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Biomedical subjects

M A Diaz

Publications and source records attributed to M A Diaz.

At least 19 recordsLinked to original sources
PubMed1998

Peripheral blood progenitor cell collection by large-volume leukapheresis in low-weight children.

Large-volume leukapheresis (LVL), defined as the processing of at least three blood volumes in a single session for peripheral blood progenitor cell (PBPC) collection, was performed in 32 small children weighing < or = 25 kg, aged 10 months to 8 years, with a variety of malignancies. Harvesting of PBPC was started after 4 days of cytokine (G-CSF, 12 micrograms/kg s.c.) alone. Procedures were performed using a continuous flow blood cell separator (COBE Spectra). The automated program of lymphocytapheresis was modified to achieve a collection rate of 0.9 ml/min. The extracorporeal line was primed with a unit of a packed red blood cells before the procedure. Acid citrate dextrose (ACD) was used as anticoagulant with an ACD inlet ratio of 1:14 and an ACD infusion rate of 1.1 ml/min/L of total blood volume. The inlet flow ranged between 6 and 35 ml/min (median 20 ml/min). A total of 37 apheresis procedures were performed (median 1, range 1-3). In 84% of patients, a single apheresis yields the minimum number of PBPC cells required for transplantation. No consistent side effects were observed, and LVL was well tolerated by children. A median of 7.7 x 10(8) kg MNC, 5.4 x 10(6)/kg CD34+, and 6.2 x 10(4)/kg CFU-GM per apheresis were harvested. Patients with neuroblastoma had a significantly lower yield than other patients. To date, 27 patients have been transplanted after myeloablative treatment, and rapid and sustained engraftment was achieved in all cases. The number of CD34+ cells infused was highly correlated with engraftment kinetics. LVL can be safely and easily performed in small children, allowing adequate PBPC collection for transplantation with rapid hematologic recovery.

Blood Specimen Collection↗
PubMed1998

Peripheral blood progenitor cells for autologous transplant in children.

Autologous peripheral blood progenitor cell transplantation has become an accepted procedure to support high dose chemotherapy in adults and children with cancer. The use of hematopoietic growth factors alone for mobilization of PBSC avoids the potential side effects of myelotoxic regimens and is as effective in reconstituting hematopoiesis as other mobilization methods. Many problems associated with apheresis procedures arise when PBPCs are harvested in small children. Large-volume-leukapheresis using a continuous flow blood cell separator allows us the collection of peripheral blood stem cells in children, even in the small ones. The speed of hematological recovery highly correlates with the number of CD34+ infused cells. We consider that a CD34+ cell dose of 5.0 x 10(6)/kg may be sufficient to ensure a rapid neutrophil and platelet recovery in pediatric patients mobilized by G-CSF.

Antigens, CD34↗
PubMed1997

Allogeneic peripheral blood progenitor cell (PBPC) transplantation in children with haematological malignancies.

We report on five children with haematological malignancies who underwent allogeneic peripheral blood progenitor cell (PBPC) transplantation. PBPC were harvested from HLA-identical sibling donors after G-CSF (10 micrograms/kg/d s.c.) mobilization. Aphereses were carried out on day 5 after G-CSF using a Cobe Spectra blood cell separator. All PBPC allografts were cryopreserved before transplantation. The median of CD34+ cells and CD3+ cells infused were 14.1 x 10(6)/kg recipient body weight (range 4.92-22.3) and 2.40 x 10(8)/kg recipient body weight (range 0.54 4.82), respectively. Engraftment occurred in all cases. The median time to a neutrophil count > 0.5 x 10(9)/l and a platelet count > 20 x 10(9)/l were 15 and 14 d, respectively. The incidence of severe acute graft-versus-host disease was 20%. These data suggest that allogeneic PBPC transplantation might be an alternative to bone marrow transplantation in children.

Child↗
PubMed1996

Acylfulvenes, a new class of potent antitumor agents.

