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Biomedical subjects

C E Marshall

Publications and source records attributed to C E Marshall.

At least 19 recordsLinked to original sources
PubMed2001

Attenuation of premature estrous behavior in postpartum beef cows synchronized to estrus using GnRH and PGF2alpha.

The efficacy of GnRH and PGF2alpha (7-day injection interval) for estrus synchronization is diminished by estrous expression before PGF2alpha (premature estrus; PE). Effects of modifications to GnRH-PGF2alpha protocols on the incidence of PE and other indicators of reproductive performance were evaluated. In Experiment 1, Angus-based crossbred cows (n=51) received 25 mg of PGF2alpha i.m. on Day 0. Animals were randomly assigned by parity and interval postpartum to receive GnRH 100 microg i.m. on either Day -7 or Day -6. Estrous detection and AI were conducted from Day -3 to Day 5. Treatment had no effect on the incidence of PE, estrous response, conception rate per AI or synchronized pregnancy rate (6- vs. 7-day interval; 8 vs. 15%; 92 vs. 93%; 77 vs. 76%; 71 vs. 70%, respectively). In Experiment 2, Angus cows (n=150) received GnRH 100 microg i.m. on Day -7 and 25 mg PGF2alpha i.m. on Day 0. Animals were randomly assigned by parity, interval postpartum, and body condition score to receive either no further treatment (Control) or 0.5 mg melengestrol acetate/hd/d from Day -7 to Day -1 (MGA). Estrous detection and AI were conducted from Day -2 to Day 7. Fewer (P < 0.05) MGA-treated cows were detected in PE (0%) compared to controls (7%). Treatment had no effect on estrous response or synchronized pregnancy rates (Control vs. MGA; 78 vs. 84%; 52 vs. 60%, respectively). Conception rate per AI of cows > or = 60 days postpartum were not affected by treatment (Control vs. MGA; 79 vs. 73%) however, control cows < 60 days postpartum tended (P < 0.10) to have lower conception rates per AI (39%) than did their MGA-treated counterparts (69%). In summary, 6- and 7-day GnRH-PGF2alpha injection intervals resulted in similar synchronized reproductive performance. Inclusion of MGA feeding between GnRH and PGF2alpha injections eliminated the occurrence of premature estrus and improved conception rate per AI of late-calving cows.

Animals↗
PubMed2001

Incidence of premature estrus in lactating dairy cows and conception rates to standing estrus or fixed-time inseminations after synchronization using GnRH and PGF(2alpha).

Fixed-time AI (TAI) after GnRH-PGF(2alpha)-GnRH treatment is a method to achieve pregnancies in dairy herds without estrous detection. However, cows that fail to respond to the initial GnRH may have compromised TAI conception rates due to asynchronous ovarian response. This study documented the percentage of GnRH-treated Holstein cows (n=345) in two herds that displayed estrus at an inopportune time for optimum TAI conception rate (< or =48h post-PGF(2alpha); premature estrus (PE)) and compared conception rates of two TAI protocols in cows that did not display PE. At biweekly herd health exams, cows diagnosed as not pregnant to a previous AI and cows >80 days postpartum with no AI were treated with 100 microg GnRH (day -7) and 25mg PGF(2alpha) (day 0). Cows detected in PE by twice-daily visual observation from day -7 to day 2 were bred by AI 8-12h later. Cows not detected in PE were randomly assigned by parity, body condition score, and postpartum interval to receive either: (1) 100microg GnRH at 48h after PGF(2alpha) and TAI 16 to 18h later (Ovsynch); or (2) TAI at 72h post-PGF(2alpha) and a concurrent 100 microg GnRH injection to those cows not detected in estrus between 48 and 72h post-PGF(2alpha) (modified Ovsynch (MOV)). All hormone injections were im. Twenty percent (68/345) of the cows were detected in estrus before 48 after PGF(2alpha), of which 5% (17/345) were detected in estrus before PGF(2alpha) (< or =day 0). Herd influenced the percentage of cows in the PE group (herd A versus herd B; 25% versus 14%; P<0.05). Conception rates were not affected by treatment (PE versus Ovsynch versus MOV; 32% (21/65) versus 30% (37/125) versus 32% (47/145); P>0.10). However, within MOV-treated cows, conception rates were greater (P<0.05) in cows detected in estrus (46% (23/50)) compared with cows not detected in estrus (25% (24/95)). In conclusion, 20% of GnRH-treated cows displayed PE and necessitates estrous detection during this period if maximal pregnancy rates are to be achieved. Although additional estrous detection is required compared to Ovsynch, reduced cow handling and hormone usage, efficient use of expensive semen through greater conception rates in cows detected in estrus, and comparable TAI conception rates, suggests the MOV protocol may be a cost effective alternative to Ovsynch in many dairy herd reproductive management programs.

