Role of Smad3 in platelet-derived growth factor-C-induced liver fibrosis

Chronic liver injury leads to fibrosis and cirrhosis. Cirrhosis, the end stage of chronic liver disease, is a leading cause of death worldwide and increases the risk of developing hepatocellular carcinoma. Currently, there is a lack of effective antifibrotic therapies to treat fibrosis and cirrhosis. Development of antifibrotic therapies requires an in-depth understanding of the cellular and molecular mechanisms involved in inflammation and fibrosis after hepatic injury. Two growth factor signaling pathways that regulate liver fibrosis are transforming growth factor-β (TGFβ) and platelet-derived growth factor (PDGF). However, their specific contributions to fibrogenesis are not well understood. Using a genetic model of liver fibrosis, we investigated whether the canonical TGFβ signaling pathway was necessary for fibrogenesis. PDGF-C transgenic (PDGF-C Tg) mice were intercrossed with mice that lack Smad3, and molecular and histological fibrosis was analyzed. PDGF-C Tg mice that also lacked Smad3 had less fibrosis and improved liver lobule architecture. Loss of Smad3 also reduced expression of collagen genes, which were induced by PDGF-C, but not the expression of genes frequently associated with hepatic stellate cell (HSC) activation. In vitro HSCs isolated from Smad3-null mice proliferated more slowly than cells from wild-type mice. Taken together, these findings indicate that PDGF-C activates TGFβ/Smad3 signaling pathways to regulate HSC proliferation, collagen production and ultimately fibrosis. In summary, these results suggest that inhibition of both PDGF and TGFβ signaling pathways may be required to effectively attenuate fibrogenesis in patients with chronic liver disease.

Activation of platelet-derived growth factor receptor alpha contributes to liver fibrosis

Chronic liver injury leads to fibrosis, cirrhosis, and loss of liver function. Liver cirrhosis is the 12th leading cause of death in the United States, and it is the primary risk factor for developing liver cancer. Fibrosis and cirrhosis result from activation of hepatic stellate cells (HSCs), which are the primary collagen producing cell type in the liver. Here, we show that platelet-derived growth factor receptor α (PDGFRα) is expressed by human HSCs, and PDGFRα expression is elevated in human liver disease. Using a green fluorescent protein (GFP) reporter mouse strain, we evaluated the role of PDGFRα in liver disease in mice and found that mouse HSCs express PDGFRα and expression is upregulated during carbon tetrachloride (CCl₄) induced liver injury and fibrosis injection. This fibrotic response is reduced in Pdgfrα heterozygous mice, consistent with the hypothesis that liver fibrosis requires upregulation and activation of PDGFRα. These results indicate that Pdgfrα expression is important in the fibrotic response to liver injury in humans and mice, and suggest that blocking PDGFRα–specific signaling pathways in HSCs may provide therapeutic benefit for patients with chronic liver disease.

Tissue-type plasminogen activator is not necessary for platelet-derived growth factor-c activation

Platelet-derived growth factors (PDGFs) are critical for development; their over-expression is associated with fibrogenesis. Full-length PDGF-C is secreted as an inactive dimer, requiring cleavage to allow receptor binding. Previous studies indicate that tissue-type plasminogen activator (tPA) is the specific protease that performs this cleavage; in vivo confirmation is lacking. We demonstrate that primary hepatocytes from tpa KO mice produce less cleaved active PDGF-CC than do wild type hepatocytes, suggesting that tPA is critical for in vitro activation of this growth factor. We developed mice that over-express full-length human PDGF-C in the liver; these mice develop progressive liver fibrosis. To test whether tPA is important for cleavage and activation of PDGF-C in vivo, we intercrossed PDGF-C transgenic (Tg) and tpa knock-out (KO) mice, anticipating that lack of tPA would result in decreased fibrosis due to lack of hPDGF-C cleavage. To measure levels of cleaved, dimerized PDGF-CC in sera, we developed an ELISA that specifically detects cleaved PDGF-CC. We report that the absence of tpa does not affect the phenotype of `PDGF-C Tg mice. PDGF-C Tg mice lacking tPA have high serum levels of cleaved growth factor, significant liver fibrosis, and gene expression alterations similar to those of PDGF-C Tg mice with intact tPA. Furthermore, urokinase plasminogen activator and plasminogen activator inhibitor-1 expression are increased in PDGF-C Tg; tpa KO mice. Our ELISA data suggest a difference between in vitro and in vivo activation of this growth factor, and our mouse model confirms that multiple proteases cleave and activate PDGF-C in vivo.

