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Biomedical subjects

G Ramirez

Publications and source records attributed to G Ramirez.

At least 145 records · Page 8Linked to original sources
PubMed1986

Longitudinal follow-up of chronic hemodialysis patients without vitamin supplementation.

Vitamin supplementation for dialysis patients is still controversial. In our study, we followed longitudinally over a period of a year, 15 patients on chronic hemodialysis who were deprived of vitamin supplementation. Microbiological assays were used to determine the levels of five vitamins of the B group (folate, niacin, B12, B6, and thiamine). Vitamin C was measured chemically. During the observation period when vitamins were not supplemented, a marked drop of many of these vitamins in blood levels were encountered. For vitamins B12 and C, the plasma levels remained within the normal range in all the subjects studied. For the other vitamins, the blood levels were found to be low in a few patients. Our data suggest that vitamin supplementation is probably not needed in most stable hemodialysis patients as it is recommended now, and that perhaps, if supplementation is indicated, less should be given than is presently prescribed. Further research is needed in this area.

Adult↗
PubMed1986

Aldosterone response to angiotensin II during hypoxemia.

Exercise in humans causes increases in plasma renin activity (PRA) and plasma aldosterone concentrations (PAC) except when performed at high altitude or while the subjects breathe hypoxic gas. Under those conditions, PRA increases with exercise but PAC does not. We speculated that the PAC suppression during hypoxemic exercise was due to hypoxemia-induced release of a circulating inhibitor of angiotensin II-mediated aldosterone secretion. To test this hypothesis, we measured the PAC response to graded infusions of angiotensin II during hypoxemia and normoxemia. Eight normal volunteers were given increasing doses of angiotensin II (first 2 ng X kg-1 X min-1 and then 4, 8, and finally 12 ng X kg-1 X min-1, each for 20-min periods) on 2 separate days, once while breathing room air and the other day while breathing hypoxic gas adjusted to maintain the subjects' hemoglobin saturation at 90%. The PAC response to different doses of angiotensin II did not significantly differ during hypoxemia from normoxemia. We conclude that our model of hypoxemia does not cause release of an inhibitor of angiotensin II-mediated aldosterone release.

Adult↗
PubMed1986

The plasma and red cell vitamin B levels of chronic hemodialysis patients: a longitudinal study.

Plasma B12, folate, B6 and thiamine, and red blood cell folate, thiamine and niacin levels were monitored for a period of 6 months in 15 clinically stable, chronic hemodialysis patients who were not supplemented with the water-soluble vitamins. Microbiological assays were used to determine the blood levels of the water-soluble vitamins. Over the period of 6 months, none of the patients had plasma or red cell vitamin levels below the normal range. No appreciable changes were observed in the plasma and red blood cell vitamin levels before and after dialysis in 5 patients. This study showed that chronic hemodialysis patients are able to maintain normal plasma and red cell levels of some water-soluble vitamins without daily supplementation.

Adult↗
PubMed1986

The effect of furosemide during normoxemia and hypoxemia.

The effect of furosemide infusion was studied in 6 normal subjects and 6 patients with severe COPD and right ventricular failure during normoxemia and hypoxemia. In normal subjects, hypoxemia alone caused an insignificant (p less than 0.15) fall in plasma aldosterone concentrations (PAC). Intravenously administered furosemide resulted in significant (p less than 0.05) increases in PAC during both normoxemia and hypoxemia. After furosemide treatment mean arterial pressure (MAP) was significantly lower and arginine vasopressin (AVP) was significantly higher (p less than 0.05) with hypoxemia than with normoxemia. These changes in MAP and AVP were strongly correlated (r = -0.84). Urinary losses of water and sodium were similar after furosemide treatment with hypoxemia and normoxemia. In patients with right ventricular failure, neither changes in oxygenation nor furosemide infusion affected the markedly elevated baseline PRA and PAC levels. Arginine vasopressin levels were significantly higher with hypoxemia than with normoxemia, but urinary losses of water and salt did not differ between the 2 study days. We conclude that hypoxemia does not affect the PAC increase or urinary volume and sodium response to furosemide.

Adult↗
PubMed1985

Bromocriptine and the hypothalamic hypophyseal function in patients with chronic renal failure on chronic hemodialysis.

Ten patients with chronic renal failure on chronic hemodialysis had the following tests to evaluate the integrity of the hypothalamic hypophyseal axis: (A) glucose tolerance test, (B) thyrotropin releasing hormone stimulation test, (C) clonidine stimulation test, (D) insulin induced hypoglycemia, and (E) LH/RH stimulation test. The majority of those tests were abnormal and prolactin values were found to be moderately elevated in all the patients. Bromocriptine (1.25 mg twice a day) was given to all the patients for 1 month and then, while on bromocriptine, the tests were repeated. Although there is a decrement in the concentration of serum prolactin level, none of the hypothalamic hypophyseal abnormalities were corrected. However, five of the ten patients reported an improvement of their impotence with bromocriptine. The patients who responded had high levels of FSH and LH with levels of testosterone above 1 mg/mL. The nonresponders had low FSH and LH levels and very low testosterone levels. Therefore, bromocriptine, although possibly beneficial in some dialysis patients, is not a drug that can normalize abnormal functioning of hormones in the dialysis population.

