Longitudinal mechanical tension induces growth in the small bowel of juvenile rats.

INTRODUCTION: The aim of our study was to apply longitudinal force to the small bowel to increase the length of intestine in juvenile rats. METHODS: Fifty juvenile rats had double barrelled, blind loop ostomies created using an isolated segment of bowel. Our intestinal lengthening device was inserted into one of the loops and the second loop served as a control. Once the device was deployed, the experimental, control, and in situ segments of bowel were evaluated for length, weight, histology, and disaccharidase enzyme activity. RESULTS: Mechanical tension increased intestinal length by 149%. The lengthened bowel also exhibited a greater total weight (218%), greater mucosal weight (122%), and increased protein mass (164%) compared with the control limb of bowel. Histologically, there was a markedly increased thickness of the muscularis propria in the lengthened bowel (200% increase compared with the control limb). Functionally, we found increased total disaccharidase activity in the lengthened bowel (between 47% and 350%, depending on the particular enzyme tested; p<0.01). CONCLUSION: Mechanical tension induces intestinal growth by increasing length, weight of the bowel and mucosa, and protein mass. Histological changes, such as increases in Paneth cells, suggest that increased proliferation and reorganisation of the mucosa and muscularis propria are a response to mechanical tension. Functionally, increased intestinal length corresponds with increased disaccharidase activity, thus implying potential increased absorptive capacity of the lengthened bowel.

Characterization of neuronal/glial differentiation of murine adipose-derived adult stromal cells.

Neural tissue has limited capacity for intrinsic repair after injury, and the identification of alternate sources of neuronal stem cells has broad clinical potential. Preliminary studies have demonstrated that adipose-derived adult stromal (ADAS) cells are capable of differentiating into mesenchymal and non-mesenchymal cells in vitro, including cells with select characteristics of neuronal/glial tissue. In this study, we extended these observations to test the hypothesis that murine (mu) ADAS cells can be induced to exhibit characteristics of neuronal and glial tissue by exposure to a cocktail of induction agents. We characterized the differentiation of muADAS cells in vitro using immunohistochemistry and immunoblotting, and examined whether these cells respond to the glutamate agonist N-methyl-D-aspartate (NMDA). We found that induced muADAS cells express proteins indicative of neuronal/glial cells, including nestin, GFAP, S-100, NeuN, MAP2, tau, and beta-III tubulin. Induced muADAS cells express gamma-aminobutyric acid (GABA), the NR-1 and NR-2 subunits of the glutamate receptor, GAP-43, synapsin I, and voltage-gated calcium channels. Finally, induced muADAS cells demonstrate decreased viability in response to NMDA. These findings suggest that muADAS cells can be induced to exhibit several phenotypic, morphologic, and excitotoxic characteristics consistent with developing neuronal and glial tissue.

Ribozyme knockdown functionally links a 1,25(OH)2D3 membrane binding protein (1,25D3-MARRS) and phosphate uptake in intestinal cells.

We used a ribozyme loss-of-function approach to demonstrate that the protein product of a cDNA encoding a multifunctional membrane-associated protein binds the seco-steroid 1,25(OH)(2)D(3) and transduces its stimulatory effects on phosphate uptake. These results are paralleled by studies in which the ability of the hormone to stimulate phosphate uptake in isolated chick intestinal epithelial cells is abolished by preincubation with Ab099 directed against the amino terminus of the protein. We now report the complete sequence of the cloned chicken cDNA for the 1,25D(3)-MARRS (membrane-associated, rapid-response steroid-binding) protein and reveal it to be identical to the multifunctional protein ERp57. Functional studies showed that active ribozyme, but not a scrambled control, decreased specific membrane-associated 1,25(OH)(2)D(3) binding, but did not affect binding to the nuclear receptor for 1,25(OH)(2)D(3). Seco-steroid-dependent stimulation of protein kinase C activity was diminished as 1,25D(3)-MARRS protein levels were reduced in the presence of the ribozyme, as judged by Western blot analyses. Phosphate uptake in isolated cells is an index of intestinal phosphate transport that occurs during growth and maturation. Whereas cells and perfused duodena robustly responded to 1,25(OH)(2)D(3) in preparations from young birds, older animals no longer responded with stimulated phosphate uptake or transport. The age-related decline was accompanied by a decrease in 1,25D(3)-MARRS mRNA that was apparent up to 1 year of age. Together, these studies functionally link phosphate transport in the chick duodenum with the 1,25D(3)-MARRS protein and point to a previously uncharacterized role for this multifunctional protein class.