Paracrine activation of hepatic stellate cells in platelet-derived growth factor C transgenic mice: evidence for stromal induction of hepatocellular carcinoma

Cirrhosis is the primary risk factor for the development of hepatocellular carcinoma (HCC), yet the mechanisms by which cirrhosis predisposes to carcinogenesis are poorly understood. Using a mouse model that recapitulates many aspects of the pathophysiology of human liver disease, we explored the mechanisms by which changes in the liver microenvironment induce dysplasia and HCC. Hepatic expression of platelet-derived growth factor C (PDGF-C) induces progressive fibrosis, chronic inflammation, neoangiogenesis and sinusoidal congestion, as well as global changes in gene expression. Using reporter mice, immunofluorescence, immunohistochemistry and liver cell isolation, we demonstrate that receptors for PDGF-CC are localized on hepatic stellate cells (HSCs), which proliferate, and transform into myofibroblast-like cells that deposit extracellular matrix and lead to production of growth factors and cytokines. We demonstrate induction of cytokine genes at 2 months, and stromal cell-derived hepatocyte growth factors that coincide with the onset of dysplasia at 4 months. Our results support a paracrine signaling model wherein hepatocyte-derived PDGF-C stimulates widespread HSC activation throughout the liver leading to chronic inflammation, liver injury and architectural changes. These complex changes to the liver microenvironment precede the development of HCC. Further, increased PDGF-CC levels were observed in livers of patients with nonalcoholic fatty steatohepatitis and correlate with the stage of disease, suggesting a role for this growth factor in chronic liver disease in humans. PDGF-C transgenic mice provide a unique model for the in vivo study of tumor-stromal interactions in the liver.

Toll-like receptor 4 and myeloid differentiation factor 88 provide mechanistic insights into the cause and effects of interleukin-6 activation in mouse liver regeneration

Partial hepatectomy (PH) consistently results in an early increase of circulating interleukin-6 (IL-6), which is thought to play a major role in liver regeneration. Activation of this cytokine after PH requires the adaptor protein, MyD88, but the specific MyD88-related receptors involved remain unidentified. It is also unknown whether the magnitude of IL-6 elevation determines the extent of subsequent hepatocyte proliferation. Here, we uncovered artifacts in the assessment of circulating IL-6 levels when using cardiac puncture in mice after PH. By using retro-orbital bleed sampling, we show that the circulating levels of IL-6 after PH were not directly correlated with the extent of hepatocyte DNA synthesis in individual mice. The IL-6 increase after PH was attenuated in all lipopolysaccharide-hyporesponsive mouse strains studied (e.g., C3H/HeJ, Tlr4 null, Cd14 null, Tlr2,4,9 null, and Tlr2,4-Caspase1 null) and was severely abrogated in Myd88 null mice. Despite attenuated IL-6 levels, Tlr4 null mice showed normal signaling downstream of IL-6 and normal hepatocyte proliferation. In contrast, Myd88 null mice showed severe impairments in signal transducer and activator of transcription 3 phosphorylation and Socs3 induction, but had enhanced and prolonged extracellular signal-related kinase 1 and 2 phosphorylation in the first 6 hours after PH. Unexpectedly, these changes were associated with accelerated initiation of hepatocyte proliferation, as assessed by hepatocyte bromodeoxyuridine incorporation, phospho-histone H3 immunostaining, and cyclin E and A protein expression.

CONCLUSION

TLR-4 signaling contributes to IL-6 activation after PH, but the Tlr4-independent component appears sufficient for ensuring intact signaling downstream of IL-6. The lack of correlation between IL-6 levels and hepatocyte proliferation after PH, and the accelerated start of hepatocyte proliferation in Myd88 null mice despite abrogated cytokine activation, may highlight relevant antiproliferative effects of IL-6 signaling, possibly via Socs3, in the regulation of liver regeneration.

Genetic influences on bone loss in the San Antonio Family Osteoporosis study

The genetic contribution to age-related bone loss is not well understood. We estimated that genes accounted for 25-45% of variation in 5-year change in bone mineral density in men and women. An autosome-wide linkage scan yielded no significant evidence for chromosomal regions implicated in bone loss.

INTRODUCTION

The contribution of genetics to acquisition of peak bone mass is well documented, but little is known about the influence of genes on subsequent bone loss with age. We therefore measured 5-year change in bone mineral density (BMD) in 300 Mexican Americans (>45 years of age) from the San Antonio Family Osteoporosis Study to identify genetic factors influencing bone loss.

METHODS

Annualized change in BMD was calculated from measurements taken 5.5 years apart. Heritability (h(2)) of BMD change was estimated using variance components methods and autosome-wide linkage analysis was carried out using 460 microsatellite markers at a mean 7.6 cM interval density.

