Prolonged bleeding time in cirrhotic patients: relationship to peripheral vasodilation and severity of cirrhosis

A prolonged bleeding time (> 540 s), measured with a Simplate single template device, was found in 0% of 50 patients with chronic hepatitis and 38% of 154 cirrhotic patients. Cirrhotic patients with a prolonged bleeding time (n = 59) had lower platelet counts (P < 0.001) and a longer prothrombin time (P < 0.001) and activated partial thromboplastin time (P < 0.001) compared with cirrhotic patients with a normal bleeding time (n = 95). A weak but significant negative correlation existed between the bleeding time and platelet count in cirrhotic patients (n = 154, r = -0.3668, P < 0.001). Patients with decompensated cirrhosis had a longer bleeding time in comparison to patients with compensated cirrhosis (621 +/- 39 vs 478 +/- 27 s, respectively, P < 0.01). The prolonged bleeding time was also discovered in 25% of 83 cirrhotic patients with a platelet count > 80 x 10(9)/L and a prothrombin time < 17 s (usually taken as safe limits for invasive procedures). Twenty-seven of the 83 cirrhotic patients received a haemodynamic study by Swan-Ganz catheterization. A lower systemic vascular resistance was found in cirrhotic patients with an abnormal bleeding time than in cirrhotic patients with a normal bleeding time (844 +/- 57 vs 1171 +/- 60 dyne.s.cm-5, respectively, P < 0.001), whereas both groups had similar hepatic venous pressure gradient (16.2 +/- 1.2 vs 18.1 +/- 1.4 mmHg, respectively, P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of tiletamine-zolazepam-ketamine and tiletamine-zolazepam-ketamine-xylazine anaesthesia in sheep

The anaesthetic effects of intravenous tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg (TK) and tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg-xylazine 0.11 mg/kg (TKX) were evaluated in six wethers. Heart rate, respiration rate, arterial blood pressure, and the electrocardiogram were monitored during anaesthesia. Analgesia was tested by electrical stimulation in the left flank. Atropine (0.03 mg/kg) was given intramuscularly before induction, but after recording of baseline heart rate and respiratory rate. The duration of analgesia was 28.7 +/- 6.9 min with TK and 82.8 +/- 26.6 min with TKX. Heart rate increased significantly within 5 min after TK or TKX administration. Respiratory rate remained unchanged after TK administration, but increased significantly from 5 to 45 min after TKX administration. Arterial blood pressure decreased significantly at 15 min with TK and 30 min with TKX. Sheep remained recumbent for 201 min with TK and 166 min with TKX. All recovered uneventfully. We conclude that either TK or TKX may be used for anaesthetising sheep.

Rearrangement and altered expression of the NFKB-2 gene in human cutaneous T-lymphoma cells

The NF-kappa b/Rel and I kappa B proteins are important regulators of lymphocyte activation and gene expression. We have identified a rearrangement of the NFKB-2 gene in the HUT 78 human cutaneous T-cell leukemia (CTCL) line, cDNA and genomic DNA sequence predicted the presence of a truncated 80 kD NFKB-2 precursor protein (p80HT), instead of the normal p100 protein. No wild-type allele was identified. Elevated levels of two aberrantly sized RNAs were detected, and high levels of p80HT and processed p52 protein were present in HUT 78 cell nuclei. The p52 protein bound to a palindromic kappa B DNA motif, however p80HT did not. Rearrangement of the NFKB-2 gene was also detected in DNA from two patients with CTCL. Rearrangement and overexpression of the NFKB-2 gene may contribute to the genesis of a subset of T-cell malignancies.

