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Biomedical subjects

J Hendricks

Publications and source records attributed to J Hendricks.

At least 19 recordsLinked to original sources
PubMed1992

Prospective, randomized trial of inpatient vs. outpatient bowel preparation for elective colorectal surgery.

A prospective, randomized trial of inpatient vs. outpatient bowel preparation for elective colorectal surgery was performed in 100 consecutive patients. Bowel preparation was standardized for both groups and consisted of 4 liters of Colyte (Reed & Carnrick, Piscataway, NJ) and oral neomycin and Flagyl (G. D. Searle & Co., Skokie, IL) the day before surgery. Patients were randomized into four subcategories: ileocolostomy, colocolostomy, abdominal perineal resection, and other. Tap water enemas were administered on the morning of surgery to ensure and adequate mechanical preparation. Ninety-six percent of the inpatient group and 97 percent of the outpatient group were able to drink three-fourths or more of the oral lavage preparation (P = 0.789, Fisher's exact text). A mean of 2.26 tap water enemas was required to achieve clear returns for the inpatient group, compared with 2.28 tap water enemas for the outpatient group (P = 0.221, Fisher's exact test). The adequacy of the bowel preparation as graded by the primary surgeon was good (84 percent), fair (12 percent), and poor (4 percent) in the outpatient group (P = 0.673, Fisher's exact test). Wound infection developed in 4 percent of the inpatient group and 4 percent of the outpatient group (P = 1.0, Fisher's exact test). Anastomotic leak of intra-abdominal abscess was seen in one patient in each group (P = 1.0, Fisher's exact test). We conclude that outpatient bowel preparation is as effective as inpatient bowel preparation for elective colorectal surgery and offers the advantage of cost savings and shorter hospitalization.

Adult↗
PubMed1992

Anticarcinogenesis in fish.

Rainbow trout respond to a range of natural and synthetic dietary tumor modulators. Observed modulations of final tumor incidence include inhibition, promotion and cocarcinogenesis, depending on modulator, carcinogen, target organ, and relative order of carcinogen and modulator exposure. Despite several obvious limitations (e.g. lung, colon, mammary gland, bladder are not available as target organs), the trout model possesses several important features that have made it valuable for tumor modulation studies. (1) The comparative advantage. Since rodents are not perfect human surrogates, studies with alternative vertebrates such as trout have provided important comparative mechanism information for confident extrapolation of animal studies to humans. For example, beta-naphthoflavone appears to inhibit aflatoxin B1 hepatocarcinogenicity by species-independent mechanisms that readily extrapolate to humans. By contrast other modulators, including butylated hydroxyanisole, inhibit aflatoxin B1 hepatocarcinogenesis in rats by an enabling mechanism shown to be absent in trout, namely the induction of an aflatoxin B1-specific glutathione S-transferase isozyme. Interestingly, evidence is presently lacking that this determinant mechanism would be operative in humans. (2) The sensitivity advantage. Trout sensitivity and small body size at exposure have permitted tumor studies with carcinogens and HPLC-purified anticarcinogen intermediates too scarce to study in rodents. (3) The low cost advantage. The very low cost of trout tumor studies has enabled statistically challenging issues in molecular dosimetry, dose-response, and risk-benefit analysis to be addressed using as many as 9600 animals per tumor study at modest budget. In particular, these designs provide modulator-mediated alterations in precisely determined carcinogen TD50 values, rather than changes in simple tumor incidence, to quantify more rigorously modulator potencies for tumor inhibition or promotion as a function of dietary concentrations.

Animals↗
PubMed1992

What are the contraindications for laparoscopic cholecystectomy?

Acute cholecystitis, morbid obesity, and previous upper abdominal surgery have been reported as relative contraindications to laparoscopic cholecystectomy. An analysis of 706 laparoscopic cholecystectomies performed at our institution was undertaken to determine if these relative contraindications led to increased morbidity, an increased rate of conversion to the open technique, or longer operating time. One hundred ninety-seven patients demonstrated one or more relative contraindications to laparoscopic cholecystectomy. Morbidity was not increased in patients with these risk factors, but conversion to open cholecystectomy was required in a greater percentage of patients with acute cholecystitis. We favor an attempt at laparoscopic cholecystectomy in patients with these risk factors; however, they should be counseled as to the increased risk of conversion to open cholecystectomy in the presence of acute cholecystitis.

