Molecular characterization of the vaccinia virus hemagglutinin gene

The vaccinia virus hemagglutinin (HA) is a glycoprotein found on the plasma membrane of infected cells and the envelope of extracellular virus. Two forms of HA (85 and 68 kDa) are detected by immunoblot analysis. Although hemagglutination activity is only readily detectable late in infection, the 85-kDa HA appears early and accumulates throughout infection, whereas the 68-kDa form appears only late in the cycle. Production of the 68-kDa HA but not the 85-kDa HA was inhibited by either cytosine arabinoside or rifampin. Analysis of HA gene expression reveals a complex pattern of expression. The HA gene is transcribed early to yield a 1.65-kb dicistronic early transcript, consisting of the 945-bp HA open reading frame (ORF) fused to a 453-bp downstream ORF. Transcription from this site initiates 7 bases upstream of the AUG initiating codon of the HA ORF. Due to the discrepancy between the calculated size of the HA protein (33 kDa) and that reported for the unglycosylated HA protein derived from in vitro translation (58 kDa), we placed an early transcription termination signal (TTTTTAT) directly downstream of the 945-bp HA ORF. This led to a reduction in size of the early HA mRNA to 1.2 kb, as expected, but had no effect on the formation of either the 85- or 68-kDa protein. Transcripts originating from the early promoter are found throughout the infection cycle. However, after DNA replication, transcription from a second, late promoter ensues. The transcriptional start site of the late promoter is within a consensus TAAATG sequence located 135 bases upstream of the transcriptional start site of the first promoter. The late transcriptional start site is also found within an upstream ORF.

The nature of naturally occurring mutations in the hemagglutinin gene of vaccinia virus and the sequence of immediately adjacent genes

The expression of the vaccinia IHD-J hemagglutinin (HA) gene is regulated by two promoters, an early/late and a second distinct late promoter. The first promoter results in transcripts that begin early and are synthesized throughout the infection. All transcripts from this promoter initiate at the same 5' site. A second promoter is only active late in infection and initiates transcription some distance upstream of the first promoter. We have previously shown that the transcriptional start site controlled by this second, "late only" promoter lies within the coding sequence of an upstream reading frame (p16-ORF), whereas the termination of early transcription of the HA gene utilizes a transcription termination signal (TTTTTNT) located just beyond the coding region of an immediately downstream reading frame (p17-ORF). In order to assist our understanding of HA gene expression, we report here the sequence of these two ORFs adjacent to the HA gene. The HA-ORF itself consists of 945 bp, whereas the upstream p16-ORF consists of 429 bp and the downstream p17-ORF of 453 bp, sufficient to encode polypeptides of 16 and 17 kD, respectively. While many strains of vaccinia are HA+, rabbitpox virus and the variant of vaccinia IHD-J, designated IHD-W, are HA-. We report and compare here the HA gene sequences of wild-type rabbit poxvirus, two spontaneous HA+ revertants of rabbit poxvirus, and the HA- vaccinia strain IHD-W to that of the previously sequenced (1) prototype HA+ IHD-J strain of vaccinia. All differences were found to occur within the HA open reading frame.(ABSTRACT TRUNCATED AT 250 WORDS)

Velar-pharyngeal status in cleft palate patients with expected adenoidal involution

This study was designed to provide information about whether cleft palate patients with hypertrophied adenoids maintain velar-pharyngeal contact during the time of expected adenoidal atrophy. Thirty-nine subjects were selected from a large longitudinal study on the basis of availability of lateral still x-ray films taken in series from 5 to 16 years of age. Ratings of velar-pharyngeal contact and ratings of adenoid size were obtained from the films. The obtained data indicated the expected decrease in adenoid size but also, for the group, maintenance of velar-pharyngeal contact. However, three of the 39 subjects were judged to show loss of such contact during the period of study, and an additional four had surgery for velopharyngeal incompetence after the completion of the study. All seven appeared to show significant deterioration of velopharyngeal status in middle or late adolescence. Implications of these findings are discussed.