Management of cholelithiasis in pediatric patients who undergo bone marrow transplantation.

PURPOSE: The aim of this study was to determine the incidence, risk factors, and proper management for asymptomatic cholelithiasis in children undergoing bone marrow transplantation (BMT). METHODS: The authors reviewed retrospectively the records of 575 children who underwent bone marrow transplantation at a University bone marrow transplantation unit (BMT) unit between February 1991 and October 1999. Of these patients, 235 underwent abdominal ultrasonography for evaluation of jaundice, sepsis, abdominal pain, or metastasis. To identify risk factors for cholelithiasis, the authors stratified the patients based on their disease and treatment regimen. Finally, the authors analyzed the natural history and management of BMT children with cholelithiasis. RESULTS: The authors identified 20 cases of cholelithiasis (8.5%) in the 235 BMT patients who underwent ultrasonography. Children who underwent BMT to treat bone marrow failure showed a significantly increased risk of cholelithiasis compared with children treated for malignancy (27% v 7.4%; P<.01). Most children (85%) with gallstones did not require surgical intervention. Specifically, 9 (45%) died from their primary disease, 5 (25%) showed sonographic resolution of their gallstones, and 3 (15%) underwent follow-up nonoperatively with persistent cholelithiasis. Three of the 20 patients with gallstones (15%) had signs of acute cholecystitis and underwent surgery. There were no surgical complications or deaths in the operative group. CONCLUSIONS: Cholelithiasis occurs at a high incidence in pediatric bone marrow transplant patients. Children undergoing BMT for bone marrow failure are at higher risk of having gallstones than those being treated for malignancy. Finally, these data support a strategy of nonoperative management for asymptomatic cholelithiasis in this highly selected group of patients.

How body size affects middle-ear structure and function and auditory sensitivity in gekkonoid lizards.

Gekkonoid lizards increase in body size throughout life, and the present study investigates whether changes in auditory function accompany these increases. Middle-ear structures in four groups of animals, adults and juveniles of two gekkonoid species (Eublepharis macularius and Oedura marmorata), were examined. Tympanic membrane velocity and phase were also measured in all four groups. An indication of peripheral auditory function was obtained for each group by measuring compound action potentials (CAPs) from the round window membrane. The middle-ear contribution to CAP thresholds was obtained by comparing threshold levels of the CAP response with and without an intact middle-ear system. The results from these studies indicated that significant changes occurred in middle-ear structure, tympanic membrane velocity and CAP threshold between the younger and older animals. In addition, the adults of both species exhibited better auditory function when the acoustic stimulus was delivered to the tympanic membrane than when it was delivered to the columella footplate. The findings show clearly that increased body size (or age) is accompanied by functional changes in the auditory periphery.

Antisense basic fibroblast growth factor gene transfer reduces early intimal thickening in a rabbit femoral artery balloon injury model.

