Estimate of serum immunoglobulin G concentration using refractometry with or without caprylic acid fractionation

Objectives of this study were to develop a rapid calf-side test to determine serum IgG concentrations using caprylic acid (CA) fractionation, followed by refractometry of the IgG-rich supernatant and compare the accuracy of this method with results obtained using refractometry using raw serum. Serum samples (n=200) were obtained from 1-d-old calves, frozen (-20°C), and shipped to the laboratory. Samples were allowed to thaw for 1h at room temperature. Fractionation with CA was conducted by adding 1mL of serum to a tube containing 45, 60, or 75µL of CA and 0.5, 1.0, or 1.5mL of 0.06 M acetic acid. The tube contents were mixed well, allowed to react for 1 min, and then centrifuged at 3,300 × g for 0, 10, or 20 min at 25°C. The %Brix and refractive index of the fractionated supernatant were determined using a digital refractometer. Nonfractionated serum was analyzed for %Brix (BRn), refractive index (nDn), and IgG concentration by radial immunodiffusion. The mean serum IgG concentration was 19.0 mg/mL [standard deviation (SD)=9.7], with a range of 3.5 to 47.0 mg/mL. The mean serum BRn was 8.6 (SD=0.91), with a range of 6.8 to 11.0. The mean serum nDn was 1.34566 (SD=0.00140), with a range of 1.34300 to 1.34930. Serum nDn was positively correlated with IgG concentration (correlation coefficient=0.86; n=185). Fractionated samples treated with 1mL 0.6 M acetic acid and 60µL of CA and not centrifuged before analysis resulted in a strong relationship between the refractive index of the fractionated supernatant and IgG (correlation coefficient=0.80; n=45). Regression was used to determine cut points indicative of 10, 12, and 14 mg of IgG/mL to determine the sensitivity and specificity of refractometry to identify failure of passive transfer (serum IgG <10 mg/mL at 24 h old). The nDn were 1.34414, 1.34448, and 1.34480 to predict 10, 12, and 14 mg of IgG/mL of serum, respectively. The BRn cut points were 7.6, 7.8, and 8.0, respectively. The nDn cut points of 1.34448 and 1.34480 resulted in similar specificities (82.9%), whereas the 1.34414 cut point had a specificity of 60.0%. The BRn cut point of 7.6 and 7.8%Brix resulted in a similar percentage of correctly classified samples (89.7 and 90.8%, respectively); however, the 7.8% Brix cut point resulted in fewer false positives. These results suggest that Brix refractometry of nonfractionated calf serum provides a strong estimate of IgG concentration and 7.8% Brix may be used as the cut point to identify failure of passive transfer in 1-d-old calves.

Nationwide evaluation of quality and composition of colostrum on dairy farms in the United States

The objective of this study was to characterize the quality of maternal colostrum (MC) fed to newborn dairy calves in the United States and identify the proportion of MC that meets industry standards for IgG concentration and total plate count (TPC). Samples of MC (n=827) were collected from 67 farms in 12 states between June and October 2010. Samples were collected from Holsteins (n=494), Jerseys (n=87), crossbred (n=7), and unidentified dairy cattle (n=239) from first (n=49), second (n=174), third or greater (n=128), and unknown (n=476) lactations. Samples were identified as fresh (n=196), refrigerated (n=152), or frozen (n=479) before collection, as well as whether the sample was from an individual cow (n=734) or pooled (n=93). Concentration of IgG in MC ranged from <1 to 200mg/mL, with a mean IgG concentration of 68.8 mg/mL (SD=32.8). Almost 30% of MC contained <50 mg of IgG/mL. The IgG concentration increased with parity (42.4, 68.6, and 95.9 mg/mL in first, second, and third and later lactations, respectively). No differences in IgG concentration were observed among breeds or storage method; however, IgG was highest in samples collected in the Midwest and lowest in samples collected in the Southwest (79.7 vs. 64.3 mg/mL). Total plate count of samples ranged from 3.0 to 6.8 log(10) cfu/mL, with a mean of 4.9 log(10) cfu/mL (SD=0.9) and was greater in samples collected in the Southeast compared with other regions of the country. Pooled samples had greater TPC than individual samples and refrigerated samples had greater TPC than frozen and fresh samples. Almost 43% of samples collected had TPC >100,000 cfu/mL, 16.9% of the samples had >1 million cfu/mL. Only 39.4% of the samples collected met industry recommendations for both IgG concentration and TPC. Almost 60% of MC on dairy farms is inadequate, and a large number of calves are at risk of failure of passive transfer or bacterial infections, or both. Also, the data indicate that regional differences exist in colostrum quality.

