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Biomedical subjects

M Holland

Publications and source records attributed to M Holland.

At least 73 records · Page 4Linked to original sources
PubMed1994

Angiographic evaluation of a carotid-subclavian bypass graft in a patient with subclavian artery stenosis and left internal mammary artery bypass graft.

The incidence of coronary subclavian steal syndrome is estimated to be 0.4%. When revascularization is necessary, the preferred technique is the carotid-subclavian bypass graft. Failure of a carotid-subclavian graft is rare. We present a patient with subclavian stenosis who required reevaluation of both the carotid subclavian conduit and the left internal mammary bypass graft. A combined femoral and left brachial approach is recommended for evaluating the carotid-subclavian graft and left internal mammary artery graft in patients with bypassed subclavian artery stenosis and prior myocardial revascularization.

Cerebral Revascularization↗
PubMed1994

Immunoradiometric assay of thyrotropin during the first six months of life.

The aim of this preliminary study was to assess variation in thyrotropin (thyroid-stimulating hormone; TSH) levels using an immunoradiometric assay during the first 6 months of life of normal infants. One hundred and five normal newborns (59 females, 46 males) were evaluated for TSH, triiodothyronine and thyroxine at 48 h of life, and TSH was additionally determined at 15 days (n = 42), 30 days (n = 38), 60 days (n = 24), 90 days (n = 28), and 180 days (n = 30). Complete determinations during the total period of the study were obtained in 17 infants. Samples corresponding to the 48-hour period did not exhibit a normal distribution. In this group, percentile 3 corresponded to 0.9 mU/l, the median to 4.2 mU/l and percentile 97 to 17.7 mU/l. Levels of TSH similar to those of the normal adult population were reached between 30 and 60 days of life. Nevertheless, TSH levels of some of the children remained at higher values for a longer period. In summary, our results suggest that high TSH levels might not always indicate an underlying pathology. A critical evaluation of the normality criteria could avoid unnecessary studies and treatments.

Female↗
PubMed1994

[Variability of growth hormone response to repeated stimulation tests in children of normal height].

The presence of false negatives in the evaluation of patients with short stature and the variability of 24 hour growth hormone (GH) physiological studies in the normal population are well known. Therefore the reproducibility of two widely used pharmacological test was studied in normal children. Forty prepuberal children were evaluated (34 boys and 6 girls), with chronological ages ranging from 2 years 11 months to 12 years 11 months (mean: 9 years 1 month), bone ages from 3 years 2 months to 12 years 6 months (mean: 8 years 4 months) and with normal stature and growth velocity (SDS > -2) and normal body mass index (BMI < 25). Clonidine test was performed (100 micrograms/m2 surface) measuring GH (ng/ml) 0,06 and 90 min in 20 patients (Group I). Exercise-Propranolol test was performed (0,5 mg/kg weight) with basal and post-exercise GH measurements in 20 patients (Groups II). The tests were repeated at one week intervals and each child was his own control. Group I showed (mean +/- SD): 1st test: B = 1.78 +/- 1.59, Max Resp = 13.16 +/- 8.34; 2nd test: B = 1.17 +/- 0.51, Max Resp = 15.12 +/- 8.09. Group II showed (mean +/- SD): 1st test: B = 1.38 +/- 0.58, Max Resp 16.97 +/- 9.69; 2nd test: B = 1.54 +/- 1.16, Max Resp = 13.49 +/- 7.81. Wilcoxon's test did not show significant differences when comparing B vs B and Max Resp vs Max Resp in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Height↗
PubMed1993

Pubertal varicocele: correlation between clinical, Doppler, and hormonal findings.

Clinical, Doppler, and hormonal findings in puberal patients with unilateral and bilateral varicocele were evaluated. No correlation was found between clinical and hormonal findings. A significant increase was found in LH response to LH-RH in patients with bilateral varicocele as well as an increase in T to hCG in those with unilateral varicocele with prolonged reflux. Further longitudinal, hormonal, and Doppler studies in puberal patients might provide information about the most useful parameters to define those individuals at higher risk of having future problems.

Adolescent↗
PubMed1993

Contrast agents.

Pharmacologic development and clinical use of nonionic low osmolality contrast agents have lowered incidences of contrast reactions. Exclusive use of these agents may be limited owing to their high costs. Ionic high osmolality agents still provide reliable means of positive contrast enhancement, and minimal problems with reactions have been experienced in veterinary patients.

Angiography↗
PubMed1993

[Serum testosterone: a possible marker for colorectal cancer].

