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Biomedical subjects

J Thomas

Publications and source records attributed to J Thomas.

At least 487 records · Page 27Linked to original sources
PubMed1991

Legal status and the stability of coresidential unions.

Using data from the National Longitudinal Study of the High School Class of 1972, we examine the effect of the legal status of coresidential unions on the likelihood of dissolution. We find that legal unions are much more stable than nonlegal unions. In addition, current legal status is more important for predicting stability of union than is legal status at the initiation of the union. We also find that the effect of current legal status remains constant over various durations of unions and that legalizing a nonlegal union has little effect beyond that expected on the basis of a occupying a particular legal status.

Divorce↗
PubMed1991

[Long ureteral ammonium-magnesium phosphate (struvite) and calcium phospho-carbonate calculi].

The authors report about 12 cases of long ureteral calculi, 16 to 39 mm in size, observed over 10 years. They were all made of a mixture of ammonium-magnesium phosphate and calcium phosphocarbonate. Infection was the revealing symptom, either in the form of simple bacteriuria or as acute pyelonephritis or sepsis. These calculi, found in a lumbar or pelvic location, were very long, radiopaque but with a moderate radiological density, homogeneous and have regular contours. They were straight, sometimes slightly bent, rarely (one case out of 12) arciform. In 11 of 12 cases, the affected patient was female. In most cases, the urine was infected by Proteus mirabilis. In spite of their size, the calculi caused total obstruction in 3 of 12 cases only. They were or were not associated to ipsilateral coral calculi of the same chemical type. Destruction was easily achieved with physical agents. The etiological, radiological and therapeutic characteristics of these calculi give them a specific place among ammonium-magnesium phosphate calculi.

Adult↗
PubMed1991

The effect of indomethacin on Achilles tendon healing in rabbits.

In a randomized, blind study, percutaneous tenotomy was performed on the right Achilles tendon complex of 32 male, New Zealand rabbits. The rabbits were placed in long-leg casts to approximate the tendon. Sixteen rabbits received oral therapeutic doses (1.5 mg/kg/day) of indomethacin elixir; the remaining 16 rabbits received no medication and comprised the control group. At two and six weeks following tenotomy, eight rabbits in each group were sacrificed and the Achilles tendon complexes were resected. Each tendon was evaluated for tensile force-to-failure by uniaxial tensile loading using an Instron Materials Testing Machine at a velocity of 0.85 cm/second. Histologic evaluation assigned the specimens to categories of either "relatively mature" or "relatively immature," based on the degree of cellularity, neovascularity, and collagen orientation that had occurred in the healing process. The mean force-to-failure two weeks post-tenotomy for the experimental group was 75.7 +/- 42.3 Newtons (N), and 96.6 +/- 35.2 N for the control group; at six weeks post-tenotomy, the mean force-to-failure for the experimental group was 165.5 +/- 34.3 N and 160.2 +/- 31.6 N for the control group. Statistical analysis revealed no significant differences in tensile force-to-failure or histologic appearance between the experimental and control groups at either time interval. These results suggest that indomethacin, and potentially other nonsteroidal antiinflammatory drugs, may be used in conjunction with a tendon injury without significantly affecting the early healing process.

Achilles Tendon↗
PubMed1991

[Lithotripsy for pelvic lithiasis with the Dornier system with radiological location].

The authors report their results with 58 patients presenting with pelvic lithiasis who were treated by extracorporeal lithotrity with the Dornier HM3 system. They describe the appropriate procedure of analgesia and emphasize the difficulties to locate the pelvic calculi, which sometimes requires resorting to urography during the treatment. Out of the 58 cases, success was total in 55 (94.83%), after one session of lithotrity in 52 of them and after two sessions in 3. In 2 of the 3 cases of failure, the calculi were monohydrated calcium oxalate stones located very high in the ischiadic incisure. Five cases of presacral lithiasis were treated in the ventral position, successfully in 3 cases and without success in 2. Thus it appears that shock wave lithotrity with the Dornier HM3 system with radiological location is highly effective for the treatment of pelvic lithiasis.

