Mixed ruminal microbes of cattle produce isopropanol in the presence of acetone but not 3-D-hydroxybutyrate

The objective was to evaluate the ability of mixed rumen microbes to synthesize isopropanol from acetone or 3-D-hydroxybutyrate. Rumen fluid from seven mature, nonpregnant, dry Holstein cows was incubated with starch or cellulose and additions of acetone, 3-D-hydroxybutyrate, or saline. Rumen fluid was analyzed for isopropanol after 0, 3, 6, and 9 h. No isopropanol was present in any sample at 0 h, and none was present in incubations containing saline or 3-D-hydroxybutyrate at any subsequent time. Incubations that included acetone produced small amounts of isopropanol from 0 to 3 and 3 to 6 h and significantly larger amounts from 6 to 9 h. With starch as the energy substrate, production from 6 to 9 h was 3.8 micromol/min per liter of rumen fluid and 3.7 micromol/min per liter with cellulose as the energy substrate; however, these values did not differ significantly. Mixed rumen microbes could synthesize isopropanol from acetone but not from 3-D-hydroxybutyrate, and rumen microbial metabolism of acetone was the likely source of plasma isopropanol seen in ketotic ruminants.

Osseous sequestration in cattle: 110 cases (1987-1997)

OBJECTIVE

To determine risk factors for development of sequestra in cattle and identify factors associated with a successful outcome.

DESIGN

Retrospective study.

ANIMALS

110 cattle.

PROCEDURE

Medical records of cattle treated at veterinary teaching hospitals in North America were reviewed. To determine risk factors for osseous sequestration, breed, age, and sex of cattle with osseous sequestration were compared with breed, age, and sex of all other cattle admitted during the study period.

RESULTS

110 cattle were included in the study. Three had 2 sequestra; thus, 113 lesions were identified. Most sequestra were associated with the bones of the extremities, most commonly the third metacarpal or third metatarsal bone. Ninety-two animals were treated surgically (i.e., sequestrectomy), 7 were treated medically, 3 were initially treated medically and were then treated surgically, and 8 were not treated. Follow-up information was available for 65 animals treated surgically and 6 animals treated medically. Fifty-one (78%) animals treated surgically and 5 animals treated medically had a successful outcome. Cattle that were 6 months to 2 years old had a significantly increased risk of developing a sequestrum, compared with cattle < 6 months old. Cattle in which sequestrectomy was performed with the aid of local anesthesia were significantly more likely to undergo 2 or more surgical procedures than were cattle in which sequestrectomy was performed with the aid of general anesthesia.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that sequestrectomy will result in a successful outcome for most cattle with osseous sequestration.

Effects of monopolar radiofrequency energy on ovine joint capsular mechanical properties

Radiofrequency energy may provide a relatively noninvasive method to stabilize joints with excessive laxity by thermally shrinking redundant joint capsular tissue. The authors determined the percentage of shrinkage associated with five radiofrequency treatment temperatures and evaluated the effect of this energy on the structural properties of joint capsular tissue in vitro. First, 36 adult sheep femoropatellar joint capsular specimens were treated with one of five treatment temperatures (n = 6 per group) or served as a control to determine tissue shrinkage. An additional 24 specimens were treated with three temperatures that resulted in different shrinkage: 45 degrees C, 65 degrees C, and 85 degrees C. Tissue stiffness, relaxation, and failure strength were determined for each specimen (n = 6 per group). Tissue shrinkage was correlated significantly with treatment temperature. There was a significant decrease in tensile stiffness in the 65 degrees C and 85 degrees C treatment groups. There were no significant differences between stress relaxation before treatment and after treatment. Relaxation properties after treatment were not different from each other or from control values either normalized to pretreatment values or expressed as raw data. Failure strength was not affected significantly at any temperature.

