Oscar Felsenfeld

Comparative study of secretin and Lundh tests.

Exocrine pancreatic function in 19 patients with pancreatic disease and in 14 of 16 controls was measured by secretin stimulation and by the Lundh test on two different occasions. Peak bicarbonate concentration in the secretin test and mean trypsin concentration in the Lundh test emerged as the most reliable parameters. No additional diagnostic value was obtained by measuring enzymes after secretin injection. In 6 patients with chronic and in 8 of 13 patients with acute pancreatitis, both tests gave results that agreed with each other. The remaining 5 patients showed either an abnormal secretin value or an abnormal Lundh test. This is consistent with the wide variation seen in acute pancreatitis. It is concluded that the Lundh test as well as the secretin test were of value in the assessment of chronic pancreatic disease. The secretin test may be slightly more sensitive to mild and acute pancreatic damage than is the Lundh test. However stimulation of the pancreas by a test meal is easier to perform and more economic.

Comments on the laboratory diagnosis of enteric infections

Laboratory methods routinely used for the diagnosis of shigellosis, salmonellosis and amebiasis are discussed. Simple procedures are described which may be used in small laboratories. Some pitfalls in the laboratory technic are emphasized.

A study of laboratory methods for diagnosing Endamoeba histolytica and their application to 5,048 persons from the Chicago area.

The paper presents a complication of extensive studies made on methods used for the detection of Endamoeba histolytica, and the application of those methods to the examination of more than 13,000 fecal specimens from 5,048 persons during the past 7 years in Chicago and Cook County, Illinois. Combined fecal and proctosig-moidoscopic specimens examined within 30 minutes after collection, employing hematoxylin-stained slides and zinc sulfate flotation, gave optimal results. The irregular behavior of E. histolytica at different temperatures is presented, necessitating their preservation if examination is not carried out within 30 minutes. Advantages of polyvinyl alcohol and Schaudinns fixative for hematoxylin stained slides and those of formalin and D’Antoni’s iodine for flotation were pointed out. Results of stool examinations for other components than parasites and bacteria were compiled and their lack of value for etiological, but usefulness in guidance of symptomatic treatment were shown. The approximate proportion of E. histolytica infestations in patients suffering from chronic intestinal disturbances in the Chicago area is estimated as 20 ± 3 percent.

Radioisotope Precipitation Tests with 14C and 51Cr Labeled Vaccinia Antigens

Summary The radioisotope precipitation test was performed with 14C and 51Cr labeled vaccinia antigens after primary smallpox vaccination. The test gave positive results with the sera of successfully vaccinated individuals for a longer time than the neutralization test.

Investigation of enteric infections in the Caribbean area. 2. Distribution of Salmonella strains in Curacao, Jamaica and Costa Rica

Stool specimens from symptomless individuals and from persons suffering from diarrhea were examined in Curacao, Costa Rica and Jamaica. Sick animals, birds, as well as meat and milk samples were examined in Jamaica. Salmonellae were found in all three countries. In Curacao S. enteritidis, S. paratyphi B and S. typhimurim were the leading Salmonellae. Paratyphoid bacilli were not isolated in Jamaica but S. typhimurium, S. montevideo and others were frequently found. S. dublin was encountered in cattle. Fewer S. typhosa strains were isolated in Curacao and in Jamaica than expected. The incidence of Salmonellae was high in Costa Rica both in symptomless persons and in hospital patients.

In vitro Sensitivity of recently isolated Cholera Vibrios to Ten Antibiotics.

Summary Fifty-three recently isolated strains of V. comma were tested against 10 antibiotics. The results showed a wide variation of susceptibility to these drugs, according to the geographical origin of the vibrios.

Salmonellosis and shigellosis in cook county, Illinois; 1. Classification of six hundred salmonella and shigella strains isolated from patients of cook county hospital

Two hundred eighty-six Salmonella and 314 Shigella strains from patients in the Cook County Hospital in Chicago were identified. The most frequently encountered Salmonellae were (in decreasing order) S. typhimurium, S. typhosa, S. montevideo, S. Oranienburg, S. newport, S. anatum, S. enteritidis and S. paratyphi B, while often encountered Shigellae were classified as Sh. sonnei, Sh. paradysenteriae Flexner IV, Sh. alkalescens and Sh. paradysenteriae Flexner II. The occurrence of rare types is reported. There seemed to be a shift in the frequency of Salmonella strains, as compared with previous studies in the same geographic area but the distribution of Shigellae did not change. The importance of carriers and poultry in human salmonellosis were discussed.

Antigenic relationship of Salmonellae to Inaba strains of Vibrio comma isolated in Egypt.

Summary Three Inaba strains of V. comma isolated recently in Egypt harbored fractions of Salmonella I, XII and g antigens.

The importance of the Vi antigen

The characteristics of the Vi antigen present in typhoid bacilli and other Salmonellae was discussed. Vi agglutination experiments failed to produce better results than other diagnostic means. Inoculation with Vi vaccines increased mouse protecting antibodies to a fairly high level. Experiments were carried out in vitro and in mice which showed that typhoid and paratyphoid C bacilli with Vi antigen show a stronger initial multiplication than organisms without the Vi factor. The importance of these findings is discussed.

The significance of single and multiple shigella infections in institutionalized children

Summary Three hundred seventy-two strains of Shigella were isolated from 331 inmates of State institutes of the greater Chicago area during 1943. New admissions to childrens hospitals yielded 14.4 per cent carriers and hospitals for adults, 0.3 per cent carriers. Chronically institutionalized children harbored Shigella in 21.7 per cent of the examined cases; 3.4 per cent of the specimens of mentally ill adults contained these organisms. Double and triple carriers occurred in 12.3 per cent of children harboring Shigella and in 5.9 per cent of the adults. The recovery of less common Shigella types, as Sh. ceylonensis, Sh. madampensis , and Sh. gintottensis , and of organisms erroneously classified Shigella , as Sh. gallinarum and Sh. rettgeri , are discussed. Sh. gintottensis, Sh. equirulis -like organisms, and microbes of the Sh. dispar subgroup, namely, Sh. ceylonensis and Sh. madampensis , do not seem to have importance other than that of secondary invaders. Serologic reactions failed to reveal agglutinin production to a significant level for lactose-fermenting Shigella in double and triple carriers. In infections with other Shigella, the use of alcohol-treated antigens and formamide extracts with the one-tube technique gave satisfactory results.