Abdomen↗
PubMed1992

Generations and the generation of theory in social gerontology.

The process of theorizing, creating theoretical explanations, and disseminating theoretical perspectives is most frequently discussed in terms of disembodied ideas. A more insightful rendering of how theory is used in the sociology of aging literature would attend to the real individuals who promulgate the ideas. Looking at theorizing as a career-related activity engaged in by scholars who are prone to the same demographic imperatives as other human beings is a way of shedding more light on the many uses of theory. The concept of theoretical generations is utilized as a means of accounting for the succession of models and explanatory frameworks.

Aged↗
PubMed1992

Toward a political and moral economy of aging: an alternative perspective.

A conceptual framework for empowerment of the elderly is proposed, using variations on Gramsci's hegemony and Thompson's moral economy to complement recent political economic and social psychological theories. The political economy and social psychology of aging highlight structural constraints and actors' reactions without articulating a model for empowerment. Gramsci's idea of hegemony as new moral and philosophical leadership calls for principles of social and economic organization deserving assent because they maximize people's chances for a decent life at all ages. Hegemony, as normalizing dominance, reveals ways in which the elderly may be disempowered as well as possibilities for intervention. Underlying diverse forms of hegemony are economic arrangements and an array of cultural norms. In contrast to Thompson, the authors argue that norms implicit in moral economy vary with changes in social context. In the process, two ideal types of moral economy are elaborated, grounded in exchange value and use value, respectively. Empowerment may be found through a moral economy grounded in use value appropriate to advanced industrial society that is consonant with Gramsci's new hegemony. Implications for health and income maintenance policies are explored.

Aged↗
PubMed1991

Expression of ras genes in rainbow trout liver.

Members of the ras gene family have been studied in a variety of species. Two ras genes expressed in the normal liver of rainbow trout, ras-1 and ras-2, as well as a portion of a genomic ras-1 allele, are described for the first time in this report. Over 500 bp of trout ras-1 and at least 300 bp of trout ras-2 genes expressed in normal liver have been sequenced; DNA homology to the human ras genes ranges from 76.8% to 87.1%. The base changes resulting from over 400 million years of evolutionary divergence between the species were primarily silent, with few changes in protein sequence. The partial DNA sequence of the genomic ras-1 allele has 86.8% homology to the first two exons of human c-Ha-ras, and its intron has several conserved sequences characteristic of vertebrate intron-exon junctions. However, the predicted amino acid sequence of trout ras-1 differs at only one of the first 172 amino acid residues from human c-Ki-ras with the alternate exon 4b. Since trout ras-1 differs at 17 and 18 residues from the human c-N-ras and c-Ha-ras proteins, respectively, over this region, we conclude that trout ras-1 is a c-Ki-ras gene. The highly conserved nature of this gene suggests that the ras p21 protein has identical functions in normal and neoplastic cells among higher and lower vertebrates.

Animals↗
PubMed1991

Analysis of ras gene mutations in rainbow trout liver tumors initiated by aflatoxin B1.

