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Biomedical subjects

A J Thomas

Publications and source records attributed to A J Thomas.

At least 19 recordsLinked to original sources
PubMed1992

Fibrotic lesions of the testicle: sonographic patterns mimicking malignancy.

All testicular sonograms performed over a 2.5-year period were retrospectively reviewed, yielding eight patients with pathologically proven lesions consisting primarily of tubular sclerosis and interstitial fibrosis. Only two patients (25%) had a palpable abnormality. A variety of sonographic patterns was found, including focal hypoechoic or hyperechoic lesions and diffuse heterogeneity of the testicular parenchyma. The clinical and sonographic findings prompted open biopsy or orchiectomy in all cases. In the same time period, nine pathologically proven testicular malignancies were evaluated sonographically and displayed either well-defined hypoechoic or diffusely heterogeneous echo patterns. All but two of these patients (78%) had palpable abnormalities. This study demonstrates a significant overlap in the sonographic appearance of benign fibrotic lesions and testicular malignancies. When careful palpation of a sonographically heterogeneous or focal hypoechoic lesion fails to reveal a mass and serum tumor markers are negative, an open biopsy with frozen section analysis should be considered rather than proceeding directly to orchiectomy. Homogeneously hyperechoic masses can be considered benign and do not require surgery.

Adult↗
PubMed1992

A model of ventilatory instability induced in the unrestrained rat.

A classic conditioning paradigm was used to examine the hypothesis that perturbations during sleep in the neonate rat can have a lasting impact on breathing. During the first 4 wk of life, stimuli were presented to rats during behaviorally defined sleep. In a conditioned hypoxic (CH) group, brief periods of hypoxic gas were used as the unconditioned stimulus. Tactile and auditory stimuli were used as the conditioned stimuli. In a conditioned control (CC) group, air was used as the unconditioned stimulus. A third group of unconditioned control (UC) rats was not exposed to the conditioning paradigm. Animals were provided routine care for 3.5 mo; ventilation was then assessed using plethysmography. Conditioning during neonatal life produced increased ventilatory irregularities and apnea during behaviorally defined sleep in adult rats. Both CH and CC rats showed a significantly greater number of apneic events compared with UC rats. Over a 2-h sleep period, CH rats exhibited a total of 105.1 +/- 9.4 (SE) apneic events, CC rats 69.4 +/- 4.2 events, and UC rats 42.1 +/- 3.1 events [F(2,18) = 25.568; P < 0.0001]. These findings suggest that experiences in the first few weeks of life will alter ventilatory patterning in the adult animal.

Acoustic Stimulation↗
PubMed1991

Results of 1,469 microsurgical vasectomy reversals by the Vasovasostomy Study Group.

During a 9-year period 1,469 men who underwent microsurgical vasectomy reversal procedures were studied at 5 institutions. Of 1,247 men who had first-time procedures sperm were present in the semen in 865 of 1,012 men (86%) who had postoperative semen analyses, and pregnancy occurred in 421 of 810 couples (52%) for whom information regarding conception was available. Rates of patency (return of sperm to the semen) and pregnancy varied depending on the interval from the vasectomy until its reversal. If the interval had been less than 3 years patency was 97% and pregnancy 76%, 3 to 8 years 88% and 53%, 9 to 14 years 79% and 44% and 15 years or more 71% and 30%. The patency and pregnancy rates were no better after 2-layer microsurgical vasovasostomy than after modified 1-layer microsurgical procedures and they were statistically the same for all patients regardless of the surgeon. When sperm were absent from the intraoperative vas fluid bilaterally and the patient underwent bilateral vasovasostomy rather than vasoepididymostomy, patency occurred in 50 of 83 patients (60%) and pregnancy in 20 of 65 couples (31%). Neither presence nor absence of a sperm granuloma at the vasectomy site nor type of anesthesia affected results. Repeat microsurgical reversal procedures were less successful. A total of 222 repeat operations produced patency in 150 of 199 patients (75%) who had semen analyses and pregnancy was reported in 52 of 120 couples (43%).

Adult↗
PubMed1991

Gamma/delta T cells and the diagnosis of coeliac disease.

Gamma/delta T cells are increased in the gut epithelium of patients with coeliac disease compared with normal controls. The aim of this study was to determine whether the increase in gamma delta intraepithelial lymphocytes (IEL) is specific for coeliac disease, in which case it could be of diagnostic importance. Biopsies were obtained from children with no intestinal disease, coeliac disease, cow-milk-sensitive enteropathy/post-enteritis syndrome (CMSE PES) and miscellaneous other enteropathies (n = 67). Intraepithelial CD3+ and gamma delta T cells were identified in frozen sections using peroxidase immunohistochemistry. In normal biopsies there were 0-7 gamma delta IEL/100 cells in the epithelium. In untreated coeliac patients this increased to 9-22 gamma delta IEL/100 cells in the epithelium (P = 0.000004). Of 27 patients with morphologic intestinal damage which was not due to coeliac disease, four with CMSE/PES had gamma delta IEL/100 cells in the epithelium in the same range as the patients with coeliac disease. Of these, two had high densities of CD3+ IEL in the epithelium and were indistinguishable from patients with untreated coeliac disease. The other two could be excluded as possible coeliacs because their CD3+ IEL/100 epithelial cells were in the normal range. Thus an increase in gamma delta IEL is not specific for coeliac disease. However, enumeration of both of gamma delta IEL and CD3+ IEL densities will be useful in the exclusion of coeliac disease as a diagnosis in some children.