Assessing cognitive abilities and dementia in a predominantly illiterate population of older individuals in Kinmen

A community survey of dementia was conducted on a Chinese islet. A total of 221 men and 234 women in the age range of 50-92 were assessed. The Cognitive Abilities Screening Instrument (CASI), a 100-point cognitive test designed for cross-cultural studies and adapted in Chinese for individuals with little or no formal education, was administered twice by trained field workers with a retest interval of 3 to 4 weeks. In addition, all participants were assessed by physicians who did not know the CASI scores. The physicians' assessment included a complete neurological examination, plus semi-structured tests and interviews covering cognitive abilities, daily activities, depression, cerebrovascular disease, and Parkinson's disease. Dementia was diagnosed by consensus among the physicians according to the DSM-III-R criteria. Among the 455 participants, 16 cases of dementia were identified, including 13 with probable Alzheimer's disease and 1 each with vascular dementia, Parkinson's disease, and alcoholism. The rates of dementia were 0, 3.9 and 11.5% for the age groups of 50-69, 70-79 and 80-92; and 4.4, 2.0 and 0% for the education groups of 0-1, 2-6 and 7-15 years of schooling. No sex difference was found after controlling for education. The Chinese version of the CASI had an intraclass retest reliability of 0.90. Using a cut-off score of < or = 50 for dementia, the sensitivity was 0.88 and the specificity was 0.94. The preliminary study suggests that the CASI can be used in Chinese populations with generally low education levels and that Alzheimer's disease was the most common type of dementia in this population.

Stress fractures of the ribs in amateur golf players

BACKGROUND

Stress fractures of the ribs are sometimes seen at the Outpatient Department in patients with a history of playing golf enthusiastically. Many are diagnosed as "muscle strain" or "myofascial pain" and patients are simply advised to take some rest or are treated with analgesics and local injection. This case study investigated 11 amateur golfers whose chief complaint was anterior, posterior or lateral chest pain. After X-ray and bone scan evaluation, "stress fracture of the ribs" was diagnosed. A questionnaire presented to them trying to find the possible mechanisms of these stress fractures. Biomechanical analysis showed that the bending force of the ribs was located at posterolateral segments where fractures tend to occur. Overuse, poor technique and inadequate stretch in beginners are postulated as causes for apparent increased susceptibility to these skeletal injuries.

METHODS

Questionnaires inquired about (1) warm-up time, (2) number of strikes, (3) fracture sites, (4) pain patterns, (5) combined injuries.

RESULTS

All 11 patients were beginners with right side hand dominance who had begun to play golf within the year. Right side ribs fracture occurred in six cases; left side ribs fracture occurred in eight cases including three patients with two fracture sites. Localized pain was reported in six cases and there were five cases with radiating pain along costal margins. All the golfers had spent no more than 10 minutes in warm up them. Seven patients suffered from multiple injuries after they had played. Five were diagnosed by X-ray and six showed positive finding after Tc-99m MDP bone scan. All lesions were located at the posterolateral segments of the ribs.

CONCLUSIONS

Stress fractures of the ribs in amateur golfers are certainly not uncommon. Predominant muscle forces are generated by forced coupling of scapular retraction and protraction, acting through the serratus anterior. With early diagnosis and relative rest for four to eight weeks, the pain will improve. Overuse, poor technique and inadequate stretch will probably lead to stress fracture of the rib.

Milk production in cows with endotoxin-induced mastitis treated with isotonic or hypertonic sodium chloride solution

Milk production was monitored in 16 cows for 6 milkings after intramammary infusion of 1 mg of endotoxin in a single forequarter. The cows were randomly assigned to 1 of 2 treatment groups; 8 cows were treated with isotonic saline solution and 8 cows were treated with hypertonic saline solution. Saline solutions were administered IV (5 ml/kg of body weight) 4 hours after infusion of endotoxin. Mean cumulative change in milk yield and interval change in milk yield were greater in cows treated with isotonic saline solution than in cows treated with hypertonic saline solution. Significant differences between treatment groups were not detected.