Pelvic exenteration for advanced pelvic malignancy

Pelvic exenteration is a demanding, yet potentially curative operation, for patients with advanced pelvic cancer. The majority will present with recurrence after prior surgery and radiotherapy. After exenteration, 5-year survival is 40% to 60% in patients with gynecologic cancer as compared to 25% to 40% for patients with colorectal cancer. Physiologic age and absence of co-morbidities appear to be more important when selecting patients for exenteration than chronological age. Careful pre-operative staging, including either computed tomography (CT) scan or magnetic resonance imaging (MRI), usually will identify patients with distant metastases, extrapelvic nodal disease, or disease involving the pelvic sidewall (which generally precludes surgery). The recent application of intra-operative radiotherapy or postoperative high-dose brachytherapy for patients with more advanced pelvic disease, which may include sidewall involvement, may expand the standard indications for exenteration. However, the intent of this procedure, with or without radiotherapy, should be resection of all tumor with the aim of cure since the place of palliative exenteration is controversial at best. The operative details of exenteration are presented, as are two surgical approaches to composite resection of pelvic structures in continuity with sacrectomy. Filling the pelvis with large tissue flaps, usually a rectus abdominus flap, has decreased morbidity rates, particularly with small bowel complications. Peri-operative mortality is usually 5% to 10%, and significant morbidity occurs in over 50% of patients. Restorative techniques for both urinary and gastrointestinal tracts can diminish the need for stomas and, along with vaginal reconstruction, can significantly improve quality of life for many patients after exenteration. These advances in surgery and radiotherapy help make the procedure a viable option for patients with otherwise incurable pelvic malignancy.

Development and evolution of pelvic exenteration: historical notes

Fifty years after the development of pelvic exenteration, the operation remains a gold standard in the surgical management of advanced pelvic malignancy. The operation has evolved through several predictable phases including technical improvements, lowered morbidity and mortality, and improved patient selection. Despite progress in supportive peri-operative care, pelvic exenteration is a major undertaking that should be performed in centers with proven interest and expertise in the field. We trace the early developments of the operation, the period of maturation, and the current place of this procedure in the armamentarium of the oncologic surgeon.

Exenterative pelvic surgery

A review of the history, indications, basic technique, end results, and complications of exenterative surgery for pelvic neoplasms is provided. The authors discuss their broad personal experience with the operation. Much of this experience evolved from work at Barnes Hospital and the Ellis Fischel State Cancer Hospital. The techniques are applicable to advanced neoplasms of the cervix uteri, scrotum, urinary bladder, and other, less frequent neoplasms still confined to the pelvis.

Pelvic exenteration for carcinoma of the colon and rectum

Carcinoma of the colon and rectum is one of the most common causes of cancer deaths in the United States. The mortality of patients treated by surgery alone is 55% within 5 years of surgery. Despite efforts to decrease local recurrence and their concomitant problems of pain and disability, a significant number of patients will still have pelvic recurrences that carry a significant morbidity. In selected cases, pelvic exenteration may cure or provide palliation of the symptoms of colorectal carcinoma. Pre-operative evaluation is performed to detect signs of unresectability. During surgery, exploration is performed for evidence of metastases to the liver, omentum, and peritoneum, followed by an assessment of the local extent of the tumor. The margins of resection must be clear even if resection of contiguous organs or bony structures is necessary. The urinary tract is resected with an ileal loop, sigmoid or transverse colon conduits, or continent urinary diversion. Depending upon the involvement of neighboring structures, exenterative pelvic surgery can be modified for organ preservation.

Pelvic exenteration for advanced pelvic malignancy

Pelvic exenteration is a demanding, yet potentially curative operation, for patients with advanced pelvic cancer. The majority will present with recurrence after prior surgery and radiotherapy. After exenteration, 5-year survival is 40% to 60% in patients with gynecologic cancer as compared to 25% to 40% for patients with colorectal cancer. Physiologic age and absence of co-morbidities appear to be more important when selecting patients for exenteration than chronological age. Careful pre-operative staging, including either computed tomography (CT) scan or magnetic resonance imaging (MRI), usually will identify patients with distant metastases, extrapelvic nodal disease, or disease involving the pelvic sidewall (which generally precludes surgery). The recent application of intra-operative radiotherapy or postoperative high-dose brachytherapy for patients with more advanced pelvic disease, which may include sidewall involvement, may expand the standard indications for exenteration. However, the intent of this procedure, with or without radiotherapy, should be resection of all tumor with the aim of cure since the place of palliative exenteration is controversial at best. The operative details of exenteration are presented, as are two surgical approaches to composite resection of pelvic structures in continuity with sacrectomy. Filling the pelvis with large tissue flaps, usually a rectus abdominus flap, has decreased morbidity rates, particularly with small bowel complications. Peri-operative mortality is usually 5% to 10%, and significant morbidity occurs in over 50% of patients. Restorative techniques for both urinary and gastrointestinal tracts can diminish the need for stomas and, along with vaginal reconstruction, can significantly improve quality of life for many patients after exenteration. These advances in surgery and radiotherapy help make the procedure a viable option for patients with otherwise incurable pelvic malignancy.