RESULTS

Rate of BMD change was heritable at the forearm (h(2) = 0.31, p = 0.021), hip (h(2) = 0.44, p = 0.017), spine (h(2) = 0.42, p = 0.005), but not whole body (h(2) = 0.18, p = 0.123). Covariates associated with rapid bone loss (advanced age, baseline BMD, female sex, low baseline weight, postmenopausal status, and interim weight loss) accounted for 10% to 28% of trait variation. No significant evidence of linkage was observed at any skeletal site.

CONCLUSIONS

This is one of the first studies to report significant heritability of BMD change for weight-bearing and non-weight-bearing bones in an unselected population and the first linkage scan for change in BMD.

Targeting stromal cells for the treatment of platelet-derived growth factor C-induced hepatocellular carcinogenesis

Non-invasive therapies for the treatment of hepatocellular carcinoma (HCC) would be of great benefit to public health. To this end, we have developed a platelet-derived growth factor-C (PDGF-C) transgenic (Tg) mouse model, which mimics many aspects of human liver carcinogenesis. Specifically, overexpression of PDGF-C results in liver fibrosis, which is preceded by activation and proliferation of hepatic stellate cells, and is followed by the development of dysplastic lesions and angiogenesis, and progression to HCCs by 8 months of age. Here, we show that PDGF-C overexpression induces the proliferation of endothelial-like cells that are present in tumors and adjacent non-neoplastic parenchyma. The protein tyrosine kinase inhibitor, imatinib (Gleevec), decreases the proliferation of non-parenchymal cells (NPC) in vitro and in vivo, with concomitant inhibition of Akt. In vivo treatment with imatinib also blocks the expression of CD34 in PDGF-C Tg mice. Decreased NPC proliferation and CD34 expression correlated with lower levels of active ERK1/2 and total levels of PDGF receptor alpha (PDGFRalpha). In summary, the small molecule inhibitor imatinib attenuates stromal cell proliferation in PDGF-C-induced HCC, which coincides with decreased expression of both CD34 and PDGFRalpha, and activated Akt. Our findings suggest that imatinib may be efficacious in the treatment of hepatocarcinogenesis, particularly when neovascularization is present.

Proinflammatory cytokine production in liver regeneration is Myd88-dependent, but independent of Cd14, Tlr2, and Tlr4

TNF and IL-6 are considered to be important to the initiation or priming phase of liver regeneration. However, the signaling pathways that lead to the production of these cytokines after partial hepatectomy (PH) have not been identified. Enteric-derived LPS appears to be important to liver regeneration, possibly by stimulating proinflammatory cytokine production after surgery. To determine whether LPS signaling pathways are involved in the regulation of the proinflammatory cytokines TNF and IL-6 during the priming phase of liver regeneration, we performed PH on mice lacking the TLRs Tlr4 and Tlr2, the LPS coreceptor, Cd14, and Myd88, an adapter protein involved in most TLR and IL-1R pathways. In MyD88 knockout (KO) mice after PH, both liver Tnf mRNA and circulating IL-6 levels were severely depressed compared with heterozygous or wild-type mice. Activation of STAT-3 and three STAT-3 responsive genes, Socs3, Cd14, and serum amyloid A2 were also blocked. In contrast, Tlr4, Tlr2, and Cd14 KO mice showed no deficits in the production of IL-6. Surprisingly, none of these KO mice showed any delay in hepatocyte replication. These data indicate that the LPS receptor TLR4, as well as TLR2 and CD14, do not play roles in regulating cytokine production or DNA replication after PH. In contrast, MyD88-dependent pathways appear to be responsible for TNF, IL-6, and their downstream signaling pathways.

Platelet-derived growth factor C induces liver fibrosis, steatosis, and hepatocellular carcinoma

Members of the platelet-derived growth factor (PDGF) ligand family are known to play important roles in wound healing and fibrotic disease. We show that both transient and stable expression of PDGF-C results in the development of liver fibrosis consisting of the deposition of collagen in a pericellular and perivenular pattern that resembles human alcoholic and nonalcoholic fatty liver disease. Fibrosis in PDGF-C transgenic mice, as demonstrated by staining and hydroxyproline content, is preceded by activation and proliferation of hepatic stellate cells, as shown by collagen, alpha-smooth muscle actin and glial fibrillary acidic protein staining and between 8 and 12 months of age is followed by the development of liver adenomas and hepatocellular carcinomas. The hepatic expression of a number of known profibrotic genes, including type beta1 TGF, PDGF receptors alpha and beta, and tissue inhibitors of matrix metalloproteinases-1 and -2, increased by 4 weeks of age. Increased PDGF receptor alpha and beta protein levels were associated with activation of extracellular regulated kinase-1 and -2 and protein kinase B. At 9 months of age, PDGF-C transgenic mice had enlarged livers associated with increased fibrosis, steatosis, cell dysplasia, and hepatocellular carcinomas. These studies indicate that hepatic expression of PDGF-C induces a number of profibrotic pathways, suggesting that this growth factor may act as an initiator of fibrosis. Moreover, PDGF-C transgenic mice represent a unique model for the study of hepatic fibrosis progressing to tumorigenesis.