Molecular subtypes of env sequences around V3 region of human immunodeficiency virus type 1 in Taiwan

Samples of peripheral blood mononuclear cells (PBMC) were collected during 1990-91 from seropositive healthy, male HIV-1 carriers visiting Taipei Venereal Disease Control Center, and a male AIDS patient admitted to a general hospital. The V3 and its flanking nucleotide (nt) sequences in their DNA were amplified by polymerase chain reaction (PCR) and compared with those of known HIV-1 prototypes. The nt sequences obtained from 21 individuals (e.g., TW92) clustered as Group A, which were highly homologous (95.6-99.5%) to that of HXB2 virus while those from 6 individuals (TW90, TW91, TW97, TW99, TW102 and TW104) were classified as Group B showing low similarities (73.2-84.2%) to those of HXB2 and moderate similarities (80.7-90.0%) to those of SC and Bangkok (BK) viruses. By comparison of their deduced amino acid sequences with those of consensus sequences for subtypes A-F as defined by Myers et al. (1993), both Groups A and B viruses (except TW102) together with those of HXB2, SC and BK viruses could be identified as members or variants of subtype B, and the TW102 virus as a member of subtype E viruses. Individuals with the Group A viruses included 4 homosexual and 17 heterosexual Taiwanese males, 2 of the latter having a history of i.v. drug abuse. Among individuals with Group B viruses, those with TW97, TW99, TW104 and TW91, who was an AIDS patient, were heterosexual Taiwanese males, whereas both TW90 and TW102 viruses were from individuals who were overseas heterosexual Chinese from Thailand, the former with a history of i.v. drug abuse and the latter without.

FL-120A-D', new products related to kinamycin from Streptomyces chattanoogensis subsp. taitungensis subsp. nov. I. Taxonomy, fermentation and biological properties

Six new kinamycin antibiotics, designated as FL-120A-D' (1-6) were isolated from the culture filtrate of Streptomyces sp. strain IY2-13. Based on its cultural, physiological, morphological and chemical characteristics, this strain was identified as a new subspecies of Streptomyces chattanoogensis and named S. chattanoogensis subsp. taitungensis. These kinamycins have demonstrated a potent activity against Gram-positive aerobic and anaerobic bacteria.

Elevated serum levels of TNF soluble receptors in patients with positive anti-neutrophil cytoplasmic antibodies

ANCA are found in various systemic vasculitis and are supposed to play a role in the pathogenesis of the disease, in co-operation with other factors such as cytokines. A total of 36 ANCA-positive and 10 ANCA-negative serum samples were analysed for the presence of TNF soluble receptors (TNF-sR), which are shed from the surface of activated cells and may act as TNF inhibitors. Of the ANCA-positive samples, 67% had elevated TNF-sR75 and 72% had elevated TNF-sR55 compared to ANCA-negative specimens (mean [S.E.] 18.7 [17.3] vs 3.6 [1.5] and 10.5 [9.7] vs 1.9 [0.7] ng/ml, P < 0.01). Elevation of TNF-sR in patients with ANCA suggests that cytokines and their inhibitors are involved in the pathogenesis of ANCA-associated autoimmune diseases.

Stimulation of duodenal motility by hyperosmolar mannitol depends on local osmoreceptor control

Duodenal motility is stimulated by hyperosmolar solution. Since intestinal distension also stimulates intestinal motility, this increase in the motility response may be due to either stimulation of duodenal local osmoreceptor control or intestinal distension resulting from osmotic equilibration. To test which mechanism is primarily responsible for this osmotically sensitive effect, we compared the number of duodenal spike bursts in five dogs equipped with duodenal fistulas that allowed for the preservation or removal of intestinal distension. The response to 300 vs. 1,200 mosM mannitol was compared under three experimental perfusion methods: 1) distension was preserved both proximal and distal to the fistula (DD); 2) distension proximal to the fistula was removed (rD); and 3) distension both proximal and distal to the fistula was removed (rr). The test solutions had access to either the whole gut (DD and rD) or only the first 10 cm of the duodenum (rr). We found that 1) there were more spike bursts after the hyperosmolar solution (dose effect, P < 0.05, analysis of variance); 2) there was no significant difference between the three experimental methods; and 3) the stimulating effect of hyperosmolar solution depended on the first 10 cm of the duodenum. Thus, since hyperosmolar solution increased duodenal motility regardless of whether intestinal distension was preserved or removed, the stimulating effect of hyperosmolar solution on duodenal motility was primarily the result of a local osmoreceptor control mechanism located in the first 10 cm of the duodenum.