The influence of pre-operative radiation therapy on the patterns of recurrence in rectal adenocarcinoma

From January 1976 to December 1994, we evaluated the institutional experience of local recurrence and survival in patients with rectal adenocarcinoma treated with pre-operative radiation therapy (PRT) as compared to those treated with radical surgery alone. There were 412 patients, divided into two groups: 259 patients (142 males and 117 females) in Group I and 153 patients (88 males and 65 females) in Group II. The median age was 56 years. Group I patients with locally advanced tumors, either tethered or fixed, received PRT at doses of 45 Gy delivered to the pelvis in two fields; 4 to 8 weeks later, radical surgery was performed. Patients with mobile tumors underwent radical surgery only (Group II). The operative mortality was 4.6% in Group I as compared to 1.9% in Group II (P = 0.18). At median follow-up of 89 months, there were local recurrences in 12.9% of Group I as compared to 36.2% in Group II (P = 0.0000001). The administration of PRT was associated with a low rate of local recurrence, but this improvement corresponded with a high morbidity rate, especially in patients who underwent abdominoperineal resection or pelvic exenteration.

An in vitro biomechanical comparison of an interlocking nail system and dynamic compression plate fixation of ostectomized equine third metacarpal bones

OBJECTIVE

To compare the mechanical properties of two stabilization methods for ostectomized equine third metacarpi (MC3): (1) an interlocking nail system and (2) two dynamic compression plates. Animal or Sample Population-Ten pairs of adult equine forelimbs intact from the midradius distally.

METHODS

Ten pairs of equine MC3 were divided into two test groups (five pairs each): caudocranial four-point bending and torsion. Interlocking nails (6 hole, 13-mm diameter, 230-mm length) were placed in one randomly selected bone from each pair. Two dynamic compression plates one dorsally (12 hole, 4.5-mm broad) and one laterally (10 hole, 4.5-mm broad) were attached to the contralateral bone from each pair. All bones had 1 cm mid-diaphyseal ostectomies. Five construct pairs were tested in caudocranial four-point bending to determine stiffness and failure properties. The remaining five construct pairs were tested in torsion to determine torsional stiffness and yield load. Mean values for each fixation method were compared using a paired t-test within each group. Significance was set at P<.05.

RESULTS

Mean (+/-SEM) values for the MC3-interlocking nail composite and the MC3-double plate composite, respectively, in four-point bending were: composite rigidity, 3,454+/-407.6 Nm/rad and 3,831+/-436.5 Nm/rad; yield bending moment, 276.4+/-40.17 Nm and 433.75+/-83.99 Nm; failure bending moment, 526.3+/-105.9 Nm and 636.2+/-27.77 Nm. There was no significant difference in the biomechanical values for bending between the two fixation methods. In torsion, mean (+/-SEM) values for the MC3-interlocking nail composite and the MC3-double plate composite were: composite rigidity, 124.1+/-16.61 Nm/rad and 262.4+/-30.51 Nm/rad; gap stiffness, 222.3+/-47.32 Nm/rad and 1,557+/-320.9 Nm/rad; yield load, 94.77+/-7.822 Nm and 130.66+/-20.27 Nm, respectively. Composite rigidity, gap stiffness, and yield load for double plate fixation were significantly higher compared with interlocking nail fixation in torsion.

CONCLUSIONS

No significant differences in biomechanical properties were identified between an interlocking nail and double plating techniques for stabilization of ostectomized equine MC3 in caudocranial four-point bending. Double plating fixation was superior to interlocking nail fixation in torsion.

Massive fetomaternal hemorrhage: how long should children with good evolution be controlled? A case report

We report on a term infant with a severe fetomaternal hemorrhage that caused a serious anemia that was surmounted after several transfusions. After the initial complications, such as persistent pulmonary circulation, severe anemia and thrombocytopenia, the outcome was good. We discuss the importance of a long-term follow-up of affected children, as well as their mothers. No clear parameters for a real prognosis are available. A follow-up is needed in order to detect possible complications in neurological development.

