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G A Broderick

Publications and source records attributed to G A Broderick.

At least 55 records · Page 3Linked to original sources
PubMed1999

Diabetes and vascular impotence: does insulin dependence increase the relative severity?

AIM OF THE STUDY: Diabetes is a well documented risk factor for vascular erectile dysfunction (ED). We evaluated the relative roles of insulin dependence (IDDM) vs oral agent controlled diabetes (NIDDM) in predicting the etiologies and severity of ED: arterial insufficiency (AI), venous leakage (CVOD), and mixed vascular disease. The impact of additional risk factors were also analyzed: hypertension (HTN), coronary artery disease (CAD), and smoking (SM). METHODS: Retrospective data on 105 patients complaining of impotence who underwent pharmacotesting with PGE1 (Caverject) and color duplex Doppler was reviewed. Penile blood flow study (PBFS) data following a period of privacy and self-stimulation was compared. PBFS diagnostic criteria were: AI for peak systolic velocity (PSV) < 25 cm/s; CVOD for PSV > or = 35 cm/s and resistive index (RI) < 0.9; mixed vascular disease for PSV > or = 25 cm/s, PSV < 35 cm/s and RI > 0.9. Consistent dosing of PGE1 was used; 6 mcg for age < 60 y and 10 mcg for age > or = 60 y. Patients were NIDDM (79 out of 105) and IDDM (26 out of 105). Mean ages for NIDDM and IDDM were respectively 60, and 55 y. The relative significance of insulin dependence was assessed by Student's t-test. RESULTS: The most common etiology of ED was arterial insufficiency: mean PSV's did not significantly vary and were: 23.5 cm/s for NIDDM, and 21.6 cm/s for IDDM. PBFS parameters did not vary significantly for the risk factors of SM or HTN and diabetes. Mean peak systolic velocities were significantly different among diabetics with coronary artery disease: NIDDM/CAD, 22.9 cm/s compared to IDDM/CAD, 14.8 cm/s (P = 0.006). CONCLUSIONS: We found among the 105 diabetics the most common etiology of vascular ED based on Doppler criteria was arterial insufficiency, 64%. Statistical analysis of additional risk factors (SM, HTN, CAD) suggested that patients with IDDM and CAD have more severe cavernosal arterial insufficiency than patients with NIDDM and CAD. This data tends to support the theory that microangiopathy is the predominant factor in diabetic impotence, and that insulin dependent diabetes with 'large vessel' coronary heart disease have a similar pathology in the 'small vessels' regulating penile inflow which is unfortunately worse than their non-insulin dependent counterparts.

Alprostadil↗
PubMed1999

Retrospective review of flow patterns following retropubic prostatectomy.

AIM OF THIS STUDY: We retrospectively evaluated penile inflows in 103 previously potent individuals who underwent standard nerve sparing radical retropubic prostatectomy (RRP) for the treatment of prostate cancer. No effort to identify or spare the accessory pudendal artery (APA) was made in any case. Our goal was to investigate the role of the accessory internal pudendal artery (APA) in the maintenance of erections in this population. We hypothesize that if the APA is present in a significant number of men, and its ligation significantly contributes to post-RRP impotence, then there should be an increased incidence of asymmetry between R/L cavernous arterial flows among post RRP patients with vascular impotence. MATERIALS AND METHODS: One hundred and three previously potent individuals complaining of persistent erectile dysfunction for at least six months after RRP were studied with color duplex Doppler, following age specific dosing of PGE1. Vascular assessment was performed before and after self-stimulation, measuring peak systolic velocity (PSV), end diastolic velocity (EDV), and resistive index (RI). Erections were visually rated as inadequate (INA), adequate (ADE) for penetration, or excellent (EXC) with sustained rigidity for at least 20 min. Cavernous artery asymmetry (CAA) was defined as a >10 cm/s difference between right and left sided arterial flows. RESULTS: Mean duration between surgery and Doppler study was 14.7 months. 27 out of 103 (26%) of patients developed excellent rigidity consistent with isolated neurogenic impotence (PSV=32.0 cm/s, mean RI=0.95); 24 out of 103 (23%) had adequate vascular responses making it impossible to infer presence or absences of neurogenic impotence; 52 out of 103 (51%) had inadequate rigidity consistent with vascular insufficiency (PSV=23.7 cm/s, mean RI=0.66). We noted that of patients with EXC response, 48% (13 out of 27) had CAA. Among patients with severe inflow disease (INA responders), CAA was seen in only 21% of cases (11 out of 52). CONCLUSIONS: The incidence of APA has been reported as being from 4-70%, and its significance in the maintenance of erections has been questioned. Assuming that the APA provides significant inflow in some patients, we expected an increase in CAA in individuals in whom it was sacrificed. We found a higher incidence of CAA among post-RRP patients with normal vascular erectile responses to PGE1 (48%) compared to men with true vasculogenic impotence post-RRP (21%). These data do not support the importance of the APA in the maintenance of erections in the post-RRP patient.