Relationships between the severity of cirrhosis and haemodynamic values in patients with cirrhosis

The relationship between the severity of cirrhosis and systemic and hepatic haemodynamic values was evaluated in 193 patients with cirrhosis, most of whom were diagnosed with post-necrotic cirrhosis. It was found that the hepatic venous pressure gradient and cardiac output in Pugh's A patients (13.6 +/- 4.8 mmHg and 6.2 +/- 1.6 L/min, mean +/- s.d.) were significantly lower than in both Pugh's B (16.8 +/- 4.3 mmHg and 7.3 +/- 2.1 L/min) and Pugh's C (18.8 +/- 5.5 mmHg and 7.4 +/- 2.3 L/min) patients (P < 0.01), respectively. In contrast, the systemic vascular resistance in Pugh's A patients (1232 +/- 369 dyn/s per cm5) was significantly higher than in both Pugh's B (1016 +/- 345 dyn/s per cm5) and Pugh's C (935 +/- 234 dyn/s per cm5) patients (P < 0.01), respectively. Additionally, not only was there a positive correlation found between Pugh's score and cardiac output and hepatic venous pressure gradient, but a negative correlation was found between Pugh's score and systemic vascular resistance. It was also confirmed that the degree of portal hypertension and the hyperdynamic circulation were more severe in patients with ascites than in those without ascites. However, there were no statistically significant differences in hepatic venous pressure gradient among patients with F1, F2 and F3 esophageal varices (15.7 +/- 4.0, 17.0 +/- 4.8 and 18.0 +/- 4.8 mmHg, respectively). It is concluded that in those patients with cirrhosis, the severity of cirrhosis is closely related to the degree of the hyperkinetic circulatory state and portal hypertension.

On the molecular nature of the Duarte variant of galactose-1-phosphate uridyl transferase (GALT)

Galactosemia is an inborn error of galactose metabolism secondary to deficiency of galactose-1-phosphate uridyl transferase (GALT). GALT is a polymorphic enzyme and Duarte (D) is the most common enzyme variant. This variant is characterized by faster electrophoretic mobility and reduced activity. Duarte/galactosemia compound heterozygotes (D/G) are commonly identified in galactosemia newborn screening programs. However, these patients do not generally require treatment. By using a "candidate mutation" approach to define the molecular basis of the Duarte variant of GALT, a close association between the previously reported N314D polymorphism and the Duarte variant of GALT was found. We suggest that N314D encodes the D variant of GALT and that molecular testing for N314D might be useful to confirm a biochemical diagnosis of Duarte variant of GALT.

Study on the vascular reactivity and alpha 1-adrenoceptors of portal hypertensive rats

1. Vascular hyporesponsiveness in portal hypertension has been demonstrated to various vasoconstrictors including noradrenaline (NA). The present study aimed to determine whether the attenuated vascular responsiveness to NA is due to a change in the affinity or the number of alpha 1-adrenoceptors. 2. Partial portal vein ligation (PVL) was performed in Sprague-Dawley rats to produce portal hypertension. Vascular responsiveness to NA was assayed in portal vein, mesenteric artery or tail artery. The affinity and number of alpha 1-adrenoceptors were determined by specific binding of [125I]-HEAT (2-beta-4-hydroxy-3-iodophenyethyl-aminomethyltetralone). 3. In the presence of yohimbine (10(-7) M, an alpha 2-adrenoceptor antagonist), propranolol (10(-6) M, a beta-adrenoceptor antagonist), and two catecholamine uptake inhibitors, desipramine (10(-7) M) and normetanephrine (10(-6) M), the maximum responses to NA were decreased in all three blood vessels of PVL rats: 45% decrease in portal vein, 25% in mesenteric artery and 18% in tail artery. 4. The EC50 values of NA and the pA2 values of prazosin, an alpha 1-adrenoceptor antagonist, in all three blood vessels were not significantly different between sham-operated and PVL rats. 5. The KD and Bmax values for specific binding of [125I]-HEAT or the Ki values for NA in the crude membrane preparations of either mesenteric artery or tail artery were also not significantly different between the two groups. 6. It is concluded that the vascular hyporesponsiveness to NA in the mesenteric artery or tail artery of PVL rats is not due to changes in the affinity or number of alpha 1-adrenoceptors.