Animals↗
PubMed2001

Seminal plasma addition attenuates the dilution effect in bovine sperm.

Dilution of semen to low cell numbers/dose can result in a bull-dependent reduction in the post-thaw viability of cryopreserved bovine spermatozoa. It is possible that essential seminal plasma components are lacking at the greater dilution rates, thereby contributing to the deleterious effects of semen dilution. Ejaculates of 6 Holstein bulls were diluted to 120 x 10(6) sperm/mL in an egg yolk citrate extender (EYC). Split samples were further diluted to 80, 40, 20 and 4 x 10(6) sperm/mL in EYC extender with (+SP) and without (-SP) the addition of frozen/thawed seminal plasma previously obtained from a vasectomized bull. Serial dilutions for the +SP treatments were calculated and performed such that each dilution contained a volume of seminal plasma equal to the original 120 x 10(6) sperm/mL dilution. Samples were then loaded into 0.5-mL French straws yielding final sperm concentrations of 30, 20, 10, 5 and 1 x 10(6)/dose. Straws from each dilution were analyzed using 2 stain combinations: the sperm viability stain, SYBR-14 and propidium iodide (PI); or the mitochondrial-specific, membrane potential-dependent stain JC-1 along with PI. Split-plot analysis of variance indicated that within bulls, there were greater proportions of viable spermatozoa in aliquots containing added seminal plasma than in aliquots without added seminal plasma (P < 0.05). Contrast analyses showed that sperm viability significantly decreased as sperm concentration decreased in the -SP samples. Although the dilution effect was also observed in the +SP samples, the magnitude of the effect was less than in the -SP samples. At most sperm concentrations, the proportions of spermatozoa that stained with JC-1 were correlated (r > 0.84; P < 0.05) with the percentages of SYBR- 14 stained spermatozoa. Furthermore, the proportions of JC-1-stained spermatozoa were greater in the +SP aliquots than in the -SP samples at a concentration of 10 x 10(6) sperm/0.5 mL. These results suggest that the addition of seminal plasma can be beneficial to sperm viability when semen is diluted to low cell numbers/dose.

Animals↗
PubMed2001

The Positively Aging teaching materials improve middle school students' images of older people.

PURPOSE: The Positively Aging program is an innovative set of interdisciplinary teaching materials that uses examples from geriatrics and gerontology to teach sixth through eighth grade curricular elements. The purpose of this study was to determine if use of the Positively Aging teaching materials by regular classroom teachers could change middle school students' images of elders. DESIGN AND METHODS: At the beginning of the 1998-1999 school year, students at two San Antonio, Texas, middle schools were asked to draw a typical older person. These drawings were coded as positive, neutral, or negative portrayals of elders. One school then used the Positively Aging materials as part of the curriculum; the other school served as the control. Second drawings were obtained from the students at the end of the school year and compared to those from baseline. RESULTS: Both drawings were completed by 60% of students at the intervention school and 55% of students at the control school. Of the 782 paired drawings from the intervention school, 34% were more positive at Time 2 compared to 25% of 591 paired drawings from the control school (chi2 = 13.9, p < .001). In addition, only 20% of the second drawings from the intervention school were more negative than the first drawing compared to 27% from the control school (chi2 = 11.3, p < .001). Using a generalized logit model, we adjusted for each student's baseline drawing (positive-neutral-negative), grade level, gender, ethnic group, and socioeconomic status. After adjustment, students in the intervention school were more likely to draw positive (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.13, 1.94) or positive and neutral images (OR 1.58, 95% CI 1.21, 2.19) at follow-up compared to the control school. IMPLICATIONS: This controlled study demonstrated that use of the Positively Aging teaching materials and activities moved middle school students toward a more positive view of elders. Interdisciplinary teaching materials based on geriatrics and gerontology can be successfully developed and tested in public school systems to affect attitudes about aging.