Adult↗
PubMed1985

Effect of hypoxemia on the renin-angiotensin-aldosterone system in humans.

Hypoxemia was induced in five subjects older than 40 (group 1) and five younger than 35 yr (group 2) on normal and low-salt diets by having the subjects breathe hypoxic gas. The fractional inspired O2 of the hypoxic gas was regulated so that group 1 hemoglobin saturations fell to 90% for 1 h. Group 2 subjects had desaturation to 90% for 1 h followed by desaturation to 80% for a 2nd h. Plasma renin activity (PRA), angiotensin-converting enzyme activity (ACE), and plasma cortisol levels did not change during hypoxemia. Plasma aldosterone levels fell in both groups during the 1st h of hypoxemia. Decreases were greatest during salt restriction and were significant (P less than 0.01) for the combined groups. Plasma aldosterone levels plateaued during the 2nd h of more severe hypoxemia in group 2. Hepatic blood flow, measured by indocyanine green clearance, and the adrenal response to exogenous adrenocorticotropic hormone, measured by changes in plasma cortisol and aldosterone, were not changed by hypoxemia in group 2 subjects. These results indicate that plasma aldosterone falls during hypoxemia despite unchanged PRA, ACE, hepatic blood flow, and adrenal function.

Adrenal Glands↗
PubMed1985

Effect of normoxemic and hypoxemic exercise on renin and aldosterone.

Five subjects (group 1) performed progressive treadmill exercise on 2 separate days, once while breathing room air (normoxemic) and the other time while breathing gas with a fractional inspired O2 of 17% (hypoxemic). Five other subjects (group 2) performed two progressive treadmill exercise tests on each of 2 separate days in a crossover design. On 1 day normoxemic exercise was first, followed by hypoxemic exercise, and on the other day the pattern was reversed. Plasma renin activity (PRA) increased to a similar extent with hypoxemic exercise as with normoxemic exercise. Plasma aldosterone concentrations (PAC) rose to a significantly higher level during normoxemic exercise than with hypoxemic exercise. Comparing changes in PRA to PAC with progressive exercise revealed dissociation of PAC from PRA during hypoxemic exercise. The PAC response remained depressed when normoxemic exercise followed hypoxemic exercise. These results indicate that hypoxemia interferes with PRA-mediated aldosterone secretions. The mechanism of this inhibition is unclear.

Adolescent↗
PubMed1985

Ankylosing spondylitis and glomerulonephritis. Study of a case.

Ankylosing spondylitis is a seronegative spondyloartropathy associated with IgA glomerulonephritis. We described a case not associated with IgA immunoglobulin deposition in the glomerulus, but with C3 complement deposition. At the same time circulating immune complexed of the IgG type were found. The possible association of glomerulonephritis and seronegative spondyloartropathies are discussed.

Complement C3↗
PubMed1985

Lymphocytotoxic activity of monoclonal immunoglobulins in plasmalymphocytic diseases.

95 of 1,019 (9.3%) sera with monoclonal immunoglobulins (MIg) were found to have cold-reacting lymphocytotoxins (LCT). There was no difference in the prevalence of LCT in multiple myeloma, macroglobulinemia, cancer, lymphoma or benign monoclonal gammopathy. Prevalence of LCT was similar in various classes and types of MIg with the exception of the IgG/lambda group in which LCT were more common than in IgG/K (p = 0.013). IgMs had the most potent whereas IgAs had the weakest LCT activity. MIg were purified from 61 LCT-positive sera. 25 pure MIg (41%) had LCT activity. In the rest, LCT activity resided in other fractions. 64 sera with LCT were tested against B and T cells; 56% were equally cytotoxic to B and T cells, 39% killed more B cells and 5% killed more T cells. 18 purified lymphocytotoxic MIg killed both B and T cells. When serial dilutions of sera, and of purified MIg were tested, in all but one instance the reactivity with the T cells weakened more than that with the B cells. Lymphocytotoxins absorbed to and eluted from the peripheral blood lymphocytes or separately from B or from T cells retained LCT activity against B and T lymphocytes. It may be concluded that about one tenth of sera with M components have lymphocytotoxic activity and that in about 40% of these positive sera, this activity is related to the monoclonal immunoglobulins. LCT react with both B and T cells. Antilymphocyte activity of MIgs may play a role in immunoregulatory abnormalities in plasmalymphocytic diseases.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1985

The skin in IgA nephropathies.