Bone mineral density, carotid artery intimal medial thickness, and the vitamin D receptor BsmI polymorphism in Mexican American women

Low bone mineral density (BMD) is a predictor of cardiovascular mortality, suggesting that osteoporosis and cardiovascular disease may share common risk factors. We assessed the relationship between BMD and intimal medial thickening (IMT) of the common carotid artery, a marker of sub-clinical atherosclerosis, in 471 women examined as part of the San Antonio Family Osteoporosis Study, a population-based study of osteoporosis risk conducted in Mexican American families. Because of the documented role of vitamin D metabolism in bone metabolism and its possible role in cardiovascular function, we further evaluated whether allelic variation at the vitamin D receptor locus (VDR) influenced joint variation in BMD and IMT. The association of BMD with IMT depended on age, with low BMD being correlated with high IMT in older women, but with low IMT in younger women [age by IMT interaction effects significant at the spine (P = 0.042), radius ultradistal (P = 0.010), and hip (P = 0.006)]. In all women, the VDR BsmI BB genotype was associated with significantly higher forearm BMD (P = 0.005 for both radius ultradistal and midpoint), higher IMT (P = 0.05), and higher spine BMD in older women (P = 0.06), but not with hip BMD. The association of the VDR genotype with IMT was independent of its association with BMD. Although a functional consequence of the BsmI polymorphism on vitamin D metabolism has not been established, these findings support a possible biological relationship among VDR, bone metabolism, and atherosclerosis. We conclude that VDR polymorphisms may be one of multiple factors influencing the joint risk of atherosclerosis and osteoporosis.

Genes influencing variation in serum osteocalcin concentrations are linked to markers on chromosomes 16q and 20q

Osteocalcin (OC) is an important constituent of bone that is synthesized by osteoblasts. Serum levels of OC have been used as a biochemical marker of bone turnover. To identify the genes influencing variation in serum OC levels, we conducted a genome-wide scan in 429 individuals comprising 10 large multigenerational families. OC levels were measured by immunoassay, and genetic markers were typed at approximately 10-cM intervals across the genome. Quantitative trait linkage was tested using a multipoint analysis based on variance component methodology, adjusting for the effects of age, sex, and oral contraceptive use. Significance levels for linkage were obtained empirically, by Monte Carlo simulation. The heritability of OC levels in this population was 62 +/- 8%. We detected significant evidence for linkage between a quantitative trait locus influencing serum OC levels and markers on chromosome 16q, and suggestive evidence for linkage of OC levels with markers on chromosome 20q. The multipoint lod scores peaked at 3.35 on chromosome 16 and 2.78 on chromosome 20, corresponding to P values of 0.00004 and 0.00017, respectively. A potential candidate gene for bone formation in the linked region on chromosome 20 is CDMP1, which encodes cartilage-derived morphogenetic protein 1. Future studies should evaluate whether variation in CDMP1 or in other genes in the linked regions on chromosomes 16 and 20 influence the rate of bone turnover.

Ductal carcinoma in situ-associated nipple discharge: a clinical marker for locally extensive disease

BACKGROUND

This study evaluates the diagnosis and treatment of women with pathologic nipple discharge caused by ductal carcinoma in situ (DCIS).

METHODS

Women with unilateral spontaneous bloody, serous, or brown nipple discharge who presented between January 1, 1988 and August 1, 1996 were identified by retrospective chart review. Women with nonspontaneous, physiologic discharge were excluded.

RESULTS

Two hundred seventy-seven women with a mean age of 59.5 years (range, 24 to 88 years) underwent duct exploration and biopsy for pathologic discharge, with 43 (15.5%) found to have DCIS. The discharge was bloody in 29, clear in eight, and brown in six women. Seven of 12 (58%) women with an associated breast mass were found to have a microinvasive component with the DCIS. Discharge cytology showed malignant cells in only two of 12 (16%) women examined. A ductogram was performed on 20 women, with filling defects seen in 10, ectasia in 3, narrowing in 4, and normal ducts in 3. The DCIS included 17 (40%) specimens with cribriform pattern, 17 (40%) micropapillary, 8 (18%) comedo, and 2 (2%) solid. Twelve microinvasive cancers were found in combination with DCIS. After duct exploration, 37 (86%) patients were found to have extensive or multifocal DCIS to the margin, or both, with 32 (74%) patients requiring mastectomy to achieve free surgical margins. There was residual disease in 27 of 32 (84%) mastectomy specimens after initial biopsy. Breast conservation was possible in only 11 (26%) women. Forty of 43 (93%) are disease-free with a median follow-up of 37 months.

