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Biomedical subjects

F Martinez

Publications and source records attributed to F Martinez.

At least 109 records · Page 6Linked to original sources
PubMed1996

Familial association of primary pulmonary hypertension and a new low-oxygen affinity beta-chain hemoglobinopathy, Hb Washtenaw.

A Hungarian-American kindred with familial primary pulmonary hypertension (PPH) and a new, low-oxygen affinity beta-chain variant hemoglobin, Hb Washtenaw, is described. The index case presented with severe PPH and was found to have the abnormal hemoglobin. Two siblings with the abnormal hemoglobin also demonstrated increased pulmonary artery pressures on exercise echocardiography suggestive of early PPH. The occurrence of PPH and the abnormal hemoglobin could be due to genetic or biochemical factors or simply coincidental. A previous study had described a possible association of an abnormal beta-chain variant hemoglobin, Hb Warsaw, and PPH. It was suggested that the putative gene for familial PPH may be located near the beta-globin gene on chromosome 11. The association of PPH and the beta-chain variant hemoglobin in this kindred adds further support to this hypothesis.

Base Sequence↗
PubMed1996

[Treatment of cardiac failure with angiotensin-converting enzyme inhibitors and diuretics].

Congestive cardiac failure is characterised by redistribution of blood flow to the brain and the heart at the expense of the kidneys. The prognosis of this condition at its most advanced stage (stage IV) is poor with a mortality of about 50% at 5 years. The reduction of renal perfusion will lead to stimulation of all vasoconstrictor and anti-natiuretic mechanisms, and to a parallel activation of vasodilator and natiuretic systems. There is, therefore, a clear conflict of interest between the heart, which attempts to preserve its perfusion and function, and the kidneys which aggravate the haemodynamic disturbances by salt and water overload and the risk of arrhythmias due to hypokalaemia and hypomagnesaemia. The diuretics and ACE inhibitors are essential therapeutic classes for the treatment of congestive cardiac failure. The prevention of the secondary effects of diuretics and ACE inhibitors on renal function, serum sodium, potassium and magnesium concentrations, is based on an initial low dose prescription, the detection and correction of risk factors and strict clinical and biological surveillance. In order to avoid the risks of hyperkalaemia during the association of ACE inhibitor and diuretic therapy with a potassium sparing agent, the initial dose of these two drugs should be as low as possible.

Aged↗
PubMed1996

Modulation of matrix Ca2+ content by the ADP/ATP carrier in brown adipose tissue mitochondria. Influence of membrane lipid composition.

The role of the adenine nucleotide translocase on Ca2+ homeostasis in mitochondria from brown adipose tissue was examined. It was found that in mitochondria incubated with 50 microM Ca2+, ADP was not needed to retain the cation, but it was required for strengthening the inhibitory effect of cyclosporin on membrane permeability transition as induced by menadione. In addition, carboxyatractyloside was unable to promote matrix Ca2+ release, even though it inhibits the ADP exchange reaction. However, when the Ca2+ concentration was increased to 150 microM carboxyatractyloside did induce Ca2+ release, and ADP favored Ca2+ retention. Determination of cardiolipin content in the inner membrane vesicles showed a greater concentration in brown adipose tissue mitochondria than that found in kidney mitochondria. It suggested that the failure of the adenine nucleotide translocase to influence membrane permeability transition depends on the lipid composition of the inner membrane.

Adenosine Diphosphate↗
PubMed1996

Presence of an NAD(P)H dehydrogenase and A b-type cytochrome different from the respiratory chain in submitochondrial particles from human placenta.

Placental submitochondrial particles can synthesize progesterone. Both, progesterone synthesis and oxygen consumption were stimulated in the presence of succinate, NADH, or NADPH. NADPH reduced the cytochromes of the respiratory chain in a similar way as NADH. NADPH oxidation was not achieved by NADH-DH from the respiratory chain, and the presence of an NAD(P)H-DH is suggested. Submitochondrial particles contain at least two b-type cytochromes, one inhibited by antimycin when the electron donor is succinate, whereas the other is less sensitive to antimycin in the presence of pyridine nucleotides. The results suggest a connection between the respiratory chain and cytochrome P450, through an NAD(P)H-DH and a b-type cytochrome, both different from the respiratory chain.