A reduction of circulating testosterone has been reported in lung, stomach and pancreatic carcinoma. In order to evaluate the concentration of this hormone in patients with colorectal cancer, we studied 58 men with histologically confirmed disease. Seric testosterone, estradiol and carcinoembryogenic antigen were simultaneously measured in 24 patients under pre-surgical evaluation (group I) and in 34 patients after surgical resection (group II). The results were compared with a control group carrying benign gastrointestinal pathologies. According to the Kruskal-Wallis test, the testosterone level in cancer groups was significantly lower than in the control group (p < 0.0001). We have also observed a statistical significance between subgroups I and II compared to the control group (p < 0.001), while no conspicuous differences were perceived in estradiol concentrations between benign and cancer groups. Decreased serum levels of testosterone were found in 69% of patients with colon or rectal carcinoma and 56.9% of them had raised levels of carcinoembryonic antigen. The combined determination of both biomarkers increase to 86.2% the sensitivity of tumor screening compared with a single detection. Our results suggest that the combination of testosterone and carcinoembryonic antigen enhances the efficiency of tumor screening. We conclude that the evaluation of circulating testosterone could be a new and more sensitive assay for diagnosis and follow-up of colorectal carcinoma in males, specially in patients with normal levels of carcinoembryonic antigen.

Adult↗
PubMed1992

W-7, a calmodulin antagonist, and contracture of malignant hyperthermia susceptible skeletal muscle.

1. In malignant hyperthermia susceptible muscle fibers, the calmodulin antagonist, W-7 (10 microM), evoked contractures and potentiated halothene (3%) induced contracture. No effect was seen at 0.1 or 1.0 microM) W-7. 2. Dantrolene sodium (6 microM) prevented and reversed W-7 induced contracture: nifedipine did not. 3. In chemically skinned fibers, 10 microM, 1.0 microM, and 0.1 microM W-7 released 100%, 30%, and 10% of stored calcium respectively, and the effect of 10 microM W-7 was irreversible in that the SR was unable to re-sequestor calcium after exposure to the drug. 4. The release of calcium by W-7 was not prevented by exogenously added calmodulin (3 microM), nor mimicked by mastoparan (10 microM). 5. Calcium release by W-7 appears to be independent of calmodulin inhibition.

Animals↗
PubMed1992

Altered mechanical responses of malignant hyperthermic skeletal muscle during repetitive stimulation.

This investigation examined the mechanical responses of malignant hyperthermic (MH) and normal porcine skeletal muscle to repetitive stimulation. Twitch and maximal tetanic tensions were not significantly different between muscle types. Tensions produced during stimulation at 20-80 Hz were significantly less in MH muscle than in normal muscle. In addition, MH muscle showed significantly greater force decline (tetanic fade) at the end of contractions evoked by 20-80 Hz stimulation. When stimulated to fatigue, both normal and MH muscle exhibited similar rates of tension decline during the initial minutes. Further stimulation caused additional decline in normal muscle, but a tension plateau in MH muscle. In all cases, normal muscle had greater magnitudes of fatigue than did MH muscle. Results show that there are marked differences between MH and normal muscle in the mechanical responses to repetitive stimulation. Due to its inability to properly regulate intracellular Ca2+ exchange, it is possible that MH muscle might be a useful tool for identifying the mechanisms of muscle fatigue in normal muscle.

Animals↗
PubMed1992

Synergistic effects of oral nonsteroidal drugs and topical corticosteroids in the therapy of sunburn in humans.

The ability to modify skin injury due to ultraviolet light (UVB) by the nonsteroidal anti-inflammatory drugs (NSAIDs) oral ibuprofen (IB) or indomethacin (IN) plus topical betamethasone dipropionate (BD) was studied in 24 subjects in this open-label, four-way, cross-over trial. All subjects received UVB at weekly intervals: group 1 was randomized to IB, BD, IB + BD or control, and group 2 to IN, BD, IN + BD or control. Oral medications were given prior to and after exposure to UVB, but BD was applied only afterwards. The skin response to UVB [erythema and increased skin blood flow (SBF)] was measured serially for 96 h. A skin biopsy was taken at 24 h after each dosing with UVB. At maximum erythema (8-12 h after UVB), the following approximate reductions in SBF (compared to control responses) were noted: 42-58% for combination therapies, 33-40% for IB or IN alone, and 17% for BD alone. SBF tended to equalize across all treatments by 24 h and remained until 96 h. Skin biopsy results were consistent with the noninvasive findings. Thus, we observed a synergistic effect of reduction of UVB-induced erythema and SBF with combinations of oral NSAIDs and topical corticosteroids. This study could have implications for the therapy of sunburn in humans.