Adolescent↗
PubMed2001

Effect of GnRH pretreatment on reproductive performance of postpartum suckled beef cows following synchronization of estrus using GnRH and PGF2alpha.

The effect of GnRH pretreatment on estrus detection rate, precision of estrus, and reproductive performance of postpartum beef cows synchronized to estrus using GnRH and PGF2alpha was evaluated. In Exp. 1, Angus cows (n = 87) were randomly assigned by parity, postpartum interval, and body condition score (BCS) to receive either 1) GnRH on d -7 and PGF2alpha on d 0 (GP) or 2) the GP treatment and an additional injection of GnRH on d -16 (GGP). Estrus detection and AI were conducted twice daily from d -3 to d 3. At 72 h after PGF2alpha, all animals not previously detected in estrus were bred by AI and received a concurrent injection of GnRH (TAI). Synchronized pregnancy rates were numerically increased (P = 0.15) in cows treated with GGP (55%) compared with those on the GP treatment (44%). In Exp. 2, 1,276 spring-calving, suckled beef cows in nine herds were randomized to treatments as described for Exp. 1, except that the initial GnRH injection for the GGP treatment was administered on d -14. Herd affected all indicators of reproductive performance (P < 0.05). The percentage of animals detected in estrus prematurely (d -3 to d 0; 7%) was not affected by treatment. Estrus response rate was influenced by postpartum interval (< 60 vs > or = 60; 61 vs 73%; P < 0.01) and a three-way interaction of parity, BCS, and treatment (P < 0.01). Within animals with a BCS > or = 5.5, the GGP treatment tended to increase the detection of estrus in primiparous cows (GP vs GGP; 76 vs 91%; P = 0.11) and decrease detection in multiparous cows (GP vs GGP; 78 vs 72%; P < 0.10). However, because conception rate to TAI in animals with a BCS > or = 5.5 was greater (P < 0.05) in the GGP than in the GP group (28 vs 8%, respectively), this interaction was interpreted to represent a shift in interval to estrus induced by the GGP treatment, rather than a reduction in the synchronization of ovarian function. Conception rates of animals inseminated to an observed estrus did not differ among treatments (P = 0.15). Synchronized pregnancy rate tended (P = 0.06) to be greater in GGP- (53%) than in GP-treated animals (47%). In conclusion, pretreatment with GnRH tended to increase pregnancy rates during a 6-d synchronization period, primarily through enhanced conception rates of cows bred by TAI. In contrast to our hypothesis, GnRH pretreatment did not increase the percentage of animals detected in estrus or the precision of estrus expression.

Animal Husbandry↗
PubMed2000

Effects of pre- and post-thaw thermal insults on viability characteristics of cryopreserved bovine semen.

The magnitude of damage to the viability of cryopreserved bovine spermatozoa by pre- and post-thaw thermal insults was compared. Semen collected by artificial vagina from 5 Holstein bulls was diluted in egg yolk-citrate-7% glycerol extender (EYCG) and cryopreserved in 0.5 mL French straws at a sperm concentration of 40 to 60 x 10(6) cells/mL. In Experiment 1, straws were subjected to 22, 5 or -18 degrees C static air temperature for a duration of 1, 2, 3, 4 or 5 min before or after thawing in a 37 degrees C water bath for 1 min. Control straws were thawed in a 37 degrees C water bath for 1 min without further thermal insult. In Experiment 2, straws were thawed for 1 min in a 37 (control), 20 or 5 degrees C water bath, or were loaded into an insemination gun and plunged into a 37 degrees C water bath for 3 min. In both experiments, straws were returned to a 37 degrees C water bath for incubation prior to viability analysis. Viability evaluations, conducted in triplicate, included the percentage of motile spermatozoa at 1 min and at 3 h post thermal insult and the percentage of intact acrosomal membranes at 3 h post thermal insult. In both experiments, acrosomal integrity was more sensitive than motility to thermal insult. In Experiment 1, a significant interaction was observed between timing of thermal insult (pre- or post-thaw), static air temperature and duration of straw exposure. At 22 and 5 degrees C, thermal insults applied before thawing significantly (P<0.05) reduced acrosomal integrity at > or = 2 and > or = 4 min of exposure, respectively. However, post-thaw exposure to 22 and 5 degrees C for up to 5 min had no effect on any of the sperm viability parameters evaluated. In contrast, at -18 degrees C static air temperature, post-thaw exposure for > or = 3 min decreased acrosomal integrity (P<0.05), while 5 min of pre-thaw exposure was required for alteration of acrosomal integrity. In Experiment 2, each alternative thawing method resulted in significantly (P<0.05) lower incubated acrosomal integrity relative to the controls. These findings suggest that bovine spermatozoa cryopreserved in EYCG extender are more sensitive to pre-thaw than post-thaw thermal insults and that acrosomal integrity following 3-h incubation at 37 degrees C is superior to motility evaluations for detection of damage to sperm viability due to thermal insult.