Antimycin A↗
PubMed1995

The frameless GyneFix intrauterine implant: a major improvement in efficacy, expulsion and tolerance.

The CuFix (GyneFix), conceived in 1985, was developed to minimize three major problems frequently associated with discontinuation of IUD use: expulsion, bleeding and pain. Since the initial clinical investigations, over 10,000 woman years of experience and up to 8 years of follow-up in international multicenter, non-comparative and comparative clinical trials, including a large proportion of nulligravid/nulliparous women, have been collected. Based on new clinical information about the GyneFix from a long-term multicenter clinical trial, conducted in young nulligravid/nulliparous and parous women, the importance of this new contraceptive is discussed. The following conclusions were reached: The unique design characteristics of the GyneFix (frameless, flexible and fixed to the fundus of the uterus) have resulted in optimal tolerance and almost complete absence of expulsion. The result is enhanced effectiveness (comparable to OCs and male/female sterilization) and a high rate of continued use. The GyneFix reduces the IUD failure rate to a minimum and is, therefore, a welcome reversible alternative to OCs and female surgical contraception. Framelessness and flexibility explain the absence of side-effects and adverse events caused by dimensional incompatibility between the frame of conventional IUDs and the uterine cavity and may also explain the absence of PID and ectopic pregnancies in any of the clinical studies. The GyneFix is a promising new, highly effective and safe, contraceptive option for parous women and an equally effective and well-accepted method for nulliparous women.

Adolescent↗
PubMed1995

IUD expulsion solved with implant technology.

In an attempt to minimize the problem of IUD expulsion, implantation technology has been developed and tested. The trials have extended from 1985 until the present time for interval as well as for immediate postabortal and post-placental insertion and fixation of the CuFix IUD (Gyne-Fix). The present article reports on an ongoing study with GyneFix interval insertion, with an improved inserter, in 820 women, observed up to 3 years, of whom 213 (25.9%) are nulligravid/nulliparous. The cumulative expulsion rate is 0.6 per 100 women-years at 3 years and is not significantly higher in the nulligravid/nulliparous group. The cumulative pregnancy rate is 0.6 and the cumulative removal rate for medical reasons 3.2 at 3 years. The total experience in this multicenter study covers approximately 14,000 woman-months. It is concluded that the design characteristics of the GyneFix (fixed, frameless, and flexible) explain the low expulsion, high efficacy and high acceptability rates. The implantation technology is very effective and the improved inserter allows easy insertion and optimal anchoring.

Adult↗
PubMed1995

International Study of Asthma and Allergies in Childhood (ISAAC): rationale and methods.

The aetiology of asthma and allergic disease remains poorly understood, despite considerable research. The International Study of Asthma and Allergies in Childhood (ISAAC), was founded to maximize the value of epidemiological research into asthma and allergic disease, by establishing a standardized methodology and facilitating international collaboration. Its specific aims are: 1) to describe the prevalence and severity of asthma, rhinitis and eczema in children living in different centres, and to make comparisons within and between countries; 2) to obtain baseline measures for assessment of future trends in the prevalence and severity of these diseases; and 3) to provide a framework for further aetiological research into genetic, lifestyle, environmental, and medical care factors affecting these diseases. The ISAAC design comprises three phases. Phase 1 uses core questionnaires designed to assess the prevalence and severity of asthma and allergic disease in defined populations. Phase 2 will investigate possible aetiological factors, particularly those suggested by the findings of Phase 1. Phase 3 will be a repetition of Phase 1 to assess trends in prevalence.

Adolescent↗
PubMed1994

Characterization of SPf(66)n: a chimeric molecule used as a malaria vaccine.