CONCLUSION

Women presenting with pathologic nipple discharge require duct exploration regardless of cytologic or radiologic findings. When discharge is the result of DCIS, extensiveness of disease in relation to central location and intraductal spread may preclude breast conservation in as many as 27 of 43 (63%) cases.

Lobular carcinoma in situ with microinvasion

Six patients with lobular carcinoma in situ with microinvasion were described in this report. Lobular carcinoma in situ is not known to progress to microinvasive disease. Although this feature is rare, the current under standing that lobular carcinoma in situ is a marker needs to be revised.

Spinal bone density and tooth loss in a cohort of postmenopausal women

Osteoporosis has been suggested to contribute to the edentulous condition. However, studies specifically designed to examine the relationship between tooth loss and osteoporosis are scarce, and reported results have been mixed. This study investigated the correlation between tooth loss and spinal bone density in a nonHispanic white female population. Forty-four subjects were recruited and divided into high and low spinal bone density groups based on whether the bone density was higher or lower than the age-adjusted population mean bone density. Missing teeth and periodontal status in these groups were assessed and analyzed. Tooth loss was not significantly different between subjects with low spinal bone density (4.90 +/- 0.89 teeth) and high spinal bone density (3.81 +/- 0.90 teeth). Tooth loss did not differ after age and periodontal adjustment. However, the loss of attachment levels (relative to the cementoenamel junction) was greater in the low spinal bone density subjects (3.42 +/- 0.30 mm) than in the high spinal bone density subjects (2.37 +/- 0.26 mm) (P < .05). The difference may have resulted from gingival recession (P < .05), because the gingival pocket depths were not significantly different between the two groups. In this study, total tooth loss was not directly associated with systemic bone density. However, periodontal disease was negatively associated with spinal bone density. Whether periodontal disease will ultimately lead to greater tooth loss in low spinal bone density group merits further investigation.

Comparison of histologic diagnosis between stereotactic core needle biopsy and open surgical biopsy

BACKGROUND

This study correlates the histologic findings of stereotactic core needle biopsy (SCNB) with open surgical biopsy (OSB) and identifies which lesions can be treated definitively based only on the SCNB histology.

METHODS

Women who underwent SCNB between July 1, 1993, and January 1, 1969, were identified by retrospective chart review. Mammographic (MGM) lesions found by SCNB to be ductal or lobular hyperplasia with atypia, or carcinoma underwent OSB. When the histologic findings by SCNB were inconsistent with the MGM findings, the lesion also underwent OSB.

RESULTS

799 women underwent SCNB with 96 (12%) of these going on to OSB. MGM findings in the 92 who presented without a palpable mass included microcalcifications (MCS) in 39, mass in 47, MCS and mass in 7, and tissue distortion in 3. One hundred one breast lesions biopsied first by SCNB, then by OSB were correlated histologically. Sensitivity of SCNB is 89%, with a specificity of 94%. Eight-four women (88%) were able to have definitive treatment at time of OSB because of prior SCNB, and 703/799 (88%) of women were spared OSB entirely.

CONCLUSION

SCNB accurately identifies benign breast histology and invasive cancers in women with MGM abnormalities, a distinct advantage over fine needle aspiration cytology. SCNB does not reliably identify women with DCIS and invasion. All women with SCNB diagnosis of ductal or lobular atypia should also undergo OSB.

The effect of an ambulatory internal medicine rotation on students' career choices

PURPOSE

To assess the effect of an ambulatory care experience on medical students' perceptions of internal medicine and their choices of careers (as measured by residency selections).

METHOD

In 1990-91, the 196 third-year students enrolled in the 12-week internal medicine clerkship at the University of Texas Medical School at San Antonio were randomized to a curriculum that included a three-week ambulatory care component or to a traditional, exclusively inpatient curriculum. The ambulatory curriculum included the evaluation of walk-in-patients, exposure to community internists, and a lecture series. The students' perceptions of internal medicine were surveyed before and after the clerkship. Their career choices were determined by their residency selections at graduation. Data analysis employed chi-square tests, t-tests, and logistic regression.

RESULTS

Of the 196 students, 184 (76 in the ambulatory and 108 in the traditional curricula) provided complete data. The ambulatory care students were somewhat more likely to enter an internal medicine residency (odds ratio = 1.49; 95% CI, 0.72 to 3.09) than were the traditional students. The ambulatory care students' perceptions of internal medicine did not change significantly from before to after the clerkship.

CONCLUSION

The ambulatory curriculum had a modest but favorable effect on the students' selections of careers in internal medicine, but was not associated with changes in their perceptions of internal medicine.