Use of metoclopramide, domperidone, and cisapride in the management of diabetic gastroparesis

The pathophysiology, diagnosis, and treatment of diabetic gastroparesis are reviewed, and the mechanisms of action, pharmacokinetics, clinical efficacy, adverse effects, and dosage of metoclopramide, domperidone, and cisapride are described. Diabetic gastroparesis is a state of delayed gastric emptying that reportedly affects 20-30% of diabetic patients. Symptoms include nausea, early satiety, postprandial bloating and fullness, and vomiting. Diabetic gastroparesis has been managed most successfully with drugs that stimulate gastric emptying. Of the three agents studied--metoclopramide, domperidone, and cisapride--only metoclopramide is commercially available in the United States. The clinical efficacy of metoclopramide, domperidone, and cisapride has been well documented in several placebo-controlled trials. Metoclopramide effectively decreases mean gastric emptying time, although tolerance to this stimulation of gastric emptying may develop with long-term therapy. However, symptomatic relief persists with long-term therapy because of metoclopramide's antiemetic properties. Domperidone, which has also been shown to stimulate gastric motility and to possess antiemetic properties, improves symptoms in patients suffering from diabetic gastroparesis. Cisapride appears to have continued beneficial effects on gastric motility with long-term therapy. All three agents have favorable adverse-effect profiles. Although metoclopramide is currently the first-line agent for the management of gastroparesis, domperidone and cisapride both possess properties that may make them useful alternatives in patients who are unresponsive to or cannot tolerate metoclopramide therapy.

Critical evaluation of the cocaine test in the diagnosis of Horner's syndrome

We evaluated the effectiveness of the cocaine test for diagnosing Horner's syndrome. The test was administered to 119 patients with a diagnosis of Horner's syndrome and to 50 normal subjects. We compared the cocaine-induced anisocoria in the two groups by measuring photographs of the pupils. We found the cocaine test to be highly effective in separating normal subjects from patients with Horner's syndrome. The chances of having Horner's syndrome increased with the amount of cocaine-induced anisocoria. Through the use of logistic regression analysis, we determined the odds ratio of having Horner's syndrome compared with not having it for each 0.1-mm increment of anisocoria measured after cocaine administration. A postcocaine anisocoria value of 0.8 mm gave a mean odds ratio of approximately 1050:1 that Horner's syndrome was present (lower 95% confidence limit = 37:1). We found that simply measuring the postcocaine anisocoria provided a better prediction of Horner's syndrome than taking the trouble to calculate the net change in anisocoria. Odds ratios should help the clinician decide if the result of a cocaine test is indicative of Horner's syndrome.

Motility changes in opossum esophagus from experimental esophagitis

We assessed how acute inflammation affects the contractile activity of the esophageal body. Two models of esophagitis were used: nine opossums had an esophageal perfusion of 100 meq hydrochloric acid for 2 hr and were studied at 24 hr. Ten had the perfusion for 4 h and their esophagitis were studied in vitro after 72 hr. Comparisons were made in all instances to animals who had esophageal saline perfusion for identical periods. All acid-perfused animals developed gross and histologic evidence of mucosal inflammation; in three animals, inflammatory changes extended into the submucosa and the muscularis propria. Manometric recordings in the acid-perfused animals revealed esophageal shortening, frequent failure of primary peristalsis and frequent occurrence of spontaneous contractions. Recordings of isometric tension of muscle in vitro revealed spontaneous contractions in strips from the mucosa and from the circular and from the longitudinal muscle. The amplitude of contractions in response to electrical stimulation was decreased, but the duration of contractions was increased largely because of a prolonged recovery phase. These changes in mechanical response occurred with stimulus parameters directed at both the muscle and the intrinsic nerves. We conclude that esophageal inflammation can lead to an increased irritability and decreased stimulus response of the smooth muscle of the esophagus even where it is not directly involved in an inflammatory response. These changes correspond to the functional abnormalities of the esophagus seen in patients with reflux esophagitis.

Animal procedure laboratory surveys: use of the animal laboratory to improve physician confidence and ability

Animal laboratories have been used for many years to teach procedures. Our department has a weekly swine laboratory devoted to training residents, interns and students in resuscitative procedures. Physicians who participated in our swine procedure laboratory over the past three years were queried as to their prelaboratory and postlaboratory comfort levels with six different resuscitative procedures, and 57 (76%) physicians responded. Statistical analysis of the data showed significant improvement in comfort levels for all six procedures. Every responder felt the swine laboratory helped or will help them perform the procedures on humans. We also surveyed all U.S. emergency medicine residency program directors from established programs regarding the status of their animal procedure laboratories, and 67 of the 68 (98%) directors responded. Of these responders, 62% offer an animal procedure laboratory. Overall, 97% of the residency directors rated the laboratory successful, and 97% of the residents rated the laboratory successful. Therefore, we conclude that an ongoing emergency medicine animal procedure laboratory is a valuable tool for improving physician-in-training ability and confidence.