Aged↗
PubMed1999

Effect of feeding macerated alfalfa silage on nutrient digestibility and milk yield in lactating dairy cows.

Five feeding studies were conducted with 141 lactating Holstein cows comparing macerated and control alfalfa silage harvested at two cuttings in each of 2 yr. Overall, silage made from macerated alfalfa contained more ash (suggesting improved soil contamination); greater fiber and lower nonprotein nitrogen (NPN) content suggested greater fermentation in the silo. In a digestion study, two diets were fed containing [dry matter (DM) basis] 72% of either control or macerated second-cutting alfalfa. Apparent digestibility of neutral detergent fiber and acid detergent fiber (ADF) was increased by maceration, and similar changes in digestibility were observed with Yb or indigestible ADF as marker; indigestible ADF was used as a marker in later studies. Lactation trials were conducted with first- and second-cutting alfalfa from each year. In each study, diets were formulated from alfalfa silage plus concentrate based on processed high moisture ear corn; mean compositions were (DM basis): negative control (61% control alfalfa silage), macerated (61% macerated alfalfa silage), and positive control (50% control alfalfa silage). All diets contained 2% crude protein from either roasted soybeans or low-solubles fish meal; soybean meal was added to make the positive control isonitrogenous (but not equal in ruminal undergraded protein). Milk yield was greater on macerated than negative control in two of four trials but not different in the other two trials. Yields of milk and milk components were not different between macerated and positive control in one of four trials. Versus the negative control, milk fat synthesis was depressed on macerated alfalfa in one trial. Overall performance on macerated versus negative control indicated greater apparent digestibility of organic matter (OM), greater yield of milk, protein, and solids not fat, but lower milk fat content. Yields of milk and milk components were greater overall on positive control versus macerated. Estimation of net energy for lactation (NEL) from maintenance, milk yield, and body weight gain indicated that control and macerated alfalfa silage contained, respectively, 1.36 and 1.42 Mcal of NEL of OM, an increase of about 5% due to maceration of alfalfa in these trials.

Animal Nutritional Physiological Phenomena↗
PubMed1999

Effect of replacing alfalfa silage with high moisture corn on ruminal protein synthesis estimated from excretion of total purine derivatives.

Twenty-four multiparous dairy cows (eight with ruminal cannulae) were blocked by days in milk and assigned to six balanced 4 x 4 Latin squares with 21-d periods. The four diets, formulated from alfalfa silage plus a concentrate mix based on ground high moisture ear corn, contained (dry matter basis): 1) 20% concentrate, 80% alfalfa silage (24% nonfiber carbohydrate; NFC), 2) 35% concentrate, 65% alfalfa silage (30% NFC), 3) 50% concentrate, 50% alfalfa silage (37% NFC), or 4) 65% concentrate, 35% alfalfa silage (43% NFC). Soybean meal and urea were added to make diets isonitrogenous with equal nonprotein nitrogen (NPN) (43% of total N). Total urine was collected with indwelling Folley catheters for 24 h during each period. There was no effect of diet on urinary creatinine excretion (average 29 mg/kg of BW/d). There were quadratic effects of diet on total urinary ecretion of allantoin, uric acid, and purine derivatives (allantoin plus uric acid), and on ruminal synthesis of microbial N estimated from purine derivatives; maxima occurred at about 35% dietary NFC. Urinary excretion also was estimated with spot urine samples from creatinine concentration and the mean daily creatinine excretion. Daily excretion of allantoin, uric acid, and purine derivatives estimated from spot urine sampling followed the same pattern as that observed with total collection; differences between measured and estimated urine volume were significant only for 35% dietary concentrate. Spot urine sampling appeared to yield satisfactory estimates of purine derivative excretion. Maximal urea N excretion was estimated to occur at about 31% dietary NFC. Milk allantoin secretion increased linearly with concentrate and accounted for 4 to 6% of the total purine derivative excretion. Microbial yield was maximal at 35% dietary NFC, suggesting that this was the optimal level for utilization of dietary NPN from alfalfa silage and other sources.