Therapy for inflammatory breast cancer: impact of doxorubicin-based therapy

BACKGROUND

Inflammatory breast cancer (IBC) carries an ominous prognosis. Before 1988, women with IBC at our institution were treated with neoadjuvant cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) with or without vincristine and prednisone (CMF/VP). After 1988, women with IBC were treated with cyclophosphamide, doxorubicin, and 5-fluorouracil (FAC). This study compares these two regimens with regard to response and survival.

METHODS

The records of all women presenting between January 1973 and December 1991 with a stage IIIB (T4d, any N, MO) breast cancer with proven dermal lymphatic invasion by tumor cells were reviewed retrospectively.

RESULTS

The study comprised 38 women; 28 received CMF (22 CMF, 6 CMF/VP), and 10 received FAC. The overall response rate to induction chemotherapy in the CMF/VP group was 57% (40% PR, 17% CR), and 100% (60% PR, 40% CR) in the FAC group. The median overall survival for women receiving CMF/VP was 18 months compared with 30 months for women receiving FAC (p = 0.02). The median disease-free survivals for the CMF/VP and FAC groups were 6 and 24 months, respectively (p < 0.001). When comparing responders and nonresponders with CMF/VP induction therapy, the responders had a significantly longer overall median survival (24 versus 10 months) (p < 0.001) and disease-free median survival (8 versus 2 months) (p < 0.001). All of the five patients remaining alive received FAC with 80% (four of five) having a complete response. These four patients subsequently underwent mastectomy and radiation.

CONCLUSION

This study suggests that a doxorubicin-containing chemotherapy regimen improves overall and disease-free median survivals when compared with the previously used CMF combination in the treatment of IBC. A favorable response to induction chemotherapy also appeared to be associated with an improved survival.

Adenocarcinoma of the small intestine: 21-year review of diagnosis, treatment, and prognosis

BACKGROUND

The purpose of this study was to evaluate the tumor characteristics and treatment associated with an improved overall survival in patients with adenocarcinoma of the small intestine.

METHODS

The records of all patients with primary adenocarcinoma of the small bowel seen between January 1971 and December 1991 were reviewed retrospectively. The study comprised 38 patients, 22 (58%) with duodenal tumors, 11 (29%) with jejunal tumors, and five (13%) with ileal tumors.

RESULTS

Although not statistically significant, the patients with duodenal adenocarcinoma lived longer than the patients with jejunal or ileal lesions (p = 0.77). The overall survival was 23% and seemed to correlate best with absence of lymph node metastases (p = 0.04) and pancreaticoduodenectomy for localized duodenal tumors (p = 0.04). The patient's age, duration of symptoms, disease-free interval, tumor location, type of recurrence, and histologic grade did not significantly influence survival.

CONCLUSIONS

The lethality of small-intestinal adenocarcinoma appears to be related to a delay in diagnosis and treatment. When a definitive surgical procedure is performed before lymph node metastases appear, the patient's chance for long-term survival is greatly improved.

The association of obesity and glucose and insulin concentrations with bone density in premenopausal and postmenopausal women

Obese subjects have increased bone density relative to non-obese subjects, yet this relationship is not fully understood. We examined whether alterations in glucose or insulin concentrations might explain the effect of obesity on bone density in 317 women from the San Antonio Heart Study, a population-based study of diabetes. We measured fasting and 2-hour plasma glucose and fasting and 2-hour serum insulin levels. Bone density was assessed by a Hologic dual-photon absorptiometer. Lumbar spine and femoral neck density were positively correlated with body mass index (BMI). Femoral neck density also was positively correlated with fasting insulin level in younger women after adjustment for age (r = .214, P < .01). After further adjustment for BMI, femoral neck density was not significantly correlated with fasting insulin level (P = .08). The magnitude of the estimated femoral neck density difference for a 32.2-microU/mL decrease in fasting insulin level (the difference in insulin concentrations between nondiabetics and diabetics) was 0.13 g/cm2. Adjustment for glucose and insulin concentrations does not explain the association between bone density and obesity.

Impact of legal liability, family wishes, and other "external factors" on physicians' life-support decisions

PURPOSE

The purpose of this study was to determine the impact of external factors on physicians' life-support decisions. "External factors" are those factors that promote the interests of people other than the patient. Examples of external factors include physician legal liability and family wishes about patient care.

SUBJECTS AND METHODS

A nationwide sample consisted of 300 randomly selected physician-members from the American Society of Law and Medicine (ASLM) and 300 from the Society for Critical Care Medicine (SCCM); 179 ASLM physicians (60%) and 165 SCCM physicians (55%) responded. A mailed questionnaire presented three cases, each requiring the physician to make a life-support decision. For each case, the physician chose one of several life-support options and rated the importance to his or her decision of specific "decision factors," including some external factors. We assumed the physician would choose the management option supported by the decision factors that the physician considered most important. For this reason, we used discriminant analysis to identify the factors whose importance ratings best predicted management choices.

