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Biomedical subjects

T Hicks

Publications and source records attributed to T Hicks.

At least 19 recordsLinked to original sources
PubMed2003

The classification and discrimination of glass fragments using non destructive energy dispersive X-ray microfluorescence.

Frequency of analytical characteristics is best estimated on glass recovered at random. However, as such data were not available to us, we decided to use control windows for this estimation. In order to use such a database, one has to establish that the recovered fragment comes from a window. Therefore, elemental analysis was used both for classification and discrimination of glass fragments. Several articles have been published on the subject, but most methods alter the glass sample. The use of non destructive energy dispersive X-ray microfluorescence (microXRF) for the analysis of small glass fragments has been evaluated in this context. The refractive index (RI) has also been measured in order to evaluate the complementarity of techniques. Classification of fragments has been achieved using Fisher's linear discriminant analysis (LDA) and neural networks (NN). Discrimination was based on Hotelling's T2 test. Only pairs that were not differentiated by RI followed by the Welch test were studied. The results show that neural network and linear discriminant analysis using qualitative and semi-quantitative data establishes a classification of glass specimens with a high degree of reliability. For discrimination, 119 windows collected from crime scene were compared: using RI it was possible to distinguish 6892 pairs. Out of 129 remaining pairs, 112 were distinguished by microXRF.

Journal Article↗
PubMed1997

Perineal repair of rectal prolapse.

Perineal approaches to the repair of rectal prolapse are frequently used in elderly or high-risk patients. These repairs have lower operative mortality and morbidity than intra-abdominal repairs but in general have higher recurrence rates. This study reviews our recent results with perineal prolapse repairs, briefly summarizes the literature, and discusses the available perineal operations. Eight patients (mean age 75 years) underwent surgical prolapse repair over an 18-month period. Treatment was by Altemeier's procedure (perineal rectosigmoidectomy) in 6 patients and Delorme's procedure in 2 patients. There were no operative mortalities, and an anastomotic dehiscence in 1 patient was managed nonoperatively. All patients with preoperative constipation improved and no patient reported worsening of continence. Surgical approaches from the perineum may be used in elderly and poor risk patients to treat rectal prolapse with low mortality and morbidity. These techniques have not adversely affected fecal continence and have improved symptoms of constipation with an acceptable rate of recurrence.

Aged↗
PubMed1996

Procedures used by North Carolina dairies for vitamins A and D fortification of milk.

New research findings have documented fortification errors in fortified milk products all across the US milk industry. Also, the consumption of overfortified bovine milk has led the public to question whether vitamin fortification is safe. Therefore, North Carolina dairies were surveyed to determine vitamin fortification procedures used and to determine differences among these procedures. Of the parameters surveyed, the general conditions under which vitamin preparations were stored, the method used to add vitamin preparations to milk, and the point during processing at which vitamin preparations were added to milk were different among dairies. Forty-six percent of the dairies stored vitamin preparations under refrigerated conditions, and 54% stored vitamin preparations at ambient temperatures. The addition of vitamin preparations to bovine milk was accomplished by metered injection at 64% of the dairies and batch addition techniques at 36%. Vitamin preparations were added before fat content standardization and separation by 23% of the dairy processors; 77% added the vitamin preparations after this point. When dairies were asked at what point they added their vitamin preparations to the milk, nine different answers were given. Although other sources of error could also contribute to inconsistent concentrations of vitamin fortification, differences in fortification procedures may have a large impact upon the problem. The diversity of vitamin fortification practices used in North Carolina may be an indication of nationwide trends.

Animals↗
PubMed1995

Practice parameters for sigmoid diverticulitis. The Standards Task Force American Society of Colon and Rectal Surgeons.

It should be recognized that these guidelines should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all of the circumstances presented by the individual patient.

Acute Disease↗
PubMed1993

Congenital cytomegalovirus infection and neonatal auditory screening.

Auditory screening of newborn infants has been recommended on the basis of the presence of risk criteria, including congenital infection. We assessed the ability of risk criteria-based neonatal auditory brain stem response to identify infants with hearing loss resulting from congenital cytomegalovirus (CMV) infection. Data from 6 1/2 years of risk criteria-based neonatal auditory screening were compared with the results of screening of all newborn infants for congenital CMV infection. Infants with congenital CMV infection received follow-up hearing evaluations. Congenital CMV infection was found in 167 (1.3%) of 12,371 infants; 134 had follow-up hearing evaluations, and 14 (10.4%) had confirmed sensorineural hearing loss. The rate of sensorineural hearing loss resulting from congenital CMV infection was 14 per 12,371 infants, of 1.1 per 1000 live births; the rate of bilateral loss > or = 50 dB was 0.6 per 1000. Although 2036 infants received auditory screening because of risk criteria, only 34 (20%) of 167 infants with congenital CMV infection were included. Only 2 (14%) of 14 children with sensorineural hearing loss caused by CMV were identified by risk criteria-based screening. We conclude that congenital CMV infection is an important cause of hearing impairment. Neonatal auditory screening based on the presence of risk criteria will fail to identify the majority of cases of sensorineural hearing loss caused by congenital CMV infection.