Acrosome↗
PubMed2000

Elder abuse. Using clinical tools to identify clues of mistreatment.

Elder abuse occurs most commonly in residential rather than institutional settings, and the most likely perpetrators are known by the victim. Although a defined set of risk factors has not been developed, careful questioning and assessment can help determine whether a patient is at increased risk. The common types of elder maltreatment include caregiver and self-neglect, emotional and psychological abuse, fiduciary exploitation, and physical abuse. Assessment consists of comprehensive physical examination, including scrutiny of the musculoskelatal and genitourinary systems, neurologic and cognitive testing, and detailed social and sexual histories. Clues that cannot be explained medically may signal elder abuse. To properly intervene, clinicians should be familiar with state laws governing reporting procedures and patient privacy.

Aged↗
PubMed1999

Analysis of chromosome 9p21 deletion and p16 gene mutation in salivary gland carcinomas.

The chromosomal locus 9p21 contains the p16(INK4a/CDKN2/MTS1) tumor suppressor gene that has been implicated in a variety of tumor types, including carcinomas of the head and neck, esophagus, and pancreas. To determine whether the loss of this gene is involved in salivary gland cancers, 35 carcinomas and paired nonneoplastic specimens were analyzed for loss of heterozygosity (LOH) of polymorphic genetic markers located in the region of interest. Five types of salivary gland tumors were studied: mucoepidermoid carcinoma, salivary duct carcinoma, adenoid cystic carcinoma, acinic cell carcinoma, and polymorphous low-grade adenocarcinoma. Seven of 9 salivary duct carcinomas showed LOH of 1 or more polymorphic markers. In 1 case of salivary duct carcinoma with LOH, we confirmed a deletion of bp 240-254 within exon 2. In addition, another salivary duct carcinoma showed a homozygous deletion of p16 in differential polymerase chain reaction analysis. Loss of heterozygosity was found in 1 of 10 adenoid cystic carcinomas and 1 of 8 mucoepidermoid carcinomas and was absent in the remaining subtypes. No mutations in exon 1 or exon 2 or homozygous deletion of p16 were found in these 2 particular neoplasms with LOH. These results suggest that inactivation of p16 is important in the development or progression of at least some salivary duct carcinomas, but we found no evidence that its alteration plays a role in the other subtypes examined.

Adenocarcinoma↗
PubMed1999

KIT protein expression and analysis of c-kit gene mutation in adenoid cystic carcinoma.

The c-kit proto-oncogene encodes a transmembrane receptor tyrosine kinase (KIT), which is expressed in several normal human tissues, especially mast cells and interstitial cells of Cajal. Expression of KIT has been noted in several types of neoplasms and gene mutation has been shown as a mechanism of c-kit oncogene activation in some tumors. Recently, a single adnexal adenoid cystic carcinoma (ACC) was reported to demonstrate KIT expression, however, examination of KIT expression or c-kit mutation in ACC of salivary glands has not been performed. We examined archival tissue samples from 30 ACC of major and minor salivary glands for KIT protein expression by immunohistochemistry with a polyclonal antibody and c-kit gene mutation by polymerase chain reaction amplification and DNA sequencing. KIT protein expression was noted in 90% of ACCs. An association between the presence of at least 50% KIT positive neoplastic cells and Grade 3 ACC or a solid growth pattern was observed (P < .05). KIT expression in normal or nonneoplastic salivary gland tissue was absent. No c-kit juxtamembrane domain (exon 11) or phosphotransferase domain (exon 17) mutations were found in any of the tumors examined. In conclusion, KIT protein expression is correlated with tumor grade of salivary ACC. However, gene mutation of exon 11 or exon 17 is not a mechanism of c-kit activation in these neoplasms.