Allantoin↗
PubMed1998

Biochemical outcome after radical prostatectomy, external beam radiation therapy, or interstitial radiation therapy for clinically localized prostate cancer.

CONTEXT: Interstitial radiation (implant) therapy is used to treat clinically localized adenocarcinoma of the prostate, but how it compares with other treatments is not known. OBJECTIVE: To estimate control of prostate-specific antigen (PSA) after radical prostatectomy (RP), external beam radiation (RT), or implant with or without neoadjuvant androgen deprivation therapy in patients with clinically localized prostate cancer. DESIGN: Retrospective cohort study of outcome data compared using Cox regression multivariable analyses. SETTING AND PATIENTS: A total of 1872 men treated between January 1989 and October 1997 with an RP (n = 888) or implant with or without neoadjuvant androgen deprivation therapy (n = 218) at the Hospital of the University of Pennsylvania, Philadelphia, or RT (n = 766) at the Joint Center for Radiation Therapy, Boston, Mass, were enrolled. MAIN OUTCOME MEASURE: Actuarial freedom from PSA failure (defined as PSA outcome). RESULTS: The relative risk (RR) of PSA failure in low-risk patients (stage T1c, T2a and PSA level < or =10 ng/mL and Gleason score < or =6) treated using RT, implant plus androgen deprivation therapy, or implant therapy was 1.1 (95% confidence interval [CI], 0.5-2.7), 0.5 (95% CI, 0.1-1.9), and 1.1 (95% CI, 0.3-3.6), respectively, compared with those patients treated with RP. The RRs of PSA failure in the intermediate-risk patients (stage T2b or Gleason score of 7 or PSA level >10 and < or =20 ng/mL) and high-risk patients (stage T2c or PSA level >20 ng/mL or Gleason score > or =8) treated with implant compared with RP were 3.1 (95% CI, 1.5-6.1) and 3.0 (95% CI, 1.8-5.0), respectively. The addition of androgen deprivation to implant therapy did not improve PSA outcome in high-risk patients but resulted in a PSA outcome that was not statistically different compared with the results obtained using RP or RT in intermediate-risk patients. These results were unchanged when patients were stratified using the traditional rankings of biopsy Gleason scores of 2 through 4 vs 5 through 6 vs 7 vs 8 through 10. CONCLUSIONS: Low-risk patients had estimates of 5-year PSA outcome after treatment with RP, RT, or implant with or without neoadjuvant androgen deprivation that were not statistically different, whereas intermediate- and high-risk patients treated with RP or RT did better then those treated by implant. Prospective randomized trials are needed to verify these findings.

Adenocarcinoma↗
PubMed1998

Evidence based assessment of erectile dysfunction.

