Should we perform elective inguinal hernia repair in the elderly?

PURPOSE: Many surgeons are reluctant to offer elective inguinal and femoral hernia repair (IHR) to the elderly due to concerns of increased risk. The authors sought to evaluate the outcomes of elderly patients undergoing IHR compared to the general population. METHODS: We performed a retrospective review of the 2011 NSQIP database evaluating 19,683 patients undergoing IHR. Patients were divided by age into three categories: <65, 65-79 and >80. Logistic regression analysis was used to assess impact of comorbid conditions and type of surgery on outcomes. Patients were analyzed for mortality and complications based on their age and the types of surgery (elective, urgent, emergent, laparoscopic versus open) and comorbid conditions. RESULTS: There were 17,375 male patients (88 %). 92.7 % were elective. 70 % were performed using an open technique. Age distribution was 63.4 % < 65, 26.6 % 65-79, 10 % >80. Mortality was similar across age groups in elective repair. Mortality was increased in emergency repair in all age groups (p < 0.001). Mortality was increased in emergency surgery compared to elective surgery in patients >80 (OR = 57, p < 0.001). Mortality was similar between laparoscopic and open in <65 (OR = 0.96, p = 0.97) and unable to be assessed in other age groups. Dyspnea and COPD predicted higher mortality and complications with emergency surgery in the elderly (age 65-79 OR 15.3 and 14.9, respectively, age >80 OR 56.5 and 14.9, respectively). CONCLUSIONS: Elective inguinal hernia repair carries a similar mortality in the elderly compared to the general population. Emergent IHR carries a very high risk of death in the elderly. The authors recommend considering elective IHR regardless of age.

Type of cottonseed and level of gossypol in diets of lactating dairy cows: effects on lactation performance and plasma gossypol.

Objectives were to determine the effects of feeding whole linted Upland (WUP) and cracked Pima cottonseed (BUPCP) to lactating cows on plasma gossypol concentrations and lactation performance. Holstein cows (n = 813) from three commercial dairies were assigned to one of two diets starting at 13+/-11 d in milk (DIM) for a 170-d experimental period. Cottonseed was included at 10% of the diet dry matter, and treatments consisted of replacing WUP with a 1:2 blend of BUPCP. Blood was collected from all cows at 61 and 91 DIM and from a subset of 56 cows on one dairy at 10, 33, 61, 91, 120, and 152 DIM. Intakes of free gossypol increased 32% in cows receiving the BUPCP diet, and concentrations of total gossypol (TG), as well as the proportion of TG as minus (-) isomer in plasma, were higher for cows fed BUPCP than WUP. Plasma TG increased linearly with increasing DIM, but cows fed the BUPCP, especially multiparous cows, had a higher increase in plasma TG over time. Yields of milk and milk components did not differ between the two treatments, although, yields of milk and milk components were greater in cows with higher plasma TG. Replacement of WUP cottonseed with BUPCP cottonseed increased plasma gossypol, but dry matter intake and yields of milk and milk components were not affected.

Differential inhibition of human CYP3A4 and Candida albicans CYP51 with azole antifungal agents.

The inhibition by azole antifungals of human cytochrome CYP3A4, the major form of drug metabolising enzyme within the liver, was compared with their inhibitory activity against their target enzyme, Candida albicans sterol 14alpha-demethylase (CYP51), following heterologous expression in Saccharomyces cerevisiae. IC(50) values for ketoconazole and itraconazole CYP3A4 inhibition were 0.25 and 0. 2 microM. These values compared with much lower doses required for the complete inhibition of C. albicans CYP51, where IC(50) values of 0.008 and 0.0076 microM were observed for ketoconazole and itraconazole, respectively. Additionally, stereoselective inhibition of CYP3A4 and CYP51 was observed with enantiomers of the azole antifungal compounds diclobutrazol and SCH39304. In both instances, the RR(+) configuration at their asymmetric carbon centres was most active. Interestingly, the SS(-) enantiomeric form of SCH39304 was inactive and failed to bind CYP3A4, as demonstrable by Type II binding spectra.

California ground squirrel body temperature regulation patterns measured in the laboratory and in the natural environment.