Adult↗
PubMed1998

Effect of cryopreservation of bovine sperm organelle function and viability as determined by flow cytometry.

Flow cytometry was used to compare the functional status of fluorescently stained sperm organelles from 12 Holstein bulls after storage for 24 h at 5 degrees C and after cryopreservation. The organelle-specific stains, SYBR-14 and LysoTracker Green DND-26, identified spermatozoa with intact plasmalemma and those with intact acrosomes, respectively. The mitochondria-specific stain, 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolyl-carbocyan ine iodide (JC-1), identified two populations of spermatozoa. One population stained red-orange because the JC-1 accumulated in the mitochondria as aggregates (characteristic of cells exhibiting a high membrane potential); a second population stained green because of JC-1 monomers within the mitochondria (characteristic of cells exhibiting a lower membrane potential). Analysis of variance revealed that within bulls, the properties of sperm viability, intact acrosomes, and mitochondrial status differed in spermatozoa stored for 24 h (p < 0.001) but not in cryopreserved spermatozoa (p > 0.11). Linear regression analyses resulted in significant models in which the proportions of stained spermatozoa stored for 24 h were indicative of those proportions observed in the cryopreserved fractions. These findings suggest that the plasmalemma, the acrosome, and the mitochondria of unfrozen spermatozoa varied as to their functional status. The cryopreservation process, however, resulted in a more uniform status of sperm organelles.

Animals↗
PubMed1997

Subchronic nasal toxicity of hexamethylphosphoramide administered to rats orally for 90 days.

Rats were administered hexamethylphosphoramide (HMPA) at dosages of 10, 100, 300, and 1000 ppm in drinking water or at 15, 40, or 120 mg/kg/day by gavage for approximately 90 days. Another group of rats was implanted subcutaneously with HMPA-filled osmotic minipumps, designed to deliver a dosage of 40 mg/kg/day to prevent the possibility of direct contact of HMPA with the nasal epithelium. After 90 days at 10 ppm in the drinking water, some rats had tracheas lined with regenerated epithelium, but no HMPA-related lesions were present in any other organs and tissues. At 100 ppm, nasal lesions (epithelial denudation, regeneration, and squamous metaplasia) were mostly in the maxilloturbinates, tips of nasoturbinates, and the adjacent septum in the anterior nasal cavity (level I), but the lesions were confined to the ventral region of the mid-anterior nasal cavity (level II) and to recesses of the posterior nasal cavity (levels III and IV). At 300 ppm, nasal turbinates in level I were partially adhered to the nasal septum by fibrous tissue. In level II the lesions were mainly confined to the ventral medial meatus, but were scattered diffusely in levels III and IV. Denuded turbinates showed minimal bone proliferation. At 1000 ppm, the anterior nasal cavity was partially occluded by extensive adhesion of the turbinates to the nasal septum by granulation tissue and proliferating turbinate bone. The general architecture of the posterior nasal cavity was obliterated by the marked proliferation of turbinate bone and fibrous tissue in the interturbinate spaces. Tracheas showed regenerated epithelium and bronchi had focal epithelial denudation at 100, 300, and 1000 ppm. Foamy alveolar macrophages (histiocytosis) were increased in the lungs at 300 and 1000 ppm. Testicular atrophy occurred at 1000 ppm. No other tissues were affected by HMPA treatment. Nasal lesions in rats given HMPA by gavage were identical in nature to, but sometimes slightly more severe than, the lesions in rats given HMPA in the drinking water. Rats given 40 mg/kg/day HMPA via an osmotic minipump had slightly less severe nasal lesions than did the rats given the same dosage of HMPA by gavage. Testicular atrophy was present in the rats given 120 mg/kg/day by gavage. The results of this study show that, with the exception of bone proliferation, systemic delivery of HMPA or its metabolites to the nasal tissue following oral administration causes tissue damage similar to that caused by direct exposure of the nasal tissue via inhalation. Oral administration of HMPA is a less potent route for producing nasal lesions than is inhalation.

