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Biomedical subjects

R D Lentz

Publications and source records attributed to R D Lentz.

14 recordsLinked to original sources
PubMed2006

Solute response to changing nutrient loads in soil and walled ceramic cup samplers under continuous extraction.

This report evaluates a vacuum-assisted walled percolation sampler preconditioned in soil, and examines the dynamic response of leachate solutes. The 20-cm walled percolation sampler extracted soil water under continuous tension via a ceramic cup collector embedded in a silica flour layer, whose upper surface interfaced with field soil. In the laboratory, alternating solutions with high and low NO3-N (232 or 3.6 mg L(-1)), molybdate-reactive P (MRP) (1.75 or 0.0 mg L(-1)), K+ (568 or 3.6 mg L(-1)), and Br- (9.6 or 0.0 mg L(-1)) concentrations were delivered directly to the (i) sampler ceramic cup; (ii) silica flour bed surface, or (iii) 12-mm soil layer placed over the silica flour bed. For alternating input solutions delivered to the silica-flour bed surface, (i) solute breakthrough (95% equivalency) occurred in 4 pore volumes and was the same for both the high and low concentration input phases of the application, and (ii) concentrations of NO3-N, Br-, and MRP in cumulative extracted water volumes were within 5% of those in corresponding input volumes. Alternating nutrient loads from high to low levels in the fixed flow rate input waters caused excess MRP (1.6 times that in the high concentration MRP solution) to leach from the calcareous soil. The dynamic character of P transport in K-fertilized soils deserves further study and may have important environmental implications.

Automation↗
PubMed1993

Endometrial ablation. A report of four cases.

Three women had evidence of atypical endometrial hyperplasia at the time of endometrial ablation, discovered because they had mechanical preparation of the endometrium rather than medical preparation. In one of these patients, a frozen section revealed atypical endometrial hyperplasia, and the ablation was cancelled. A fourth woman had an unsuccessful endometrial ablation; repeat ablation was followed by nine months of amenorrhea, at which time she began spotting and requested a hysterectomy. The pathology report on the hysterectomy specimen revealed adenomatous hyperplasia. Gynecologists must be vigilant in their evaluation of the endometrium before, during and after endometrial ablation.

Adult↗
PubMed1990

When a depressed patient fails to improve.

In all depressed patients, an accurate and complete diagnosis of psychiatric as well as other medical conditions is essential. Diagnosis must be followed by adequate use of medications and an effective treatment plan that addresses all the relevant issues. In patients who have complex depressions and those who are unresponsive to adequate initial treatment with antidepressants, evaluation by a psychiatrist is recommended. A referral for psychotherapy, whether to a psychiatrist or other competent therapist, should follow appropriate diagnosis.

Depressive Disorder↗
PubMed1988

Prevalence of major depression, simple phobia, and other psychiatric disorders in patients with long-standing type I diabetes mellitus.

To examine the prevalence of psychiatric disorders in patients with long-standing type I diabetes mellitus, we assessed a series of candidates for pancreas transplantation. Using the Diagnostic Interview Schedule, six-month and lifetime prevalences of psychiatric disorders were established for the candidates and their potential donors (first-degree relatives). Excluding tobacco use disorder and psychosexual dysfunction, 38 diabetic subjects (51%) received one or more psychiatric diagnoses. The lifetime prevalence of major depression was comparable for female (11 of 48 [22.9%]) and male (seven of 27 [25.9%]) diabetics; both rates were significantly higher than rates in first-degree relatives and the general population. Among female diabetics, the six-month and lifetime prevalences of simple phobia were increased vs donors and the general population; among male diabetics, the lifetime prevalence of antisocial personality disorder was greater than that in the general population. None of these disorders was found to be related to the duration of diabetes or the presence of various complications. The data suggest that increased rates of psychiatric disorder in type I diabetics have both gender-independent and gender-related components.

Adolescent↗
PubMed1978

Treatment of severe hypophosphatemia.

Aspects of phosphate biochemistry pertinent to therapy, the distribution of phosphorus in body compartments, therapeutic phosphorus preparations, prevention of hypophosphatemia, therapeutic guidelines, and side-effects of phosphorus therapy are reviewed. Severe hypophosphatemia (less than 0.32 mmol/litre or less than 1 mg/dl) can occur with normal or depleted body stores. Because a large amount of phosphorus may shift rapidly between the extracellular and intracellular or bone compartments, the size of a possible total body deficit cannot be estimated from the serum phosphorus level. Similar shifts may occur unpredictably during repair of hypophosphatemia. Therefore, correction of hypophosphatemia in any patient must be empiric and the response of serum levels to therapy should be followed closely. We discuss a method likely to correct hypophosphatemia while minimizing side-effects.

Chemical Phenomena↗
PubMed1977

Postpubertal evaluation of gonadal function following cyclophosphamide therapy before and during puberty.

Evaluation of pituitary gonadotropins, gonadal steroids, spermatogenesis, and menstrual function was undertaken in 32 patients (19 males and 13 females) treated with cyclophosphamide because of nephrotic syndrome. Patients were treated before, during, or after puberty. Evaluations took place after or in very late puberty. Spermatogenic dysfunction occurred in six of 15 boys who received the entire course before and during puberty and was probably dose related. Menstrual dysfunction did not occur following treatment of six prepubertal or pubertal girls, though only low total doses were used. Therapy after puberty was associated with spermatogenic dysfunction in all four boys, but did not cause menstrual dysfunction in any of seven women. Tentative guidelines are suggested that many minimize gonadal toxicity when cyclophosphamide is used in children with nephrotic syndrome. Factors of particular importance in the interpretation of gonadotropin determinations and of sperm counts in young cyclophosphamide-treated patients are discussed.

Cyclophosphamide↗
PubMedDate not supplied

Psychiatric diagnosis and the surgical outcome of pancreas transplantation in patients with type I diabetes mellitus.

To examine the role of psychiatric diagnosis in the surgical outcome of pancreas transplantation, we studied candidates with type I diabetes mellitus. Eighty of 140 candidates underwent transplantation. Survival analysis found the extent of human leukocyte antigen-DR (HLA-DR) matching, two diagnoses, and patients' perceived support from first-degree relatives to be related to duration of full-graft function. Lifetime diagnoses of tobacco use disorder (P = 0.029) and alcohol abuse/dependence (P = 0.006) were associated with less favorable outcomes; perceived support was associated with positive outcomes (P = 0.048). Subsequent analysis suggested that the four variables independently and directly affect outcome.

Adaptation, Psychological↗