Body temperature (Tb) was measured by telemetry in both laboratory maintained and natural environment California ground squirrels, Spermophilus beecheyi. Laboratory animals had a mean diurnal Tb of 37.5 degrees C under conditions of LD 14:10, 20 degrees C and 36.5 degrees C under conditions of LD 10:14, 20 degrees C (P < 0.01). Nocturnal mean Tbs were 37.1 and 35.2 degrees C, respectively (P < 0.05). Mean diurnal Tbs for each animal in the natural environment ranged from 39.3 to 40.1 degrees C (mean = 39.6 degrees C) during both study seasons which included the hot season months of March through August and the cool season months of December through February. Natural environment hot season mean Tb was not significantly different from cool season mean Tb but both mean Tbs were significantly different from the diurnal mean Tbs measured in the laboratory (P < 0.05). California ground squirrels exhibit an open-field stress induced hyperthermia in the laboratory which can be extended for periods up to 6 h. The hyperthermic response is blocked by L-propranolol at a dosage of 15 mg kg-1. Laboratory animals do not habituate to repeated open-field exposures over a five consecutive day period. It is suggested that stress hyperthermia might be a normal component of thermoregulation in some free-living ground squirrels because of the openness of the habitat in which they exist.

Stereoselective interaction of the azole antifungal agent SCH39304 with the cytochrome P-450 monooxygenase system isolated from Cryptococcus neoformans.

We investigated the stereoselective inhibition of growth and ergosterol biosynthesis by SCH39304 in the pathogenic fungus Cryptococcus neoformans obtained from four AIDS patients who failed fluconazole therapy and compared the results to those obtained with a wild-type strain. For all strains, the MICs of the RR isomer were approximately half those of the racemate, with the SS enantiomer showing no inhibitory activity. The 50% inhibitory concentrations for in vitro ergosterol biosynthesis correlated with the MIC data, indicating stereoselective inhibition of their target P-450 enzyme, sterol 14alpha-demethylase, as the cause of this difference. The RR enantiomer produced classical type II spectra on addition to microsomal extracts of the strains, whereas the SS enantiomer showed an absence of binding. Stereo- and regio-specific localization of N-1 substituent groups of SCH39304 within the active site of the enzyme determined the unique discrimination between its two enantiomers, and the inability to bind to sterol 14alpha-demethylase is also true of other P-450 enzymes contained in the microsomal fraction. As previously observed for other antifungal azoles, isolates obtained following failure of fluconazole therapy showed resistance to SCH39304 and its RR enantiomer. This resistance could be associated with an alteration in the sensitivity of ergosterol biosynthesis in vitro. These alterations did not cause any changes allowing the SS enantiomer to bind to the P-450 mediating sterol 14alpha-demethylation.

Differential inhibition of Candida albicans CYP51 with azole antifungal stereoisomers.

Azole antifungal compounds are important in agriculture and in the treatment of mycotic infection. The target enzyme, sterol 14 alpha-demethylase (CYP51), is inhibited through binding of triazole N-4 to the haem of this P450, as a sixth ligand together with the N-1 substituent groups interacting in some way with the apoprotein. Here we use Saccharomyces cerevisiae expression systems for the target enzyme of Candida albicans to investigate binding of enantiomers of the azole antifungal compounds SCH39304 and tetraconazole. A molecular model produced previously provided qualitative explanations for these differences. Interaction of the azole antifungal aromatic group with Phe-233 or -235 may cause the higher activity for (R)-tetraconazole while inactivity of the (SS)-enantiomer of SCH39304 was predicted to result from incompatibility of the hydrophilic sulfonyl moiety when located into the hydrophobic pocket of the active site.

Characterization of Saccharomyces cerevisiae CYP61, sterol delta22-desaturase, and inhibition by azole antifungal agents.

Cytochrome P-45061 (CYP61) was a cytochrome P-450 revealed during the yeast genome project when chromosome XIII was sequenced. Here we report on the properties of this second microsomal P-450 of vegetatively growing yeast. The enzyme kinetics associated with its endogenous role in sterol Delta22-desaturation revealed a Km of 20.4 microM and a Vmax of 2.9nmol/min/nmol CYP61. The affinity of the enzyme for antifungal drugs was characterized to investigate its potential role in determining tolerance to these sterol 14alpha-demethylase (CYP51) inhibitors. Drug binding induced a type II spectral change, which became saturated at equimolar concentrations of azole drug and P-450. Fluconazole exhibited slightly reduced affinity in comparison to ketoconazole as indicated by carbon monoxide displacement. These and Ki determination for fluconazole (0.14 nM) revealed CYP61 to have a similar affinity to azole drugs when compared with data available for CYP51, and the implications for antifungal treatment were considered.

The mutation T315A in Candida albicans sterol 14alpha-demethylase causes reduced enzyme activity and fluconazole resistance through reduced affinity.