Fifteen men (average age 54.6 +/- 14.6 years) with IgA-associated glomerulonephritis underwent concomitant skin and renal biopsies to clarify any potential diagnostic relationships. Both types of tissues were studied by standard light, immunofluorescent, and electron microscopic techniques. The glomeruli of all the patients studied showed renal mesangial IgA deposits. All corresponding skin biopsy specimens showed no IgA deposition in the cutaneous blood vessels. The negative association suggests that examination of the skin biopsy specimen alone is not reliable in establishing the diagnosis of primary IgA nephritis. In view of the known skin involvement in Henoch-Schönlein nephropathy, we propose that skin biopsy specimens be examined routinely when renal biopsy specimens demonstrate IgA deposits, to differentiate primary IgA nephropathy from a forme fruste of Henoch-Schönlein purpura.

Adult↗
PubMed1984

Phase II trial of PCNU in advanced colorectal carcinoma. An Eastern Cooperative Oncology Group pilot study.

PCNU, a chloroethylnitrosourea with high alkylating activity, low carbamoylating activity, optimal octanol: water partition coefficient, and broad activity in animal systems was administered to 30 evaluable patients with measurable advanced colorectal carcinoma by brief intravenous infusions every 6 weeks. The initial dose was 75 or 100 mg/m2, with escalation or reduction for toxicity, and a total of 64 evaluable courses were given. Half of the patient population had received no prior chemotherapy. Two objective partial responses occurred. The response rate was 6.7% with a 95% confidence interval of 0.8-22.1%. Thrombocytopenia was dose-limited and leukopenia was relatively mild. Gastrointestinal toxicity was less severe than expected for clinically available nitrosoureas. In colorectal carcinoma, PCNU has limited clinical activity that does not appear to be superior to that of other nitrosoureas.

Adenocarcinoma↗
PubMed1984

Goldblatt phenomenon in a single kidney: the importance of subselective renal vein renins.

We have reported a case of renovascular hypertension in a patient with a solitary kidney with a significant stenosis of one of three separate renal arteries. Elevated renins were detected only with segmental sampling. We believe cases of renovascular hypertension may be overlooked on angiography and consequently, without segmental renin samples, lateralizing renin elevation may not be discovered.

Humans↗
PubMed1984

Cardiac arrhythmias on hemodialysis in chronic renal failure patients.

A high incidence (40%) of cardiac arrhythmias was found in patients while on dialysis. This incidence was significantly higher than on nondialysis days. A comparison study of patients with significant cardiac arrhythmia and patients with cardiac arrhythmia was made. There was no difference in the echocardiogram, total body potassium, plasma renin activity, aldosterone, catecholamines, serum sodium, potassium and calcium between the two groups. Significant alkalinization occurred in all patients at the end of dialysis. Blood levels of total PTH and C peptide were higher in the arrhythmic patients versus the nonarrhythmic patients. No explanation was found as to why patients developed arrhythmias or what differentiated the two groups.

Adult↗
PubMed1984

Aggressive combined modality therapy for advanced local-regional breast carcinoma.

Thirty-two women with advanced local regional breast carcinoma, including nine patients with histologically diagnosed inflammatory cancer, were entered on a prospective pilot study. They were treated aggressively with initial surgery, two courses of induction chemotherapy with cyclophosphamide, methotrexate, 5-fluorouracil, +/- prednisone, +/- tamoxifen (CMF [P] [T]), local-regional radiotherapy, and then maintenance chemotherapy with CMF(P) (T) alternating with doxorubicin, vincristine, +/- tamoxifen (AV[T]). The patients have been followed for 19-70 months from the time of mastectomy and their actuarial three-year survival is 65% with a median survival that has not yet been reached. Median disease-free survival (time to progression) is currently 29.5 months. Women whose gross disease could not be totally resected surgically had shorter disease-free survivals than those rendered surgically free of disease (p = 0.01). Clinically evident cardiotoxicity was seen in 25% of the patients and was felt to be primarily due to the combination of doxorubicin and radiation therapy. It was significantly more common (Plt less than 0.05) in patients with left chest irradiation (seven of 18 women) as opposed to those with right-sided irradiation (one of 14).

Adult↗
PubMed1984

Cobalt therapy prophylaxis of recurrence of T1 bladder cancer.

Eighteen patients with T1 transitional cell carcinoma of the urinary bladder were submitted to transurethral resection of the tumor, followed by Cobalt therapy (5,500 rads to the pelvis and 6,500 rads to the bladder in six weeks). The recurrence rate at three years follow-up was 33% (6/18). Recurrence of transitional cell carcinoma of the urinary bladder is a well known condition in stage O and A, even when low grade is present. Recurrence rates at one year as high as 84% (Loening et al., 1983) are reported in the current literature. In recent years many studies have been performed which were oriented to the use of intravesical chemotherapy in order to reduce the recurrence rate (Adolphs and Bastian, 1983; Huland, 1983; Loening et al., 1983; National Bladder Cancer Collaborative Group A, 1977; Rodriguez and Caserta, 1983; Zincke et al., 1983) of this tumor. We started a protocol on treatment of the transitional cell carcinoma of the urinary bladder in 1963. The protocol calls for transurethral resection of the tumor followed by Cobalt therapy. This is an interim report on stage T1 (stage A) with such a treatment.

Adult↗