The incidence and significance of hemostatic abnormalities in patients with head injuries

Abnormal coagulation and fibrinolysis is a frequent complication in patients with head injury. This complication can be severe enough to lead to hemorrhage or thrombosis. A study was undertaken to determine if the hemostatic abnormalities are reliable indicators of outcome. Hemostasis in 269 patients with head injuries alone was screened using platelet count (PC), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin clotting time (TCT), fibrinogen assay (FIB), level of fibrin-fibrinogen degradation products (FDP), and disseminated intravascular coagulation (DIC) score in the first 24 hours after injury. Test results were compared with the outcome (discharged or dead) in the entire group and in subgroups divided on the basis of the severity of injury as determined by the Glasgow coma score (GCS). Increased consumptive coagulopathy at admission, as reflected in the DIC score, predicts the outcome of head-injured patients with a high degree of accuracy. The degree of increase of the initial FDP level and prolongation of TCT also correlated positively with the outcome. Prolongation of the APTT correlated strongly with unfavorable outcome in a large group of patients, and in a small group, markedly accelerated APTT also predicted death. Stepwise logistic regression analysis demonstrated that GCS, FDP level, and DIC score predicted outcome. Other tests did not provide additional predictive value. Abnormal hemostasis frequently complicates the course of patients with head injuries. This study demonstrates that hemostasis tests are predictors of outcome in these patients.

Duodenal resistance to the emptying of various solutions from the isolated cat stomach

Experiments were conducted to determine to what extent the duodenum resists the emptying of various solutions from the isolated stomach. Cat stomachs were maintained in Krebs solution in vitro, and filled with 100 ml isotonic saline solution, isotonic glucose, hypertonic saline solution, hypertonic glucose, or dilute acid. Gastric pressure was constantly monitored; gastric output was collected constantly by a cannula in the proximal or distal duodenum. For all solutions, cumulative gastric output at all times was considerably less with the distal than the proximal cannula position. This difference was almost entirely caused by a smaller fractional gastric output during the first minute of gastric emptying, and by reduced amplitude of the gastric stroke volume with the distal cannula position. Some differences were observed in the gastric emptying rate for the various solutions; isotonic saline solution emptied particularly slowly and hydrochloric acid emptied particularly fast. In addition, the various solutions produced different gastric pressure patterns, which could not be entirely explained by differences in residual gastric volume. We concluded that the cat duodenum provides a resistance to gastric emptying over and above that generated by the pylorus, and that the duodenal resistance is caused by limitations in duodenal capacity. It is furthermore concluded that the mechanical activity of the isolated stomach and duodenum is affected by the chemical composition of their luminal contents.

Changes in jejunal myoelectrical activity during exercise in fed untrained dogs

Seven female dogs (15-20 kg) were instrumented with seven bipolar electrodes sutured at 3-cm intervals to the serosal surface of the proximal jejunum and were exercised at different intensities and durations on a motor-driven treadmill. Slow-wave frequency increased (P less than 0.05) from preexercise control during prolonged (90 min) exercise and during recovery after short-term exercise (30 min) at 70% heart rate reserve (HRR). These changes were associated with an increase in core temperature. Spike-burst frequency (SBF) increased (P less than 0.05) with moderate exercise (50% HRR), but the magnitude was small. When exercise was extended beyond 30 min and during all recovery periods, SBF decreased significantly. Exercise produced migrating myoelectrical complexes in three experiments and less dramatic pattern changes characterized as "clustered contractions" (regular spike bursts preceded and followed by the absence of spike bursts) in at least nine other experiments. We conclude that exercise does alter jejunal myoelectrical activity, but myoelectrical patterns may be more important in explaining exercise-induced gastrointestinal symptoms than changes in spike-burst frequency or duration.