Do we need impotence testing? Yes, it is the clinician's obligation to establish the etiology of impotence: end organ vascular failure vs neurologic dysfunction vs psychosexual dysfunction, classify the severity of that dysfunction, and select a therapy that is not only acceptable to the patient but also addresses his pathology. The most commonly utilized diagnostic tests for erectile dysfunction are outlined in this monograph. Nocturnal erections are evaluated by tests commonly known as nocturnal penile tumescence (NPT) studies. NPT has been measured by each of the following methods: stamp test, Snap Gauges, strain gauges, NPTR (Rigiscan, Osbon Medical Systems), and sleep lab NPTR. Normal Nocturnal Penile Tumescence and Rigidity (NPTR) depends on both the integrity of the corticospinal efferents to the penis and vascular responsiveness of the penile tissues to those nerve signals. When nocturnal erections are of appropriate duration and strength the central and peripheral neuroeffectors and intra-corporal regulators of penile hemodynamics are intact. Unfortunately, abnormal NPTR is of little value in determining the etiology or classifying the severity of vascular impotence; the most prevalent kind of end organ failure. The sacral reflex arc of erection consists of somatosensory afferents via the dorsal and pudendal nerves and autonomic efferents via the pelvic and cavernous nerves. These afferents have been measured indirectly by somatosensory evoked potentials (SSEP) and bulbocavernosus reflex latency (BCR). Penile EMG's have recently been recorded, corporal cavernosal smooth muscle electrical activity: CC-EMG. This technology is far from standardized; computer-assisted interpretations of penile electrical potentials may eventually differentiate afferent nerve pathologies so long inferred in: diabetes, spinal cord injury and following radical pelvic surgery. Numerous diagnostic tests have been employed to evaluate penile hemodynamics: penile plethysmography, penile blood pressures, penile brachial index, selective internal pudendal pharmacoangiography, Doppler sonography, dynamic infusion cavernosometry/cavernosography, nuclear washout radiography, and color duplex Doppler ultrasound. Insufficient corporal veno-occlusion is implicated in up to 50% of patients. The diagnosis and demonstration of venous leakage requires complete smooth muscle relaxation. Veno-occlusive dysfunction is associated with poorly sustained erections; this pathology has traditionally been evaluated with Dynamic Infusion Cavernosometry and Cavernosography. DICC is an invasive test, and is now primarily reserved for patients considering the option of vascular reconstructive procedure. Pharmacotesting consists of intracavernous injection and visual rating of the subsequent erection; the test is the most commonly used office procedure for diagnosing erectile dysfunction. It is simple, minimally invasive, and performed without monitoring equipment. Hemodynamic investigations suggest that a positive injection test is associated with normal veno-occlusion, but not necessarily with normal arterial function. When the penile response to pharmacotesting is suboptimal or equivocal, diagnostic testing with duplex Doppler assessment should be performed. The penile blood flow study (PBFS) provides an objective, minimally invasive evaluation of a suboptimal/equivocal erectile response.

Animals↗
PubMed1997

The use of combined radiation therapy and hormonal therapy in the management of lymph node-positive prostate cancer.

PURPOSE: To determine the rate of tumor response and patterns of relapse following combined hormonal-radiation therapy of adenocarcinoma of the prostate and to measure the survival in a group of men with tumor metastatic to pelvic lymph nodes. METHODS AND MATERIALS: 66 patients with adenocarcinoma of the prostate with pathologically confirmed pelvic lymph node involvement were treated with combined radiation therapy and hormonal therapy. An additional five patients declined hormonal therapy. The patients treated with combined therapy represented a group with locally advanced disease including 44 patients (67%) with T3 or T4 tumors and 51 patients (80%) had N2 or N3 lymph node metastases. The pelvic lymph nodes were treated to a dose of 45 Gy and the prostate was boosted to a dose of 65 to 71 Gy. Hormonal therapy began up to 2 months before radiation and continued indefinitely. Patients were allowed to select their hormonal therapy and could choose DES (2 patients), orchiectomy (21 patients), LHRH agonist (7 patients) or combined androgen blockade (34 patients). RESULTS: Median follow-up is 49 months (range 12 to 131 months) and 21 patients have been followed for longer than 5 years. There have been 15 recurrences the entire group including three local recurrences in the prostate, seven patients with distant metastases, four patients with biochemical recurrences without clinical evidence of disease, and one patient where the location was unknown. Two of the PSA recurrences occurred in patients who elected to discontinue hormones after less than 3 years of therapy. The overall survival at 5 and 8 years is 94 and 84%, the clinical disease free survival is 85 and 67%, and the biochemical disease-free survival is 78 and 47%. There was no increased toxicity of the combined modality regimen compared to the expected effects of radiation and hormonal therapy. CONCLUSION: Combined hormonal and radiation therapy represents an effective treatment option for patients with adenocarcinoma of the prostate metastatic to pelvic lymph nodes. Combined modality therapy appears to extend the disease-free survival and allow patients to maintain their independent function.

