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B Collins

Publications and source records attributed to B Collins.

14 recordsLinked to original sources
PubMed1991

Resolution-enhanced Fourier transform infrared spectroscopy study of the environment of phosphate ion in the early deposits of a solid phase of calcium phosphate in bone and enamel and their evolution with age: 2. Investigations in the nu3PO4 domain.

Resolution-enhanced Fourier Transform Infrared (FTIR) spectra of early mineral deposits in enamel and bone show bands at 1020, 1100, 1110, 1125, and 1145 cm-1 in the nu3PO4 domain which do not belong to well crystallized stoichiometric hydroxyapatite. Bands at 1020 and 1100 cm-1 have been shown to occur in nonstoichiometric apatites containing HPO4(2-) ions and the weak band at 1145 cm-1 has been assigned to HPO4(2-) ions. Though the bands at 1110 and 1125 cm-1 have not been found in any well crystallized apatite, they are present in newly precipitated apatite. These latter bands disappear progressively during maturation in biological as well as synthetic samples, and partial dissolution of synthetic apatites shows that they belong to species that exhibit an inhomogeneous distribution in the mineral, and that are the first to be solubilized. Comparison of the FTIR spectra of biological apatites with those of synthetic, nonapatitic-containing phosphate minerals shows that the presence of these bands does not arise from nonapatitic, well-defined phases; they are due to the local environment of phosphate ions which may possibly be loosely related or perhaps unrelated to the phosphate groups present in the well-crystallized nonapatitic calcium phosphates. Resolution-enhanced FTIR affords a very precise characterization of the mineral phases which may be very useful in characterizing pathological deposits of Ca-P mineral phases.

Animals↗
PubMed1991

Fourier transform infrared spectroscopic study of the carbonate ions in bone mineral during aging.

The environment of CO3(2-) ions in the bone mineral of chickens of different ages and in bone fractions of different density have been investigated by resolution-enhanced Fourier Transform Infrared (FTIR) Spectroscopy. Three carbonate bands appear in the upsilon 2 CO3 domain at 878, 871, and 866 cm-1, which may be assigned to three different locations of the ion in the mineral: in monovalent anionic sites of the apatitic structure (878 cm-1), in trivalent anionic sites (871 cm-1), and in unstable location (866 cm-1) probably in perturbed regions of the crystals. The distribution of the carbonate ions among these locations was estimated by comparing the intensities of the corresponding FTIR spectral bands. The intensity ratio of the 878 and 871 cm-1 bands remains remarkably constant in whole bone as well as in the fractions obtained by density centrifugation. On the contrary, the intensity ratio of the 866 cm-1 to the 871 cm-1 band was found to vary directly and decreased with the age of the animal. In bone of the same age, the relative content of the unstable carbonate ion was found to be highest in the most abundant density centrifugation fraction. A resolution factor of the CO3(2-) band (CO3 RF) was calculated from the FTIR spectra which was shown to be very sensitive to the degree of crystallinity of the mineral. The crystallinity was found to improve rapidly with the age of the animal. The CO3 RF in the bone samples obtained by density centrifugation from bone of the same animal was found to be essentially constant.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1991

A resolution-enhanced Fourier transform infrared spectroscopic study of the environment of the CO3(2-) ion in the mineral phase of enamel during its formation and maturation.

A resolution-enhanced Fourier Transform Infrared (FTIR) Spectroscopic study of the CO3(2-) ion in pig enamel of increasing age and maturity has demonstrated the existence of four different, main carbonate locations. The major CO3(2-) site arises as a result of the substitution of CO3(2-) ions in the positions occupied by PO4(3-) ions in the apatitic lattice. In addition, two minor locations have been identified in positions in which the CO3(2-) ions substitute for OH- ions. The fourth carbonate group appears to be in an unstable location. Its concentration has been found to decrease with aging and maturation, during which there is a progressive increase in the amount of mineral deposited in the enamel. The distribution of the carbonate ions in the different apatitic sites varies randomly during the formation of the mineral phase in enamel and during its maturation. Although these changes have been shown to be related to changes in the composition of the mineral phase, a comparison of the parameters assessing the degree of crystallinity of the mineral phase from upsilon 2CO3(2-) and upsilon 4PO4(3-) infrared absorption data reveals a significant discrepancy related to the nonhomogeneous partition of the CO3(2-) ion in the mineral phase. After maximum mineralization is reached, the composition of the mature mineral phase is decidedly different than that of the initial mineral deposited; the changes affect principally the concentrations of Ca2+, OH-, and HPO4(2-) ions, but not the CO3(2-) ions.