Meckel's diverticulum

Meckel's diverticulum is a cause of significant morbidity and mortality. Often this is related to the delay in diagnosis. Based on a US population of 200 million people and a 2% incidence, there are 4 million Meckel's diverticula present waiting to cause symptoms. Considering that most Meckel's diverticula are asymptomatic and that many authors have described the condition as a great mimic, the diagnosis is often quite elusive. Therefore, a high index of suspicion is needed to diagnose Meckel's diverticulum correctly and expeditiously as the source of disease in the patient with an often unclear abdominal presentation. The difficulty with diagnosis should be lessened if one considers that Meckel's diverticulum presents largely in the male and younger age groups with the three major symptom complexes of bowel obstruction, gastrointestinal bleeding, and inflammation. Use of 99mTc pertechnetate scintigraphy appears to be the diagnostic study of choice if Meckel's diverticulum is suspected and the patient is clinically stable. When one considers the potential for bad outcome if Meckel's diverticulum is missed in the setting of possible obstruction or hemorrhage (i.e., bowel infarction or exsanguination), a high index of suspicion and diagnostic aggressiveness is warranted. Lastly, if one thought is to be left behind, it should be: "Meckel's is a great mimic that must be considered in all cases of intra-abdominal disease in which the cause is not readily apparent."

Temporal variations of glandular kallikrein, protein and amylase in mixed human saliva

Variations in the level of glandular kallikrein in human saliva may reflect physiological changes. Diurnal or circadian variations of many salivary components are important in relating changes in such components to oral or systemic conditions especially as most clinical studies are conducted between 0800 and 1700 h. Whole saliva was collected from 14 healthy young subjects at 0800, 1100, 1400 and 1700 h on two Fridays. Samples were centrifuged at 10,000 g for 10 min at 4 degrees C and the supernatant fractions stored at -20 degrees C. The enzymic activity of kallikrein was measured with D-valylleucylarginine-p-nitro-anilide as substrate. The activity of alpha-amylase and the total protein concentration (biuret) were also determined. Results were analysed in a repeated-measures design: there were no significant differences in kallikrein levels either within days or across days. There were significant differences for total protein and alpha-amylase levels within days but, in general, not across days. Minimal individual levels for protein and alpha-amylase were mostly at 0800 h; maxima were generally at 1400 or 1700 h. Kallikrein levels had no marked pattern of maximal or minimal distribution.

Emptying of saline meals by the cat stomach as a function of pyloric resistance

The effect of the pylorus on the rate of gastric emptying and on the pattern of flow from the stomach to the duodenum was studied. Cat stomachs were filled with 50, 100, or 150 ml of 0.9 N saline, and intragastric pressure and gastric fluid output were monitored continuously. The tip of the collecting cannula was positioned either in the duodenum thus allowing the pylorus to close) or in the pyloric segment thus preventing the pylorus from interfering with gastric outflow). Initial experiments demonstrated that fluid output was similar for the cat stomach in situ and in vitro. Incremental output (i.e., the absolute volume emptied per collection period) increased with the meal size and was proportional to the fluid volume actually remaining in the stomach; fractional gastric output (i.e., the volume emptied as a percentage of the actual gastric volume) did not change with meal size. The half time for gastric emptying was greater with the collecting cannula positioned in the duodenum than in the pylorus (e.g., with the 100-ml meal, 154 vs. 46 s). With the cannula in the pylorus, gastric outflow was constant and ceased only when gastric emptying had terminated. With the cannula in the duodenum, outflow was pulsatile and ceased intermittently at gastric volumes that were subsequently emptied. We conclude that the cat pylorus renders the outlet of the stomach continent even to liquids; furthermore, the pylorus imparts a pulsatile pattern to flow of liquids from the stomach to the duodenum.

Bladder cancer risk among auto and truck mechanics and chemically related occupations

Male participants in the NCI National Bladder Cancer study were evaluated for risks in auto and truck mechanic and in chemically related exposure occupations compared with those who had never worked in these areas. In nonsmokers the adjusted rate ratios (RR) for mechanics equalled 1.33, (95% CI 0.77, 2.31). The adjusted RR in the nonsmoker chemically related group was 1.53 (95% CI 1.13, 2.07). Duration of exposure as a mechanic was not clearly associated with bladder cancer risk regardless of smoking status.