The suspect human hepatocarcinogen aflatoxin B1 (AFB1) is a well-known potent initiator of hepatic tumors in rainbow trout (Oncorhynchus mykiss). Both hepatocellular carcinomas and mixed hepatocellular/cholangiocellular carcinomas are induced by AFB1 in trout, with the mixed form predominating. We previously isolated two c-ras genes from trout liver cDNA, and in the present study we analyzed DNA from 14 AFB1-induced trout liver tumors for point mutations in exon 1 of both genes. Using the polymerase chain reaction (PCR) and oligonucleotide hybridization methods, a high proportion (10/14) of the AFB1-initiated tumor DNAs showed evidence of activating point mutations in the trout c-Ki-ras gene. Of the 10 mutant ras genotypes, seven were codon 12 GGA----GTA transversions, two were codon 13 GGT----GTT transversions, and one was codon 12 GGA----AGA transition. Nucleotide sequence analysis of cloned PCR products from four of these tumor DNAs provided definitive evidence for two codon 12 GGA----GTA mutations, one codon 12 GGA----AGA mutation, and one codon 13 GGT----GTT mutation, in complete agreement with the oligonucleotide hybridization results. No mutations were detected in exon 1 of a second trout ras gene also expressed in liver, nor in DNA from control livers. This is the first report of experimentally induced ras gene point mutations in a lower vertebrate fish model. The results indicate that the hepatocarcinogen AFB1 induces c-Ki-ras gene mutations in trout similar to those in rat liver tumors.

Adenoma, Bile Duct↗
PubMed1991

Laparoscopic cholecystectomy: a multicenter study.

Laparoscopic cholecystectomy has been developed as an alternative to open cholecystectomy for the treatment of symptomatic cholelithiasis. A collaborative study of 261 patients undergoing laparoscopic cholecystectomy at three Texas institutions was performed to determine the effectiveness and safety of this technique. There were 65 males and 196 females with a mean age of 49 years (range 17-94 years). Acute cholecystitis was present in 38 patients and chronic cholecystitis in 223 patients. Mean length of surgery was 80 minutes (20 min to 4 hr). Fifteen patients were converted to the open technique intraoperatively due to bleeding, adhesions, or difficulty of dissection. There were no perioperative deaths and morbidity was 3% including urinary retention, small bowel obstruction, arrhythmia, wound infection, and bile leakage. There were no common duct injuries. Hospitalization ranged from outpatient surgery to 7 postoperative days with a mean of 1.2 days. We conclude that laparoscopic cholecystectomy can be performed safely and with low morbidity and offers shorter hospitalization and postoperative recovery.

Adolescent↗
PubMed1990

[Regeneration of bone following thermal injury].

In an animal experiment we could prove, that a spontaneous regeneration of periosteum on thermally injured bone is not to be seen within three month, when the bone is covered by soft tissue only. Using a periosteal flap to cover a burned bone, regeneration could be observed from the endosteum and the periosteum alike. After making the bone with a fluorescent labels, paths and velocity of bony regeneration could be defined.

Animals↗
PubMed1989

The effect of intravenous nutrition on muscle mass and exercise capacity in perioperative patients.

This study was undertaken to compare the efficacy of four different types of perioperative intravenous nutritional support. Fifty-five patients undergoing routine major surgery were studied. They were prospectively assigned to one of four study groups. Group 1 received formal total parenteral nutrition (90 g amino acids, 3,000 calories as glucose, per day); Group 2, 100 g glucose per day; Group 3, 90 g amino acids per day; and Group 4, peripheral parenteral nutrition (90 g amino acids plus 1,600 calories, 60 percent as fat per day). Group 1 was maintained on therapy for 3 weeks and the other groups for 8 days. Nitrogen balance, maintenance of body cell mass, serum albumin levels, and maintenance of exercise capacity were measured. Patients receiving peripheral parenteral nutrition maintained their nutritional parameters, as did those receiving total parenteral nutrition. These infusions were both markedly superior to those receiving glucose alone or those receiving amino acids alone. Nitrogen balance was not correlated with maintenance of function, but maintenance of body cell mass was correlated with maintenance of exercise capacity (r = 0.66, p less than or equal to 0.01). We conclude that perioperative peripheral parenteral nutrition, in contradistinction to hypocaloric infusions of glucose or amino acids, is capable of maintaining postoperative muscle mass and function close to preoperative levels after major surgery, and in situations of relatively mild surgical stress, approaches the efficacy of total parenteral nutrition in this regard. A significant correlation exists between changes in body cell mass determined from isotope dilution and changes in the exercise capacity of large muscle masses.

Adult↗
PubMed1988

Social dimensions of mental illness among rural elderly populations.