Clinical and clinicopathologic changes in cows with endotoxin-induced mastitis treated with small volumes of isotonic or hypertonic sodium chloride administered intravenously

We characterized the clinicopathologic manifestations of experimentally induced endotoxin-induced mastitis. Responses to hypertonic fluid therapy also were assessed. Eight cows received 1 mg of endotoxin by intramammary infusion in the left forequarter. Four hours after endotoxin administration, cows received 0.9% NaCl, 5 ml/kg of body weight (n = 4) or 7.5% NaCl, 5 ml/kg (n = 4) IV. Endotoxin-infused cows had expanded plasma volume, hyponatremia, transient hyperchloremia and hypophosphatemia, increased serum glucose concentration, and decreased serum activities of liver- and muscle-specific enzymes. Calculated plasma volume increased at 6 hours in cows receiving hypertonic NaCl, and at 12, 24, and 48 hours after endotoxin infusion in both groups. Concurrent observations of decreased serum protein concentration, erythrocyte count, and hematocrit supported observations of increased plasma volume. Relative plasma volume was greater in cows receiving hypertonic NaCl (124.3%) than in cows receiving isotonic NaCl (106.6%) at 6 hours after endotoxin infusion. Cattle receiving hypertonic NaCl had increased voluntary water intake after IV fluid administration. Increased water consumption was not accompanied by increased body weight, indicating probable occurrence of offsetting body water loss. Serum sodium concentration in cows receiving hypertonic NaCl was increased 2 hours after fluid administration, but the magnitude of the change was minimal (< 4 mmol/L) and transient, indicating rapid equilibration with either interstitial or intracellular spaces. Serum sodium concentration was decreased in cows receiving isotonic NaCl at 12, 24, and 48 hours after endotoxin administration, compared with concentration prior to endotoxin administration, indicating selective loss of sodium.

A case report on the use of guaifenesin-ketamine-xylazine anesthesia for equine dystocia

In 4 mares suffering from dystocia, general anesthesia was induced with xylazine (1.1 mg/kg, IV) and ketamine (2.2 mg/kg, IV) and maintained with continuous intravenous infusion of ketamine (2 mg/ml), xylazine (0.5 mg/ml) and guaifenesin (50 mg/ml) in 1 L of 5% dextrose. The duration of the procedure of these mares were 40, 45, 180, and 35 minutes, respectively. For procedures required more than 1 hour (Mare 3), the dose of ketamine and xylazine in the mixture was reduced to 1 mg/ml and 0.25 mg/ml, respectively. Average infusion rate of the mixture used to maintain anesthesia for each mare was 2.5, 2.67, 2.28, and 2.21 ml/kg/hr. Recovery to standing occurred at 55, 75, and 180 minutes after termination of infusion for mares 1, 2, and 3, respectively. Xylazine reversal agent, tolazoline (2.2 mg/kg), was given to mare 1 to hasten the recovery; the mare stood within 30 minutes after tolazoline administration. Continuous infusion of guaifenesin-ketamine-xylazine can be an alternative anesthetic technique for prolonged obstetrical procedures under field conditions when suitable anesthetic equipment is not available. If recovery to standing is extended over 30 to 40 minutes, yohimbine or tolazoline can be administered to hasten recovery.

Erythromycin accelerates solid emptying at the expense of gastric sieving

Erythromycin accelerates gastric emptying by inducing antral contractions similar to phase III of interdigestive MMC. These powerful contractions are capable of forcing coin-sized indigestibles out of the stomach. In contrast, fed motility is associated with submaximal contractions that fragment (trituration) and propel solids while retaining large (> 0.5 mm) pieces for further size reduction (gastric sieving). In this study, using dogs with duodenal fistulas, we tested the hypothesis that erythromycin-induced acceleration of gastric emptying resulted in the passage of inadequately triturated (> 0.05 mm) chunks of solids into the duodenum. We found that gastric emptying was accelerated by erythromycin (vs 0.15 M NaCl control, P < 0.05). However, the percentage of chyme collected in the > 0.5-mm fraction was much greater (P < 0.01) in the erythromycin-treated experiments (63 +/- 9%) than the controls (7 +/- 1%). Correspondingly, while a fine gruel was passed during controls, under erythromycin infusion, most of the solids were emptied as large chunks virtually unchanged from the swallowed pieces. We conclude that erythromycin accelerates gastric emptying at the expense of gastric sieving.