RESULTS

In the first case, 46% of ASLM respondents and 55% of SCCM respondents chose to stop the ventilator of a chronically comatose patient with unknown preferences about life support. Thirty-one percent of ASLM and 27% of SCCM respondents chose to continue the ventilator, and 21% of ASLM and 14% of SCCM respondents chose to apply for a judicial decision. Importance ratings for the external factor, physician legal liability, best predicted management choices. In the second case, 95% of ASLM and 94% of SCCM respondents chose to resuscitate a cancer patient at the patient's request; 3% of ASLM and 4% of SCCM respondents chose no resuscitation. Importance ratings for patient preferences best predicted management choices. In the third case, 38% of ASLM and 35% of SCCM respondents honored a stroke patient's previous refusal of tube feedings, but 59% of ASLM and 62% of SCCM respondents authorized tube feedings in order to secure nursing home placement. Importance ratings for patient preferences best predicted management choices in this case. External factors impacted management choices considerably in the first case and more modestly in the second and third cases.

CONCLUSION

External factors impact the life-support decisions of physicians. Physician legal liability may have an especially great impact on these decisions when patients' preferences are not known.

Ethnic differences in hip fracture: a reduced incidence in Mexican Americans

To confirm a previous report of lower risks of hip fracture in Mexican Americans, we calculated the incidence of hip fractures among Hispanics, blacks, and non-Hispanic whites residing in Bexar County, Texas, during 1980. A total of 576 residents with hip fracture not due to severe trauma were identified. The 1980 census data were used to calculate ethnic-specific incidence rates which were age-adjusted using the entire 1980 US population as the standard. Hip fractures were more common among non-Hispanic white women (139 per 100,000; 95% confidence interval (CI) = 124-153) than among Mexican-American (67 per 100,000; 95% CI = 51-82) or black (55 per 100,000; 95% CI = 27-83) women. Thus, Mexican Americans and blacks are relatively protected from hip fractures, and they may benefit less than whites from prophylactic therapies for osteoporosis.

Low risk of vertebral fracture in Mexican American women

Ethnicity is important in assessing risk for osteoporotic fractures, and should be considered in decision-making about the use of prophylactic treatments. Few data are available, however, on fracture risks among Hispanic patients. To assess the risk of vertebral fracture in Mexican Americans, we determined the prevalence of vertebral fracture among 822 patients, aged 15 to 86 years, who underwent spinal roentgenography in a study of low-back pain. After adjusting for age, use of steroids, drug or alcohol abuse, and recent trauma, the odds ratio for Mexican American women compared with non-Hispanic whites was 0.55 (95% confidence interval, 0.32 to 0.95), indicating a substantially lower risk. These results are concordant with earlier data documenting a reduced risk of hip fracture among Mexican American women. Thus, recommendations for prophylactic treatments for osteoporosis may be different for Mexican Americans than for non-Hispanic whites.

Correlates of medication compliance in non-insulin-dependent diabetes mellitus

Maintaining compliance with medications is important in the management of patients with non-insulin-dependent diabetes mellitus. We examined correlates of medication compliance in 77 patients followed up prospectively for 24 weeks. Of the demographic, socioeconomic, and clinical variables examined, only older age and greater education were related to compliance. While statistically significant, the differences observed were small and unlikely to be useful to clinicians. Factors reflecting the process of care, including frequency of appointments, minutes spent with the provider, and patient satisfaction were not related to compliance. Symptoms associated with poor glucose control and fasting glucose levels were also not significantly related. The patient's report of his own compliance, however, was strongly associated with our independent measures of medication taking. We conclude that rather than attempting to predict compliance from sociodemographic characteristics, symptoms, or glucose values, the physician should directly inquire about medication taking in a nonthreatening manner.

Area variation in mortality from diseases amenable to medical intervention: the contribution of differences in morbidity

Several conditions, whose timely and appropriate therapy should decrease case fatality, have been proposed as indicators of medical care quality for the National Health Service. Mortality rates for these diseases vary widely within the UK. To evaluate the contribution of varying incidence rates to these mortality differences, routinely collected morbidity and mortality data for 1974-1978 were analysed for 98 Area Health Authorities (AHAs) in England and Wales. Although differences in morbidity (as measured by hospital discharge and disease registration rates) and socioeconomic factors account for some of the area variation in mortality, significant heterogeneity persists after these factors are taken into account. This finding suggests that morbidity and socioeconomic factors are not the only determinants of mortality variation among areas for these particular diseases. Variation in quality of medical care may account for this result, although regional diagnostic and reporting differences and variation in disease severity among areas must also be considered.

