Effect of postpartum calcium supplementation on serum calcium and parathyroid hormone concentrations in multiparous Holstein cows.

Although postpartum Ca supplementation strategies are often employed to prevent subclinical hypocalcemia in dairy cows, these strategies have produced a mix of beneficial, neutral, and detrimental results when assessing milk yield and subsequent disease outcomes. Because the mechanisms underlying these differing results are unknown, our objectives were to determine how common postpartum Ca supplementation strategies affect blood Ca concentrations and parathyroid hormone (PTH). We conducted a randomized controlled trial with 74 multiparous dairy cows on a commercial dairy in central New York. Cows were assigned to 1 of 4 supplementation groups immediately after calving: (1) control (CON; no Ca supplementation, n = 15); (2) conventional oral Ca supplementation (BOL-C; 43 g of oral Ca bolus administered immediately after calving and 24 h later, n = 17); (3) delayed oral Ca supplementation (BOL-D; 43 g of oral Ca bolus administered 48 and 72 h after calving, n = 15); or (4) subcutaneous infusion (SQ; 500 mL of 23% Ca borogluconate infused subcutaneously once immediately after calving, n = 15). Blood samples were collected immediately after calving (0 h) and at 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96, 120, and 168 h postpartum for a total of 15 blood samples per cow. Cows were excluded if administered Ca, via any route, by farm employees or if they died or were sold within 96 h following parturition, which left 62 cows for analysis. Linear mixed models, accounting for repeated measures, were created to analyze changes in serum total Ca (tCa) and PTH over the first 168 h after parturition and assess differences between supplementation groups. Serum tCa and PTH concentrations were not different at the time of calving among supplementation groups. There was a supplementation group by hour postcalving interaction for mean tCa concentration in which SQ cows had reduced tCa concentrations from 32 to 64 h compared with CON cows, 32 to 96 h compared with BOL-C cows, and 40 to 64 h compared with BOL-D cows. Mean PTH concentration did not differ among supplementation groups across 168 h after enrollment and was 158.1 pmol/L (95% confidence interval [CI] = 148.2 to 168.0) for CON cows, 164.0 pmol/L (95% CI = 154.9 to 173.1) for BOL-C cows, 158.7 pmol/L (95% CI = 149.2 to 168.1) for BOL-D cows, and 153.2 pmol/L (95% CI = 143.6 to 162.8) for SQ cows. Our findings suggest that although serum tCa does not differ between cows that receive conventional or delayed oral Ca bolus supplementation at calving and cows that receive no supplemental Ca, subcutaneous infusion of Ca at calving reduces serum tCa for a substantial period between 32 and 64 h postsupplementation. However, as PTH concentrations did not differ among groups across 168 h postpartum, the mechanism by which tCa is reduced remains unclear.

Calcium dynamics and associated temporal patterns of milk constituents in early-lactation multiparous Holsteins.

At the onset of lactation, calcium (Ca) homeostasis is challenged. For the transitioning dairy cow, inadequate responses to this challenge may result in subclinical hypocalcemia at some point in the postpartum period. It has been proposed that dynamics of blood Ca and the timing of subclinical hypocalcemia allow cows to be classified into 4 Ca dynamic groups by assessing serum total Ca concentrations (tCa) at 1 and 4 days in milk (DIM). These differing dynamics are associated with different risks of adverse health events and suboptimal production. Our prospective cohort study aimed to characterize the temporal patterns of milk constituents in cows with differing Ca dynamics to investigate the potential of Fourier-transform infrared spectroscopic (FTIR) analysis of milk as a diagnostic tool for identifying cows with unfavorable Ca dynamics. We sampled the blood of 343 multiparous Holsteins on a single dairy in Cayuga County, New York, at 1 and 4 DIM and classified these cows into Ca dynamic groups using threshold concentrations of tCa (1 DIM: tCa <1.98 mmol/L; 4 DIM: tCa <2.22 mmol/L) derived from receiver operating characteristic curve analysis based on epidemiologically relevant health and production outcomes. We also collected proportional milk samples from each of these cows from 3 to 10 DIM for FTIR analysis of milk constituents. Through this analysis we estimated the milk constituent levels of anhydrous lactose (g/100 g of milk and g/milking), true protein (g/100 g of milk and g/milking), fat (g/100 g of milk and g/milking), milk urea nitrogen (mg/100 g of milk), fatty acid (FA) groups including de novo, mixed origin, and preformed FA measured in grams/100 g of milk, by relative percentage, and grams/milking, as well as energy-related metabolites including ketone bodies and milk-predicted blood nonesterified FA. Individual milk constituents were compared among groups at each time point and over the entire sample period using linear regression models. Overall, we found differences among the constituent profiles of Ca dynamic groups at approximately every time point and over the entire sample period. The 2 at-risk groups of cows did not differ from each other at more than one time point for any constituent, however prominent differences existed between the milk of normocalcemic cows and the milk of the other Ca dynamic groups with respect to FA. Over the entire sample period, lactose and protein yield (g/milking) were lower in the milk of at-risk cows than in the milk of the other Ca dynamic groups. In addition, milk yield per milking followed patterns consistent with previous Ca dynamic group research. Though our use of a single farm does limit the general applicability of these findings, our conclusions provide evidence that FTIR may be a useful method for discriminating between cows with different Ca dynamics at time points that may be relevant in the optimization of management or development of clinical intervention strategies.