Administration, Intranasal↗
PubMed1997

Fluorometric assessments of acrosomal integrity and viability in cryopreserved bovine spermatozoa.

The combination of specific fluorometric staining and flow cytometry provides a rapid and precise means of assessing the functional status of cells. We sought to utilize this approach to quantify two important seminal characteristics, acrosomal integrity and sperm viability, and to compare these with classical microscopic measurements of acrosomal integrity and sperm motility. Samples of thawed, cryopreserved sperm packaged in 0.5-ml French straws were obtained from 12 Holstein bulls. Classical acrosomal assessments and sperm motility estimates were made using differential interference contrast microscopy. Fluorescent acrosomal probes included LysoTracker Green DND-26 (LYSO-G), fluorescein-labeled peanut agglutinin, the biotinylated isocoumarin serine protease inhibitor Bi-Aca-Aca-OMe-IC that was secondarily labeled with fluorescein-avidin, and rabbit antibodies to bovine acrosin that were secondarily labeled with fluoresceinated anti-rabbit immunoglobulin. The fluorescent probes for sperm viability were a combination of SYBR-14 and propidium iodide (PI) or of SYTO-17 and PI. Significant differences were found among methods and among bulls, but not among straws (n = 3). All four fluorescent measures of acrosomal integrity showed highly significant correlations with both classical measurements. These data indicated that the quality of cryopreserved bovine sperm samples could be readily quantified using a variety of organelle-specific fluorescent staining techniques.

Acrosin↗
PubMed1997

Fluorometric assessments of mitochondrial function and viability in cryopreserved bovine spermatozoa.

Mitochondrial function and sperm viability were quantified in samples of cryopreserved bovine spermatozoa from 12 bulls using fluorometric techniques. The active mitochondria of the spermatozoa were fluorescently stained using three different fluorophores: rhodamine 123 (R123), 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolyl-carbocyan ine iodide (JC-1) or MitoTracker Green FM (MITO). The stained spermatozoa, and companion aliquots that had been stained with SYBR-14 (a living-cell nucleic acid stain) and propidium iodide to assess viability, were quantified using flow cytometry. The resulting fluorescent measurements of mitochondrial function were compared with microscopic assessments of progressive sperm motility immediately after thawing, with motility after 3-h incubation at 37 degrees C, and with the fluorescent assessment of sperm viability. Staining with either R123 or MITO resulted in a single green population. In contrast, the JC-1 staining of mitochondria produced both green and red-orange populations of spermatozoa and sometimes a progressive gradient between the two populations. The ability of JC-1 to discriminate between mitochondria exhibiting high membrane potential from those having low to medium membrane potential provided a more rigorous estimate of metabolic function than the other two fluorescent stains. Overall, the three fluorometric measurements of mitochondrial function were highly correlated with each other, with the SYBR-14 assessment of viability, and with the microscopic estimates of motility.

Animals↗
PubMed1994

Pathogenesis and prevention of native valve infective endocarditis in elderly dental patients.

Elderly dental patients are at risk of developing infective endocarditis. Increased longevity is associated with an increased prevalence of cardiac valvular disease and impairment of the immune system. Aortic stenosis commonly occurs in persons between 60 and 75 years of age. Degenerative calcification of the mitral valve ring leading to valve incompetency often develops in those over age 70 years. Men over the age of 60 years with mitral valve prolapse and systolic hypertension are at risk of infective endocarditis because the excessive haemodynamic load placed upon the abnormal valve causes extensive stretching of cusps and loss of valve surface endothelium. Dental procedures, that result in mucosal or gingival bleeding (most notably dental extractions, periodontal probing, scaling and surgery, endodontics and restorative procedures which extend below the gingival line), frequently produce a bacteraemia. Anaerobic strains of bacteria are isolated twice as frequently as aerobic strains. Antibiotic prophylaxis decreases the level of bacteraemia, prevents adherence of bacteria to the damaged valvular epithelium and suppresses the growth of those microbes that manage to adhere to the valve. The standard prophylactic regimen consists of amoxicillin 3g 1 hour before the dental procedure, then 1.5g 6 hours after the initial dose. Erythromycin is a good alternative for penicillin-allergic patients. Topical chlorhexidine 5 minutes before initiating dental therapy reduces the bacterial inoculum and the likelihood of endocarditis.