The effect of radiofrequency energy on the ultrastructure of joint capsular collagen

This study evaluated the effect of radiofrequency energy on the histological and ultrastructural appearance of joint capsular collagen. Femoropatellar joint capsular specimens from adult sheep were treated with one of three treatment temperatures (45 degrees C, 65 degrees C, and 85 degrees C) with a radiofrequency generator or served as control in a randomized block design. Twenty-four specimens (n = 6) were processed for histological examination as well as ultrastructural analysis using transmission electron microscopy. A computer-based area determination program was used to calculate the area affected in histological samples. Histological changes consisted of thermal tissue damage characterized by collagen fiber fusion and fibroblastic nuclear pyknosis at all application temperatures with clear demarcations between treated and untreated tissue. Mean tissue affected ranged from 50.4% for 85 degrees C to 22.5% for 45 degrees C. There was a strong correlation between treatment temperature and percent area affected (P < .001, R2 = .65). Ultrastructural alterations included a general increase in cross-sectional fibril diameter and loss of fibril size variation with increasing treatment temperature. Longitudinal sections of collagen fibrils showed increased fibril diameter and the loss of cross-striations in the treated groups. Thermally induced ultrastructural collagen fibril alteration is likely the predominant mechanism of tissue shrinkage caused by application of radiofrequency energy.

Urinary obstruction in a hermaphroditic llama

A 24-hour-old cria was admitted for evaluation of stranguria evident shortly after birth. On physical examination, the prepuce appeared to be normally formed and small drops of fluid dripped from it as the cria strained to urinate. Testes could not be palpated. Ultrasonographic examination revealed that the bladder was distended. The only abnormality detected on serum biochemical analysis was high creatinine concentration. Tube cystostomy was performed, and the cria was treated with saline (0.9% NaCl) solution administered intravenously and antibiotics. Four days after admission, the cria could not urinate normally when the cystostomy tube was occluded. Five days after admission, normograde cystography and retrograde urethrography were performed. Radiographic findings indicated the cria was an intersex llama with urethral duplication. The llama was euthanatized at the owner's request. Necropsy revealed bilateral ovotestes with a phenotypically female reproductive tract and urethral duplication. Urethral duplication should be considered as a cause of stranguria in male neonatal crias, and hermaphroditism should be included as a cause of urethropathies in llamas.

Disruption of the guanylyl cyclase-C gene leads to a paradoxical phenotype of viable but heat-stable enterotoxin-resistant mice

Heat-stable enterotoxins (STa), which cause an acute secretory diarrhea, have been suggested to mediate their actions through the guanylyl cyclase-C (GC-C) receptor. The GC-C gene was disrupted by insertion of neo into exon 1 and subsequent homologous recombination. GC-C null mice contained no detectable GC-C protein. Intestine mucosal guanylyl cyclase activity was approximately 16-fold higher in wild-type mice than in the GC-C null mice, and STa-stimulable guanylyl cyclase activity was absent in the null animals. Thus, GC-C is the major cyclase activity present in the intestine, and also completely accounts for the STa-induced elevations of cGMP. Gavage with STa resulted in marked fluid accumulation within the intestine of wild-type and heterozygous suckling mice, but GC-C null animals were resistant. In addition, infection with enterotoxigenic bacteria that produce STa led to diarrhea and death in wild-type and heterozygous mice, while the null mice were protected. Cholera toxin, in contrast, continued to cause diarrhea in GC-C null mice, demonstrating that the cAMP signaling pathway remained intact. Markedly different diets (high carbohydrate, fat, or protein) or the inclusion of high salt (K+, Na+) in the drinking water or diet also did not severely affect the null animals. Given that GC-C is a major intestinal receptor in all mammals, the pressure to retain a functional GC-C in the face of diarrhea-inflicted mortality remains unexplained. Therefore, GC-C likely provides a protective effect against stressors not yet tested, possibly pathogens other than noninvasive enterotoxigenic bacteria.