Impact of irradiation and immunoglobulin G concentration on absorption of protein and immunoglobulin G in calves fed colostrum replacer

The objective of this study was first to evaluate whether irradiation treatment of a commercial colostrum replacer (CR) affected acquisition of passive immunity. If the irradiation treatment negatively affected the acquisition of passive immunity, the second objective was to evaluate whether an increased total IgG mass, in a single feeding of CR derived from bovine serum fractions, could compensate for this effect. Acquisition of passive immunity was assessed by 24-h serum IgG levels, serum protein levels, apparent efficiency of absorption (AEA) of IgG, and the ability to prevent failure of passive transfer (FPT) in day-old dairy calves fed a single feeding of CR. Single-dose packs of CR were sent to a commercial irradiation facility for electron-beam irradiation at 3 to 7 kGy (low irradiation) or 15 to 20 kGy (high irradiation). Fifty-six Holstein, Jersey, or crossbred calves were randomly assigned to 1 of 5 treatments: 1) 130 g of IgG (460 g of CR), no irradiation; 2) 130 g of IgG (460 g of CR), low irradiation; 3) 160 g of IgG (518 g of CR), low irradiation; 4) 190 g of IgG (575.4 g of CR), low irradiation; and 5) 130 g of IgG (460 g of CR), high irradiation. All CR were reconstituted in water and mixed in a household blender to a constant solids concentration of 18.7%. Increasing doses of irradiation (130 g of Ig with no, low, or high irradiation) resulted in a linear decrease in 24-h serum IgG and AEA of IgG, and increased the percentage of calves with FPT. Increasing the IgG mass in the CR (130, 160, and 190 g of Ig with low irradiation) resulted in a linear increase in 24-h serum IgG and serum total protein levels, and a linear decrease in AEA of IgG. There was no effect of increasing the mass of IgG fed on the percentage of calves with FPT. The correlation between serum IgG and serum total protein at 24 h was positive; however, at 24 h the irradiation treatments reduced the serum IgG-to-serum total protein ratio. In this study, CR isolated from bovine serum, providing 130 g of IgG in the first feeding and receiving either no irradiation or a low irradiation treatment, was sufficient to prevent FPT in calves.

Comparison of the effects of nitric oxide donors and calcium channel blockers on the intrinsic myogenic tone of sheep isolated internal anal sphincter

BACKGROUND

Chronic anal fissure is associated with considerable pain and anal hypertonia. Numerous clinical studies attest to the effectiveness of individual nitro-containing drugs and organic calcium channel blockers in this condition but there are few comparative studies.

METHODS

Isolated segments of sheep internal anal sphincter were prepared for isometric tension recording. The effect of various drugs on myogenic tone was examined in the absence or presence of sodium orthovanadate (SOV), an agent used to mimic anal hypertonia by increasing myogenic tone.

RESULTS

All the drugs tested produced concentration-dependent inhibition of myogenic tone, with the maximum effect ranging from 66.4 per cent (verapamil) to 100 per cent (sodium nitroprusside). Sodium nitroprusside and diltiazem were the most potent, followed by glyceryl trinitrate (GTN), nifedipine and verapamil, which had similar potency, and finally nicorandil. The potency of GTN and diltiazem was reduced threefold in the presence of 1 mmol/l SOV. The combined effect of GTN and diltiazem was greater than the effect of either agent alone, even in the presence of 3 mmol/l SOV.

CONCLUSION

Nitro-containing drugs and organic calcium channel blockers are potent inhibitors of anal sphincter myogenic tone that may be used in combination to treat chronic anal fissure.

Effect of fructose-induced hypoglycemia on cessation of macromolecular transport in the neonatal calf

Fructose was used as a hypoglycemic agent to determine whether availability of glucose during early life mediates the cessation of intestinal transport of Ig (closure). Either glucose or fructose (100 g in 2 L of electrolyte solution) was fed to calves deprived of colostrum at 3, 6, 9, 12, 15, 18, and 21 h postpartum. Colostrum (1 kg) was fed to all calves at 24, 36, and 48 h postpartum. Venous blood was sampled, and plasma was harvested, for the measurement of glucose, fructose, insulin, and IgG. During the first 24 h, means for plasma glucose from calves treated with glucose and fructose, respectively, were 282 and 24 mg/dl. The latter value reflects the degree of hypoglycemia induced by feeding fructose. During the same period, corresponding concentrations of plasma fructose were 4 and 230 mg/dl. Plasma insulin concentrations for precolostral calves were 101 and 11 microU/ml for calves treated with glucose and fructose, respectively. Peak IgG concentrations were extremely low for both groups of calves, indicating that intestinal transport of Ig had virtually ceased by the end of the 24-h treatment period. Thus, fructose-induced hypoglycemia had no effect on the time of intestinal closure in the newborn calf.