Aging↗
PubMed1990

Unintentional injuries to students at school.

Unintentional injuries at school have been identified as a significant public health problem. A major barrier to the development of injury prevention policy has been the absence of national data on the circumstances of injuries to students which occur at school. This study sought to determine the incidence, nature, and circumstances of injuries which resulted in death or hospitalization. Fatalities were identified from national mortality data for 1977-86 inclusive. Coroners' files were then examined to obtain details of the circumstances of injury. Hospitalization cases were identified from the national hospital discharge summary for 1986. Fifteen fatalities were identified. The circumstances of the deaths were diverse with the most frequent event being a fall (n = 4). A total of 1013 first admissions to hospital were identified, giving an overall incidence rate of 152/100,000 students/year. Injury rates declined with increasing age, and males had higher rates than females for all ages. Fractures of the upper and lower limbs and intracranial injury represented more than three-quarters of all injury. The two leading causes of injury, falls, and incidents involving striking against or being struck by a person or object, represented 89% of all incidents. The use of playground equipment and involvement in sporting activity were two of the more common aspects of many injury events. The results suggest that prevention policy should place emphasis on those in their first 2 years of schooling, falls from playground equipment, provision of protective equipment for sporting activities, sporting activities designed to minimize physical contact, establishment of standardized injury referral procedures, first-aid training, and a standardized injury reporting system.

Adolescent↗
PubMed1990

Thyroid and adrenal function tests in adult male ferrets.

Effects of thyroid-stimulating hormone (TSH) and thyrotropin-releasing hormone (TRH) on plasma concentrations of thyroid hormones, and effects of ACTH and dexamethasone on plasma concentrations of cortisol, were studied in adult male ferrets. Thirteen ferrets were randomly assigned to test or control groups of eight and five animals, respectively. Combined (test + control groups) mean basal plasma thyroxine (T4) values were different between the TRH (1.81 +/- 0.41 micrograms/dl, mean +/- SD) and TSH (2.69 +/- 0.87 micrograms/dl) experiments, which were performed 2 months apart. Plasma T4 values significantly (P less than 0.05) increased as early as 2 hours (3.37 +/- 1.10 micrograms/dl) and remained high until 6 hours (3.45 +/- 0.86 micrograms/dl) after IV injection of 1 IU of TSH/ferret. In contrast, IV injection of 500 micrograms of TRH/ferret did not induce a significant increase until 6 hours (2.75 +/- 0.79) after injection, and induced side effects of hyperventilation, salivation, vomiting, and sedation. There was no significant increase in triiodothyronine (T3) values following TSH or TRH administration. Combined mean basal plasma cortisol values were not significantly different between ACTH stimulation (1.29 +/- 0.84 micrograms/dl) and dexamethasone suppression test (0.74 +/- 0.56 micrograms/dl) experiments. Intravenous injection of 0.5 IU of ACTH/ferret induced a significant increase in plasma cortisol concentrations by 30 minutes (5.26 +/- 1.21 micrograms/dl), which persisted until 60 minutes (5.17 +/- 1.99 micrograms/dl) after injection. Plasma cortisol values significantly decreased as early as 1 hour (0.41 +/- 0.13 micrograms/dl), and had further decreased by 5 hours (0.26 +/- 0.15 micrograms/dl) following IV injection of 0.2 mg of dexamethasone/ferret.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Function Tests↗
PubMed1979

Reversal by testosterone of atrophy of accessory genital glands of castrated male sheep. A histologic and morphometric study.

The histologic features of male accessory genital glands of entire sheep (group I), castrated sheep (group II), castrated sheep treated with 40 daily intramuscular injections of 50 milligrams testosterone propionate (group III), and castrated sheep treated with 600 milligrams testosterone propionate 72 hours before death (group IV) were compared. Sheep were castrated at 3 months old and all sheep were killed when 15 months old. Volume fractions of glandular tissue, intralobular fibromuscular tissue and perilobular fibromuscular tissue of the seminal vesicles and Cowper's glands fluctuated significantly (P less than 0.05) during postcastration atrophy and after repeated testosterone treatment. Atrophy in sheep in group II was least in the prostate but greatest in Cowper's glands, seminal vesicles and ampullae of vasa deferentia. Seminal vesicle plexi, whose cytons had a statistically significant (P less than 0.05) degree of shrinkage, also were atrophied. After treatment with testosterone the postcastration atrophy of plexal neurons was almost reversed in sheep in group III. There also was hypertrophy of epithelial cells but the testosterone treatment failed to reduce to normal the fibromuscular volume fraction of the accessory genital glands. Testosterone propionate treatment of sheep in group IV failed to elicit appreciable morphologic changes. These results are compared with our previous findings on the content and uptake of zinc by the accessory genital glands. It is suggested that accumulation of zinc in the accessory genital glands of sheep is not necessarily closely linked to normal histologic appearance.