Administration, Oral↗
PubMed1992

Na(+)-Ca2+ exchange influences halothane and caffeine contractures of malignant hyperthermic skeletal muscle.

These experiments sought to determine the influence of sarcolemmal Na(+)-Ca2+ exchange on halothane and on caffeine contractures of malignant hyperthermic (MH) skeletal muscle. Fiber bundles excised from MH susceptible pigs (Pietrain) were exposed to halothane (3%) and caffeine (0.5-8.0mM) while Na(+)-Ca2+ exchange was inhibited by reducing extracellular Na+ from 100% to 50, 25 and 0% of control. Halothane contracture magnitude was not altered by 50 or 25% Na+ whereas 0% Na+ increased the contractures by 51%. 0 and 25% Na+ increased the magnitude of caffeine contractures (2-8mM) by 53-176%. These results suggest that external Na+ and the Na(+)-Ca2+ exchange mechanism influences contractures of MH skeletal muscle.

Animals↗
PubMed1991

Homeostatic action of interleukin-4 on endogenous and recombinant interleukin-2-induced activated killer cell function.

Cytokine-secreting, major histocompatibility complex-unrestricted activated killer (AK) cells are toxic to a wide range of virus-infected or malignant target cells and may be generated endogenously, eg, after bone marrow transplantation, or by infusion of cytokines such as recombinant interleukin-2 (rIL-2). Although AK cells secrete cytokines such as gamma-interferon and tumor necrosis factor, which are themselves able to recruit fresh cytokine-secreting AK cells, activation in both settings is short-lived, implying the existence of homeostatic regulatory mechanisms. We now demonstrate one mechanism by which rapid homeostasis is achieved. We show that IL-4 is produced in patients with both endogenously and exogenously generated AK cells. The cytokine was detected in serum after marrow transplantation, and IL-4 transcripts appeared in circulating lymphocytes during rIL-2 infusion. Although IL-4 inhibited the induction phase of AK cell function, it had no significant inhibitory effect on the ability of AK cells from these individuals to respond to restimulation. Nonetheless, neutralization of the IL-4 induced during cell activation doubled the half-life of AK function, once activating stimuli were removed, from 18 to 44 hours and produced a 2-log increase in AK cell secretion of tumor necrosis factor and gamma-interferon. These data suggest that IL-4 induced in vivo during lymphocyte activation abbreviates AK cell responses once the triggering stimuli have been removed. Neutralization of endogenous IL-4 in vivo by appropriate monoclonal antibodies might prolong the duration of AK function.

Bone Marrow Transplantation↗
PubMed1991

BAY K 8644 and nifedipine alter halothane but not caffeine contractures of malignant hyperthermic muscle fibers.

The purpose of these experiments was to determine if the Ca2+ agonist BAY K 8644 and the Ca2+ antagonist nifedipine alter the mechanical responses of malignant hyperthermia-susceptible (MHS) skeletal muscle to halothane and caffeine. Muscle fiber bundles were dissected from MHS porcine skeletal muscle and exposed to BAY K 8644 (10 microM), nifedipine (1 microM), low-Ca2+ media [Ca2+ replaced by 1 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid], or diltiazem (30 microM) administered alone and with halothane (3%) or caffeine (0.5-0.8 mM). When administered alone, both halothane and BAY K 8644 evoked a significant change in resting tension (i.e., contracture) of 193.7 +/- 61.0 and 51.9 +/- 21.5 mN/cm2, respectively. When administered in combination, BAY K 8644 had no effect on the magnitude of the halothane contracture (195.2 +/- 58.6 mN/cm2) but reduced its onset time from 306.7 +/- 36.3 to 105.9 +/- 8.9 s. Nifedipine, low Ca2+, and diltiazem significantly reduced the halothane contracture (103.1 +/- 30.3, 123.1 +/- 20.6, and 112.6 +/- 16.2 mN/cm2, respectively) but had no effect on its onset time. In addition, low Ca2+ reduced the magnitude of the BAY K 8644 contracture (8.2 +/- 2.1 mN/cm2). BAY K 8644 also increased contractures induced by low caffeine concentrations (0.5-2.0 mM) but did not alter contractures induced by 4.0 and 8.0 mM caffeine, whereas nifedipine, low Ca2+, and diltiazem had no effect on these contractures. These results suggest that extracellular Ca2+ influx may have some influence on halothane but not on caffeine contractures of MHS skeletal muscle.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