Adenocarcinoma↗
PubMed1997

Peptidases of the rumen bacterium, Prevotella ruminicola.

Prevotella (formerly Bacteroides) ruminicola is a numerous rumen bacterium which plays a significant role in the metabolism of proteins and peptides in the rumen. Measurement of the hydrolysis of synthetic aminopeptidase substrates by sonicated extracts and whole cells of different species of rumen bacteria indicated that P. ruminicola had the greatest range and specific activity of dipeptidyl peptidases among the species tested. Streptococcus bovis hydrolysed some dipeptidyl peptidase substrates to a lesser extent, and several species broke down Ala2-p-nitroanilide, including Ruminobacter amylophilus, Ruminococcus spp. and Veillonella parvula. Dipeptidyl peptidases, which cleave dipeptides from the amino-terminus of longer peptides, were much more active than aminopeptidases removing single amino acids in P. ruminicola. Ion-exchange chromatography of sonicated extracts of P. ruminicola M384 revealed at least four distinct activities: one hydrolysed Ala2-p-nitroanilide, ValAla-p-nitroanilide, Ala4and Ala5; another was an O2-sensitive activity hydrolysing GlyArg-4-methoxynapthylamide, ArgArg-4-methoxynaphthylamide, Gly5 and ValGlySerGlu, similar to dipeptidyl peptidase type I DPP-1); a third hydrolysed GlyPro-p-nitroanilide and GlyPro-4-methoxynapthylamide and was similar to dipeptidyl peptidase type IV XDPP-4); a fourth broke down LysAla-4-methoxynaphthylamide. All of the enzymes, and particularly those active against Ala2-p-nitroanilide and GlyPro-p-nitroanilide, were inhibited by serine protease inhibitors, and all except DPP-4 were inhibited by EDTA. Both DPP-1 and the enzyme hydrolysing LysAla-4-methoxynaphthylamide were inhibited strongly by iodoacetate. DPP-4 was inhibited completely by diprotin A. Competitive inhibition experiments suggested that DPP-1 was less important than the other enzymes in the breakdown of peptide mixtures.

Journal Article↗
PubMed1997

Collagen injection therapy for post-radical retropubic prostatectomy incontinence: role of Valsalva leak point pressure.

PURPOSE: We retrospectively evaluated the role of Valsalva leak point pressure as a predictor of successful management of post-radical retropubic prostatectomy incontinence with collagen injection. MATERIALS AND METHODS: Urodynamic studies and Valsalva leak point pressures of 31 men who received retrograde collagen injection for post-radical retropubic prostatectomy incontinence were reviewed. Patients were interviewed before and after treatment to assess pad use and the American Urological Association quality of life index (scale 0 to 6). Parameters for success were postoperative quality of life score 3 or less or 50% or greater decrease in pad use and that the patient would recommend collagen therapy to someone else. RESULTS: Of 31 patients 11 (35%) met the criteria for success, 2 (6%) were completely dry and 9 (29%) were improved. Successfully treated patients had a mean Valsalva leak point pressure of 64.0 cm. water compared to 42.2 cm. water in the failure group (p <0.01). Of patients with Valsalva leak point pressure of 60 cm. water or greater, 70% responded favorably to collagen injection (positive predictive value), while 81% with Valsalva leak point pressure less than 60 cm. water had treatment failure (negative predictive value) (p <0.02). There were no other statistically significant differences between those successfully treated with collagen injection and those in whom treatment failed, including mean age (62.7 to 68.1 years), mean volume of collagen (26.1 to 28.9 ml.), mean number of treatment sessions (2.45 to 2.65), mean followup (14.9 to 15.1 months), preoperative quality of life score (5.1 to 4.9), and preoperative pads per day (4.0 to 3.37). CONCLUSIONS: Our data suggest that collagen injection improves 35% but cures a minority of patients (less than 10%) with post-radical retropubic prostatectomy incontinence. A pretreatment Valsalva leak point pressure of 60 cm. water or greater has high predictive value for a beneficial outcome after collagen injection. We propose a role for Valsalva leak point pressure to select men cost-effectively with post-radical retropubic prostatectomy incontinence for therapy with collagen injection.