Adolescent↗
PubMed1990

Zona drilling enhances fertilization by mouse caput epididymal sperm.

Spermatozoa from the caput epididymis are known to be much less capable of fertilization when compared to sperm from more distal segments of the epididymis. The purpose of this study was to determine if two micromanipulative techniques, zona drilling (ZD) and a modification of partial zona dissection (PZD), could be used to enhance fertilization with caput epididymal sperm. A mouse in vitro fertilization model was used. Inseminating oocytes with 500-1,000 sperm/oocyte from the cauda epididymis as a control resulted in fertilization of 98 of 300 (32.6%) oocytes. Of those fertilized, 47 developed to the blastocyst stage (47.9%). Caput sperm fertilized 13 of 116 (11.2%) nonmanipulated oocytes. Only 1 of 13 developed into a blastocyst, while with oocyte ZD, caput sperm fertilized 24 of 144 (16.7%) oocytes, 50% of those fertilized developing to blastocyst (P = 0.0129). When modified PZD was performed on oocytes, only one of 23 was fertilized, with no blastocyst development. These results indicate that acid Tyrode ZD enhances both fertilization and early embryonal development when caput epididymal sperm are used for insemination. These mouse studies suggest that ZD or other micromanipulation techniques may prove clinically useful in men with proximal epididymal obstruction where only caput sperm are available.

Animals↗
PubMed1990

Thiamine status of healthy and institutionalized elderly subjects: analysis of dietary intake and biochemical indices.

Thiamine status was assessed in healthy young and elderly subjects and institutionalized elderly patients by measuring dietary intake, erythrocyte levels of thiamine and the activity of the thiamine-dependent enzyme, erythrocyte transketolase, with and without the addition of excess thiamine pyrophosphate (the TPP effect). Healthy elderly subjects had a reduced intake of thiamine compared with the younger subjects but erythrocyte levels of thiamine and the TPP effect were comparable, suggesting adequate thiamine status. The institutionalized elderly patients had a low intake of thiamine compared with the healthy elderly as well as abnormal biochemical indices suggestive of suboptimal thiamine status. Thiamine deficiency does not appear to be a problem in healthy elderly people but those in institutions are at risk of deficiency which might adversely affect their clinical state.

Adult↗
PubMed1990

Metastatic carcinoma of the prostate with hypercalcemia.

A patient presented with advanced cancer of the prostate and underwent bilateral orchiectomy. After 2 years, hypercalcemia developed and was managed successfully with saline diuresis, furosemide, and oral glucocorticoid therapy. It is believed that the patient's hypercalcemia was caused by a metabolic complication of progressive, advanced disease.

Adenocarcinoma↗
PubMed1990

Current management of varicoceles.

In spite of all that has been written about the varicocele, it is still not clear who will benefit from occlusion of the spermatic vein or why improvement in semen takes place in some patients but not in others. Because fertility is usually assessed in the framework of a couple who are trying to establish a pregnancy, it is important to evaluate both partners before making any recommendations regarding therapy. If the man is found to have a varicocele and semen analyses that indicate deficits in either the quantity or quality of the sperm, surgical ligation or transvenous occlusion should be considered as one appropriate form of therapy. Varicocele ligation and embolotherapy both can be performed as an outpatient procedure with minimal morbidity and equal effectiveness regarding pregnancy outcome. The cost, if the procedures are done in an outpatient facility, should be approximately equal. The obvious benefits of the percutaneous technique are a slightly lower recurrence rate and a more rapid return to full physical activity. The surgical procedure described by Marmar and associates appears to have a similar rate of recurrence and short postoperative period of recovery. Greater experience by more urologists using this technique needs to be gained to compare it adequately with the other methods described. Varicocele ligation by the inguinal or retroperitoneal routes is familiar to most urologists and does not require the operating microscope or other special instruments. With greater understanding of the venous anatomy and with careful dissection, the persistence and recurrence rate can be acceptably low and the postoperative recovery relatively rapid and smooth.

Humans↗
PubMed1989

Failure of spermatozoa from T/t mice to fertilize in vitro is overcome by zona drilling.

Failure of epididymal spermatozoa from T/t mutant mice, but not from t/t individuals, to fertilize oocytes in vitro was partially overcome by opening a small aperture in the zona pellucida with acidified Tyrode's solution to permit direct access of the spermatozoon to the vitellus. This study provides a model system to evaluate requirements for successful zona drilling in the treatment of human infertility and further insights into the effects of the t complex on sperm fertility.

Animals↗
PubMed1989

Calcium, magnesium and phosphorus status of elderly inpatients: dietary intake, metabolic balance studies and biochemical status.