Patterns of Fourier-transform infrared estimated milk constituents in early lactation Holstein cows on a single New York State dairy.

Cows undergo immense physiological stress to produce milk during early lactation. Monitoring early lactation milk through Fourier-transform infrared (FTIR) spectroscopy might offer an understanding of which cows transition successfully. Daily patterns of milk constituents in early lactation have yet to be reported continuously, and the study objective was to initially describe these patterns for cows of varying parity groups from 3 through 10 d postpartum, piloted on a single dairy. We enrolled 1,024 Holstein cows from a commercial dairy farm in Cayuga County, New York, in an observational study, with a total of 306 parity 1 cows, 274 parity 2 cows, and 444 parity ≥3 cows. Cows were sampled once daily, Monday through Friday, via proportional milk samplers, and milk was stored at 4°C until analysis using FTIR. Estimated constituents included anhydrous lactose, true protein, and fat (g/100 g of milk); relative % (rel%) of total fatty acids (FA) and concentration (g/100 g of milk) of de novo, mixed, and preformed FA; individual fatty acids C16:0, C18:0, and C18:1 cis-9 (g/100 g of milk); milk urea nitrogen (MUN; mg/100 g of milk); and milk acetone (mACE), milk ß-hydroxybutyrate (mBHB), and milk-predicted blood nonesterified fatty acids (mpbNEFA) (all expressed in mmol/L). Differences between parity groups were assessed using repeated-measures ANOVA. Milk yield per milking differed over time between 3 and 10 DIM and averaged 8.7, 13.3, and 13.3 kg for parity 1, 2, and ≥3 cows, respectively. Parity differences were found for % anhydrous lactose, % fat, and preformed FA (g/100 g of milk). Parity differed across DIM for % true protein, de novo FA (rel% and g/100 g of milk), mixed FA (rel% and g/100 g of milk), preformed FA rel%, C16:0, C18:0, C18:1 cis-9, MUN, mACE, mBHB, and mpbNEFA. Parity 1 cows had less true protein and greater fat percentages than parity 2 and ≥3 cows (% true protein: 3.52, 3.76, 3.81; % fat: 5.55, 4.69, 4.95, for parity 1, 2, ≥3, respectively). De novo and mixed FA rel% were reduced and preformed FA rel% were increased in primiparous compared with parity 2 and ≥3 cows. The increase in preformed FA rel% in primiparous cows agreed with milk markers of energy deficit, such that mpbNEFA, mBHB, and mACE were greatest in parity 1 cows followed by parity ≥3 cows, with parity 2 cows having the lowest concentrations. When measuring milk constituents with FTIR, these results suggest it is critical to account for parity for the majority of estimated milk constituents. We acknowledge the limitation that this study was conducted on a single farm; however, if FTIR technology is to be used as a method of identifying cows maladapted to lactation, understanding variations in early lactation milk constituents is a crucial first step in the practical adoption of this technology.

Boosting clinical performance: The impact of enhanced final year placements.