Adult↗
PubMed1997

Development of prostate cancer after pituitary dysfunction: a report of 8 patients.

OBJECTIVES: Eight patients with a history of pituitary dysfunction were seen in the Department of Radiation Oncology at the Hospital of the University of Pennsylvania for evaluation of their prostate carcinoma. Because prostate cancer is a hormonally responsive cancer, hormonal abnormalities from pituitary dysfunction may have played a role in its development. In addition, many patients with pituitary dysfunction receive exogenous hormonal replacement. The histories of these 8 patients were reviewed to look for any common underlying factor in the development of their prostate cancer. METHODS: The radiation oncology charts, hospital charts, and pathology reports were reviewed. The cause and treatment of the pituitary disorder were reviewed. Hormonal dysfunction, hormonal replacement, and treatment duration were recorded. The interval to the development of prostate cancer, stage at diagnosis, prostate-specific antigen level, Gleason score, treatment, and treatment outcome were also investigated. RESULTS: We found a variety of pituitary disorders and treatments. However, all patients received testosterone replacement therapy prior to the development of their prostate cancer (median of 30 months). The time to the development of the cancer ranged from 26 to 250 months (median 98). Patients had Stage T2 or T3 tumors at diagnosis. Patients were treated either with radical prostatectomy or radiation therapy. Six of the 8 patients were alive and doing well at their last follow-up examination. CONCLUSIONS: Prostate cancer has been shown to be androgen responsive. All the patients in this series were placed on physiologic testosterone replacement for pituitary dysfunction. The role of testosterone in the initiation of prostate cancer has been debated. However, at the present time, it seems appropriate to establish close monitoring for prostate cancer in patients receiving androgen therapy for pituitary dysfunction.

Aged↗
PubMed1997

Acidosis impairs rabbit trabecular smooth muscle contractility.

PURPOSE: The aim of our study was to define the effects of acidosis on the contractility of trabecular smooth muscle. METHODS: Rabbit corpus cavernosal strips were mounted in organ chambers to measure isometric tension. Additionally, intracellular free Ca2+ concentration ([Ca2+]i) and tension were measured simultaneously utilising the intracellular fluorescent dye, FURA-2, and isometric tension recordings. RESULTS: Contraction of corpus cavernosum smooth muscle following transmural electrical stimulation (TES) of constrictor nerves or exposure to norepinephrine was depressed under acidic (pH 6.9) vs. control (pH 7.4) conditions. Twenty mM K(+)-induced contractions were also inhibited by acidosis, however 40, 80, and 120 mM K+ contractions were unaffected. Relaxation responses to acetylcholine and electrical stimulation, in phenylephrine contracted tissues, were unaffected by acidosis. Tissues contracted with 20 mM K+ under control conditions, relaxed approximately 50% when exposed to an acidic environment. This relaxation was blocked by exposing the tissue to 80 mM K+. Acidic conditions inhibited basal tone and [Ca2+]i as well as normal increases in both intracellular free Ca2+ and tension upon exposure to 20 mM K+, while 80 mM K(+)-induced increases in Ca2+ and tension were comparable under both neutral and acidic conditions. CONCLUSION: Acidosis impairs trabecular smooth muscle contractility. This alteration is probably secondary to the interference of [H+] with the intra and extracellular mechanisms that regulate homeostasis of [Ca2+]i. Since acidosis is an early complication of ischemic priapism, we propose that the reduced contractility of trabecular smooth muscle may be a significant factor in the perpetuation of the ischemic state.

Acetylcholine↗
PubMed1997

Excretion of purine derivatives by Holstein cows abomasally infused with incremental amounts of purines.