The calcium, magnesium and phosphorus status of a group of elderly inpatients was studied by use of duplicate meal analysis over a 5 d period and biochemical indices in twenty-one patients, and metabolic balance (5 d) in six of these. Mean daily Ca intake was lower than that of apparently healthy elderly subjects in metabolic equilibrium, although commensurate with present UK recommendations. Metabolic balance was negative for Ca. Mean daily Mg intake was approximately half the US recommendation, and half the intake at which metabolic balance has been observed in healthy elderly people. The five patients studied were in metabolic balance for Mg. Mean daily P intake was close to the UK recommendation, but negative metabolic balance was observed. The disparity between official recommendations for Ca-intake, factors contributing to suboptimal Ca status, and measures that may improve Ca status in this group are discussed.

Aged↗
PubMed1989

Selenium and vitamin E status of healthy and institutionalized elderly subjects: analysis of plasma, erythrocytes and platelets.

Levels of selenium in whole blood, plasma, erythrocytes and platelets, glutathione peroxidase (EC 1.11.1.9; GSH-Px) activity in erythrocytes and platelets and vitamin E, low-density-lipoprotein (LDL)-cholesterol and vitamin E: LDL cholesterol in plasma were measured in seventy-five healthy subjects aged less than 65 years and twenty-eight healthy and twenty-three institutionalized elderly people aged greater than 65 years. Healthy elderly subjects had significantly lower levels of Se in whole blood and plasma when compared with younger subjects. Other measurements of Se status were not significantly different. In the healthy subjects plasma levels of vitamin E and LDL-cholesterol increased with age to 60 years and decreased above 80 years. Vitamin E: LDL cholesterol values were not affected by age. Measurements of Se and vitamin E status in the institutionalized elderly compared with the healthy elderly were all reduced with the exception of platelet Se levels and erythrocyte GSH-Px activity. Ageing per se had minimal effect on Se and vitamin E status but intercurrent illness and decreased food intake can lead to reduced levels in the elderly.

Adult↗
PubMed1989

Iron status of hospitalized and housebound elderly people: dietary intake, metabolic balances, haematological and biochemical indices.

The iron status of housebound and hospitalized elderly people was studied by duplicate diet analysis, metabolic balance, biochemical and haematological investigations. Evidence of biochemical iron deficiency in the hospital group was accompanied by low dietary intake and negative metabolic balance. Metabolic equilibrium in the housebound group was seen with intakes similar to those found in healthy elderly though biochemical measures suggested a borderline iron deficient state.

Aged↗
PubMed1988

Osteoporosis.

Explore the source record for details and available documents.

Humans↗
PubMed1988

Energy, protein, zinc and copper status of twenty-one elderly inpatients: analysed dietary intake and biochemical indices.

1. Duplicate diet analysis for energy, protein, zinc and copper with estimates of biochemical status for Zn and Cu were undertaken in twenty-one elderly long-stay inpatients (mean age 82 (range 63-89) years) consuming their customary hospital diet and in a stable medical condition. Fourteen patients had a long-standing and significant healing problem, either a leg ulcer or pressure sore. 2. Mean daily intakes of energy (5.2 MJ), protein (45 g), Zn (85 mumol) and Cu (14 mumol) were low in comparison with both official recommendations and levels of intake at which metabolic equilibrium was observed in healthy elderly people studied by the same methods (Bunker et al. 1984a). 3. Mean leucocyte Zn (9 pmol/10(6) cells) and Cu (7.5 pmol/10(6) cells) were low in comparison with results from healthy elderly people (Bunker et al. 1984a), implying suboptimal status for these elements. Those patients with healing problems tended to have the lower values within the range. 4. Recommendations are made with respect to improving nutritional status in this disadvantaged group of people.

Aged↗
PubMed1987

Length-tension relationship of abdominal expiratory muscles: effect of emphysema.

The present study examined the active and passive length-tension relationship of the abdominal expiratory muscles in vitro during electrically stimulated contractions. Studies were performed on isolated strips of transverse abdominis and external oblique muscle from nine adult hamsters with normal lung function. The effect of chronic hyperinflation on the two muscles was assessed in eight hamsters with elastase-induced emphysema. In normal animals the maximal active tension per cross-sectional area (Po) was equal in the two muscles. The absolute muscle fiber length at which Po occurred (Lo) was less for the external oblique than the transverse abdominis and the length-tension curve operated at shorter fiber lengths. However, the change in tension produced by an increase or decrease in muscle length expressed in relative terms (i.e., as %Lo) was greater for the transverse abdominis than the external oblique. Mean total lung capacity of emphysematous animals was 198% of control. Po of the transverse abdominis and external oblique were the same in emphysematous and control animals. However, Lo and the length-tension curve of the transverse abdominis occurred at shorter fiber lengths in emphysematous animals because of a reduction in the number of sarcomeres in series along the fiber. The length-tension curve and the number of sarcomeres in the external oblique was the same in emphysematous and control animals. These results in normal animals indicate that the magnitude of the change in active and passive tension produced by a change in muscle length differs in the transverse abdominis and external oblique. Moreover, chronic hyperinflation of the thorax produced by elastase injection alters the length-tension relationships of some but not all the expiratory muscles.

Abdomen↗