Nonemployment Income and the Economic Base of Michigan Counties: 1959–1986

ABSTRACT Despite the fact that nonemployment income makes up approximately one-third of all personal income, its impact on local area economies has not been closely examined. This study uses Michigan county data to examine the impact of nonemployment income on nonbasic income over a twenty-seven-year period. This impact is compared to the impact of basic income by employing regression analysis to estimate comparative multiplier effects for both types of income. Nonemployment income is found to have a significant impact on nonbasic income, particularly in metropolitan and nonmetropolitan urban counties, where its impact appears to be stronger than that of basic income.     

Comparative prevalence of four enterotoxin genes among Escherichia coli isolated from swine

Presence of Escherichia coli enterotoxin genes LT (heat-labile enterotoxin), STaP (heat-stable enterotoxin a, porcine genotype), STaH (heat-stable enterotoxin a, human genotype), and STb (heat-stable enterotoxin b) among 874 swine isolates of E coli was determined, using DNA probes and the DNA colony hybridization technique. Of the 874 isolates evaluated, 45% hybridized with at least one of the enterotoxin gene probes and were designated as enterotoxigenic E coli (ETEC). Eighty-five percent of the ETEC were from pigs with enteric colibacillosis. The remaining 15% were from pigs with edema disease or various other diseases, and from healthy swine. Seventy-four percent of the ETEC hybridized with the STb probe, 52% with STaP, and 31% with LT; ETEC did not hybridize with the STaH probe. Most of the ETEC hybridized with more than one enterotoxin gene probe. Isolates that hybridized with the LT probe also hybridized with STb. The most prevalent gene combination was LT-STb. However, 35% of the ETEC from neonatal (less than or equal to 1 week old) swine with enteric colibacillosis were of the STaP-only genotype, and 33% of the ETEC from older swine with enteric colibacillosis were of the STb-only genotype.     

Microscopic alterations in jejunal epithelium of 3-week-old pigs induced by pig-specific, mouse-negative, heat-stable Escherichia coli enterotoxin

The objective of this study was to determine whether exposure of swine jejunum to crude culture filtrates containing Escherichia coli pig-specific, mouse-negative, heat-stable enterotoxin (STb) induces structural alterations in the jejunal mucosa of pigs. Two ligated intestinal loops in each of twelve 3-week-old pigs were exposed for 2 hours to sterile E coli culture filtrates from each of the following strains: 431 (STa-producing), 1261 (STa and STb-producing), and 1790 (STb-producing); recombinant strain HB101-pRAS-1 (STb-producing); the nontoxigenic K-12 variant HB101; or trypticase soy broth. Formalin-fixed sections from these loops were examined for sloughed cells around villi, and a lesion score was determined, indicating a change in villous epithelium from columnar to cuboidal or squamous cell types or to discontinuous epithelium. Villous lengths and crypt depths also were determined. For loops exposed to culture filtrates containing STa and STb or containing only STb, lesion scores and numbers of sloughed cells were greater (P less than 0.05) and villous length was shorter (P less than 0.01) than in loops not exposed to toxin. For loops exposed to culture filtrates containing STa, lesion scores, villus lengths, and numbers of sloughed cells were not different from those of loops not exposed to toxin. Therefore, exposure of swine jejunum to STb induced structural alterations in intestinal mucosa (ie, loss of villous absorptive cells and partial atrophy of villi) that were consistent with those causing compromised absorptive capacity.     

Localization of Transforming Growth Factor Beta3 in Squamous Metaplasia of the Porcine Oviduct: a Case Report

Squamous metaplasia of the oviduct epithelium is a rare disorder of reproductive organs. We noted squamous metaplasia of the oviduct epithelium in a sow routinely slaughtered at day 2 of the oestrous cycle. Expression of transforming growth factor beta3 (TGF beta3) in the metaplastic epithelia was evaluated by immunohistochemistry, because TGF beta3 appears to play a key role as regulator of a variety of tissue remodelling events. Our results show that TGF beta3 immunostaining was specifically localized to foci of squamous metaplasia of the epithelial linings. Non‐metaplastic epithelial cells of the oviduct were not immunostained with anti‐TGF beta3 antibody. At the subcellular level, TGF beta3‐labelled cells occasionally showed signs of apoptotic cell death. It is concluded that signals produced by TGF beta3 in metaplastic lesions of the oviduct are potentially involved in pathophysiological processes.