Sterol 14alpha-demethylase (P45051) is the target for azole antifungal compounds, and resistance to these drugs and agrochemicals is of significant practical importance. We undertook site-directed mutagenesis of the Candida albicans P45051 heterologously expressed in Saccharomyces cerevisiae to probe a model structure for the enzyme. The change T315A reduced enzyme activity 2-fold as predicted for the removal of the residue that formed a hydrogen bond with the 3-OH of the sterol substrate and helped to locate it in the active site. This alteration perturbed the heme environment, causing an altered reduced carbon monoxide difference spectrum with a maximum at 445 nm. The changes also reduced the affinity of the enzyme for the azole antifungals ketoconazole and fluconazole and after expression induced by galactose caused 4-5-fold azole resistance in transformants of S. cerevisiae. This is the first example of a single base change in the target enzyme conferring resistance to azoles through reduced azole affinity.

Purification and reconstitution of activity of Saccharomyces cerevisiae P450 61, a sterol delta 22-desaturase.

P450 was purified from microsomal fractions of a strain of Saccharomyces cerevisiae which contained detectable P450 despite the disruption of CYP51A1. The P450 had a molecular mass of 58 kDa, similar to P450 51A1, and in a reconstituted assay with rabbit NADPH-P450 reductase and dilauryl phosphotidylcholine exhibited activity for conversion of ergosta-5,7-dienol into ergosterol. N-Terminal amino acid sequencing of the purified protein corresponded to the translated sequence of P450 61 which was recently identified during sequencing of chromosome XIII. This allowed the function of this family of P450 to be identified as sterol delta 22-desaturation in the pathway of ergosterol biosynthesis.

Resistant P45051A1 activity in azole antifungal tolerant Cryptococcus neoformans from AIDS patients.

Azole antifungal compounds are important in the treatment of Cryptococcosis, a major cause of mortality in AIDS patients. The target of the azole drugs is P450 mediated sterol 14 alpha-demethylase. We have investigated the P450 system of Cryptococcus neoformans with respect to azole tolerance observed in clinical isolates which were obtained following the failure of fluconazole therapy. The clinical failure was correlated with in vitro tolerance of azole antifungal when compared to wild-type strains. The microsomal P450 system was typical of yeast and fungi and fluconazole tolerance was not associated with defective sterol biosynthesis. The strains had slightly elevated P450 content and slightly reduced azole levels in the cells, but a clear cause for resistance was the increased level of drug needed to inhibit the sterol 14 alpha-demethylase in vitro.

Mode of action and resistance to azole antifungals associated with the formation of 14 alpha-methylergosta-8,24(28)-dien-3 beta,6 alpha-diol.

Azole antifungal compounds inhibit sterol 14 alpha-demethylase. They are used extensively for the treatment of immunocompromised patients where fungal infection is common and often results in death. Resistance to the compounds is emerging, particularly in fungal pathogens obtained from AIDS patients undergoing prolonged therapy. We show here that cell growth arrest correlates with the accumulation of 14 alpha-methyl-ergosta-8,24(28)-dien-3 beta,6 alpha-diol in a yeast strain with a sterol 14 alpha-demethylase gene disruption, which mimics stringent treatment conditions. Cells can overcome the effect of such a block by a suppressor mutation in sterol delta 5,6 desaturation and acquire azole resistance. Plasmid-based complementation of sterol 14 alpha-demethylase defect does not alter the azole susceptibility of strains containing these suppressor mutations, showing resistance is due entirely to the delta 5.6 desaturase defect.

Resistance to amphotericin B associated with defective sterol delta 8-->7 isomerase in a Cryptococcus neoformans strain from an AIDS patient.

Two Cryptococcus neoformans strains isolated from an AIDS patient were investigated, a pretreatment isolate (CN1) and a second isolate (CN3) following failure of fluconazole and amphotericin B treatment. No difference in fluconazole sensitivity, but relative resistance to amphotericin B was observed for CN3. The sterol composition of CN3 indicated a defect in sterol delta 8-->7 isomerase in this strain and depletion of ergosterol, the major sterol of the CN1.

Benzo(a)pyrene hydroxylase activity in yeast is mediated by P450 other than sterol 14 alpha-demethylase.

Benzo(a)pyrene hydroxylation has been observed in Saccharomyces cerevisiae and the role of sterol 14 alpha-demethylase (CYP51A1) in this activity has been examined by using a strain which contains a gene disruption of CYP51A1. This strain still contained P450 protein(s) with a Soret absorption maximum at 448nm in reduced carbon monoxide difference spectra of the microsomal fraction. On addition of benzo(a)pyrene to this microsomal extract a typical Type I substrate-binding spectrum was obtained and was also observed for the isogenic sister strain containing no CYP51A1 gene disruption. Microsomal extracts of both strains had equivalent activity in the aryl hydrocarbon hydroxylase assay. These results indicate a yeast benzo(a)pyrene hydroxylase activity distinct from sterol 14 alpha-demethylase P450.

Experimental prevention of bitterweed (Hymenoxys odorata) poisoning of sheep.