Despite growing concern with rural elderly populations, little attention has focused on their mental health, ways it may correlate with physical health, or how rural mental health patterns compare to urban. Popular wisdom contends that elderly people in general, and rural elderly persons in particular, are at increased risk for mental illness. This article examines these questions. A review of available literature suggests that elderly people may be at only slightly greater risk of mental illness than the population at large, though there are some indications that rates of depression may be somewhat higher among the elderly population. Much of this same literature implies that objective environmental conditions play a significant role in the incidence of depression. Analysis of data gathered in a statewide random poll (N = 743) indicates that while physical health tends to be poorer among rural populations, when health is held constant there is actually an inverse relationship between age and depression. Therefore, rural elderly persons are no more likely to be depressed than their urban counterparts despite harsher living conditions. Both conceptual and policy implications are discussed.

Adolescent↗
PubMed1987

Idiopathic hemorrhagic pericardial effusion with organized thrombi in a dog.

A dog was examined because of cardiac tamponade secondary to pericardial effusion. Masses adjacent to the right atrial and ventricular walls were revealed by echocardiography. Pericardectomy and biopsies of the masses established the diagnosis of idiopathic hemorrhagic pericardial effusion with organized thrombi. The dog was healthy 3 months after surgery. These organized thrombi mimicked cardiac neoplasia echocardiographically, and such a possibility should be included in the list of differential diagnoses of cardiac masses.

Animals↗
PubMed1987

Metabolism and DNA-binding in vivo of aflatoxin B1 in medaka (Oryzias latipes).

1. The medaka (Oryzias latipes), a small aquarium fish, was shown to possess the capacity to rapidly activate AFB1 in vivo at 25 degrees C to intermediates that bind to DNA. 2. The dose-response for in vivo AFB1-DNA binding was linear over the range 70-550 micrograms AFB1/kg body weight. 3. Maximum binding occurred within the first 24 hr after i.p. injection of [3H]AFB1, followed by a rapid loss of adducts. 4. Aflatoxicol (AFL) and unreacted AFB1 were found by HPLC analysis to be the major products excreted into water after AFB1 exposure, with excretion of AFL as early as 2 min after AFB1 injection. 5. These studies show that medaka possess enzymatic systems similar to rainbow trout (Salmo gairdneri) for biotransformation of AFB1 to the epoxide and to other phase I and phase II metabolites.

Aflatoxin B1↗
PubMed1987

Initiation, promotion, and inhibition of carcinogenesis in rainbow trout.

The identification of etiological agents in feral fish neoplasia epizootics has been hampered in part by the lack of suitable fish models, and complicated by the likely existence of environmental agents which can act to stimulate or reduce population responses to genotoxin insult. The response of fish to tumor inhibitors and promoters, and the underlying mechanisms of modulation, have been studied in the rainbow trout model. Dietary treatment of trout with the compounds indole-3-carbinol (I3C), beta-naphthoflavone (BNF), or the polychlorinated biphenyl (PCB) complex Aroclor 1254, before and during exposure to aflatoxin B1 (AFB1), was shown to reduce the final incidence of hepatocellular carcinoma after 12 months, compared to fish receiving AFB1 only. By contrast, treatment of trout with BNF or I3C following AFB1 initiation led to a significant enhancement of ultimate tumor response. Similarly, simultaneous treatment of trout with PCB and the carcinogen N-nitrosodiethylamine led to syncarcinogenic enhancement, rather than inhibition, of tumor response. Mechanisms of inhibition of AFB1 carcinogenesis by PCB, BNF, and I3C were investigated. PCB and BNF, but not I3C, are known to be strong inducers of trout cytochrome P448 and associated activities. Dietary induction by BNF or PCB was shown to be accompanied in isolated hepatocytes by considerably altered AFB1 metabolism, and by significantly reduced rates of DNA adduct formation for all three agents. All agents differentially altered in vivo AFB1 pharmacokinetics, enhanced bile elimination of AFB1 as the aflatoxicol-M1 glucuronide, and significantly reduced peak levels of liver DNA adduct formation. No effects were seen on repair of AFB1-DNA adducts, which was very slow in trout.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1979

Attitudes of women and men physicians.