Adolescent↗
PubMed1991

Immunobiology of the xenograft response: xenograft rejection in immunodeficient animals.

These studies provide insight into the immunobiology of xenograft rejection. They suggest that xenograft rejection involves T-cell phenomena, although the ability of the nude rat (functionally known to be T-cell deficient) to reject the vascularized xenograft normally is striking and clearly indicates a need for future studies of this phenomenon. These studies strongly suggest a role for NK and K cell-type activity in xenograft rejection, although they also indicate this immune function is only an ancillary one and that xenograft rejection will eventually occur despite deficiencies in these systems. These studies are most provocative in showing a failure of efficiency of skin graft rejection in the purest model of B-cell deficiency, the XID model. Since these results are obtained with the so-called secondarily vascularized xenograft (skin grafts) it is not possible to exclude the role of B-cell and B-cell-associated phenomena in vascularized organ grafts without further studies.

Animals↗
PubMed1991

Bull horn injuries.

Bull horn injury is not uncommon, and during a 12 year period from 1977 to 1988, 101 patients required inpatient treatment at the Christian Medical College Hospital, a teaching hospital at Vellore in South India. The ages of these patients ranged from two years to 90 years and the male to female ratio was 4:1. Sixty-one per cent of the injuries occurred either to the perineum or abdomen and wounds were directed obliquely upward. Thirty-five per cent required extensive surgical intervention. The over-all wound infection rate was 12.9 per cent. Of wounds that were primarily closed, 42.9 per cent had wound infection, while only 6.3 per cent that were secondarily closed developed infection. Two patients died as a consequence of the injury. Based on the results of this study, we recommend that a careful evaluation of the injury and timely and appropriate management of each patient must be done to reduce morbidity and mortality. Primary closure of wounds must be avoided even when surgical intervention is possible soon after injury.

Abdominal Injuries↗
PubMed1991

Prevention of coronary heart disease in black adults.

Development of strategies to prevent CHD in blacks is impeded by the virtual absence of clinical trials demonstrating the feasibility and effectiveness of interventions in blacks. The wholesale generalization that interventions effective (or ineffective) in whites are similarly effective in blacks may risk the employment of worthless or even dangerous interventions in blacks. Using available epidemiologic data, a number of risk factors may be more important in blacks than whites by virtue of higher prevalence, increased relative risk, or both. These may include hypertension, lipoprotein (a), smoking, diabetes, and obesity. Thus, health agencies might emphasize these risk factors when developing preventive programs targeted at black populations. Prevention programs may best seek to prevent the onset of risk factors found highly prevalent in black communities, rather than the costly and side-effect-prone interventions to treat risk factors once established. Thus, there is a role for community-based as well as a high-risk approaches. The community-based approaches should seek to work with organizations such as churches, which traditionally play strong roles in the black community. Physicians treating black patients should be aware of the potentially different roles played by risk factors, and treat aggressively those individuals identified to be at high risk. Risk factor management should be emphasized, rather than reduced, in patients with already established CHD. CHD has been clearly shown to be preventable; both blacks and whites should benefit from specific interventions aimed toward this worthy goal.

Adult↗
PubMed1990

Hormonal determinants of apolipoprotein B,E receptor expression in human liver. Positive association of receptor expression with plasma estrone concentration in middle-aged/elderly women.