To examine the effects on bitterweed toxicity of dietary factors known to increase thiol concentrations in the body, 36 lambs were fed one of the following diets (12 lambs/diet) for a minimum of 9 days prior to bitterweed administration: diet 1, 10% crude protein; diet 2, 20% crude protein, 0.5% methionine, 0.5% sodium sulfate, and 1,102 IU of vitamin E/kg; and diet 3, diet 2 with 0.5% ethoxyquin hydrochloride added. Four lambs fed each diet were euthanatized prior to bitterweed administration (initial euthanasia group). Four lambs fed each diet were administered bitterweed (0.68% hymenoxon, air-dried basis) at a rate of 0.25% of live weight for 5 consecutive days. The remaining four lambs on each diet served as unchallenged controls. In the initial euthanasia group, diet 2 increased extracellular blood thiol concentrations (1.12 vs 0.94 mg of SH/d1, P less than 0.10), rumen fluid thiol concentrations (4.46 vs 1.88 mg of SH/d1, P less than 0.05), and liver thiol concentrations (263.6 vs 109.3 micrograms SH/g of wet wt, P less than 0.05), compared with diet 1. Ethoxyquin hydrochloride (diet 3) reduced blood thiol concentrations (0.94 vs 1.12 mg of SH/dl, P less than 0.10) and liver thiol concentrations (151.6 vs 263.6 micrograms of SH/g of wet wt, P less than 0.05), compared with diet 2. Kidney thiols were unaffected by treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Differences in the inhibitory effects of N-(1-n-dodecyl)-heterocycles on the 2,3-oxidosqualene lanosterol-cyclase of rat liver and yeast.

The ability of thirteen N-(1-n-dodecyl)-heterocyclic compounds and one N-(1-n-fluoroalkyl)-heterocyclic compound to inhibit the 2,3-oxidosqualene lanosterol-cyclase of rat liver and yeast has been tested. Eight of the N-(1-n-dodecyl)-heterocycles inhibited the rat liver enzyme well but none inhibited the yeast enzyme at 100 microM concentrations. The N-(1-fluoroalkyl)-heterocycle inhibited the rat liver enzyme mildly but did not inhibit the yeast enzyme at 100 microM concentration. It is evident that the rat liver and yeast cyclases are different; the possible nature of these differences is discussed.

Effect of experimental infection with ovine ureaplasma upon the development of uroliths in feedlot lambs.

Urinary calculi development in grain-fed lambs is a cause of serious economic loss to sheep producers in the USA. Rations containing sorghum grain and cottonseed meal, particularly, are calculogenic especially in those cases in which the calcium and phosphorus ratio is not balanced. The chemical composition of calculi taken from lambs is most often magnesium ammonium phosphate. Ureaplasmas have been isolated from the urinary tract of sheep with urinary calculi. These isolates, as well as certain other isolates of ovine ureaplasma, produce a sediment in aged cultures that is composed primarily of magnesium ammonium phosphate. In order to determine the relationship of ureaplasmal infections to the formation of calculi in the urinary tract, four treatment groups were established, comprising uninoculated-balanced ration, uninoculated-calculogenic ration, inoculated-balanced ration, and inoculated-calculogenic ration. As signs of calculosis developed, the wethers were necropsied and calculi collected and weighed. Also, culture material was obtained from four sites in the urinary tract and urine was collected for examination. A significant difference appeared in the number of lambs developing calculi between the calculogenic and noncalculogenic rations. No significant difference was evident in the total number of cases of urinary calculi in the inoculated compared with the uninoculated group. However, a very large difference in the total weight of calculi (15.4 g) was observed between the inoculated and uninoculated groups. Although the correct formulation of the ration is of prime importance in preventing urinary calculi formation in sheep, it is possible that ureaplasmal infections may influence the total amount of calculi produced and perhaps the physical characteristics of the calculi crystals.

Effects of bitterweed (Hymenoxys odorata) on voluntary feed intake and serum constituents of sheep.

Effects of daily dosing with bitterweed (Hymenoxys odorata) on voluntary feed consumption and concentrations of serum constituents were determined in 2 experiments, using 12 lambs each. Feed intake decreased linearly as the bitterweed dose increased. Serum total protein and albumin decreased and urea nitrogen, creatinine, and total bilirubin increased with the increasing bitterweed dose. Serum lactic dehydrogenase, aspartate transaminase, and creatine kinase activities increased at the highest bitterweed dose (0.264% of live body weight/day, air-dry basis). Depression in voluntary feed intake was more sensitive to the bitterweed dose than were serum constituents. This dose-related decrease in ad libitum feed intake provides a useful and less expensive short-term assay for assessing treatments for reducing bitterweed toxicosis, compared with the customary LD50 tests.