Acylfulvene, derived from the sesquiterpene illudin S by treatment with acid (reverse Prins reaction), is far less reactive to thiols than illudin S. However, it is reduced readily to an aromatic product, in the same way as illudin S. This may explain its greatly improved therapeutic index compared to that of the parent compound.

Animals↗
PubMed1996

Collection and transplantation of peripheral blood progenitor cells mobilized by G-CSF alone in children with malignancies.

Results of collection and transplantation of peripheral blood progenitor cells (PBPC) mobilized by G-CSF in 31 children with different malignancies were analysed. A total of 43 aphereses were performed, following administration of granulocyte colony-stimulating factor (G-CSF), using a continuous flow blood cell separator (Cobe Spectra) through a central venous catheter. For patients weighing 0.5 x 10(9)/l and a platelet count of 20 x 10(9)/l without platelet support were 9.5 and 18, respectively. The number of CD34+ cells infused correlated highly with engraftment kinetics. The extra-medullary toxicity was low and manageable.

Adolescent↗
PubMed1996

A unique dysembryonic neoplasm of the adrenal gland composed of nephrogenic rests in a child.

A primary neoplasm of the right adrenal gland in a 4-year-old boy was discovered after the patient developed bowel obstruction following an appendectomy. Until the histologic examination, the tumor was thought to be a neuroblastoma. However, the intra-adrenal tumor was composed of blastematous nodules, primitive tubules, and glomeruloid structures whose overall composition resembled a Wilms' tumor. Other than a single focus of mucinous glands, the tumor lacked the range of somatic tissue types of a teratoma. Approximately 50 cases of putative extrarenal Wilms' tumor have been reported. The retroperitoneum is one of the more common primary sites, yet our case is the first documented example of a neoplasm with features of a Wilms' tumor arising in the adrenal. Based on the embryologic and anatomic relationship between the adrenal gland and kidney, it is somewhat surprising that other instances of similar appearing tumors have not been described before the present case. Our patient was managed on a Wilms' tumor protocol and remains tumor free 15 months after surgery.

Adrenal Gland Neoplasms↗
PubMed1996

Non-tunneled catheters in children undergoing bone marrow transplantation.

We analyzed the use of non-tunneled (polyurethane double lumen) central venous catheters (CVCs) in 62 children undergoing bone marrow transplantation. The catheters were inserted in the Critical Care Unit without surgery or general anesthesia. The complications were pneumothorax in two patients and hemopneumothorax in two other patients (6.06%), entry site infection in six patients (9.6%), catheter-related infection in eight patients (12.9%) and catheter-related sepsis in nine patients (14.5%). The catheters were removed upon completion of therapy in 46 patients (74.1%), death in seven patients (11.3%) and in nine cases (14.5%) for infection. Despite the complications specific to non-tunneled catheter insertion, we believe this is indicated for patients during conditioning, transplantation and immediate post-transplantation periods.

Adolescent↗
PubMed1996

Allogeneic peripheral blood progenitor cell (PBPC) transplantation in children.

The use of peripheral blood as a source of hematopoietic precursors is an alternative to the bone marrow in allogeneic transplantation. Although pediatric allogeneic PBPC experience is limited, there is no reason to believe that the outcome and benefit with PBPC should be different than adults. We describe our initial experience in two children who received PBPC allogeneic transplantation in whom the donors were mobilized with filgrastim. Hematopoietic recovery was achieved on days 14 and 16, and the patients did not develop severe GVHD.

Adolescent↗
PubMed1996

Pediatric experience with autologous peripheral blood progenitor cell transplantation: influence of CD34+ cell dose in engraftment kinetics.