Five multiparous, ruminally cannulated Holstein cows (two lactating and three dry) weighing (X +/- SD) 667 +/- 35 kg were used to study the effect of abomasal purine infusion on the excretion of purine derivatives. Cows were fed corn silage four times daily at 90% of ad libitum intake (X = 9.16 kg of dry matter/d). Purines were infused into the abomasum as brewer's yeast suspensions in five incremental amounts (0 to 380 mmol/d) during five experimental periods according to a 5 x 5 Latin square design. Periods were 7 d; purine infusions were conducted during the last 4 d, and urine was collected during the last 3 d of each period. Ruminal purine outflow in all cows was measured during an experimental period immediately preceding and immediately following the five infusion periods and in each cow during the 0-mmol/d infusion period of the experiment. The relationship between total (milk plus urine) daily excretion of purine derivatives (allantoin plus uric acid) and total (abomasal infusion plus ruminal outflow) daily purine flow was quantified by linear regression analysis and was described by the relationship: Y = 0.856X + 103 (r2 = 0.93). The slope (0.856) indicated that 86% of purines that reached the omasum were excreted as purine derivatives. In the two lactating cows, urinary purine derivatives accounted for 98.4% of the total purine derivatives that were excreted. Ruminal flow of microbial CP can be estimated from the CP:purine ratio of ruminal microorganisms and the excretion of purine derivatives.

Abomasum↗
PubMed1997

Effects of supplementation of energy or ruminally undegraded protein to lactating cows fed alfalfa hay or silage.

Alfalfa was harvested as silage or hay and fed in two 12-wk trials with a 4 x 4 Latin square design that used 12 (trial 1) or 24 (trial 2) multiparous lactating cows (4 ruminally cannulated cows per trial). Diets contained (dry matter basis) 75 or 50% alfalfa plus 24 of 40% high moisture corn (trial 1) or 50% alfalfa, 44 or 41% high moisture corn, with (3%) or without fish meal (trial 2). Experiments were conducted to evaluate the responses of cows fed alfalfa hay or alfalfa silage diets to an increase in protein supply from microbial protein synthesis (trial 1) or from the supplementation of ruminally undegraded protein (RUP) (trial 2). In trial 1, the increase in high moisture corn in the diet increased both milk protein and microbial crude protein yields (estimated from the excretion of purine derivatives) to a greater extent for the cows fed the alfalfa silage diets (170 and 337 g/d, respectively) than for the cows fed the alfalfa hay diets (100 and 100 g/d, respectively). In trial 2, RUP supplementation (as fish meal) increased milk protein yield 100 g/d for cows fed alfalfa silage diets and 20 g/d for cows fed alfalfa hay diets. These results indicated that protein status was poorer and, thus, more responsive to absorbable protein from microbial protein (trial 1) or RUP (trial 2) for cows that consumed alfalfa conserved as silage versus those that consumed alfalfa conserved as hay.

Allantoin↗
PubMed1997

Comparison of in situ and in vitro techniques for measuring ruminal degradation of animal by-product proteins.

Ruminally undegraded protein (RUP) values of blood meal (n = 2), hydrolyzed feather meal (n = 2), fish meal (n = 2), meat and bone meal, and soybean meal were estimated using an in situ method, an inhibitor in vitro method, and an inhibitor in vitro technique applying Michaelis-Menten saturation kinetics. Degradation rates for in situ and inhibitor in vitro methods were calculated by regression of the natural log of the proportion of crude protein (CP) remaining undegraded versus time. Nonlinear regression analysis of the integrated Michaelis-Menten equation was used to determine maximum velocity, the Michaelis constant, and degradation rate (the ratio of maximum velocity to the Michaelis constant). A ruminal passage rate of 0.06/h was assumed in the calculation of RUP. The in situ and inhibitor in vitro techniques yielded similar estimates of ruminal degradation. Mean RUP estimated for soybean meal, blood meal, hydrolyzed feather meal, fish meal, and meat and bone meal were, respectively, 28.6, 86.0, 77.4, 52.9, and 52.6% of CP by the in situ method and 26.4, 86.1, 76.0, 59.6, and 49.5% of CP by the inhibitor in vitro technique. The Michaelis-Menten inhibitor in vitro technique yielded more rapid CP degradation rates and decreased estimates of RUP. The inhibitor in vitro method required less time and labor than did the other two techniques to estimate the RUP values of animal by-product proteins. Results from in vitro incubations with pepsin.HCl suggested that low postruminal digestibility of hydrolyzed feather meal may impair its value as a source of RUP.