Malignancy-related ascites: a diagnostic pitfall of spontaneous bacterial peritonitis by ascitic fluid polymorphonuclear cell count

To define patients with an ascitic fluid polymorphonuclear cell count > or = 250 cells/mm3 or > or = 500 cells/mm3 but without spontaneous bacterial peritonitis, 166 patients with sterile cirrhotic ascites, 46 patients with spontaneous bacterial peritonitis, 123 patients with hepatocellular carcinoma, 67 patients with peritoneal carcinomatosis or massive liver metastasis and 12 patients with other miscellaneous diseases were studied. The sensitivity, specificity and accuracy of the diagnosis of spontaneous bacterial peritonitis were 100, 86 and 88% with the cut-off value of an ascitic fluid polymorphonuclear cell count > or = 250 cells/mm3; and were 93, 91 and 92% with that value > or = 500 cells/mm3, respectively. With the cut-off value > or = 250 cells/mm3 or > or = 500 cells/mm3, the prevalence was 18% or 14% in hepatocellular carcinoma; and 30% or 19% in peritoneal carcinomatosis or massive liver metastasis. The ascitic fluid lactate concentration was insensitive and nonspecific. Among the patients with an ascitic fluid polymorphonuclear cell count greater than the cut-off values, an ascitic fluid erythrocyte count > or = 10,000 cells/mm3, a ratio of ascitic fluid erythrocyte to total leukocyte count > or = 100, and the ratio of ascitic fluid polymorphonuclear cell to total leukocyte count < or = 75% indicated hepatocellular carcinoma, while serum to ascites albumin gradient < or = 1.1 g/dl and a ratio of ascitic fluid polymorphonuclear cell to total leukocyte count < or = 75% indicated peritoneal carcinomatosis or massive liver metastasis.

Effects of anesthesia induced and maintained by continuous intravenous administration of guaifenesin, ketamine, and xylazine in spontaneously breathing sheep

Anesthesia was induced and maintained in 6 Suffolk wethers by continuous i.v. infusion of guaifenesin (50 mg/ml), ketamine (1 mg/ml), and xylazine (0.1 mg/ml) in 5% dextrose in water (triple drip) to assess the anesthetic and cardiopulmonary effects. All sheep were positioned in right lateral recumbency. Dosages of triple drip used for induction and maintenance of anesthesia were 1.2 +/- 0.02 ml/kg and 2.6 ml/kg/h, respectively. Lack of gross purposeful movement of sheep to electrical stimulation indicated that analgesia and muscular relaxation induced by triple trip were adequate for surgical procedures. Heart rates and arterial blood pressure remained unchanged from baseline values during a 1-hour period of anesthesia. Arterial blood pressures were measured indirectly, using an inflation cuff placed over the metatarsal artery at the heart level. Significant decrease in arterial partial pressure of O2 (PaO2), coupled with an increase in arterial partial pressure of CO2 (PaCO2), from baseline values was observed throughout the course of the study. Decrease in PaO2 was observed concomitantly with significant (P < 0.05) increase in respiration rate. Changes in arterial blood gas tensions observed in this study were attributed to respiratory depressant effect induced by anesthetic drugs and right-to-left shunting, perfusion/ventilation mismatch, or both caused by right lateral recumbency. Administration of 100% O2 via the endotracheal tube reduced the magnitude of the decrease in PaO2. All sheep recovered smoothly and stood within 96.3 +/- 48.9 minutes after termination of triple drip administration.

