Refinement of the Region for Split Hand/Foot Malformation 5 on 2q31.1.

Background: Deletions that encompass 2q31.1 have been proposed as a microdeletion syndrome with common clinical features, including intellectual disability/developmental delay, microcephaly, cleft palate, growth delay, and hand/foot anomalies. In addition, several genes within this region have been proposed as candidates for split hand-foot malformation 5 (SHFM5). Methods: To delineate the genotype-phenotype correlation between deletions of this region, we identified 14 individuals with deletions at 2q31.1 detected by microarray analysis for physical and developmental disabilities. Results: All subjects for whom detailed clinical records were available had neurological deficits of varying degree. Seven subjects with deletions encompassing the HOXD cluster had hand/foot anomalies of varying severity, including syndactyly, brachydactyly, and ectrodactyly. Of 7 subjects with deletions proximal to the HOXD cluster, 5 of which encompassed DLX1/DLX2, none had clinically significant hand/foot anomalies. In contrast to previous reports, the individuals in our study did not display a characteristic gestalt of dysmorphic facial features. Conclusion: The absence of hand/foot anomalies in any of the individuals with deletions of DLX1/DLX2 but not the HOXD cluster supports the hypothesis that haploinsufficiency of the HOXD cluster, rather than DLX1/DLX2, accounts for the skeletal abnormalities in subjects with 2q31.1 microdeletions.

Novel ring chromosome composed of X- and Y-derived material in a girl with manifestations of Ullrich-Turner syndrome.

We present a female infant who has a novel genetic variant of Ullrich-Turner syndrome. Chromosome analysis on amniotic fluid cells obtained because of ultrasound observation of nuchal thickening showed 45,X in all cells. The infant was born with a low posterior hairline and moderate edema over hands and feet. Postnatal chromosome analysis demonstrated two cell lines-47% of the metaphases were 45,X, but 53% had a ring chromosome in addition to the normal X. FISH studies using alpha satellite probes, an X-whole-chromosome-paint (WCP) probe, and a Y-cocktail probe determined that the ring was composed of both X and Y sequences. FISH studies also determined that the KAL locus was present on the ring, but that XIST was absent. PCR-based analysis of lymphocyte DNA documented that the ring contained sequences from both the short and the long arm of the Y chromosome. X-chromosome analysis using a panel of highly polymorphic markers indicated that the ring contained material derived only from Xp22.1 to Xp21.3. No Xq material was identified on the ring, and androgen receptor-based X-inactivation studies suggested that the intact X chromosome was not subject to random X inactivation.

Changes in atrioventricular conduction properties with refractory-period modulation.

Dofetilide, clofilium, and risotilide, three drugs known to prolong cardiac action potentials and refractory periods, were studied by using a perfused isolated rabbit heart preparation with intermittent premature pacing and bipolar surface electrograms. The rate-related effects of these drugs on atrioventricular (AV) conduction were tested by pacing at a long (400 ms) and a short (250 ms) basic cycle length (BCL). All three drugs increased refractory periods in a concentration-dependent manner in most segments of the AV axis. The maximal atrio-His (AH) conduction interval (AHmax) and delta AH (AHmax - AHmin) produced by premature pacing was decreased by the highest concentration of each drug at the 400-ms BCL, whereas only clofilium reduced AHmax and delta AH at the 250-ms BCL. Changes in delta AH correlated best with changes in the atrial functional refractory period. The His-Purkinje system conduction interval (HV), represented by delta HV, was unaffected by any drug at either BCL. These results show that if atrial or nodal refractory periods are increased sufficiently, AHmax but not AHmin was decreased at the 400-ms BCL. Because dofetilide and risotilide did not affect AHmax at the 250-ms BCL, these drugs may be less effective at preventing AV nodal reentrant tachycardias than a drug such as clofilium that displays less rate dependency.

Storage and display characteristics of electrically stimulated, hot-boned and nonstimulated, cold-boned beef.

One side, randomly selected from each of 33 carcasses from forage-fed steers, was electrically stimulated within 30 min of exsanguination and hot-bonded (ESHB). Opposite sides were not electrically stimulated and were cold-boned (NESCB) following a 24 h chill (0°C). From 17 ESHB sides, portions of the longissimus dorsi (LD) and semimembranosus (SM) muscles were removed and immediately vacuum packaged. LD and SM muscles were removed from the remaining 16 ESHB sides, wrapped in polyvinyl chloride film, chilled (0°C) for 22 h and then vacuum packaged. LD and SM muscles from NESCB sides (n = 33) were removed and the vacuum packed at 24 h post mortem. Whole muscle characteristics were evaluated initially and after storage periods of 7, 14 or 21 days and steaks were displayesd for 5 years thereafter. Neither hot versus cold-boning nor storage for 21 days affected retail display characteristics of LD and SM steaks (P > 0·05). As retail display time increased, retail lean color, fat color and overall appearance scores decreased.