Effect of insulin-induced hypoglycemia on cessation of macromolecular transport in the neonatal calf

The effect of hypoglycemia on the absorption of colostral Ig was studied in 12 neonatal calves. Hypoglycemic calves received 1 cc (100 units) of insulin at birth; control calves received 1 cc of saline. Two dietary regimens were imposed; colostrum was fed at birth or at 24 h. Glucose, insulin, and IgG were measured in venous blood. Insulin induced decreases in circulating glucose in insulin-treated calves from 12 to 42 h postnatally; insulin concentrations were significantly higher from 12 through 24 h. Concentrations of glucose also were decreased in calves deprived of initial colostrum compared with those fed at birth over the same period, although insulin concentrations were not different. Time of closure was delayed in insulin-treated calves relative to saline-treated calves (40 and 29 h, respectively) and in calves deprived of initial colostrum relative to those fed at birth (45 and 23 h, respectively). Glucose availability may influence timing of closure in the calf, although the decreased rate of absorption of IgG in hypoglycemic calves prevents them from realizing any benefit in peak IgG concentrations higher than those of their normoglycemic counterparts.

Hypoxia in neonatal calves: effect on selected metabolic parameters

The effect of reduced oxygen tension in arterial blood (hypoxic hypoxia) for 24 h postpartum on selected metabolic parameters was studied in 12 neonatal calves. During this period, inspired air for hypoxic calves contained 10.5% O2, whereas that for normoxic calves contained 21% O2. After 24 h, inspired air for all calves contained 21% O2. Three dietary treatments also were imposed during the initial 24-h period: colostrum at 0 and 12 h, whole milk at 0 and 12 h, or fasting. All calves were fed colostrum at 24, 36, and 48 h and whole milk at 60 and 72 h. Parameters included plasma glucose, lactate, fructose, and IgG; arterial blood gases; and pH. Arterial partial pressure of oxygen was maintained near 25 mm Hg throughout the period of hypoxia. Arterial partial pressure of carbon dioxide was unchanged during the period of hypoxia (approximately 45 mm Hg) but was lower (39 mm Hg) in posthypoxic calves. Glucose tended to be lower in hypoxic calves; however, this difference was not statistically significant. Hypoxic calves had significantly higher plasma lactate concentrations contributing to a progressive primary metabolic acidosis.

Hypoxia in neonatal calves: effect on intestinal transport of immunoglobulins

The effect of reduced oxygen tension in arterial blood (hypoxic hypoxia) for 24 h postpartum on the absorption of colostral Ig was studied in 12 neonatal calves. During this period, inspired air for hypoxic calves contained 10.5% O2, whereas that for normoxic calves contained 21% O2. After 24 h, inspired air for all calves contained 21% O2. Three dietary regimens also were imposed during the initial 24-h period: colostrum at 0 and 12 h, whole milk at 0 and 12 h, or fasting. Colostrum was fed to all calves at 24, 36, and 48 h. During the initial 24-h period, means for arterial partial pressure of oxygen were 26 and 73 mm Hg for hypoxic and normoxic calves, respectively. In those fed colostrum at 0 and 12 h, hypoxia extended the period of Ig absorption from 20 to 40.5 h. In calves fed whole milk or those that were fasted, no such effect was noted. These observations suggest that the effect of hypoxia on the cessation of Ig absorption by the small intestine is mediated through a secondary and as yet undetermined mechanism.

Treatment of chancroid. Comparison of sulfamethoxazole-trimethoprim with recommended therapies

Thirty-five men with chancroid were randomly treated with oral sulfisoxazole, sulfisoxazole and tetracycline, sulfamethoxazole-trimethoprim, or intramuscular streptomycin. The highest rate of cures were obtained in 13 of 13 patients treated with streptomycin and in ten of ten patients treated with sulfamethoxazole-trimethoprim. Only seven of nine patients treated with sulfisoxazole and five of eight treated with sulfisoxazole and tetracycline were cured. We conclude that the sulfamethoxazole-trimethoprim combination is as efficacious as streptomycin and probably superior to sulfisoxazole and tetracycline in the treatment of chancroid.

Primary extragenital cutaneous gonorrhea

A case report of a gonococcal pustule of the middle finger, presumably acquired from digital-genital contact, is presented herein. Gram stain and positive culture of the contents confirmed the diagnosis. The lesion resolved with drainage of the pustule and did not require systemic antibiotic therapy.