BACKGROUND: This study follows on from a study that investigated how to develop effective final year medical student assistantship placements, using multidisciplinary clinical teams in planning and delivery. AIMS: This study assessed the effects on objective structured clinical examination (OSCE) performance of the in-course enhanced "super-assistantship" placement introduced to a randomly selected sample of 2013-14 final year medical students at Leeds medical school. METHODS: Quantitative data analysis was used to compare the global grades of OSCE stations between students who undertook this placement against those who did not. RESULTS: There was a small overall improvement in the "super-assistantship" student scores across the whole assessment (effect size = 0.085). "Pre-op Capacity", "Admissions Prescribing" and "Hip Pain" stations had small-medium effect sizes (0.226, 0.215, and 0.214) in favor of the intervention group. Other stations had small effect sizes (0.107-0.191), mostly in favor of the intervention group. CONCLUSIONS: The "super-assistantship" experience characterized by increasing student responsibility on placement can help to improve competence and confidence in clinical decision-making "in a simulated environment". The clinical environment and multidisciplinary team must be ready and supported to provide these opportunities effectively. Further in-course opportunities for increasing final year student responsibility should be developed.

Troponin I and myocardial injury in the ICU.

Cardiac troponin I (cTnI) is a protein that is specific to heart muscle. Increased concentrations appear in serum after myocardial cell injury. cTnI was compared with creatinine kinase MB (CK MB), myoglobin and the 12-lead ECG for detection of myocardial injury in an unselected series of 109 medical and surgical ICU patients. Clinical observations and daily 12-lead ECG were recorded prospectively. Samples for cTnI, myoglobin and CK MB serum analysis were collected each day. Increased serum cTnI concentrations (> 0.1 microgram litre-1) were observed in 70.6% (n = 77) of the ICU group. Tachycardia, arrhythmia, hypotension and treatment with inotropic drugs were associated with higher concentrations. The standardized mortality ratio by APACHE III for the ICU sample was 0.98. All subjects in an unmatched control group of 98 medical unit emergency admissions without a primary cardiac diagnosis had serum cTnI concentrations < 0.1 microgram litre-1. We conclude that increased serum cTnI concentrations occur frequently in the ICU suggesting that there is a high incidence of cardiac injury in these patients.

Atropine-resistant secretory responses of the ovine parotid gland to reflex and direct parasympathetic stimulation.

A study was made of mechanisms involved in the parasympathetic control, especially of protein concentration in, and also flow, of ovine parotid secretion. The effects of distension of the caudal thoracic oesophagus were characterized in four anaesthetized sheep each with a unilateral chronic superior cervical sympathetic ganglionectomy. Oesophageal distension produced increases in both the flow and protein concentration of saliva from the control glands similar to that from the sympathectomized glands indicating the response was mediated by the parasympathetic innervation. Atropine, in doses which completely abolished increases in flow and protein concentration produced by bethanechol infusion, reduced, but did not abolish, the responses to oesophageal distension providing evidence of non-cholinergic transmission. Electrical stimulation of the parotid (parasympathetic, postganglionic) nerve during atropinization produced ca. 70% increases in flow and ca. 100% increases in protein concentration of parotid saliva thus giving further evidence of such a mechanism. Intracarotid infusion of vasoactive intestinal polypeptide (VIP) evoked responses with similarities to those observed with oesophageal distension and nerve stimulation during atropinization. This observation adds to other evidence indicating that VIP acts as a parasympathetic neurotransmitter involved in the control of salivary secretion.

Granulocyte contamination of Ficoll-Hypaque preparations of mononuclear cells following thermal injury may lead to substantial overestimation of lymphocyte recovery.

During ongoing flow cytometric studies of burned patient blood leukocytes, it was noted frequently that large numbers of granulocytes were present along with the mononuclear cells at the plasma/Ficoll-Hypaque (F-H) interface following centrifugation over F-H. Since differential WBC counts are not routinely performed on F-H interface cells, it is possible that many previous immunologic studies of burned patients have greatly overestimated numbers of lymphocytes recovered. The present study sought to quantify the extent to which granulocyte contamination of F-H separated cells occurs following burn injury. Blood from 15 thermally injured patients (7-55% total body surface area burn) was studied serially at 24 hr, 48 hr, and weekly thereafter through 6 weeks postburn (PB). Controls were age-matched normals (No. of control bloods = 59). Three-part differential cell counts (lymphocytes, monocytes, and granulocytes) were performed on both F-H interface cells and RBC-lysed whole blood. Counts were performed by light scatter analysis on a flow cytometer. Except at 48 hr, at every time studied through 4 weeks PB, there was significant contamination of F-H interface cells with granulocytes. At 24 hr PB, 41 +/- 9% of the interface cells were granulocytes while at 4 weeks, PB 24 +/- 8% of the interface cells were granulocytes. The data did not support the interpretation that this increase in F-H interface granulocytes was simply reflective of the granulocytosis commonly observed after burn. Thus artificial generation of granulocytosis by addition of extra normal leukocytes to normal blood resulted in complete separation of granulocytes from mononuclear cells following centrifugation over F-H.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of the effects of vasoactive intestinal polypeptide on secretion from the submaxillary gland of the sheep and pig.