Aged↗
PubMed1989

Influence of smoking and plasma factors on patency of femoropopliteal vein grafts.

OBJECTIVE: To determine the effects of smoking, plasma lipids, lipoproteins, apolipoproteins, and fibrinogen on the patency of saphenous vein femoropopliteal bypass grafts at one year. DESIGN: Prospective study of patients with saphenous vein femoropopliteal bypass grafts entered into a multicentre trial. SETTING: Surgical wards, outpatient clinics, and home visits coordinated by two tertiary referral centres in London and Birmingham. PATIENTS: 157 Patients (mean age 66.6 (SD 8.2) years), 113 with patent grafts and 44 with occluded grafts one year after bypass. MAIN OUTCOME MEASURE: Cumulative percentage patency at one year. RESULTS: Markers for smoking (blood carboxyhaemoglobin concentration (p less than 0.05) and plasma thiocyanate concentration (p less than 0.01) and plasma concentrations of fibrinogen (p less than 0.001) and apolipoproteins AI (p less than 0.04) and (a) (p less than 0.05) were significantly higher in patients with occluded grafts. Serum cholesterol concentrations were significantly higher in patients with grafts that remained patent one year after bypass (p less than 0.005). Analysis of the smoking markers indicated that a quarter of patients (40) were untruthful in their claims to have stopped smoking. Based on smoking markers, patency of grafts in smokers was significantly lower at one year by life table analysis than in non-smokers (63% v 84%, p less than 0.02). Patency was significantly higher by life table analysis in patients with a plasma fibrinogen concentration below the median than in those with a concentration above (90% v 57%, p less than 0.0002). Surprisingly, increased plasma low density lipoprotein cholesterol concentration was significantly associated with improved patency at one year (85%) at values above the median compared with patency (only 68%) at values in the lower half of the range (p less than 0.02). CONCLUSIONS: Plasma fibrinogen concentration was the most important variable predicting graft occlusion, followed by smoking markers. A more forceful approach is needed to stop patients smoking; therapeutic measures to improve patency of vein grafts should focus on decreasing plasma fibrinogen concentration rather than serum cholesterol concentration.

Aged↗
PubMed1989

Analysis of drug-drug interactions among nursing home residents.

The extent of clinically important drug-drug interactions in the patient population of a nursing home was studied. The administration of medications to all 138 residents of two wards of the hospital-affiliated facility was monitored for 15 days through a review of nurses' medication-administration records and patients' charts. Information on the nature and timing of administered drug combinations was compared with published information to identify potential drug interactions. If a serious drug interaction was suspected, the recorded information was verified through the nurse in charge of that patient. Few of the drug interactions commonly reported to occur in nursing homes were observed at the facility, where drug therapy is monitored by a team of geriatric practitioners that includes two pharmacists. Of the 24 suspected interactions that were identified, 11 had potential clinical importance, and all 11 involved drug combinations that could alter the metabolism or action of one of the drugs. However, only two patients were exposed to any substantial degree of risk, and dosages of the drugs involved were adjusted. An additional 13 patients were taking a combination of drugs that could have altered the intestinal absorption of one of the drugs. Careful timing of drug administration avoided this potential problem. With proper education of the nursing staff, immediate clarification of medication orders, and optimal timing of drug administration, many clinically important drug-drug and drug-food interactions can be avoided in nursing home patients.

Adult↗
PubMed1988

Deep white matter infarction: correlation of MR imaging and histopathologic findings.

Focal and confluent areas of periventricular hyperintensity have been reported on magnetic resonance (MR) images in 30% of patients over 60 years of age. In order to better understand the pathologic basis of these lesions, the authors studied 14 formalin-fixed brains with MR imaging. Multiple focal areas of hyperintensity were identified in the periventricular white matter in three of the 14 brains studied (21%). Subsequent gross and microscopic pathologic examination of both hyperintense and normal-intensity areas was performed on 87 tissue sections. The larger lesions were characterized centrally by necrosis, axonal loss, and demyelination and therefore represent true infarcts. Reactive astrocytes oriented along the degenerated axons were identified at distances of up to several centimeters from the central infarct. This is called isomorphic gliosis and is associated with increased intensity on T2-weighted images that increases the apparent size of the central lesion.

Aged↗