The relationships of the expression of hepatic low-density lipoprotein (LDL) receptors (apo B,E receptors) to several plasma hormone concentrations were examined in 15 fasted women aged 37-75 years (mean, 57 years), who were undergoing laparotomy for non-neoplastic disease. No subject had clinical or biochemical evidence of familial hypercholesterolemia, renal disease, hepatic disease, or endocrine disease. Hepatic apo B,E receptor expression was quantified in vitro as the EDTA-suppressible binding of 125I-labeled human LDL (15 micrograms protein/ml) by liver homogenate at 37 degrees C; values were 23-75 ng LDL protein/mg cell protein (mean, 47 ng/mg). Receptor expression was strongly correlated with plasma estrone concentration (rs = +0.70, P = 0.035), but was unrelated to the concentrations of testosterone, thyroxine, free triiodothyronine, cortisol, sex hormone-binding globulin (SHBG) or cortisol-binding globulin. Insulin and estradiol concentrations were mostly very low. The correlation of receptor expression with plasma total estrone concentration reflected associations with both the albumin-bound (rs = +0.78, P = 0.014) and unbound (rs = +0.80, P = 0.009) fractions, but not with the SHBG-bound fraction (rs = -0.22, P = 0.574), of this hormone. As the non-SHBG-bound fractions of gonadal steroids are considered to be the biologically active components, these results are consistent with experimental evidence that the synthesis of apo B,E receptors in hepatocytes is stimulated by estrogens, and suggest that circulating estrone may be the major hormonal determinant of receptor expression in fasted middle-aged/elderly women.

Adult↗
PubMed1990

The spliceosomal snRNAs of Caenorhabditis elegans.

Nematodes are the only group of organisms in which both cis- and trans-splicing of nuclear mRNAs are known to occur. Most Caenorhabditis elegans introns are exceptionally short, often only 50 bases long. The consensus donor and acceptor splice site sequences found in other animals are used for both cis- and trans-splicing. In order to identify the machinery required for these splicing events, we have characterized the C. elegans snRNAs. They are similar in sequence and structure to those characterized in other organisms, and several sequence variations discovered in the nematode snRNAs provide support for previously proposed structure models. The C. elegans snRNAs are encoded by gene families. We report here the sequences of many of these genes. We find a highly conserved sequence, the proximal sequence element (PSE), about 65 bp upstream of all 21 snRNA genes thus far sequenced, including the SL RNA genes, which specify the snRNAs that provide the 5' exons in trans-splicing. The sequence of the C. elegans PSE is distinct from PSE's from other organisms.

Animals↗
PubMed1990

Pharmacokinetics of the recombinant fusion protein DAB486IL-2 in animal models.

The kinetics of the in vitro cytotoxicity of DAB486IL-2, a genetically engineered fusion protein containing a portion of diphtheria toxin and human interleukin-2, were examined in the C91/PL cell line, which constitutively expresses IL-2 receptors. Maximal inhibition of protein synthesis was observed by 4-6 h after DAB486IL-2 addition at a concentration of 300 ng/ml. The tissue distribution, urinary excretion, and plasma pharmacokinetics of DAB486IL-2 in the rat and its plasma pharmacokinetics in the monkey were also examined. In rats the primary site of distribution of [35S]-DAB486IL-2 outside the vasculature appears to be the liver, followed by the kidney, spleen, and lung. Persistence of radioactive material in the liver and urinary excretion of metabolic degradation products suggest that labeled protein is metabolized by hepatic tissue. Following i.v. bolus administration of DAB486IL-2, the initial serum half-life for both the rat and the monkey was approximately 5 min. The overall clearance rate of drug for the two species differed, with DAB486IL-2 being cleared from circulation 2-3 times more rapidly in the monkey. Presence of high levels of neutralizing antibodies to diphtheria toxin in the rat significantly influenced the clearance of bioactive DAB486IL-2. However, the question as to whether the presence of in vitro biological activity for the molecule is masked by the presence of antibodies cannot be clearly answered.

Animals↗
PubMed1990

Causes of death after therapy for early stage Hodgkin's disease entered on EORTC protocols. EORTC Lymphoma Cooperative Group.