PURPOSE: The purpose of this study was to determine whether endogenous basic fibroblast growth factor (bFGF) production contributes to the intimal hyperplastic response to injury in a model of rabbit femoral artery balloon injury. Inhibition of de novo production of bFGF protein was targeted by intramural adenoviral gene transfer of antisense bFGF (Ad.ASbFGF) RNA. The adenovirus was delivered locally intraluminally at the time of arterial injury. METHODS: New Zealand White rabbits underwent balloon injury of the superficial femoral artery, followed by intraluminal delivery of an adenoviral vector encoding a rat antisense bFGF (ASbFGF) transcript at a concentration of 1 x 10(10) plaque-forming units per milliliter. Control animals were treated in a similar fashion, using either an adenovirus encoding the lac Z reporter gene (Ad.lacZ) or phosphate-buffered saline solution (PBS; vehicle) alone. Two weeks after balloon injury, rabbits were killed and perfusion fixed. Femoral arteries were harvested for histomorphometric analysis. Intimal and medial wall thickness was measured at eight points around the vessel perimeter, and mean intimal/medial (I/M) thickness ratios were compared by analysis of variance and Student's t test. In addition, medial cell proliferation in Ad.ASbFGF and Ad.lacZ treated arteries was evaluated 4 days and 2 weeks after balloon injury by 5-Bromo-2'-deoxyuridine labeling. RESULTS: At 14 days (n = 25) after balloon injury, histomorphometric analysis revealed a significant inhibition of intimal thickening in Ad.ASbFGF-treated arteries as compared with Ad.lacZ-treated and PBS-treated controls (I/M thickness ratios +/- SD, 0.43 +/- 0.22 for Ad.ASbFGF vs 1.03 +/- 0.28 for Ad.lacZ and 0.86 +/- 0.19 for PBS; p < 0.0001 and p = 0.004, respectively). There was no significant difference in the I/M thickness ratios of Ad.lacZ-treated and PBS-treated vessels (p = 0.27). Although there was no significant difference in the proliferation index of Ad.ASbFGF-treated and Ad.lacZ-treated vessels 4 days after injury, an increase in apoptosis was noted in the Ad.ASbFGF-treated vessels 4 days after balloon injury. CONCLUSIONS: The use of ASbFGF RNA gene transfer, designed to inhibit de novo bFGF synthesis after balloon injury, results in a significant inhibition of neointimal formation. This suggests that continued bFGF synthesis contributes to the arterial response to injury in rabbits. ASbFGF gene transfer may be an effective strategy in limiting the intimal hyperplastic response after vascular reconstructive procedures.

Management of pancreaticoduodenal artery aneurysms presenting as catastrophic intraabdominal bleeding.

BACKGROUND: Pancreaticoduodenal artery aneurysms (PDAs) are rare, accounting for only 2% of all visceral artery aneurysms. The majority of reported cases of patients with PDA have presented subsequent to rupture. Presentation without rupture also has been reported and is often associated with abdominal discomfort or diagnosed incidentally on radiologic studies. PDA rupture is associated with a high mortality rate, with fatal bleeding into the retroperitoneal space, intraperitoneal cavity, or gastrointestinal tract. METHODS: This article reports two cases of ruptured PDA, both presenting as catastrophic intraabdominal bleeding and both treated successfully at celiotomy. In addition, the literature concerning PDA is reviewed. RESULTS: Only 11 cases of PDA associated with sudden, severe abdominal pain and shock have been described. The mortality rate in these 11 cases was 36%, with half the patients not reaching the operating room alive. Successful management includes rapid resuscitation and control of the bleeding site with minimal pancreatic dissection, angiography for confirmation of vascular control and anatomic localization, and further definitive treatment if obliteration is incomplete. CONCLUSIONS: The aneurysm should be obliterated whenever possible to avoid both rebleeding and local complications related to mass effect such as pancreatic duct obstruction or erosion of the mass into neighboring structures. With appropriate and expeditious treatment, these gravely ill patients can be managed effectively and good outcomes obtained.

Thermal preconditioning before rat arterial balloon injury: limitation of injury and sustained reduction of intimal thickening.