Chilled drinking water effects on lactating Holstein cows in summer.

In Experiment 1, 12 multiparous lactating cows (six per group) were offered drinking water ad libitum at temperatures of 10 or 30 degrees C in a switchback design. The treatment group received 10 degrees C water from 1235 to 2000 h and was then changed to 30 degrees C water for the remaining 16.5 h/d. The control group received 30 degrees C water 24 h/d. Respiratory rates, rectal temperatures, and rumen motilities were measured at 1100, 1440, and 1810 h, 3 d/wk. Water consumed was recorded for 1235 to 2000 h and 2001 to 1234 h of the next day. Water consumption for the treatment group was 3.90 L/h per cow compared to 5.40 L/h per cow for the control group from 1235 to 2000 h. However, the 10 degrees C water absorbed 65.6 kcal/h more heat than the 30 degrees C water. No differences were found in respiratory rates, rectal temperatures, rumen motilities, or milk yield. Cows that drank 10 degrees C water consumed 3.67 kg of feed DM/100 kg of body weight compared with 3.36 kg of feed for the controls. In Experiment 2, the same two groups of cows were offered 9.5 degrees C water ad libitum for 24 h/d or 27.5 degrees C water for a 48 h comparison. The treatment group tended to consume more water than the control group and to have lower respiratory rates and body temperatures.

Effects of drinking water temperature on physiological responses of lactating Holstein cows in summer.

Nine lactating Holstein cows were offered drinking water of 7.2, 15.6, and 23.9 degrees C in a 3 X 3 Latin square design in Experiment 1. Water was offered for 10 min at 1300 h to simulate time in a milking parlor. Water consumption declined as drinking water temperature decreased. Respiration rates decreased as the drinking water temperature decreased. In Experiment 2, 8 lactating Holstein cows were offered water of 12.8 and 26.7 degrees C in a 2 X 2 changeover design. Results were consistent with Experiment 1. In experiment 3, 16 lactating Holstein cows were offered drinking water of 10, 16, 22, and 28 degrees C in a 4 X 4 Latin square design. Water was offered for 10 min at 1400 h. Respiration rates and deep rectal temperatures were taken before and after watering. Water consumption declined as drinking water temperature decreased, but the cooling effect of the low temperature water was greater. Lower drinking water temperature decreased respiration rates postwatering. Deep rectal temperatures were not affected as drinking water temperature decreased. Both respiration rates and deep rectal temperatures began to increase within 40 min after watering, indicating a transient cooling effect of the chilled water.

Effects of drinking water temperature on production responses in lactating Holstein cows in summer.

During late summer, 24 lactating Holstein cows were offered 10 or 28 degrees C (control) drinking water ad libitum at 1400 h for 10 min to investigate the effects on respiration rates, body temperatures, dry matter intake, and milk production. Experimental design was a 2 X 3 factorial arrangement of the two drinking water temperatures with .8, 1.1, and 1.4% dietary potassium associated with another experiment. Following 1 wk adjustment and 1 wk standardization, cows were blocked by dry matter intake as a percentage of body weight within parity and randomly assigned to treatments within blocks. Cows were denied access to water from 0900 until 1400 h. Respiration rates and rectal temperatures were recorded before and after watering. Tympanic membrane temperatures (8/h) were recorded during the comparison period using 4 cows per water treatment. No interaction occurred between water and potassium. Water at 10 degrees C had a greater cooling effect than 28 degrees C water. No differences were found between treatments in respiration rates and rectal temperatures after drinking water was temperatures after drinking water was offered. Chilled drinking water decreased tympanic membrane temperatures, which remained lower longer. Cows that drank 10 degrees C drinking water increased dry matter intake and milk yield.

Effect of drinking water temperature on heat stress of dairy cows.

Experiments were to determine the effectiveness of chilled drinking water in reducing heat stress of lactating dairy cows. Using a 4 X 4 Latin square statistical design, 16 cows (4/treatment) were deprived of water from 0800 until 1400 h at which time they were given chilled water (10, 16, 22 degrees C) or a control water (28 degrees C) ad libitum. Cows were rotated weekly among treatments. Eight of the cows (2/treatment) were selected at random and monitored continuously for body temperature measured in the middle ear near the tympanic membrane. The coldest water (10 degrees C) reduced body temperature (.75 degrees C) more than 28 degrees C water (.46 degrees C). The coldest water also reduced respiration rate and kept body temperatures lower longer. Chilled water was only about 32% effective in reducing body temperature, and it is doubtful if the effect was prolonged enough (about 2 h) to keep the body temperature of cows from rising above the critical temperature of thermoneutrality. Offering chilled water at milking time may provide an incentive for the cows to enter the milking parlor.