The effects, on secretion of fluid and protein from the submaxillary gland of intracarotid injections of acetylcholine or vasoactive intestinal polypeptide (VIP), and intracarotid infusions of VIP during a background of muscarinic stimulation, were examined in sheep and pigs. Intracarotid injections of VIP produced secretion of saliva from the ovine gland which continued after administration of atropine, phentolamine and propranolol. The protein concentration of this saliva was over 5-fold greater than that secreted in response to acetylcholine. Intracarotid injection of VIP did not evoke secretion from the porcine submaxillary gland but increased 3-fold the protein concentration in saliva evoked by subsequent intracarotid injection of acetylcholine. Intracarotid infusions of VIP in sheep produced dose-related increases in both flow (up to 1.9-fold) and protein concentration (up to 42-fold) of submaxillary saliva secreted in response to a background infusion of bethanechol. In pigs, intracarotid infusions of VIP at 0.015, 0.15 and 1.5 nmol/min produced increases in both flow and protein concentration of bethanechol-evoked saliva. The increases in protein concentration (up to 2.8-fold) were dose-related, but the increases in flow were not, being ca. 25% with each dose of VIP. The experiments provide evidence that VIP may effect mobilization of protein into saliva even in a species (pig) in which VIP does not evoke secretion of fluid.

Effects of the vagus nerves on gastric motility and release of vasoactive intestinal polypeptide in the anaesthetized lamb.

1. Effects of the vagus nerves on the activity of the reticulo-omasal orifice (ROO) and the abomasum and the concentration of vasoactive intestinal polypeptide (VIP) in gastric and intestinal venous effluent were studied in anaesthetized lambs. 2. Both excitatory and inhibitory effects of the vagus on the ROO and abomasum were demonstrated. Excitation of activity of the ROO was dominant with stimulation at lower frequencies (less than or equal to 20 Hz) whereas higher frequencies (50-70 Hz) caused inhibition. 3. Inhibition but not stimulation of the ROO and abomasum were obtained with vagal stimulation after administration of atropine (200-500 micrograms kg-1 I.V.). 4. The concentration of VIP in gastric venous effluent blood rose by 41 +/- 10 pmol l-1 (n = 13) within 90 s of the start of stimulation (10 Hz, 5 ms pulse duration, 10 V for 180 s) of a vagus nerve and fell within 60 s of its cessation to or near basal levels. The effects of vagal stimulation in changing the concentration of VIP were not altered by administration of atropine. 5. The concentration of VIP in the intestinal venous effluent increased during stimulation (10 Hz, 5 ms pulse duration, 10 V, for 180 s) of a vagus nerve by 15 +/- 5 pmol l-1 (n = 11) and remained elevated for more than 10 min after the stimulus had ceased. 6. The changes in gastric motility and in concentration of VIP in gastric and intestinal venous blood with stimulation of the vagus nerves have been discussed in relation to similar alterations which occur in lambs during sucking of milk.

Gastric electromyographic activity in the milk-fed lamb.