Heat shock proteins (HSPs) are a family of highly conserved proteins, essential to cell survival, that are induced during times of physiological stress. These proteins, when induced, can provide tolerance to subsequent injury. Several studies have documented that HSPs play an important role in the response of vascular cells to injury or stress. Whether the vasculature itself can be effectively preconditioned before arterial injury is unknown. Vascular HSP induction by whole-body hyperthermia (WBH) was evaluated with regard to its effects on the vascular response to balloon injury. WBH treatment of Sprague-Dawley rats (colonic temperatures of 41 to 42 degrees C for 15 minutes) resulted in maximal arterial HSP expression within 8 to 12 hours. Rats (male, 300 g, n=59) were randomly assigned to undergo either WBH or no treatment 8 hours before standard carotid balloon injury. At 14 (n=26) and 90 (n=21) days after balloon injury, histomorphometric analysis revealed a significant limitation of intimal accumulation in preconditioned arteries as compared to controls (intimal/medial area ratios+/-SEM: 14 days, 0.57+/-0.07 versus 0.86+/-0.08, P=0.01; 90 days, 0.78+/-0.12 versus 1.19+/-0.14, P<0.05). The medial cell proliferation index at 4 days (n=12) was significantly reduced in the treated group as well (3.6+/-0.9% versus 7.2+/-1.3%, P<0.05). Conversely, the mean total cell number in the media of heated arteries was higher (393+/-20 versus 328+/-17, P<0.05). Vascular preconditioning with brief WBH induces a heat shock response in the arterial wall that is associated with a significant and sustained reduction in intimal accumulation. This effect appears to be due in part to preservation of medial cell integrity and limitation of the proliferative response. These results suggest that thermal preconditioning of vascular tissue may be an effective strategy to improve long-term results after revascularization procedures.

Antisense basic fibroblast growth factor gene transfer reduces neointimal thickening after arterial injury.

PURPOSE: To determine whether synthesis of endogenous basic fibroblast growth factor (bFGF) after arterial injury is critical to the intimal thickening response, intraluminal adenoviral gene transfer of an antisense bFGF (Ad.ASbFGF) transgene was used to inhibit the subsequent synthesis of bFGF protein after injury. METHODS: Sprague-Dawley rats underwent balloon catheter carotid artery injury and in vivo gene transfer. Isolated segments of rat common carotid artery were infected with an adenoviral vector encoding an antisense bFGF transcript at concentrations of 2 x 10(9), 1 x 10(10), or 1 x 10(11) pfu/ml. Control rats were treated with either a control adenovirus encoding the beta-galactosidase gene, (Ad.lacZ), at 1 x 10(10), or 1 x 10(11) pfu/ml, or phosphate-buffered saline solution (vehicle). Two weeks after injury the rats were killed and perfusion-fixed. Cross-sectional areas of the carotid arterial intima and media were measured by planimetry, and the intima/media ratio (I/M) was calculated for each vessel. RESULTS: The mean I/M for each Ad.ASbFGF group and controls were compared and the significance assessed by analysis of variance. At two weeks after injury, the highest dose of Ad.ASbFGF, 1 x 10(11) pfu/ml, resulted in a near total inhibition of thickening (I/M = 0.14 +/- 0.04, mean +/- SEM) when compared with phosphate-buffered saline solution alone (I/M = 0.99 +/- 0.07), or Ad.lacZ 1 x 10(10) pfu/ml (I/M = 1.01 +/- 0.10) control treatments (p < 0.01). A tenfold lower dose of Ad.ASbFGF, 1 x 10(10) pfu/ml, also caused significant reduction in intimal thickening (I/M = 0.39 +/- 0.07, p < 0.01). Treatment with 2 x 10(9) pfu/ml Ad.ASbFGF did not significantly limit intimal thickening (I/M = 0.72 +/- 0.12). CONCLUSIONS: Inhibition of bFGF synthesis in vivo using an antisense RNA strategy significantly inhibits intimal thickening after arterial balloon injury. This study suggests that continued bFGF synthesis contributes to intimal thickening after arterial injury, and that antisense bFGF may represent an effective strategy in limiting restenosis after angioplasty.

Suppression of fibrosarcoma metastasis by elevated expression of manganese superoxide dismutase.

A mouse fibrosarcoma cell line (FSa-II), which exhibits low endogenous levels of manganese superoxide dismutase, was transfected with a human manganese superoxide dismutase complementary DNA. Fifty clones were screened for manganese superoxide dismutase activity by the superoxide dismutase activity gel assay. Activity of the positive clones was measured by the nitro blue tetrazolium-reduction assay in the presence of cyanide. Three cell lines exhibiting a range of activity were chosen to be transplanted into syngeneic mice. The results indicated that the metastasis rate for all transfected cells was significantly less than that of control cells.