Cytomegalovirus Infections↗
PubMed1991

Utilization of dental services by older adults in four Ontario communities.

The elderly tend to use dental services less than most younger age groups. While the elderly's utilization rates may be rising, very low utilization by edentulous people depresses the overall rate for the group. We use data from the Ontario Study of the Oral Health of Older Adults to identify the variations in the use of dental services in the four study sites of Toronto, North York, Simcoe County and Sudbury and District. We reached 3,033 subjects by telephone and conducted dental examinations and a multi-item personal interview with 907 of them. The 907 subjects ranged in age from 50 to 87 years, 57 percent were female and two-thirds were born in Canada. Overall, 60.5 percent had seen a dentist or denturist in the previous year, but this was much lower among the edentulous (17 percent) when compared to the dentate (72 percent) (Chi-square test; p less than .0001). Of the 357 who did not visit a dentist or denturist in the previous year, nearly half (48 percent) felt they had nothing wrong and 20 percent reported they could not afford care. A high proportion (94 percent) of the edentulous reported visiting only for pain or trouble compared to 26 percent of the dentate (Chi-square test; p less than .0001). Using logistic regression, we found dental status (edentulous), community of residence (Sudbury), income (up to $20,000) and dental insurance coverage (none) were important factors in not making a dental visit in the last year. These same factors, plus education (elementary) were important where subjects reported visiting a dentist or denturist only when there was pain or trouble.

Aged↗
PubMed1985

Extracellular pH, transmembrane distribution and cytotoxicity of chlorambucil.

The effects of extracellular pH (6.2 to 7.3) on uptake and cytotoxicity of the weak acid anti-tumor drug chlorambucil were investigated. Decreasing extracellular pH from 7.3 to 6.5 had a negligible effect on the intracellular pH of Chinese hamster V79 fibroblasts, thus resulting in the formation of a transmembrane pH gradient (intracellular alkaline). Addition of high concentrations of acetate or bicarbonate partially collapsed the pH gradient. Chlorambucil (pKa = 5.8) behaved as a weak acid with enhanced accumulation and cytotoxicity at extracellular pH less than 7.0. As predicted for a weak acid, partial collapse of the transmembrane pH gradient decreased both uptake and cell killing. Since the interstitial pH of micrometastases and solid tumors of many cancers is low relative to normal tissues, these results have potential implications for both in vitro drug testing and in vivo therapy.

Animals↗
PubMed1980

Multiple ureteral diverticula.

Only 30 cases of multiple ureteral diverticula have been reported previously. We present a new case of this benign condition and review concepts concerning its etiology. Usually discovered on retrograde pyelography, multiple ureteral diverticula are only inconsistently associated with a history of obstruction or infection. When present, however, these factors may play a role in precipitating mucosal herniation through preexisting weak areas in the ureteral wall.

Aged↗
PubMed1978

Succinylcholine chloride as a euthanatizing agent in dogs.

In order to determine the efficacy of succinylcholine chloride as a euthanatizing agent, the possible situation encountered in mass euthanasia was recreated. While anesthetized or awake, sixteen 2-year-old Beagles of both sexes were subcutaneously injected with either 1.1 g or 11 mg of succinylcholine chloride/kg of body weight. Positive pressure respiration was given to 2 dogs, otherwise the treatment was allowed to run its course. Electrocardiogram, electroencephalogram, and impedance pneumogram recordings were obtained for time comparisons and for determination of the ultimate cause of death.

Animals↗
PubMed1976

Regulation of some functions of granulocytes by zinc of the prostatic fluid and prostate tissue.

Oxygen consumption, phagocytosis, and activity of hexosomonophosphate shunt (HMS) of dog and human polystyrene latex-activated polymorphonuclear leukocytes were inhibited by normal and infected human prostatic fluid (PF) and prostate extract; resting cells were not affected. Granulocytes incubated in 7 per cent PF increased five times their zinc content. Inorganic zinc added to synthetic medium which contained activated granulocytes also inhibited O2 consumption and phagocytosis of yeast particles in a concentration-dependent manner; resting cells were not affected. Incubation of PF with CaNa2 ethylenediamine tetraacetic acid (EDTA) abolished the inhibitory effect of PF; extensive dialysis of PF against this chelating agent reduced the inhibition by half. After the PF was dialyzed against saline, the low molecular weight dialysate retained inhibitory effects. Extracts from dog liver, spleen, and human saliva were not inhibitory. Polyamines, which next to zinc are also present in PF in high concentrations, had no effect on granulocytes, O2 consumption, and HMS activity. Human as well as dog PF were inhibitory to human or dog granulocytes, respectively. Besides granulocytes, rat peritoneal macrophages were inhibited by PF as well. It is concluded that PF and extract from prostate inhibit various functions of phagocytes mainly because of high concentration of zinc. The existence of other, large molecular weight, heat-resistant substances in PF which contribute to zinc effect cannot be ruled out.

Animals↗