SPf66 is a chemically synthesized 45 amino acid peptide derived from fractions of four different proteins of Plasmodium falciparum (83, 55 and 35 kDa and CS, the circumsporozoite protein) that elicits a protective immune response against malaria. In this paper we show the characterization of the SPf(66)n in batch 9 to be used in a field trial in young children at Ifakara in Tanzania. The analysis of SPf(66)n indicates that it is highly soluble in water and that the amino acid composition and sequence corresponds to that designed for the synthesis of the polypeptide. The packed product has a molecular weight ranging from 10 to 25 kDa. It is pure, free of metallic contaminants, atoxic and stable at 4 degrees C. The antibodies raised against this product in rabbits recognize the individual antigenic determinants of the molecule and the native epitopes of merozoites.

Amino Acid Sequence↗
PubMed1994

Acute renal effects of neutral endopeptidase inhibition in humans.

The acute renal effects of neutral endopeptidase 24.11 (E-24.11) inhibition induced by a single oral dose of sinorphan (100 mg) were investigated in 10 healthy normotensive subjects on normal sodium diet. Sinorphan inhibited 90% of E-24.11 activity and increased plasma atrial natriuretic peptide (ANP) and urinary guanosine 3',5'-cyclic monophosphate (cGMP) by 70 and 100%, respectively. Sinorphan increased urinary sodium output by 50% (P < 0.001) and decreased fractional distal reabsorption by 4% (P < 0.01). Sinorphan increased glomerular filtration rate (GFR) and filtration fraction by 10% 1 h after administration and decreased renal plasma flow by 10%. Mean arterial pressure, renal vascular resistance, plasma aldosterone concentration, and renin activity were unmodified. Sinorphan decreased fractional clearance of neutral dextrans over the 34- to 52-A radius range. Applying the changes along with a hydrodynamic isopore with shunt model, sinorphan significantly increased capillary pressure gradient (delta P; 39 +/- 1 vs. 34 +/- 1 mmHg; P < 0.01), whereas ultrafiltration coefficient was unchanged. In conclusion, endopeptidase inhibition increased endogenous plasma ANP and cGMP generation and induced natriuresis through both an increase in filtered load and a decrease in distal tubular reabsorption of sodium. Sinorphan increases GFR, filtration fraction, and delta P, probably through an increase in efferent over afferent arteriolar resistance ratio.

Blood Pressure↗
PubMed1994

Hb Washtenaw [ beta 11(A8)Val-->Phe]: an electrophorectically silent, unstable, low oxygen affinity variant associated with anemia and chronic cyanosis.

Hb Washtenaw [beta 11(A8)Val-->Phe] is a new, low oxygen affinity variant with a previously undescribed substitution, identified in seven members over three generations of a Hungarian-American family. The hemoglobin is mildly unstable and the family members studied are clinically asymptomatic but mildly cyanotic, and some exhibit mild anemia. The index case had severe pulmonary hypertension and some of the family members had increased pulmonary vascular resistance on echocardiography. An association between the inheritance of this abnormal hemoglobin and the pathogenesis of primary pulmonary hypertension is suggested but the mechanism is unclear.

Adolescent↗
PubMed1994

[Leishmaniasis in Ecuador. 1. Incidence of cutaneous leishmaniasis on the Pacific coast].

A clinico-epidemiologic survey on cutaneous leishmaniasis, due to Leishmania panamensis, was carried out on 961 persons in two study areas of the Pacific coast of Ecuador, to estimate the prevalence and the incidence of the disease. In the preandean hills, at Paraiso Escondido, the prevalence of active lesions was 4.8%; in the hills of the coastal cordillera, at La Tablada, it was 3.6%. The incidence of new cases in 1991 was high: 147% in the first village, and 106% in the second. These data are far higher than the Health Ministry statistics. The cumulated prevalence, obtained by addition of the scars and active lesions of leishmaniasis, was as high as 66% at Paraiso Escondido, and 47% at La Tablada. Most of the patients (62%) had only one ulcer or scar. Most of the people are contaminated during the first five years they live in these endemic areas. Nevertheless, the incidence remains high in all the age groups, because large numbers of migrants coming from non endemic regions are continuously settling in these colonization areas. Interviews have shown that the contaminations had occurred in the dry season, between July and December. These findings were confirmed by passive case detection at the Hospital A. Egas of Santo Domingo which covered the region. Contamination of young children and position of the lesions on the face suggested a domiciliary transmission, like in Panama and on the Pacific coast of Colombia.

Adult↗