Effects of reserpine administration in two models of portal hypertension in rats

The effects of reserpine were investigated in two models of portal hypertension in rats. Twenty-four hours after 1 mg/kg of reserpine was administered intraperitoneally to normal and portal vein stenosed rats, the cardiac index, mean arterial pressure, heart rate, and portal pressure were significantly decreased compared with normal and portal vein stenosed rats receiving placebo. In addition, the portal tributary blood flow was significantly decreased in portal vein stenosed rats receiving reserpine, but was unchanged in normal rats. In cirrhotic rats receiving a single dose of reserpine, 0.1 mg/kg intraperitoneally for 24 h, there were significant decreases in cardiac index, mean arterial pressure and heart rate compared with cirrhotic rats receiving placebo, while the portal pressure and portal tributary blood flow followed a decreasing trend after reserpine administration. The degree of hemodynamic change was similar in the groups of rats receiving reserpine, even though cirrhotic rats received lower doses than either normal or portal vein stenosed rats. This study suggests enhanced sympathetic nervous activity observed in cirrhotic rats.

Functional domains of the penicillinase repressor of Bacillus licheniformis

The penicillinase repressor (PENI) negatively regulates expression of the penicillinase gene (penP) in Bacillus licheniformis by binding to its operators located within the promoter region of penP.penI codes for a protein with 128 amino acids. Filter-binding analyses suggest that the active form of the repressor is a dimer. Genetic analyses of PENI derivatives showed that the repressor carrying either a 6-amino-acid deletion near the N terminus or a 14-amino-acid deletion at the C terminus was functionally inactive in vivo. A repressor derivative carrying a 6-amino-acid deletion within its N-terminal region was extensively purified and used in DNA footprinting and subunit cross-linking analyses. The results of these studies showed that the repressor derivative had lost its ability to bind operator specifically even though it could dimerize effectively. In similar studies, we demonstrated that an N-terminal portion of PENI with a molecular mass of 10 kDa derived by digestion with papain was able to bind operator specifically but with reduced affinity and had completely lost its ability to dimerize. These data suggest that the repressor has two functional and separable domains. The amino-terminal domain of the repressor is responsible for operator recognition, and the carboxyl-terminal domain is involved in subunit dimerization.

Nutrient feedback inhibition of gastric emptying plays a larger role than osmotically dependent duodenal resistance

The slowing of gastric emptying by hyperosmolar solutions has been postulated to result from the triggering of duodenal osmoreceptor feedback on the stomach. We tested the idea that the inhibition of gastric emptying by a hyperosmolar solution depended on the duodenal resistance and the triggering of nutrient-specific feedback by tracking gastric emptying of 300 and 1,200 mosmol/kgH2O test solutions in 12 dogs in which duodenal resistance was either removed (by temporarily diverting chyme from uncorked duodenal fistula) or preserved (by keeping duodenal fistula corked). Mannitol was used to test osmolality alone, and glucose was used to examine the combined effects of osmolality and nutrient-specific inhibitory feedback. We found that: 1) the slowing effect of hyperosmolality was more marked with the duodenal resistance preserved (P < 0.05; analysis of variance), 2) the slowing effect of glucose was greater than that of mannitol for all conditions (P = 0.01; analysis of variance), and 3) the inhibitory effect of mannitol was localized to the duodenum. We conclude that inhibition of gastric emptying by hyperosmolar mannitol depended primarily on duodenal resistance, while the inhibitory effect of hyperosmolar glucose depended on nutrient-specific feedback on the stomach more than duodenal resistance.