The guanylyl cyclase-deficient mouse defines differential pathways of natriuretic peptide signaling

A genetic model of salt-resistant hypertension has been developed recently through disruption of the guanylyl cyclase-A (GC-A) natriuretic peptide receptor gene (Lopez, M. J., Wong, S. K., Kishimoto, I., Dubois, S., Mach, V., Friesen, J., Garbers, D. L., and Beuve, A. (1995) Nature 378, 65-68). These genetically altered mice were used to determine which of the natural peptides with natriuretic peptide-like structures regulate blood pressure through the GC-A receptor. Atrial natriuretic peptide (ANP) or B-type natriuretic peptide (BNP) half-maximally relaxed precontracted aortic rings in wild-type mice at about 24 nM, but failed to relax such aortas in GC-A null mice, even at micromolar concentrations. C-type natriuretic peptide (CNP), in contrast, caused half-maximal relaxation at concentrations of 335 and 146 nM in aortas from either wild-type or null mice, respectively, suggesting that this peptide acted through a receptor other than GC-A. Since the in vitro results with aortic smooth muscle do not necessarily reflect the physiology of the smaller blood vessels important in blood pressure regulation, the blood pressures of conscious mice infused with the various peptides were determined. ANP caused decreases in blood pressure when infused at rates of 500 ng/kg/min, a rate which resulted in a plasma concentration of 0.8 nM. In the null mice, in contrast, ANP failed to lower blood pressure even at infusion rates of 50 microg/kg/min. Much higher infusion rates for CNP (50 microg/kg/min), which yielded final plasma concentrations of 18.3 nM, were required to lower blood pressure in wild-type mice, but the effects of CNP were not altered in GC-A null mice. Thus, two natriuretic peptides (ANP, BNP) act through GC-A whereas another (CNP) acts through another receptor to regulate blood pressure.

Craniad migration of differing doses of new methylene blue injected into the epidural space after death of calves and juvenile pigs

OBJECTIVE

To determine the relation between epidural injectate volume (ml/kg of body weight) and its craniad migration in calves and pigs.

ANIMALS

23 neonatal calves and 26 feeder pigs.

PROCEDURE

Animals were randomly assigned to receive different volumes of new methylene blue (NMB, 1.2 mg/ml in 0.9% saline solution). Injections were made into the sacrococcygeal intervertebral space in calves and the lumbosacral intervertebral space in pigs, immediately after euthanasia. Sagittal sections of the spine were made at necropsy, and craniad migration of NMB was determined and rounded to the nearest intervertebral space.

RESULTS

In calves treated with 0.05, 0.1, or 0.15 ml of NMB/kg, mean +/- SEM number of stained spinal segments was 5 +/- 0.3, 8 +/- 0.6, and 8 +/- 0.6, respectively. Craniad migration of NMB was significantly greater for 0.15 and 0.1 ml/kg volumes versus 0.05 ml/kg. In pigs treated with 0.05, 0.1, 0.2, of 0.3 ml of NMB/kg, mean number of stained spinal segments was 8 +/- 1.1, 8 +/- 0.9, 10 +/- 1.2, and 18 +/- 2.0. Craniad dye migration was significantly greater in the 0.3 ml/kg group versus the 3 lower volume groups. Linear regression performed on both sets of data after logarithmic transformation of spaces migrated to correct for non-normality was significant (P < 0.05), and R2 values of 0.49 and 0.55 were obtained for calves and pigs, respectively.

CONCLUSIONS

There is a significant correlation between volume (ml/kg) of NMB injected in the epidural space and its craniad migration in calves and pigs.

CLINICAL RELEVANCE

Results provide a basis for determination of volume of injectate to be given to reach a minimal desired level and should be a useful baseline for future investigations of epidural drug administration.

Anal leiomyoma in a Holstein heifer

A 2-year-old heifer was presented with masses on her anus that were interfering with cervical manipulation during embryo flushing. The masses had broad stalks attached within the anal sphinchter. Recovery was without incident after surgical resection. No recurrence of the masses had occurred 3 months later. Histologic diagnosis was benign leiomyoma.

Twenty-year follow-up of minimal breast cancer from the Breast Cancer Detection Demonstration Project

Since the 1960s, the potential benefits of early detection of breast cancer through screening with physical examination and mammography have been studied. In a mass screening study begun in 1973 by the Breast Cancer Detection Demonstration Project (BCDDP), mammography detected 90% of the cancers that were diagnosed. Of the women aged 35 to 74 years from the BCDDP study who were diagnosed with minimal breast cancer, the 20-year cumulative breast cancer survival rates were 95.8% for 469 women with in situ breast cancer and 82.8% for 769 women with invasive breast cancers 1 cm or smaller in size.