1. Electromyographic (EMG) activity of the reticulum, reticulo-omasal orifice (ROO) and abomasum was recorded from conscious lambs. 2. In fasted lambs diphasic reticular EMG bursts occurred at intervals of 60 +/- 13 s. In association with the second phase of the reticular EMG burst there was consistently a period of inactivity of the EMG of the ROO of 2.4-11.0 s (5.5 +/- 2.0 s, mean +/- S.D.). This period of quiescence ended with the onset of a burst of EMG activity of the ROO of 4.1 +/- 0.8 s termed here a long burst of activity. Preceding the following reticular EMG burst there were further long bursts of EMG activity of the ROO at intervals of 11.1 +/- 1.3 s or intermixing or replacement of long burst activity with short bursts which were of duration 1.1 +/- 0.3 s and which occurred at intervals of 2.4 +/- 0.5 s. 3. When the lambs were shown milk and at times when they could be expected to anticipate milk being provided, a period of inactivity of the EMG of the ROO developed for up to 60 s. In association with this there was commonly an increase in the frequency of reticular EMG bursts which at times became monophasic. 4. With the start of sucking there was quiescence of the EMG of the ROO which persisted throughout periods of sucking for up to 90 s. Simultaneously with the disappearance of activity of the ROO there was a monophasic burst of the reticular EMG, which was followed by either quiescence or disorganized low voltage activity. Inactivity of the EMG of the ROO still developed when lambs sucked milk after administration (I.V.) of atropine, phentolamine or propranolol, but not after hexamethonium. 5. In lambs observed over a period 30-60 min after feeding the diphasic reticular bursts occurred every 85 +/- 24 s and the duration of the period of inactivity of the EMG of the ROO associated with each reticular burst (3.7 +/- 1.2 s) was significantly less (P less than 0.001) than in fasted lambs. Short bursts of EMG activity of the ROO occurred more frequently than in fasted lambs. 6. In fasted lambs bursts of EMG activity of the body of the abomasum occurred at frequencies of 6-12 min-1 and those of the antrum and pylorus at ca. 6 min-1 but episodes of such activity were intermittent.(ABSTRACT TRUNCATED AT 400 WORDS)

The effects of vasoactive intestinal polypeptide on gastric motility in the lamb.

1. Intra-arterial infusions of vasoactive intestinal polypeptide (VIP) were made in anaesthetized lambs in which activity of the reticulo-omasal orifice (ROO) was recorded manometrically and in conscious lambs in which activity of the reticulum, ROO and abomasum were recorded by electromyographic (EMG) techniques. 2. Spontaneous rhythmic opening and closing movements of the ROO occurred in anaesthetized lambs at 3-5 min-1. Infusions of VIP into the left gastric artery at rates of 0.5-3.0 nmol min-1 produced changes in activity of the ROO. Within 120 s of commencement of the infusions there was an increase in frequency and magnitude of the movements of the ROO for up to 120 s. This was followed with infusion of VIP at the lower levels (0.5-1.0 nmol min-1), by a marked reduction and sometimes complete loss of the rhythmic movements. There was always complete cessation of activity of the ROO with infusion of VIP at 1.5-3.0 nmol min-1. 3. In conscious lambs the frequency of the diphasic reticular EMG bursts which recur at intervals of ca. 1 min was not affected by infusions of VIP at 3.0 nmol min-1 for 10 min. 4. Between each diphasic reticular EMG burst in the conscious lamb there was normally phasic activity of the ROO consisting of EMG bursts of long (ca. 4 s) and short (ca. 1 s) duration. Within 90 s of commencement of infusion of VIP at 3.0 nmol min-1 short-burst EMG activity disappeared with the remaining long bursts being of greater duration (5.4 +/- 1.2 s) than before infusion. After a series of four to fifteen such more prolonged long bursts there was quiescence of the EMG of the ROO. After infusion of VIP EMG activity recommenced first as a series of eight to fourteen long bursts which was followed by the reappearance also of short-burst activity. Infusions of VIP at 8-10 nmol min-1 produced a more prompt cessation of EMG activity of the ROO. Of other peptides which were infused only PHI (a peptide with N-terminal histidine and C-terminal isoleucine amide) produced cessation of the EMG activity of the ROO. However, on a molar basis VIP was 2-3 times more potent than PHI in causing cessation of activity of the ROO. 5. Infusion of VIP at 3.0 nmol min-1 produced a cessation or diminution of EMG activity of the body, antrum and pylorus of the abomasum.(ABSTRACT TRUNCATED AT 400 WORDS)

Immunochemical characterisation of somatostatin in ruminants.