Attitudinal data obtained from interviewing random samples of women and men physicians in metropolitan Detroit indicated that women were generally more liberal and egalitarian than men. Older women were more liberal/egalitarian than older men while younger men were closer in attitudes to younger women. Within specialities, women and men physicians frequently held similar attitudinal scores; however, controlling for age, sex accounted for more variation than did specialty. A weighted combination of variables which together most significantly discriminated between age and sex subgroups pointed to a sensitivity dimension. This was stronger in the women; yet men demonstrating a similar sensitivity were found in almost every age and specialty grouping. Although younger men physicians are less conservative than older men physicians, both younger and older women physicians demonstrated strong liberalism/egalitarianism.

Adult↗
PubMed1976

Interaction of concanavalin A with rabbit thymocyte plasma membranes. Distinction between low affinity assoication and positively cooperative binding mediated by a specific glycoprotein.

1. We have analyzed the interaction of the mitogenic lectin, concanavalin A, with purified plasma membranes isolated from rabbit thymocytes. 2. Scatchard analyses show that in native membranes binding is positively cooperative at low concanavalin A concentrations and non-interacting at high lectin levels. 3. In contrast, membranes treated with 0.0064 M glutaraldehyde exhibit diphasic Scatchard plots, indicating the presence of high- and low-affinity binding sites. The high-affinity zone corresponds to the region of positive cooperativity in native membranes. 4. The number of high-affinity binding sites per cell-equivalent corresponds approximately to the number of glycoprotein (mol. wt. 55000) molecules (1-10(6)/cell), but account for less than 25% of the total lectin binding. 5. Treatment of membranes with 0.0064 M glutaraldehyde selectively crosslinks the glycoprotein (mol. wt. 55000) and its multimers, correlating directly with the modifications of concanavalin A-binding. 6. We conclude that high-affinity binding of concanavalin A to thymocyte membranes is a cooperative process mediated by the glycoprotein (mol. wt. 55000). We further conclude that the bulk of concanavalin A binding is through low-affinity associations, not involving specific membrane macromolecules.

Animals↗
PubMed1975

Concanavalin A-reactive protein of rabbit thymocyte plasma membranes: analysis by crossed immune electrophoresis and sodium dodecylsulfate/polyacrylamide gel electrophoresis.

1. Thymocyte plasma membrane extracts, prepared with the non-ionic detergent Triton X-100, show 10 major protein components upon sodium dodecysulfate/polyacrylamide gel electrophoresis and at least 11 immunologic components upon crossed immune electrophoresis. 2. Concanavalin A reactive membrane proteins have been identified using crossed immune electrophoresis with receptor-ligand interaction. 3. These proteins are absorbed from Triton X-100-solubilized membranes onto immobilized concanavalin A. They are eluted in stepwise fashion, using increasing concentrations of alpha-methyl-d-glucoside, between 0.0004 M and 0.1 M. The predominant proteins eluted in each step are components with high electrophoretic mobility in crossed immune electrophoresis and are identical with a glycosylated component in sodium dodecysulfate/polyacrylamide gel electrophoresis with molecular weight of 55 000. 4. This component forms multimers in the presence of Triton X-100 which are not totally dissociated in sodium dodecylsulfate. 5. Neuramidase treatment followed by crossed immune electrophoresis of total plasma membrane isolates, as well as the purified glycoprotein fraction, indicates that the concanavalin A-reactive proteins are sialoglycoproteins. 6. Sodium dodecylsulfate component 5.1 comprises at least two different populations of glycoproteins (6 and 9) in crossed immune electrophoresis, one of which exclusively exhibits heterogenous carbohydrate antigenic sites (component 9). 7. Present data, taken together with previously published experiments, indicate that concanavalin A binding to intact thymocytes induces an increased turnover and release of the receptor protein(s).

Animals↗