Animals↗
PubMed1979

Reducing auditory feedback and the acquisition of motor response timing.

Three groups of subjects (n=10) attempted to move a lever 50 cm along a track in 1.50 sec under one of three auditory feedback conditions: Fully augmented increasing auditory feedback (FAF) in which a constant level of velocity-related auditory feedback was provided for all 25 learning trials, reducing auditory feedback (FAF) in which the level of feedback was progressively reduced over the learning trials, and no auditory feedback (NAF). All subjects performed 10 trials with no auditory feedback after a 10-min rest interval. The hypothesis that acquisition of the criterion task would be facilitated under RAF compared to FAF derived partial support. It was concluded that there is sufficient evidence to justify further investigation of reducing auditory feedback as a technique of motor skill acquisition.

Auditory Perception↗
PubMed1977

Hexachlorobenzene residues and effects on esterase activities in pre-weanling rats after a reciprocal transfer between HCB-treated and control dams.

Female Wistar rats were divided into two groups. One group was fed ad libitum powdered rat chow containing 80 ppm hexachlorobenzene (HCB) and the other was fed HCB-free diet 2 weeks before mating until the termination of the experiment. Immediately after parturition, the pups were randomly culled to 10 per litter and 5 pups were reciprocally transferred between HCB and control dams. All pups within same paired litters were sacrificed on the 16th to 17th day and on the 20th to 23rd day after birth. Liver esterase activity toward indophenyl, thiophenyl, and p-nitrophenyl acetates was determined. The liver to body weight ratio, liver esterase activity and HCB residues were significantly higher in pups nursed by HCB-fed dams than in those nursed by control dams. The HCB residue in the liver, kidney, spleen, heart and brain was analyzed by gas-liquid chromatography. At about the weaning time, the HCB residue levels in pups transferred after parturition from HCB fed to control dams were similar to those in pups which remained with the control dams. The results demonstrated that HCB in tissues at about weaning time was obtained largely through milk. In addition, transmission of HCB through milk had greater effects on esterase activities in suckling pups than placental transmission. The pups born to HCB-treated dams and nursed by the control dams were similar to the pups born and nursed by the same control dams.

Animals↗
PubMed1977

Cardioplegia without fibrillation or defibrillation in cardiac surgery.

A group of 176 patients undergoing cardiac surgery utilizing a technique of rapid core hypothermic cardioplegia with a hyperosmotic solution is presented. A cold, 2 to 4 degrees C hyperosmotic (396 mOsm) perfusate, injected under pressure, induced cardiac arrest without fibrillation within 2 to 4 seconds in every instance. At the end of each procedure, flushing of the cold solution out of the coronary system re-establishes spontaneous normal sinus cardiac rhythm in 96% (119 of 124) of coronary surgical procedures, 69% (11 of 16) of aortic valve replacements, 62% (10 of 16) of mitral valve replacements, 55% (five of nine) of aortic valve replacements combined with multiple coronary grafting, 57% (four of seven) of mitral valve replacement combined with multiple coronary grafting, and in 50% (two of four) of double valve replacements. Combined core and topical hypothermia with ice slush used in valve replacements and combined valve with coronary operations allowed periods of total ischemia up to 134 minutes without signs of detectable myocardial damage.

Aged↗
PubMedDate not supplied

Pleomorphic adenoma (benign mixed tumor) of the trachea.

A 15-year-old "asthmatic" found to have a pleomorphic adenoma of the trachea was treated by staged CO2 laser excision. Primary tracheal tumors, the clinicopathologic features of mixed tumor in this rare location, and therapeutic options are briefly reviewed. Immunohistochemical stains for cytokeratin, S-100 protein, and glial fibrillary acidic protein are reliable methods of evaluating component cell types in pleomorphic adenoma, but immunohistochemical evidence has not resolved the issue of tumor histogenesis.

Adolescent↗