Influence of anesthetic regimens on the perioperative catecholamine response associated with onychectomy in cats

Plasma catecholamine concentrations in response to onychectomy were examined in 27 cats receiving different anesthetic regimens. Each cat was anesthetized with a dissociative-tranquilizer combination, and onychectomy was performed on 1 forefoot. One week later, each cat was anesthetized with the same dissociative-tranquilizer combination plus either butorphanol or oxymorphone, and onychectomy was performed on the other forefoot. Four treatment groups were studied: tiletamine-zolazepam and tiletamine-zolazepam-butorphanol combinations were administered to group-1 cats, ketamine-acepromazine and ketamine-acepromazine-butorphanol combinations were administered to group-2 cats, tiletamine-zolazepam and tiletamine-zolazepam-oxymorphone combinations were administered to group-3 cats, and ketamine-acepromazine and ketamine-acepromazine-oxymorphone combinations were administered to group-4 cats. All drug combinations were administered IM. Central venous blood samples were drawn for catecholamine analysis after injection of drug(s), after onychectomy, and 1, 2, and 4 hours after injection. Tiletamine-zolazepam alone or tiletamine-zolazepam-butorphanol prevented epinephrine release for 2 hours after injection of drug(s). Norepinephrine concentration increased significantly (P < 0.05) from baseline after onychectomy for tiletamine-zolazepam-butorphanol and at 4 hours for tiletamine-zolazepam and tiletamine-zolazepam-butorphanol. After onychectomy, there was no difference in epinephrine values between tiletamine-zolazepam and tiletamine-zolazepam-oxymorphone. Ketamine-acepromazine prevented increases in norepinephrine and epinephrine concentrations for up to 2 hours after surgery. Addition of butorphanol to ketamine-acepromazine decreased norepinephrine values immediately after onychectomy. Addition of oxymorphone to ketamine-acepromazine resulted in lower epinephrine values 4 hours after surgery.

Immunohistochemical study of catecholamine enzymes and neuropeptide Y (NPY) in the rostral ventrolateral medulla and bulbospinal projection

The purpose of this study was to determine whether neuropeptide Y (NPY) terminals in the intermediolateral spinal cord originate from the rostral ventrolateral medulla (RVLM). Immunohistochemical staining of tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH), phenylethanolamine-N-methyltransferase (PNMT), and NPY in the rat brainstem and spinal cord were performed in this study in order to examine consequences of lesions of the RVLM and of intracisternal injections of 6-hydroxydopamine (6-OHDA) on catecholamine and NPY immunoreactivity in the intermediolateral column (IML) of rats. In addition, ricin, a retrograde neurotoxin, was applied in the superior cervical ganglion (SCG) to determine its effect on catecholamine and NPY immunoreactivity in the IML. Computer-aided image analysis was used to quantify the immunohistochemical changes in the RVLM and spinal cord. The results demonstrated that many catecholamine- and NPY-containing neurons and/or fibers existed in the RVLM and their terminals were found in the IML. After administration of 6-OHDA intracisternally, the catecholamine and NPY immunoreactivities were decreased both in the brainstem and IML of the spinal cord. Following unilateral microinjection of 6-OHDA into the RVLM, the number of NPY- and catecholamine-containing neurons decreased and there was a reduction in neuron terminals on the ipsilateral side. After injection of ricin into the SCG, the catecholamine and NPY neurons of the medulla were not affected, whereas their terminals in the IML decreased ipsilaterally. These results indicate that most of the catecholamine- and NPY-immunoreactive terminals found in the IML originated in the RVLM. These terminals appear to project towards the superior cervical ganglia.

Hemostasis in cows with endotoxin-induced mastitis

Hemostasis was evaluated in cows with experimentally induced endotoxemia and mastitis, caused by intramammary infusion of endotoxin (1 mg) derived from Escherichia coli. Hemostatic tests included prothrombin time; activated partial thromboplastin time; thrombin time; fibrinogen, fibrin(ogen) degradation products, and platelet concentrations; and antithrombin-III and plasminogen activities. Significant alterations were observed in the mean values of most analytes (prothrombin time was increased; thrombin time was increased with subsequent decrease; activated partial thromboplastin time, fibrinogen concentration, plasminogen activity, and platelet concentration were decreased; and antithrombin-III activity and fibrin(ogen) degradation products concentration were unchanged) at 1 or more postchallenge sample collection times (3, 12, or 24 hours) after endotoxin administration, compared with mean values obtained from samples prior to endotoxin administration. These data indicated activation of hemostatic mechanisms, initiated either directly by endotoxin or by inflammatory mediators released or produced in response to endotoxin infusion.