Following development and validation of a radioimmunoassay for somatostatin, the immunoreactivity of this peptide in the plasma of ruminants was measured and the levels in sheep were 9-31 pM (mean 18 +/- 7 pM, n = 48), in lambs 10-54 pM (mean 25 +/- 10 pM, n = 18) and in calves 5-35 pM (mean 12 +/- 6 pM, n = 22). Somatostatin-like immunoreactivity was present in sheep in high concentrations in the antrum (2342 +/- 280 pmol/g wet weight), duodenum (446 +/- 73 pmol/g) and pancreas (832 +/- 208 pmol/g). Lower concentrations (6-150 pmol/g) were found in other regions of the gastrointestinal tract. Molecular sieve chromatography on Bio-Gel P-10 showed that while most of the somatostatin in the antrum was somatostatin-14, in the duodenum about 30% of the total immunoreactivity was somatostatin-28.

Can thyroid stimulating hormone levels by TSH (IRMA) predict relapse of thyrotoxicosis following carbimazole treatment?

Serum thyrotrophin receptor antibody (TRAb) and thyroid stimulating hormone (TSH) (IRMA) levels were measured in 38 patients at one month after the end of a course of carbimazole/T3 therapy for Graves' disease. Despite the increased sensitivity of the IRMA assay a TSH measurement at this stage was found to be of no predictive value, in contrast to estimation of serum TRAb levels which correctly predicted relapse and remission in 90% of patients.

Expression of the mouse HPRT gene: deletional analysis of the promoter region of an X-chromosome linked housekeeping gene.

The mouse hypoxanthine phosphoribosyltransferase gene, like several other housekeeping genes, lacks many of the features associated with promoters of RNA polymerase II-transcribed genes. HPRT transcripts have multiple initiation sites and an HPRT minigene was used to show that only 49 bases of 5' flanking sequence was necessary for normal expression in cultured cells. The essential region, which occurs within a complex series of direct repeats, is homologous to sequences upstream of other housekeeping genes. When this sequence was deleted, cryptic upstream initiation sites were revealed. Similar aberrant patterns of initiation were seen with all minigenes assayed in Xenopus oocytes. We speculate that this region of the HPRT promoter is involved in a different interaction with the transcriptional machinery to that occurring at more conventional promoters.

Gastric and intestinal release of vasoactive intestinal polypeptide in the milk-fed lamb.

Vasoactive intestinal polypeptide (VIP) has been proposed as the neurotransmitter of the atropine-resistant relaxation of gastric structures in the lamb. To examine this proposal VIP concentrations in plasma from arterial, gastric venous and intestinal venous blood were measured in healthy conscious lambs before, during and after teasing with, and sucking of milk. Basal arterial plasma VIP concentrations were undetectable (less than 3 pmol/l) and remained so during and after feeding. Before feeding VIP was detected in only 2 of 12 gastric venous plasma samples (5 and 13 pmol/l). During teasing with food there were increments in VIP of 19 +/- 4 pmol/l and during feeding of 27 +/- 5 pmol/l. VIP concentration in gastric venous plasma rapidly returned to fasting levels after cessation of sucking. In contrast VIP in the intestinal venous plasma did not rise during teasing or upon commencement of sucking but a peak increment of 34 +/- 6 pmol/l occurred at 5 min after cessation of feeding. The results are consistent with the hypotheses that VIP is released in anticipation of and during sucking from inhibitory neurones involved in relaxation of gastric structures and that intestinal release of VIP is a consequence of entry of digesta into the small intestine.

Bone and gallium scans in mastocytosis: correlation with count rates, radiography, and microscopy.

Mastocytosis (urticaria pigmentosa) was proven in a patient suffering from severe back pain. A bone scan showed diffusely increased bone activity. Count rates were also abnormally elevated over several areas of the skeleton. Radiographs were consistent with mastocytosis in bone.

Phase chemistry, structure, and radiation effects in lunar samples.

Phase chemistry, structure, and radiation effects were studied in rock, breccia, and soil samples. The regolith apparently developed in the final stages of accretion and was modified by later impact processes and radiation weathering. Exposure ages indicate transfer of buried igneous rock fragments to the near surface late in lunar history. With a few exceptions igneous rock fragments, soil, and breccia share the same distinctive chemistry, probably acquired before accretion of the moon. The igneous rocks texturally resemble basaltic achondrites, and the soil and breccias contain glassy spheres analogous to chondrules.