The aim of this study was to analyze factors affecting mobilization and engraftment in 40 children undergoing autologous peripheral blood progenitor cell transplantation for different malignancies: 19 patients with haematological malignancies and 21 patients with solid tumors. Patients received 4-5 days of rhG-CSF (12 micrograms/kg/day) subcutaneously. Apheresis was performed by continuous flow blood cell separation beginning on the fifth day of rhG-CSF. For patients weighing < or = 25 kg, the extracorporeal line was primed with irradiated red blood cells. After myeloablative conditioning regimens, patients were grafted with 7.21 +/- 7.8 x 10(6)/kg CD34+ cells. Days to achieve an absolute neutrophil count > 0.5 x 10(9)/1 and a platelet count > 20 x 10(9)/1 without platelet support were 9.50 +/- 1.2 (range 7-13) and 18.1 +/- 8.3 (range 9-37), respectively. The number of CD34+ cells infused was highly correlated with engraftment kinetics (P = 0.0001). The patient's body weight and the number of previous chemotherapy courses had a negative influence on CD34+ cells collected.

Adolescent↗
PubMed1988

[Chronic lichenoid keratosis. Apropos of a case].

A male patient of 28 years, with typical clinical features and histopathological changes of keratosis lichenoides (CLK) chronica is described. CLK has some histological features similar to lichen planus, but there are also histological and clinical differences.

Adult↗
PubMed1986

Ewing's tumor in brothers. An unusual observation.

Ewing's sarcoma in two brothers is described. This has not been previously reported in the literature. Hypotheses which might explain this association are discussed. Genetic factors predisposing to the development of neoplasia are a very attractive possibility, although viral factors and chance association cannot be excluded.

Adolescent↗
PubMed1984

Sleep disorders on a psychiatric consultation service.

Of 100 consecutive patients on a psychiatric consultation service, 80 had sleep disorders; 72 had insomnia. Disturbed sleep was not mentioned in the records of 54% of the 80 patients, indicating a need for more physician education in sleep disorders.

Adolescent↗
PubMed1984

The use of MUMPS in a departmental computerized clinical data system.

The development of clinical data systems is an important task for family medicine academic units and residency programs. A computer system offers family medicine a unique opportunity to achieve its educational, clinical service, and research potential. MUMPS is recommended as a language and operating system. It was designed for medical information systems and is easily adapted to meet multiple needs.

Computers↗
PubMed1983

Effect of pH and amiloride on the intrarenal formation of kinins.

Changes in urinary kallikrein excretion are assumed to reflect changes in intrarenal formation of kinins. Yet factors that alter the enzymatic activity of renal kallikrein and kininases may alter the concentration of kinins in the nephron independent of amount of kallikrein excreted. In anesthetized rats, we measured excretion of urinary kallikrein (kininogenase activity) and kinin excretion during altered urinary pH and after amiloride, which reportedly inhibits urinary kallikrein. In rats fed a low sodium diet, urine was acidified by intravenous 0.28 M sodium sulfate. This decreased urinary pH from 6.1 +/- 0.09 to 5.3 +/- 0.17 and urinary kinin excretion from 28.0 +/- 9.0 to 10.5 +/- 5.0 pg/min. Urinary kallikrein excretion doubled from 43.0 +/- 5.0 to 82.5 +/- 13.5 ng/min. The optimum pH of kallikrein is congruent to 8.5, so the decreased excretion of urinary kinins is probably secondary to decreased kininogenase activity at lower urinary pH. Amiloride decreased urinary kinins from 35.5 +/- 7.3 to 18.2 +/- 2.5 pg/min and kallikrein from 18.7 +/- 4.9 to 9.3 +/- 1.8 ng/min, while urinary pH increased from 6.7 +/- 0.07 to 7.3 +/- 0.07. The depressed excretion of kallikrein and kinins with amiloride may not have been due to inhibition of kallikrein, since amiloride (1 mM) did not inhibit the kininogenase activity of rat urinary kallikrein (congruent to 1.2 nM) on dog or rat kininogen in vitro. We conclude that changes in urinary kallikrein may not reflect changes in intrarenal formation of kinins. These data also indicate that kallikrein excretion increases and kinin formation decreases when urine is acidified in the distal nephron and that there may be a link between the kallikrein-kinin system and the renal mechanisms affected by amiloride.

Amiloride↗