A multifocal outbreak of hepatitis A traced to commercially distributed lettuce.

From February 1 through March 20, 1988, 202 cases of hepatitis A were reported in and around Jefferson County, Kentucky. The epidemic curve indicated a common-source exposure. However, there was no apparent single source of exposure from a restaurant, or community gathering; nor was there a geographic clustering by residence. Cases were mainly adults 20-59 years old (89 percent); 51 percent were female. A case-control study using neighborhood controls found that factors associated with hepatitis A were: having eaten downtown (odds ratio [OR] = 4.0) and having dined at any one of three restaurants (OR = 21.0). Case-control studies of patrons of two of these restaurants found that eating green salad was strongly associated with acquiring hepatitis A: OR = 11.6 and OR = 4.4. The three implicated restaurants accounted for 71 percent of the cases. All three restaurants were supplied by the same fresh produce distributor; however, investigation suggested that contamination most likely occurred prior to local distribution. This outbreak of hepatitis A is the first in the United States apparently associated with fresh produce contaminated before distribution to restaurants, and raises important public health issues regarding the regulation of fresh produce.

Mandatory reporting of infectious diseases by clinicians.

Reporting of cases of communicable disease is important in the planning and evaluation of disease prevention and control programs, in the assurance of appropriate medical therapy, and in the detection of common-source outbreaks. In the United States, the authority to require notification of cases of disease resides in the respective state legislatures. We examined the laws and regulations of health departments of all US jurisdictions to ascertain diseases and conditions currently required to be reported in each state or territory. We present herein the state reporting requirements for infectious diseases and infectious disease-related conditions. To obtain additional information regarding time frames for reporting, agencies to which reports are required, persons required to report, and specific conditions under which reports are required, the reader is referred to the statutes and health department regulations of the respective states.

KIE: Accurate information on the occurrence and prevalence of communicable diseases is essential for the planning of public health programs. In the United States, compiling statistics on infectious diseases is the responsibility of state and territorial health agencies as authorized by state legislatures, and is accomplished largely through mandatory reporting requirements for physicians and other health personnel. Chorba, et al. present a table of state and territorial reporting requirements for infectious diseases and related conditions, and give a brief overview of current surveillance methods and tools.

Comparison of the general moral reasoning of small animal veterinarians vs large animal veterinarians.

This project was developed to gather data on the general moral reasoning of practicing veterinarians and to compare the responses of small animal veterinarians vs large animal veterinarians and of male veterinarians vs female veterinarians. Using the Defining Issues Test for assessing moral reasoning, it was found that there is no significant difference between the levels of moral reasoning of small animal and large animal veterinarians. However, a slightly significant (P = 0.045) difference was found between the levels of moral reasoning of male and female veterinarians. Explanations of these findings are given. This report provides baseline data on the moral reasoning of veterinarians, which can serve as a foundation and stimulus for comparison in other studies.

Radioimmunoassay for detection of antibody to hepatitis A virus. Results of clinical evaluation.

The performance of a solid-phase radioimmunoassay (HAVAB) for the detection of antibody to hepatitis A virus (HAV) was evaluated in clinical studies. The procedure was reproducible by eight investigators, and laboratory-to-laboratory variations were minimal. The sensitivity of the test was about equal to or slightly greater than that of immune adherence hemagglutination (IAHA) for detecting antibody in serum, but IAHA gives somewhat higher titer values than HAVAB. A survey of the incidence of anti-HAV in selected populations revealed an overall frequency of 48% and a correlation with age and lower socioeconomic status. The specificity of the test was demonstrated with specimens from patients who had clinical hepatitis A. Seroconversion to anti-HAV positivity was demonstrated with HAVAB to coincide with onset of illness, about two to three weeks earlier than it was detected by IAHA. HAVAB provided a convenient test for demonstrating the immune status of subjects, and was useful as an aid in diagnosing hepatitis A.