The creation and repair of diaphragmatic hernia in fetal lambs: morphology of the type II alveolar cell

A model for creating and repairing diaphragmatic hernia in fetal lambs has been developed. Morphometric studies of the type II alveolar cells were carried out in three groups of term lambs. The upper lobes only were sampled. Morphometric analysis of the 30 type II cells from each lobe showed that while there were no differences between the left upper lobe (LUL) and right upper lobe (RUL) cells in normal lambs, there were significant differences between sides in the experimental groups. In lambs with a nonrepaired diaphragmatic hernia (DH) the type II cells were significantly smaller in the LUL compared with the RUL. In lambs with a repaired DH, the LUL type II cells were significantly larger than those in the RUL. There were some trends when the groups were compared, but in general they did not reach statistical significance. These findings suggest that local factors profoundly influence the development of these cells.

Visual function abnormalities in central serous retinopathy

Eighteen patients with central serous retinopathy (CSR) underwent a battery of visual function tests when first seen and after resolution of the subretinal fluid. Eyes with CSR had minimal relative afferent pupillary defects, reduced critical flicker-fusion thresholds, prolonged visual evoked potential (VEP) latencies, increased errors on the Farnsworth-Munsell 100-hue (FM 100) test, and depressed central visual fields (Octopus). The afferent pupillary defect and critical flicker-fusion thresholds were the first to improve after resolution of the subretinal fluid. Next in rate of improvement were the visual acuity, the VEP latency, and the FM 100 test results. The threshold of the central Octopus at fixation improved the slowest and was still abnormal during long-term follow-up, indicating a prolonged depression in the threshold of central field sensitivity after resolution of the CSR. Many of these abnormalities are also seen in patients with optic nerve disease.

Predicting age of onset for individuals at risk for phakic retinal detachment

Three hundred sixty-five cases of nontraumatic phakic retinal detachment were examined by analysis of covariance to determine the degree of association among type of detachment, refractive error, and age of onset. The combination of type of detachment and refractive error explained 57% of the variation in age of onset. Discrimination among types of detachment by variation in mean age was limited. Discrimination among types of detachment by variation in mean refractive error could not be established. Detachments due to vitreoretinal adhesion, lattice degeneration, and retinal dialysis differed significantly in mean age of onset and regression of age on refractive error. A regression model was created to predict from refractive error the age of onset with 95% confidence limits for individuals who appear to be at risk for these types of detachment.

Epidemiology of retinal detachment

A survey of rhegmatogenous retinal detachment during 1976 was conducted on the population of Iowa. The annual incidences (per 100,000 populations) of four types of detachment were determined: nontraumatic phakic (6.1), traumatic phakic (1.0), nontraumatic aphakic (4.9), and traumatic aphakic (0.4). The incidences of nontraumatic phakic detachment for men and women were similar, although there was a preponderance of women that reflected their greater representation in the general population. The proportions of men were significantly higher in traumatic detachments compared with nontraumatic detachments. Men tended to be younger than women for all types of detachment; however, only in nontraumatic aphakic detachment was there a significant difference between mean ages. There was an insignificant preponderance of right eye involvement in all four detachment groups.

2-bromo-alpha-ergocryptine (CB-154) and tamoxifen (ICI 46,474) induced suppression of the genesis of mammary carcinomas in female rats treated with 7,12-dimethylbenzanthracene (DMBA): a comparison

Daily treatment of female Sprague-Dawley rats with CB-154 (prolactin suppressor) or Tamoxifen (estrogen antagonist) for 33 days before and after 7,12-dimethylbenzanthracene (DMBA) administration reduced (p less than 0.005) the incidence of mammary carcinomas by 58 and 49%, respectively. A combination of CB-154 and Tamoxifen further reduced (p less than 0.005) mammary carcinoma incidence by an additional 50-59%. Treatment with Tamoxifen for 66 days beginning 33 days after carcinogen treatment reduced (p less than 0.05) the incidence of mammary carcinomas by 65%; CB-154 treatment, during the same time period, did not significantly effect the final yield of mammary carcinomas. The combination of Tamoxifen and CB-154 was comparable to Tamoxifen alone in suppressing the incidence of mammary carcinomas in the latter study. These results demonstrate a substantial suppressive and synergistic effect of Tamoxifen and CB-154 in the initiating phases of mammary carcinogenesis while in the early promoting phases of this oncogenic process, short-term treatment with Tamoxifen was superior to CB-154 treatment; no synergism between these clinically important compounds was observed.