Animals↗
PubMed1997

A statistical evaluation of animal and nutritional factors influencing concentrations of milk urea nitrogen.

Data from 35 trials with 482 lactating cows fed 106 diets were used to study the effects of animal and dietary factors on the relationship between milk and blood urea N and the value of milk urea N in the assessment of protein status. In two trials, urea N in whole blood and in blood plasma were closely related (r2 = 0.952); the slope was not significantly different from 1.0, and the intercept was not significantly different from 0. Regression of milk urea N on blood urea N with a mixed effects model using all 2231 observations yielded the equation: milk urea N (milligrams of N per deciliter) = 0.620 x blood urea N (milligrams of N per deciliter) + 4.75 (r2 = 0.842); this model accounted for a significant interaction of cow and blood urea N. Single factors that yielded significant regressions on milk urea N with the mixed effects models were dietary crude protein (CP) (percentage of dry matter; r2 = 0.839), dietary CP per megacalorie of net energy for lactation (NEL) (r2 = 0.833), excess N intake (r2 = 0.772), N efficiency (r2 = 0.626), and ruminal NH3 (r2 = 0.574). When all factors were analyzed at once, 12 were significant in a mixed effects model. Blood urea N, body weight, yield of fat-corrected milk, dietary CP content, excess N intake, dry matter intake, and days in milk were positively related to milk urea N, and parity, milk and fat yield, dietary CP per unit of NEL content, and NEL intake were negatively related to milk urea N. In one trial, the mean urea concentration was 35 times greater in urine than in milk; lower proportions of total urea excretion in milk were observed in the a.m. sampling (1.8%) than in the p.m. sampling (3.3%). Measuring urea N in a composite milk sample from the whole day substantially improved reliability of data. The number of cows fed a specific diet that must be sampled to determine mean milk urea N within 95% confidence intervals with half widths of 1.0 and 2.0 mg of N/dl was estimated to be 16 and 4, respectively.

Ammonia↗
PubMed1997

Effect of processing high moisture ear corn on ruminal fermentation and milk yield.

Thirty-six multiparous dairy cows (8 fitted with ruminal cannulas) and 16 primiparous dairy cows were blocked by days in milk and parity and assigned to one of four diets containing 53% alfalfa silage [dry matter (DM) basis] plus 1) high moisture ear corn, 2) high moisture ear corn plus expeller soybean meal, 3) ground high moisture ear corn, or 4) ground high moisture ear corn plus expeller soybean meal. The high moisture ear corn was rolled before ensiling at 68% DM. Ground high moisture ear corn was prepared by further grinding through a 9.5-mm screen; grinding reduced the geometric mean particle size from 4.33 to 1.66 mm. Diets contained 1.69 Mcal of net energy for lactation/kg of DM. Relative to cows fed diet 1, milk yield was 4 kg/d greater for cows fed diet 2; numerically, milk yield was about 2 kg/d greater for cows fed diets 3 and 4 than for cows fed diet 1. Yield of milk components also was greater for cows fed diets 2 and 3 but not for cows fed diet 4. Intake of DM and yield of 4% FCM were greatest for cows fed diet 3 and lowest for cows fed diet 1. Digestibilities of DM, organic matter, starch, neutral detergent fiber, and acid detergent fiber were increased, and ruminal NH3 concentration was depressed, by the grinding of high moisture corn; expeller soybean meal increased ruminal NH3. Total volatile fatty acid concentration was not different among in vivo treatments, but the molar proportion of acetate decreased, and propionate increased, for cows fed diet 3. The grinding of high moisture corn significantly decreased pH, increased total volatile fatty acid concentration, and increased the rate of decline of NH3 concentration in ruminal in vitro incubations. Grinding improved the utilization of high moisture corn by lactating cows by stimulating ruminal fermentation.

Ammonia↗
PubMed1996

Impotence.

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Erectile Dysfunction↗