Risk of postmenopausal hip fracture in Mexican American women

To assess the risk of hip fracture in Mexican Americans, the ethnicity of 80 women aged 50 years and over admitted with hip fractures to a Texas hospital was compared with that of age-matched women hospitalized for other reasons. The risk of fracture for Mexican Americans was only 35 per cent that of Whites (95% CI = 19 per cent, 65 per cent). This finding was confirmed in a chart survey performed in a second hospital population. These results suggest that Mexican American women may receive less potential benefit from preventive measures for hip fracture than Whites.

Office techniques to maintain the health of aging patients

The fecal occult blood test is safe and inexpensive; however, diet, medications, desiccation of the sample, and delay in developing the specimen may affect results. If the test is used, six separate samples, two from each of three consecutive bowel movements, should be examined to obtain optimum results. Serum cholesterol need not be assessed routinely in geriatric patients. Dietary restriction of fats is a necessity only in the context of a weight reduction diet.

Combined behavioral and pharmacological treatment of essential hypertension

Fifty-two pharmacologically treated hypertensive patients were randomized to one of four treatment groups: (1) diastolic blood pressure biofeedback, (2) progressive deep muscle relaxation training, (3) self-directed relaxation training, or (4) medication alone. Data collection occurred during baseline, treatment, and 1-year follow-up phases in a laboratory, a medical clinic, and the patient's own home. Patients from all four groups combined showed mean blood pressure reductions of -10.2/-5.5 mm Hg on clinic recordings and -2.4/-.7 mm Hg on home recordings, which were maintained throughout the follow-up period. There were no significant differences among the four groups in terms of blood pressure reduction. Patients given adjunctive behavioral treatment showed significantly larger reductions in medication usage compared to patients treated with medication alone, but there were no significant differences among the three behaviorally treated groups. Patients who showed medication reductions did not show subsequent blood pressure elevation. The results suggest that combined behavioral and pharmacological therapy may be superior to pharmacological therapy alone in the treatment of essential hypertension.

Medication compliance in non-insulin-dependent diabetes: a randomized comparison of chlorpropamide and insulin

Medication compliance may be a problem in the management of patients with diabetes. Some physicians initially treat patients having non-insulin-dependent diabetes with oral sulfonylureas because they fear greater compliance problems with insulin therapy. We compared compliance with insulin and chlorpropamide in patients newly beginning medication for NIDDM. Seventy-seven adults with hyperglycemia despite diet therapy were randomly assigned to chlorpropamide or insulin. Compliance was measured four times over 24 wk. Patients then crossed over to the other medication and were followed for 24 additional weeks. Overall, there were no differences in compliance with the two medications in terms of percent of prescription used, proportion taking at least 80% of prescribed medication, self-report of medication or diet compliance, or protocol dropout rates. However, treatment satisfaction was higher with chlorpropamide, and most patients preferred chlorpropamide to insulin (P less than 0.0001). While such differences in satisfaction may affect long-term compliance, physicians should not assume that their patients will be less compliant with insulin than with oral sulfonylureas.

United Kingdom Heart Disease Prevention Project: 12-year follow-up of risk factors

Ten of the original 24 factories from the United Kingdom Heart Disease Prevention Project were resurveyed in 1983 to assess the long-term (12-year) effects of an education program on diet, smoking, and exercise. These 10 factories had previously been grouped into five pairs matched for size, location, and nature of industry, with one of each pair randomly chosen for intervention. Men in intervention factories were given advice on reduction of cholesterol in diet, stopping smoking, weight reduction, and regular exercise. High-risk workers (13%) received personal counseling in addition to the factory-wide education program. A total of 1,204 workers randomly selected from those still employed in 1978 were surveyed. There were significant differences observed in cigarette consumption, butter use, and several other dietary behaviors; however, the differences were small and insignificant for the proportion smoking and leisure-time exercise. The largest effects were in the high-risk group who had received personal counseling. This education program appears to have some lasting effects on behavior associated with coronary disease risk factors. Similarly designed programs may serve as models for community-wide coronary disease prevention programs.

Traffic accidents and minor tranquilizers: a review

Minor tranquilizers, including the benzodiazepines, have been found to impair driving skills such as hand-eye coordination and reaction time. Several studies have also demonstrated an association between minor tranquilizer use and traffic accidents; however, the association may be due entirely to more frequent alcohol use or to the underlying anxiety found in users of minor tranquilizers. Whichever the case, patients taking minor tranquilizers do have higher accident rates. It is recommended that physicians emphasize the possible risks of driving while using these medicines, particularly if used with alcohol.