The risk of dying from different causes after Hodgkin's disease (HD) therapy has been quantified from a series of 1,449 patients with early stages included in four successive clinical trials conducted by the European Organization for Research and Treatment of Cancer (EORTC) Lymphoma Cooperative Group since 1963. Overall, 240 patients died and the 15-year survival rate was 69% whereas the expected rate was 95%. The standardized mortality ratio (SMR) technique was used to quantify excess deaths as a function of time since first therapy. At each interval, SMR was significantly increased, giving: 0-3 year, 8.86 (p less than 0.001); 4-6 year, 9.25 (p less than 0.001); 7-9 year, 7.08 (p less than 0.001); 10-12 year, 9.53 (p less than 0.001); 13-15 year, 4.37 (p less than 0.01); and 16+ years, 3.80 (p less than 0.05). While the proportion of deaths as a consequence of HD progression, treatment side-effect, and intercurrent disease decreased with time, that of second cancer and cardiac failure peaked during the 10-12 year post-treatment interval. After 15 years of follow-up, the risk of dying from causes other than HD continued to increase. These findings indicate that although probably cured from HD, patients are at higher risk for death than expected, a risk that might be a consequence of therapy.

Adult↗
PubMed1990

Gender difference in susceptibility to picrotoxin-induced seizures is seizure- and stimulation-dependent.

In a dose-response study, the pattern of sex-associated susceptibility to picrotoxin-induced myoclonic, focal, akinetic, and generalized tonic-clonic (GTC) seizures was investigated in rats to determine whether the reported heightened susceptibility of females to seizures was a general phenomenon in rats or whether it was limited to specific types of seizures. The latency to and incidence of specifically categorized seizures were used as indices of susceptibility after male and female rats had been injected with picrotoxin (3-10 mg/kg). The results revealed that at low doses of picrotoxin (4 mg/kg), female rats had significantly shorter latencies to myoclonic seizures and significantly shorter latencies and higher incidences of GTC seizures. At higher doses of picrotoxin (8 and 10 mg/kg), the pattern of relative susceptibility of males and females to myoclonic seizures was reversed, with males having shorter latencies than females. There were no significant sex differences in the incidence of or latency to focal or akinetic seizures at any of the doses tested. These findings indicate 1) that there are significant sex differences in seizure susceptibility only for specific seizure categories in rats; and 2) that for seizure categories where significant sex differences were identified, the observed pattern of relative susceptibility of males and females depends on the dose of picrotoxin tested. Thus, patterns of sex-associated seizure susceptibility favoring either males or females are both seizure- and stimulation-limited and do not reflect general dispositions to seizures in either sex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

The effect of nimodipine on picrotoxin-induced seizures.

The effects of the calcium channel antagonist, nimodipine, on picrotoxin-induced myoclonic (MYO) and generalized tonic-clonic (GTC) seizures were investigated in male and female rats. In males, a dose-response study of nimodipine's effects on seizures induced by different doses of picrotoxin was conducted. In a second experiment, female rats were tested for latency to and incidence of MYO and GTC seizures after being pretreated with nimodipine 2 hr, 24 hr, or 72 hr prior to seizure testing. The results showed that, in males, various doses of nimodipine significantly increased the mean latencies to MYO and GTC seizures and significantly reduced the incidence of GTC seizures. In females, nimodipine significantly reduced the incidence and/or increased the latency of GTC seizures when given 24 hr of 72 hr prior to administration. In addition to the anticonvulsant effects, nimodopine significantly increased survival after seizures in both males and females even when it had no significant effects on seizure incidence or latency. The results of this study support the hypothesis of calcium involvement in seizure induction. However, the sex- and time-dependent nature of the nimodipine effects as well as the effects of nimodipine on survival after seizures suggest that the relationship between calcium and seizure activity is complex.

Animals↗
PubMed1990

Inheritance and expression of chimeric genes in the progeny of transgenic maize plants.

We obtained transgenic maize plants by using high-velocity microprojectiles to transfer genes into embryongenic cells. Two selectable genes were used to confer resistance to either chlorsulfuron or phosphinothricin, and genes encoding either E. coli beta-glucuronidase or firefly luciferase were used as markers to provide convenient assays for transformation. When regenerated without selection, only two of the eight transformed embryogenic calli obtained produced transgenic maize plants. With selection, transgenic plants were obtained from three of the other eight calli. One of the two initial lines produced 15 fertile transgenic plants. The progeny of these plants contained and expressed the foreign genes. Luciferase expression could be visualized, in the presence of added luciferin, by overlaying leaf sections with color film.

Base Sequence↗