be preferred.

[Percutaneous punctures guided by echography]

It is possible to carry out percutaneous injections of lesions in any organ under the direction of echography. This is particularly so in the liver, pancreas and kidney. The procedure has been used in 79 patients for diagnostic and/or therapeutic purposes and has provided very good and promising results. The technique is harmless, causes only minimum discomfort to the patient and, in many cases, enables the routine diagnostic approach to be short-circuited because more laborious, expensive techniques can be avoided.

In vitro synthesis of heat-shock proteins by mRNAs from chicken embryo fibroblasts

The pattern of proteins synthesized by chicken embryo fibroblasts changes dramatically after these cells are incubated at 45 degrees C for a few hours. Three proteins (Mr = 22,000, 76,000, and 95,000) account for almost 50% of the cell's protein synthetic capacity immediately after the heat-shock (Kelley, P.M., and Schlesinger, M.J. (1978) Cell 15, 1277-1286). When mRNAs were isolated from heat-shocked cells and translated in a cell-free protein synthesizing system, a pattern of proteins virtually identical with that made by intact heat-shocked cells was detected. Mobilities in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and radioimmune precipitation with specific antisera were used to establish the identity of in vitro- and in vivo-generated heat-shock proteins. The mRNAs coding for the major heat-shock proteins could be separated by rate zonal centrifugation in a sucrose gradient and mRNAs with sedimentation coefficients of 20 S, 18 S, and 13 S were translated in vitro to yield proteins of 95, 76, and 22 kilodaltons, respectively.